SPECIAL REPORT 97-26

Antifreeze Admixtures for Concrete

Charles J. Korhonen, Edel R. Cortez, Timothy A. Durning,

and Ara A. Jeknavorian October 1997
Abstract: The goal of this project was to develop a

chemical admixture that would reduce the need for

wintertime thermal protection of freshly placed concrete. Chemicals were investigated for their ability to

promote strength gain in concrete cured below 0°C.

The project was carried out in five phases. Phase 1

evaluated existing and new admixtures. Phase 2 measured the effect of promising chemicals on concrete

properties. Phases 3 and 4 tested the practicality of

using the new technology/admixture in the field. Phase

5 disseminated the findings through an Army conference and through the development of this report, in

addition to normal W.R. Grace advertising channels.

Laboratory strength tests established that two prototype admixtures were capable of protecting concrete

down to –5°C. Results from other laboratory tests

show that the chemicals pose no harm to the concrete

How to get copies of CRREL technical publications:

Department of Defense personnel and contractors may order reports through the Defense Technical Information Center:

DTIC-BR SUITE 0944

8725 JOHN J KINGMAN RD

FT BELVOIR VA 22060-6218

Telephone 1 800 225 3842

E-mail help@dtic.mil

msorders@dtic.mil

WWW http://www.dtic.dla.mil/

All others may order reports through the National Technical Information Service:

NTIS

5285 PORT ROYAL RD

SPRINGFIELD VA 22161

Telephone 1 703 487 4650

1 703 487 4639 (TDD for the hearing-impaired)

E-mail orders@ntis.fedworld.gov

WWW http://www.fedworld.gov/ntis/ntishome.html

A complete list of all CRREL technical publications is available from

USACRREL (CECRL-LP)

72 LYME RD

HANOVER NH 03755-1290

Telephone 1 603 646 4338

E-mail techpubs@crrel.usace.army.mil

For information on all aspects of the Cold Regions Research and Engineering Laboratory, visit our World Wide Web site:

http://www.crrel.usace.army.mil

or embedded ferrous metals. Concrete containing the

prototype admixtures passes standard freeze–thaw

tests, does not shrink unusually, does not contain

harmful alkalis, and does not produce irregular hydration products. Field tests clearly demonstrated that

working with these new admixtures requires no new

skills. The concrete can be mixed at lower temperatures, saving energy. The admixtures are easily dosed

into the mixing trucks, as is normal practice today,

and concrete is finished in the usual manner. Estimates show that the two prototype admixtures can

extend the construction season by as much as three

months in the contiguous United States. The prototype

has proved that low-temperature admixtures are possible. The industry partner sees the need to develop

admixtures that will work to –10°C before going commercial with this technology.
Special Report 97-26

Antifreeze Admixtures for Concrete

Charles J. Korhonen, Edel R. Cortez, Timothy A. Durning,

and Ara A. Jeknavorian October 1997

Prepared for

OFFICE OF THE CHIEF OF ENGINEERS

Approved for public release; distribution is unlimited.

US Army Corps

of Engineers

Cold Regions Research &

Engineering Laboratory

®®

Cold Regions Research &

Engineering Laboratory
PREFACE

This report was prepared by Charles J. Korhonen and Edel R. Cortez, Research

Civil Engineers, Civil Engineering Research Division, Research and Engineering

Directorate, U.S. Army Cold Regions Research and Engineering Laboratory (CRREL),

and by Timothy A. Durning, Project Manager, and Ara A. Jeknavorian, Chemical

Scientist, W.R. Grace & Co. (WRG).

This research project was conducted under the authority of the U.S. Army Corps

of Engineers Construction Productivity Advancement Research (CPAR) program.

The project was titled Antifreeze Admixtures for Concrete and was approved in August

1991. It was conducted in partnership between CRREL and WRG. The research work

was conducted from November 1991 to December 1994.

Technical review of this report was provided by Ken Rear, Technical Services

Manager, and Charles I. Sanders, Jr., Manager of Analytical and Technical Services

Laboratory, WRG. Although many individuals from both the Corps of Engineers

and WRG supported this research work in various ways, the authors acknowledge

the support of Kevin Grogan, Neal Berke, Mauro Scali, and Ken Nelson of WRG;

Brian Charest, Charles Smith, and Patrick Black of CRREL; and Stanley Jacek and

Kurt Romisch of the Corps of Engineers, Sault Ste. Marie Area Office.

 The contents of this report are not to be used for advertising or promotional

purposes. Citation of brand names does not constitute an official endorsement or

approval of the use of such commercial products.

ii
CONTENTS

Page

Preface ..................................................................................................................... ii

Introduction ............................................................................................................ 1

Background ........................................................................................................ 1

Project objectives ............................................................................................... 1

Approach............................................................................................................ 2

Laboratory experiments........................................................................................ 2

Phase 1: Effect of chemicals on strength gain ............................................... 2

Phase 2: Laboratory evaluation of best admixtures from Phase 1 ............. 6

Phase 3: Prototype slab-wall application ...................................................... 11

Observations and results ................................................................................. 13

Field application of developed admixtures ....................................................... 14

Soo Locks slabs .................................................................................................. 14

Observations and results ................................................................................. 15

Potential applications of antifreeze admixtures ................................................ 18

Conclusions ............................................................................................................ 19

Recommendations ................................................................................................. 20

Technology transfer and marketing plan ........................................................... 20

Objective ............................................................................................................. 20

Technology transfer .......................................................................................... 21

Marketing plan .................................................................................................. 21

Literature cited ....................................................................................................... 22

Appendix A: Phase I test results ......................................................................... 23

Appendix B: Thermal history of slab-wall prototype ...................................... 39

Appendix C: Proposed changes to USACE guidance ...................................... 45

Abstract ................................................................................................................... 47

ILLUSTRATIONS

Figure

1. Compressive strength of best admixtures of Phase 1 ........................... 4

2. Cycle polarization test .............................................................................. 8

3. Thermal history of various surfaces ....................................................... 12

4. Compressive strength of pullout cylinders from wall-slab

prototype............................................................................................... 14

5. Air temperatures at the construction site ............................................... 15

6. Concrete temperatures at various depths for the heated control

slab ......................................................................................................... 16

7. Concrete temperatures for the slab containing PolarSet...................... 16

8. Concrete temperatures for the slab containing admixture DP ........... 17

9. Compressive strength of cylinders ......................................................... 17

iii
TABLES

Page

Table

1. Research work organization ..................................................................... 2

2. Concrete mix design ................................................................................... 2

3. Test parameters ........................................................................................... 2

4. Experimental tasks in Phase 1, and number of mixes ........................... 3

5. Chemical composition of best admixtures tested in Phase 1 ............... 4

6. Tasks included in Phase 2.......................................................................... 6

7. Concrete mix design for specimens tested in Phase 2 ........................... 7

8. Set times ....................................................................................................... 7

9. Pitting potential .......................................................................................... 8

10. Corrosion rates with various admixtures ............................................... 9

11. Air content in fresh concrete ..................................................................... 10

12. Air-void parameters in concrete containing antifreeze admixtures ... 10

13. Shrinkage of concrete containing antifreeze admixtures...................... 11

14. Concrete placement time ........................................................................... 13

15. Mixture proportions per cubic meter, New Hampshire ....................... 14

16. Properties of fresh concrete, New Hampshire ....................................... 14

17. Mixture proportions per cubic meter, Michigan .................................... 18

18. Concrete placement time, Michigan ........................................................ 18

19. Properties of fresh concrete, Michigan .................................................... 18

20. Winter cost estimate ................................................................................... 18

21. Market estimate .......................................................................................... 21

iv
INTRODUCTION

Background

The American Concrete Institute (ACI) is the

technical authority on concrete technology in the

United States. In its guidance for cold weather

concrete (American Concrete Institute 1988), ACI

outlines procedures to prevent early-age freezing,

to ensure adequate strength for safe removal of

form work, and to avoid thermally induced cracking. In order to produce quality concrete, several

parameters must be carefully controlled. The air

temperature as well as the concrete temperature

needs to be monitored constantly before and after

casting to avoid cold and hot spots. Despite careful control, it is not uncommon to find excessively

cold and hot areas in the same enclosure at the

same time. Neither is it uncommon to find spots

where hot air has dried out the fresh concrete.

Local dehydration and significant temperature

gradients can result in concrete of nonuniform

properties and in concrete that is thermally

cracked.

If combustion heaters are used, carbonation of

the concrete surface may occur and cause soft

surfaces and surface crazing. Carbon monoxide

from partial combustion presents a hazard to

workers. The risk of uncontrolled fire exists wherever open flame heaters are used. Provisions for

these procedures date back to the 1930s. Basically,

the conventional practice today is to artificially

warm the environment where concrete is mixed,

cast, and cured, keeping it at or above 5°C. The

high cost of thermal protection discourages winter construction. Underutilization of resources and

seasonal unemployment are common among concrete practitioners in cold regions.

One alternative to thermal protection methods

is the use of admixtures that allow fresh concrete

to achieve acceptable strength when cured in cold

environments. These admixtures are variously

known as antifreeze admixtures, low-temperature

admixtures, or freeze-protection admixtures. The

term “antifreeze admixtures” is adopted in this

report to convey the implication that they work at

temperatures below the freezing point of water.

The concept of antifreeze admixtures for concrete

is found in foreign literature reporting early experiences in Scandinavian countries and the former

Soviet Union (Korhonen 1990). With antifreeze

admixtures, there is little need for building enclosures, insulation, or heaters. The properties of the

concrete are more uniform, and thermal gradients

are insignificant. Concerns about accidental earlyage freezeups are diminished because the internal

temperature of the concrete can be below 0°C.

Antifreeze admixtures have two purposes: to depress the freezing point of water and to accelerate

the hydration of cement at low temperature.

This research project combined the expertise of

two organizations: the U.S. Army Cold Regions

Research and Engineering Laboratory (CRREL),

which has studied low-temperature admixtures

since 1990 (Borland 1994a, b; Korhonen et al. 1994a,

b; Korhonen et al. 1995) and W.R. Grace (WRG),

which is a leading producer of admixtures for

concrete, with extensive experience with concrete

accelerators.

Project objectives

The objectives of this project were to

• Evaluate the low-temperature strength performance of Daraset, a commercial concrete

strength accelerator.

• Develop new cold weather admixtures.

• Recommend changes in construction standards.

The performance of Daraset at warm temperatures was well known, but its performance below

0°C was not. Daraset was tested along with other

Antifreeze Admixtures for Concrete

CHARLES J. KORHONEN, EDEL R. CORTEZ,

TIMOTHY A. DURNING, AND ARA A. JEKNAVORIAN
chemical formulations in search of an admixture

that would cause concrete to develop acceptable

strength at temperatures below 0°C. Because current concrete construction standards cover concrete work down to 5°C, the overall goal was to

produce an admixture that would promote concrete strength at –5°C to meet or exceed the

strength of admixture-free concrete at 5°C.

Another objective of this project was to recommend changes that integrate the findings of this

research into relevant construction standards. It

was the intention of the industry partner to develop an admixture that would provide adequate

strength at a sufficiently low temperature to justify the investment involved in the implementation of a new product line.

Approach

The research work was organized into five

phases (listed in Table 1). Phase 1 evaluated a

large number of potential chemical compounds

for their ability to promote concrete strength at

–5°C. The admixtures that provided the best strength

performance at low temperature were selected for

Phase 2. This phase was a more comprehensive

evaluation that included testing to determine the

effect of these chemicals on relevant concrete properties. Phase 3 consisted of a prototype concrete

application geared to explore practical job site issues such as placement, finishing, and curing of

full-size concrete elements. Phase 4 integrated the

experience gained in the prototype application

into an actual field application built under winter

conditions; this demonstrated the advantage of

using antifreeze admixtures over conventional

thermal protection methods. Phase 5 consists of

technology transfer efforts, such as this report.

LABORATORY EXPERIMENTS

Phase 1: Effect of chemicals

on strength gain

Objective

To develop a chemical formulation that would

allow concrete cured at –5°C to gain strength at

least as fast as control concrete cured at 5°C.

Experimental approach

Early experiments with single chemical compounds, experiences found in the literature,

physico-chemical data available for each chemical compound, and knowledge of the chemistry

of cement hydration formed the basis for the formulation of candidate admixtures. The candidate

admixtures were made of mixtures of two, three,

or four chemical compounds. These formulations

were tested for their ability to perform as antifreeze admixtures, i.e., chemicals that depress the

freezing point of water and accelerate the hydration of cement.

The experimental work began by screening a

set of chemical formulations using a strength gain

criterion. A series of concrete mixes were made

(Table 2), each including one candidate admixture at one of various dosages. A number of cylinders were cast and cured under one of several

temperatures using special coldrooms. Additionally, control concrete (admixture free) was mixed,

cast, and cured under the same conditions as the

admixtured specimens (Table 3). At the prescribed

time, the cylinders were transported out of their

coldrooms and allowed to thaw up to a controlled

temperature of about 10°C at their center of mass.

This was a necessary precaution to avoid testing

Table 1. Research work organization.

Phase no. Description

1 Effect of chemicals on strength gain

2 Evaluation of best admixtures

3 Prototype slab-wall application

4 Field application of new admixtures

5 Technology transfer

Table 2. Concrete mix design.

Cement type ASTM C150, Type I

Cement content 362.8 kg/m3 for tasks 1A to 1F

418.6 kg/m3 for task 1H

Water/cement ratio 0.48, or as indicated

Target slump 5 cm

Aggregate gradation ASTM C 33, # 6

Aggregate source Lebanon, New Hampshire

Table 3. Test parameters.

Chemical admixtures As needed

Curing temperatures 4 (20°C, –5°C, –10°C and –20°C)

Testing ages 3 (7, 14, and 28 days)

Mix size 0.04 m3

Specimen replicates 3

Specimen size 7.6 cm × 15.2 cm Cylinders

2
frozen concrete, which could

yield false high strengths that

vanish upon thawing. The

cylinders were compression

tested at various ages.

Phase 1 was divided into

ten tasks (Table 4). Each task

consisted of testing one set

of chemical formulations.

The objective was to identify

chemical formulations that

best promote the strength of

concrete cured at low temperatures. Slump, slump

loss, and set times were also

measured for several mixes.

Retarders and some adjustments to the mix design were implemented in later tasks to obtain an

adequate compromise between strength and workability.

With the exception of Task 1G*, the specimens

were concrete cylinders (7.6 × 15.2 cm) cast in

plastic molds. The cylinders were kept sealed in

their plastic molds until ready for compression

testing, and then were cast at room temperature

(hereby defined as approximately 20°C) and

brought to their corresponding curing room within

40 minutes after water was added to the mix.

On the date of their compression test, the corresponding cylinders were brought to room temperature environment, demolded, and allowed to

stand just long enough to ensure that no specimen would contain ice during testing. Typically, a

cylinder would be allowed to reach 10°C before

testing. Replicate dummy cylinders containing a

thermocouple at their center of mass were also

cast to monitor temperatures.

Mixing time and sequence

Mixing procedures followed ASTM C 192,

“Standard Method of Making and Curing Concrete Test Specimens in the Laboratory,” specifically paragraph 6.1.2:

1. Add coarse aggregate.

2. 1/3 mix water (admixture free), start mixer.

3. Fine aggregate (stop mixer if needed).

4. Cement (stop mixer if needed).

5. Remaining water containing admixture.

6. Mix for three minutes, stop mixing for three

minutes, mix for two minutes.

7. Discharge.

Phase 1, Tasks 1A to 1H

Phase 1 contained ten tasks. During the early

planning stages of this project, it was envisioned

that the search for a –5°C admixture would require two or at most three tasks. However, we

soon learned that a compromise between lowtemperature strength development and workability of the fresh concrete was needed in order for

the admixture to be practical. New admixtures

were formulated to address these issues and testing continued. Next, differences in low-temperature (–5°C and –10°C) performance indicated a

need to reformulate some of the early admixtures

to reach a balance between strength acceleration

and freeze-point depression. Finally, after ten tasks,

two admixtures code-named DPTC* and DP were

selected for further study in Phase 2.

In each task, a set of concrete mixes, each containing a given chemical admixture at a given

dosage, was mixed, and cylinders were cast, cured,

and compression-tested to determine the effect of

each admixture on the strength development of

concrete cured at various temperatures.

All Phase 1 tasks were conducted on concrete

cylinders, except tasks 1Ga, 1Gb, and 1Gc, which

were conducted on mortar specimens. Mortar was

used to expedite the study of a series of admixtures.

Experimental data

The data from only certain tasks will be discussed in this report. For those wishing more detail, the test data for all ten Phase 1 tasks are

presented in Appendix A. There, “N/A” stands

for “not available,” and it appears wherever a mix

number was not used in that particular task, or

the test was limited according to judgment of relevance. For tasks with fewer than 20 mixes, the

charts show a blank space where a mix number

was not used. The blank spaces in the charts were

included to keep a consistent format that facilitates comparison. The admixture code name, dosage, and water/cement ratio for each mix are given

in separate tables. Code names were used rather

than chemical formulations where there was a

need to preserve the industry partner’s proprietary rights.

The ACI 306 specifications for cold weather

concrete are valid for concrete cured at 5°C or

above. In this project, an antifreeze admixture was

required to deliver a seven-day strength for speci-

* Task 1G was conducted on mortar.

Table 4. Experimental tasks in

Phase 1, and number of mixes.

Task Mixes

1A 20

1B 20

1C 20

1D 8

1E 5

1F 10

1Ga 10

1Gb 5

1Gc 8

1H 7

* The chemical compositions are disclosed in Table 5 for the

selected admixtures, except for those protected by the industry partner’s proprietary rights.

3
mens cured at –5°C that was equal to or better

than that of nonadmixture concrete cured at 5°C.

The admixtures that developed higher strength at

–5°C were selected for further testing in Phase 2.

It is important to note that these temperatures are

at the center of mass of concrete cylinders. In actual concrete structures, the air temperature can

be significantly lower without harming the concrete because of the effect of the internal heat of

hydration.

Analysis of Phase 1 test results

The strength performances of the selected admixtures are presented in the figures below. The

selection criteria at this stage were chiefly

based on the strength developed at seven

days of cure at –5°C. In these graphs each

mixture is identified by a code. The first two

characters indicate the task number for which

the test results were obtained followed by

the mix number used in the corresponding

task. Figures 1a through 1d display the test

results at 20°C, –5°C, –10°C, and –20°C. Two

control curves corresponding to admixturefree concrete are included for reference. One

corresponds to concrete cured at 20°C. The

second corresponds to concrete cured at 5°C,

the lowest temperature currently covered by

the ACI 306 specification. Table 5 shows the

chemical composition of the selected admixtures. The admixtures subject to proprietary

rights are identified by their code name only.

Figure 1a, corresponding to a curing temperature of 20°C, shows that CCSN (Mix No.

1B_19) enhanced the strength of concrete for at

least the first 28 days. The admixture Ca(NO2)2 +

NaNO2 (mix 1D_7) caused lower strength at seven

days, but higher strength at 14 days and thereafter. The admixture K2CO2 + lignosulfonate (mix

1D_4) reduced the strength at all times, at least up

to 28 days. The rest of the admixtures did not

have a significant effect at room temperature.

Figure 1b, corresponding to a curing temperature of –5°C, shows that most of the selected admixtures allowed concrete strengths to be between

the values for the 20°C and 5°C control concrete.

Any strength developed at low temperature that

7000

5000

4000

3000

2000

1000

0

0 7 14 28

Concrete Age (days)

Compressive Strength (psi)

21

6000

Control +20°C

Control +5°C

1A 20

1B 19

1D 4

1D 7

1E 5

1E 3

a. 20°C.

Figure 1. Compressive strength of best admixtures of Phase 1 cured at

various temperatures. Mixes 1F_8, 1H_2, and 1H_6 were not tested at

20°C.

Table 5. Chemical composition of best admixtures tested

in Phase 1.

Antifreeze admixture Dosage Water/cement

Mix no. formulation (% CWT) ratio

1A_1* Control admixture-free 0 0.48

1A_20 KC1 (3 parts of sodium nitrate

+ 1 part of sodium sulfate) 8.0 0.48

1B_19 CCSN 4.0 0.48

1D_4 K2CO2 + lignosulfonate 6.0/1.5 0.38

1D_7 Ca(NO2)2 + NaNO2 3.0/3.0 0.48

1E_5 CM-48† 6.0 0.48

1E_3 CM-42† 6.0 0.48

1F_8 Ca(NO2)2 + WRDA-19** 4.0/0.7 0.40

1H_2 DP† 6.0 0.43

1H_6 DPTC† 6.0 0.43

* 1A_1 means mix number 1 in task 1A.

† Code name used only to protect proprietary rights.

** WRDA-19 is a high-range water-reducing admixture commercially

available from W.R. Grace, Inc.

4
1B 19

Control +20°C

Control +5°C

1A 20

1D 4

1D 7

1E 5

1E 3

1F 8

1H 2

1H 6

7000

5000

4000

3000

2000

1000

0

0 7 14 28

Concrete Age (days)

Compressive Strength (psi)

21

6000

b. –5°C.

7000

5000

4000

3000

2000

1000

0

0 7 14 28

Concrete Age (days)

Compressive Strength (psi)

21

6000

1B 19

Control +20°C

Control +5°C

1A 20

1D 4

1D 7

1E 5

1H 2

1H 6

1E 3 * 1F 8

* (Too weak to test)

c. –10°C.

7000

5000

4000

3000

2000

1000

0

0 7 14 28

Concrete Age (days)

Compressive Strength (psi)

21

6000

Control +20°C

Control +5°C

1A 20

1B 19

1D 4

1D 7

1E 5, 1E 3, 1F 8,

1H 2, 1H 6

*

* (Too weak to test)

d. –20°C.

Figure 1 (cont’d).

5
equals or exceeds that of the control concrete cured

at 5°C for seven days and for 14 days is regarded

as acceptable. Three admixtures fell below these

acceptance limits: CM-42 (mix 1E_3), Ca(NO2)2+

WRDA-19 (mix 1F_8), and CM-48 (mix 1E_5).

Figure 1c, corresponding to a curing temperature of –10°C, shows that only the KC1 admixture

(mix 1A_20) developed strengths higher than the

acceptance limit. However, its 28-day strength fell

below that of the control concrete cured at 5°C.

The admixture K2CO2 + lignosulfonate (mix 1D_4)

came close to the acceptance band. The strengths

of concrete made with all other admixtures were

lower than the acceptance limit. Figure 1d, corresponding to a curing temperature of –20°C, shows

that none of the admixtures provided acceptable

strength at this temperature.

The admixtures tested in the ten tasks of Phase

1 were formulated based on experiences found in

the literature, preliminary tests conducted by the

partner organizations prior to this project, physical and chemical data available for the chemicals

involved, and the researchers’ knowledge of cement chemistry. The admixture KC1 was developed at CRREL before this CPAR project began.

KC1 was included in this project as a benchmark

for other admixtures, and to expand the experimental data on its performance. A U.S. patent on

this admixture was granted to the Army on 22

March 1994. The low-temperature strength performance of KC1 was significantly superior to all

other admixtures tested. However, KC1 contains

significant amounts of sodium, and therefore may

pose a durability concern if used with alkali-reactive aggregates.

The research team met at the end of each task

to discuss the test results and future directions.

Some of the admixtures tested in early tasks were

then reformulated, and other new formulations

were included in later tasks. The formulations

were chiefly based on predictions of the freezepoint depression and strength acceleration effects

of individual compounds.

Because portland cement is a mixture of various chemical compounds that have individual

chemical properties, and the admixtures were

made of more than one chemical compound, the

combined chemical system for each concrete mix

was very complex. The research process involved

several cycles of formulation and empirical validation. Therefore, although some tasks did not

produce satisfactory admixtures, they provided a

foundation for the development of better admixtures in later tasks. For example, some admixtures yielded good low-temperature strength, but

set too quickly to allow proper transport, placement, and consolidation. Other admixtures kept

concrete from developing ice, but did not produce adequate strength.

At the end of each task, the research team examined the test results, improved the admixture

formulations, and planned the next task. The process included ten tasks until satisfactory admixtures were produced. Although the chief selection

parameter for the admixtures of Phase 1 was their

strength performance at –5°C at seven days, other

important parameters considered were alkali content, strength performance at room temperature,

corrosion potential, workability, slump loss, and

cost.

Two admixtures were selected for more comprehensive evaluation in Phase 2. These showed good

strength enhancement at low temperature and did

not contain significant alkalis or chloride ions.

Phase 2: Laboratory evaluation of

best admixtures from Phase 1

Objective

To evaluate the most promising admixtures from

Phase 1 in terms of the parameters most relevant

to their use in concrete. (See Table 6.)

Experimental approach

ASTM C 494 contains standards for chemical

admixtures used at temperatures above freezing.

There is no specific standard for admixtures below the freezing point of water. The parameters

chosen for the evaluations in Phase 2 were selected to approximate the standards provided in

ASTM C 494 to the extent possible. Two antifreeze

admixtures, code-named DPTC and DP, were selected based on their strength performance at

–5°C. Daraset did not perform as well as these

admixtures at –5°C, and therefore was not tested

further. Daraset performs well at temperatures

above freezing. PolarSet is a new admixture deTable 6. Tasks included in

Phase 2.

Task no. Title

1 Set times

2 Corrosion

3 Hydration products

4 Alkali-silica reaction

5 Air-void analysis

6 Shrinkage

6
veloped by WRG and sold as a low-temperature

set accelerator. PolarSet was tested in Task 1F, but

its strength performance at –5°C did not meet the

preset acceptance criteria. Neither DP nor DPTC

met the minimum strength requirements at –5°C.

PolarSet was carried into Phase 2 as a reference

and became a commercial product during the

course of this project.

Concrete containing the selected admixtures

and control concrete was mixed, cast at room temperature, and then cured at –5°C. Specimens from

this concrete were subjected to a series of laboratory tests geared to characterize specific properties.

Phase 2, Tasks 1 to 6

This phase was divided into six tasks, each

testing one relevant parameter. In addition to admixtures, the concrete used in the Phase 2 tests

was made with the mix proportions shown in

Table 7.

Task 1: Set times. In practice, workers must mix,

place, and consolidate concrete within a limited

time because concrete gradually changes from a

viscous paste to a rigid material. Therefore, it is

important that concrete be placeable and remain

workable for a reasonable time after mixing. The

loss of slump with time, and the setting times as

defined in ASTM C 143 and ASTM C 403, respectively, were measured at room temperature on

mixes containing the selected admixtures.

Two sets of mixtures labeled “A” and “B” were

tested. They were labeled this way to relate mixes

that have the same antifreeze admixture and dosage. Table 8 shows that, with proper dosage of the

admixtures, the slump and air content can be controlled. These mixtures had slumps of 15 cm ± 2

cm, and air contents of 6% ± 1%. Table 8 also

shows the setting times for each mixture. By comparing these setting times to the control concrete,

the effect of each admixture on the setting times

can be observed. It is interesting to compare the

setting times of the candidate antifreeze admixtures to those of PolarSet, which is already an

accepted commercial admixture.

Except for DPTC at 6%, all setting times were

increased by the antifreeze admixtures. Previous

studies by WRG have found that relatively high

Table 8. Set times.

Antifreeze Fresh

admixture concrete

and dosage WRDA-19† Daravair†† Slump air Initial set Final set

Mix no. (% s/s)* (g/kg)** (g/kg)** (in.) (%) (hr) (hr)

1A Control (no antifreeze admixture) 5.0 0.8 13 6.0 4.8 6.6

2A PolarSet, 6% 7.8 0.6 17 6.6 4.1 11.9

3A DPTC, 6% 7.6 0.6 17 5.9 3.8 9.4

4A DP, 6% 7.5 0.7 17 5.8 5.8 13.6

5A PolarSet, 8% 8.1 0.6 13 6.0 8.2 N/A

6A DPTC, 8% 4.1 0.5 13 5.6 >9 N/A

7A DP, 8% 8.1 0.6 16 5.9 >9 N/A

1B Control (no antifreeze admixture) 5.0 0.8 15 5.9 4.8 7.0

2B PolarSet, 6% 7.7 0.8 15 6.9 8.0 12.2

3B DPTC, 6% 9.2 0.9 13 5.3 5.3 10.6

4B DP, 6% 9.2 0.7 15 5.5 7.6 11.9

5B PolarSet, 8% 10.2 1.1 13 6.2 6.3 14.0

6B DPTC, 8% 10.2 1.2 13 6.7 8.9 N/A

7B DP, 8% 10.2 1.2 14 7.0 >9 N/A

* % s/s = percent of weight of the solids in the antifreeze admixture by weight of cement.

† WRDA-19 is a commercial water-reducing admixture.

** g/kg = Amount of admixture in grams of admixture per kilogram of cement.

†† Daravair is a commercial air-entraining admixture.

N/A = Data not available

Table 7. Concrete mix design for

specimens tested in Phase 2.

Cement type Portland Type I

Cement factor 418.6 kg/m3

Coarse aggregate 1102 kg/m3

Sand 583.1 kg/m3

Water 174.6 kg/m3

7
dosages of set accelerators (i.e., > 6% s/s) formulated with various calcium salts can prolong the

set of concrete compared to a control mix. In practice, set accelerators are rarely used above 4% s/s.

The set times for the mixtures containing DP or

DPTC at 6% are similar to those of the mixture

containing PolarSet.

Task 2: Corrosion. Two types of tests, 1) cyclic

polarization test, and 2) lollipop test, were conducted.

1) Cyclic polarization test. The most promising chemical admixtures (code names DP and

DPTC) and a control were evaluated for their tendency to pit by a cyclic polarization test. This test

subjects the surface of a metal to conditions promoting pitting in environments similar to those

found in concrete pore water. A 9-mm-diameter,

13-mm-long steel cylinder is immersed in a saturated calcium hydroxide solution with and without sodium chloride (Fig. 2). The steel cylinder is

polarized from –800 mV versus saturated calomel

electrode (SCE) at a scan rate of 5 mV/s until the

current reaches 255 μA/cm2, at which point the

potential is reversed. The test ends at a potential

of –700 mV versus SCE.

The test determines the pitting tendency of admixtures. Three important data points are obtained:

Eb = breakdown potential (the potential at

which pitting starts).

Ep = pitting potential (the potential below

which pitting cannot occur).

I = current density 200 mV below the pitting potential.

The more negative the values of Eb and Ep, the

less effective is the admixture as a corrosion inhibitor. The magnitude of the current density at

200 mV lower than the pitting potential gives

an indication of possible cathodic inhibition.

The test results for two specimens for each

condition are shown in Table 9. The full test

charts are also included for reference for those

familiar with these electrochemical tests.

Specimens 1A and 1B were the control specimens (no antifreeze admixture) tested in a

saturated calcium hydroxide solution also

containing sodium chloride at 5% by weight

of water, with no other concrete admixture

present. Notice that these specimens showed

the most negative pitting potential (more

prone to pit), as expected. Specimens 2A and

2B were like 1A and 1B, except that the antifreeze admixture code-named DP was included in the solution at 6% by weight of water.

Notice that the pitting potential was much more

positive, which indicates less pitting tendency with

this antifreeze admixture.

2) Lollipop test. This test measures the corrosion that can occur in a steel rebar partially embedded in a concrete cylinder. The rebar protrudes

from the concrete cylinder, which is partially immersed along its longitudinal axis to half its height

in a 3% sodium chloride solution. The initial resistivity is measured using standard AC impedance

techniques.

Six specimens for each admixture and a control

solution were tested. The test results are shown in

Table 10. The data suggest that these admixtures

reduce the corrosion rate compared to the control

specimens. Therefore, from the standpoint of corrosion potential, these admixtures do not lead to

increased corrosion of embedded steel.

Task 3: Hydration products. Strength, durability,

and other concrete properties are affected by the

composition and microstructure of the products

formed during hydration. The composition, structure, and overall quality of a hardened cement

paste are determined primarily by four factors: 1)

type and amount of cement, 2) the water/

cementitious material ratio, 3) moisture availabil1

2

3

4

1 = Steel Cylinder

2 = Counter Electrode

3 = Reference Electrode

4 = Ca(OH) + Admixture (if applicable)

+

–

+ –

Potentiostat

Figure 2. Cyclic polarization test.

Table 9. Pitting potential.

Test Solution [in addition to Pitting potential

 no. H2O and Ca(OH)2] (mV)

1A NaCl –550

1B NaCl –525

2A DP + NaCl –29

2B DP + NaCl –39

3A DPTC + NaCl –59

3B DPTC + NaCl –80

8
ity and curing temperature, and 4) the type and

amount of admixtures. A detailed microscopic examination of concrete specimens containing selected admixtures can provide insight into the effects that such admixtures can have on the

compressive strength and long-term durability of

hardened concrete.

The evaluation and characterization of the concrete microstructure included both conventional

and advanced imaging techniques. Preliminary

observations were conducted at relatively low

magnifications (< 75×) on both fractured and polished surfaces, using a stereomicroscope. More

detailed and advanced imaging involved the use

of high magnification (100×–1000×) reflected and

transmitted light microscopy. The latter technique

was augmented by the use of ultrathin (< 30 μm)

sections of the hardened concrete. Finally, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDXS) were used to

analyze the hydration products in each specimen.

The results of a detailed microscopic examination did not reveal any evidence of unusual or

unique microstructures in the specimens

containing the antifreeze admixtures, as

compared to paste structures observed in

control specimens. However, the specimens containing DP at 6%, and those containing DPTC at 6% and at 8%, exhibited

abnormally high concentrations of calcium hydroxide on exterior surfaces and

interior aggregate sockets. The abundance

of calcium hydroxide suggests that significant bleeding may have occurred. The

control specimens, which contained only

water reducer and air entraining admixtures, exhibited heavy concentrations of

air-void clusters along the paste/aggregate bond interface. The mix design parameters (such as water/cementitious

material ratio, aggregates quantities and

qualities, and cement factor) were kept

constant for all mixes. The admixtures

used are listed in Table 11. Other than the

differences noted above, the cement

paste/aggregate bond interface did not

show any difference in composition or

structure from those of the control specimens.

Task 4: Alkali-silica reaction. The selected

admixtures do not add sodium or potassium (the potentially harmful alkalis) to

the concrete mix. Therefore, testing for

alkali-silica reaction as planned was

found to be unnecessary, and was cut from the

testing program.

Task 5: Air-void analysis. The air content and the

spacing factor are the main parameters that determine to a large degree the freeze–thaw durability

of concrete. In this task, the total air content of

each mixture series was measured in both the fresh

and hardened states. The spacing factor, the average chord length, the number of voids per inch,

the specific surface, and the paste content were

determined on hardened concrete specimens representing each of four mixtures. An air entraining

agent, Daravair, was dosed to produce an air content of 5–7%. Also, a super plasticizer, WRDA-19

(Daracem 19), was dosed to produce a target slump

between 13 and 17 cm. The water/cementitious

material ratio was 0.417. The air-void structure in

the hardened concrete was analyzed after 28 days

of curing. The control specimens were cured at

normal room temperature, while all of the antifreeze test specimens were cured at –7°C. The

specimens were polished slabs cut from concrete

cylinders.

Table 10. Corrosion rates with various admixtures.

Initial 2-year corrosion Corrosion

Sample resistivity potential rate μA/cm2

no. Admixture (kohms/cm) (mV vs. SCE) (relative)

1A Control 5.4 –249 0.23

1B “ 5.3 –564 0.70

1C “ 5.5 –536 0.28

1D “ 6.1 –91 0.05

1E “ 5.7 –211 0.11

1F “ 5.5 –131 0.08

Average “ 5.6 –297 0.24

2A PolarSet* 3.4 –86 0.06

2B “ 3.8 –94 0.07

2C “ 3.2 –65 0.06

2D “ 3.2 –76 0.06

2E “ 3.8 –80 0.09

2F “ 4.0 –75 0.05

Average “ 3.6 –79 0.07

3A DP* 5.2 –108 0.07

3B “ 4.6 –86 0.02

3C “ 4.5 –121 0.05

3D “ 4.8 –136 0.07

3E “ 4.3 –97 0.06

3F “ 4.8 –73 0.05

Average “ 4.8 –104 0.05

4A DPTC* 4.4 –114 0.06

4B “ 5.1 –119 0.12

4C “ 5.3 –127 0.08

4D “ 4.5 –146 0.18

4E “ 4.6 –113 0.19

4F “ 4.6 –118 0.17

Average “ 4.8 –123 0.13

*The given admixture was dosed at 6% of solids by weight of the water in

the solution.

9
1) Fresh concrete air content. The air content of

each mix was measured within eight minutes from

the end of the mixing. Table 11 shows that the

target air content and slump were achieved with

and without the antifreeze admixtures. Therefore,

these admixtures are compatible with the water

reducer and the air entraining admixtures tested,

and caused no detrimental effect.

2) Hardened concrete air content. The total air

content and parameters of the air-void systems

were measured on concrete slabs, which were cut

from the center of cylinders cast from each of the

previously described mixtures. Each cylinder size

was 7.6 cm × 15.2 cm. The cylinder numbers correspond to the individual mixture identification,

disregarding whether they came from groups A

or B. Only the first four mixtures listed in Table 11

were analyzed. As indicated in that table, mixture

1 represents a control concrete with a super plasticizer and an air-entraining admixture, but with

no antifreeze admixture. Mixture 2 contains the same ingredients as mixture

1, except for the commercial low-temperature admixture PolarSet dosed at

6% of solids by weight of portland cement. Similarly, mixture 3 contains the

selected antifreeze admixture DPTC at

6% dosage. Mixture 4 contains the selected antifreeze admixture DP. The air

contents and other air-void parameters

are summarized in Table 12.

ACI 201 Guide to Durable Concrete and ASTM C

457 recommend that the total air content be between 4.5% and 7.5%, and that the specific surface

be greater than 24 (1/mm), and that the average

spacing factor be 200 μm or less. The test results

indicate that mixtures 1 and 2 meet the required

air content. Mixture 3 is only slightly short of

meeting the minimum air content, while mixture

4 had an excess of air voids. Too much air content may weaken the strength of concrete. The

total air content in mixture 3 is slightly (0.1%)

below the recommended minimum value for

durable concrete. However, its spacing factor is

favorable, which indicates an abundance of very

small voids that may provide adequate freeze–

thaw protection.

The total air content and average void spacing

factor are the most important parameters for

gauging the freeze–thaw durability of hardened

concrete. The use of antifreeze admixtures does

Table 11. Air content in fresh concrete.

Antifreeze Curing

admixture temperature Fresh

Mix and dosage WRDA-19 Daravair Slump air concrete

no. (% s/s)* (g/kg)† (g/kg)† (cm) (°C) (%)

1A Control (no antifreeze admixture) 5.0 0.8 13 22 6.0

2A PolarSet, 6% 7.8 0.6 17 –7 6.6

3A DPTC, 6% 7.6 0.6 17 –7 5.9

4A DP, 6% 7.5 0.7 17 –7 5.8

5A PolarSet, 8% 8.1 0.6 13 –7 6.0

6A DPTC, 8% 4.4 0.5 13 –7 5.6

7A DP, 8% 8.1 0.6 16 –7 5.9

1B Control (no antifreeze admixture) 5.0 0.8 15 22 5.9

2B PolarSet, 6% 7.7 0.8 15 –7 6.9

3B DPTC, 6% 9.2 0.9 13 –7 5.3

4B DP, 6% 9.2 0.7 5.75 –7 5.5

5B PolarSet, 8% 10.2 1.1 15 –7 6.2

6B DPTC, 8% 10.2 1.2 13 –7 6.7

7B DP, 8% 10.2 1.2 14 –7 7.0

* % s/s = Percent of weight of the solids in the antifreeze admixture by weight of cement.

† g/kg = Amount of admixture in grams of admixture per kilogram of cement.

Table 12. Air-void parameters in concrete containing antifreeze

admixtures.

Air-void parameters Mixture 1 Mixture 2 Mixture 3 Mixture 4

Air content (%) 5.5 7.5 4.4 8.5

Chord length (μm) 124 135 109 152

Voids per cm 4.3 5.5 3.9 5.5

Specific surface (1/mm) 31.9 29.8 36.9 26.1

Spacing factor (μm) 152 137 145 140

Paste content (%) 30.7 30.7 30.7 30.7

10
not seem to have a significant effect on the overall

quality of the air-void parameters. Therefore, it is

deduced that these admixtures do not adversely

affect the freeze–thaw durability of concrete.

Task 6: Shrinkage. In addition to strength and

durability, concrete must exhibit adequate volume stability. Excessive expansion or contraction

of concrete elements can lead to joint damage,

bulging, and cracking. Chemical admixtures have

been known to affect the drying shrinkage of concrete during the curing period. Concrete mixtures

containing the candidate admixtures and admixture-free control mixtures were tested for drying

shrinkage that occurred during their first seven

days of curing. Beam specimens (25 mm2, 285 mm

in length) were cast and tested according to ASTM

C 157. The specimens were mixed and cast at

room temperature. The control specimens were

cured at room temperature and the others were

cured at –7°C. Their initial length was measured

24 hours after casting. The specimen lengths were

measured again four and seven days later. These

measurements were compared to the initial reading for each specimen. The length changes expressed as a percentage of the initial lengths for

each specimen are presented in Table 13.

The data show that there was a significant increase in the shrinkage of all specimens containing the admixtures at the higher percent (8%).

While PolarSet at 6% increased the shrinkage by

more than 50% compared to the shrinkage of the

control specimens, use at the normal dosage range

recommended by the manufacturer conforms to

the requirements in ASTM C 494. DPTC at 6%

slightly decreased the shrinkage. DP at 6% decreased the shrinkage by 29% compared to the

control specimens.

The shrinkage test results suggest that the candidate antifreeze admixtures are benign to concrete at 6% dosage. The 8% dosage shows a tendency toward increased shrinkage. The potential

for shrinkage should be checked on actual job

concrete when admixtures are used above 6%

dosage.

Phase 3: Prototype

slab-wall application

Objective

To assess the practicality of using the newly

developed antifreeze admixtures in a full-scale

structure with low risk and easy access for monitoring.

Experimental approach

Numerous chemical combinations were investigated for approximately two years before two

formulations were selected for final consideration.

The two prototype admixtures are referred to as

DP and DPTC. Disclosure of their chemical composition is withheld as the formulations are proprietary.

At CRREL, a composting bin consisting of a

16.5-cm-thick reinforced slab on grade 3.7 m wide

by 4.6 m long with 0.9-m-high, reinforced 20.3-

cm-thick walls on three sides was cast 17–18 February 1994. Site preparation consisted of removing a meter of snow from the ground, placing

about 10 cm of dry sand on the newly exposed

but frozen ground, and setting the forms and reinforcing steel. The concrete was placed in the

forms, consolidated, and finished as usual. A plastic sheet was placed over the concrete for three

days to minimize water loss. The wood forms

were removed from the walls 20 hours after the

concrete was cast. No thermal protection was provided to the concrete. Plastic pullout cylinders 10

cm in diameter by 15 cm long were cast into the

slab and the top of the wall to provide in-situ

strength-gain results. No control concrete was cast

on this application.

Thermocouples were embedded in the concrete

at selected locations to monitor the air and concrete temperatures by means of electronic data

loggers. Special attention was given to workability, finishability, thermal effect of the concrete mass, temperature gradients, and strength

development.

Table 13. Shrinkage of concrete containing

antifreeze admixtures.

Mixture Dosage Percent length change

no. Admixture (%) at 4 days at 7 days

1A Control 0 –0.008 –0.024

1B Control 6 –0.007 –0.025

2A PolarSet 6 –0.020 –0.046

2B PolarSet 6 –0.009 –0.031

3A DPTC 6 –0.003 –0.022

3B DPTC 6 –0.005 –0.023

4A DP 6 –0.001 –0.019

4B DP 6 –0.003 –0.016

5A PolarSet 8 –0.014 –0.045

5B PolarSet 8 –0.021 –0.052

6A DPTC 8 –0.024 –0.054

6B DPTC 8 –0.016 –0.049

7A DP 8 –0.019 –0.049

7B DP 8 –0.015 –0.045

* Negative sign indicates shrinkage (negative expansion).

11
0 2 4 6 8 10 12 14 16 18 20 22

20

15

5

0

–5

–10

–15

–20

Days

Temperature (°C)

10

Surface

Air

a. A slab surface.

c. A point 4 cm into wall.

Figure 3. Thermal history of various surfaces.

0 2 4 6 8 10 12 14 16 18 20 22

20

15

5

0

–5

–10

–15

–20

Days

Temperature (°C)

10

4 cm Into South Side

Air

b. A wall surface.

0 2 4 6 8 10 12 14 16 18 20 22

20

15

5

0

–5

–10

–15

–20

Days

Temperature (°C)

10

South Surface

Air

12
Observations and results

Workability

The concrete water content was reduced at the

ready-mix plant to account for the water to be

added with the admixtures to the concrete truck

at the construction site. Accordingly, the water/

cement ratio at the plant was 0.34 and became

0.43 after the respective admixture solution was

added. The negative effect of holding back water

during initial mixing was that the concrete air

contents were very low (i.e., 3% instead of the

desired 6%). The impact of such a low air content

is that the concrete may not be as durable as it

would have been had the concrete contained 6%

air. It was also noticed that adding the admixture

at the mix plant, though producing a concrete of

correct air content, had the tendency to result in

stiffer mixes at the job site. The DPTC mixture lost

slump relatively fast, perhaps because the concrete and the air temperatures were higher than

anticipated, and because it did not have a plasticizer. The slump was 5 cm during placing.

Finishability

Finishing antifreeze concrete was the same as

finishing normal concrete. The trowel did not

freeze to the surface of the concrete and the resulting finish looked good. The main complaint from

the finishers was that some of the mixes arrived

very stiff. This may be corrected by adding a plasticizer.

Thermal record

Five thermocouples were equally positioned

through the thickness of the slab and six through

the wall beginning at the outside surface. An additional thermocouple was positioned slightly

away from the concrete, out of direct sunlight, to

record air temperature. The complete thermal

records can be found in Appendix B. A 21-day

temperature history for the most relevant locations is presented in Figures 3a–c. The outside

surface was the coolest portion of the slab and

wall. It cooled more quickly and experienced

wider temperature excursions than the interior

concrete.

Table 14 shows the approximate time each concrete was placed. The air temperature during transportation of the concrete on the 17th began at

–16°C, rose to a high of 4.5°C at 2:00 p.m., and

then dropped off to well below freezing that night.

The slab concrete temperature at placement was

10°C. It rose to 12°C by noon and then dropped

off to –0.4°C by 4:00 a.m. Though the air temperature during the next three nights got quite cold

(–15°C at 6:30 a.m. on the 18th, –10.3°C at 6 a.m.

on the 19th, and –5.4°C at 2 a.m. on the 20th), the

concrete did not freeze. It dipped to a low of

–1.2°C, which is not a freezing temperature for

these mixes, at 6:30 a.m. on the 19th. The slab

finally cooled to below –5°C at 8:00 p.m. on the

26th, and remained below that temperature for

five days, until 5 a.m. on 3 March. It then rose

slowly for the next seven days to near 0°C on 10

March. These low temperatures, though harmful

to fresh concrete, were not harmful to the nineday-old concrete.

The low ground temperature, which acted as a

heat sink, caused concern that the bottom of the

concrete would not be able to warm the ground

above –5°C , and that the concrete would freeze

from the bottom up. The temperature data show

that freezing did not happen. For several days the

bottom of the concrete slab remained near 0°C. It

remained slightly warmer than the top surface of

the slab, even after a week of curing. This result

has implications for normal winter concreting, in

which placing fresh concrete on frozen ground is

prohibited because of the danger of freezing.

The wall was placed on 18 February. The

wooden forms were erected and the rebar was set

during the morning. Concrete placement began at

11:35 a.m. Figure 3b gives the wall surface temperature history. The air temperature at 11:35 was

1.8°C, rose to 2.5°C at 3 p.m., and fell to below

freezing that night. The concrete arrived somewhat warmer than the prior day’s concrete. It began at 13°C, rose to 19.7°C at 3:30 p.m. and (unlike

the slab) its coldest portion, the surface, did not

cool off appreciably over the next several days.

The combination of the insulation effect provided

by the wooden forms and the fact that there was

no cold substrate to place concrete against helped

the concrete to remain warmer longer. The forms

were removed at 9:30 a.m. on the 19th, allowing

the concrete to cool somewhat but to remain significantly above ambient temperature until the

22nd, three days after being cast. From that point

on, the wall temperature tracked air temperature,

which indicates that much of the chemical reacTable 14. Concrete placement

time.

Mix Date Start

PolarSet 17 Feb 9 a.m.

DP 18 Feb 11:35 a.m.

DPTC 18 Feb 11:55 a.m.

13
PS-Room

PS-Field

DP-Room

DP-Field

DPTC-Room

DPTC-Field

Control +20°C

Control +5°C

8000

4000

2000

0

0 7 14 28

Concrete Age (days)

Compressive Strength (psi)

21

6000

Figure 4. Compressive strength of pullout cylinders from wall-slab

prototype.

Table 15. Mixture proportions per cubic meter, New Hampshire.

Coarse aggregate Sand Air- Water Admixture dosage

(19-mm crushed (natural, Portland entraining reducer (wgt active

ledge, 0.5% 1.1% abs. cement admixture (WRDA ingredient per

2.89 SG) 2.71 SG) Type II w/c (Daravair) w/Hycol) cement wgt)

Mixture (kg) (kg) (kg) ratio (cm3) (cm3) (%)

PS 1010 787 422 0.44 133 798 6

DP 1015 784 416 0.43 266 798 6

DPTC 1021 784 422 0.42 237 828 6

Table 16. Properties of fresh concrete, New

Hampshire.

Air Unit Concrete

Slump content weight temperature

Mixture (cm) (%) (kg/m3) (°C)

PolarSet 8 3 2293 10

DP 11 7.2 2293 13

DPTC 5 6.4 2341 13

tion between the cement and water

had been completed by then.

The slab reached a mostly uniform

temperature within 18 hours. The

wall achieved uniform temperature

almost immediately. The wall, having two surfaces exposed to the ambient air, was most easily affected

by surrounding air.

Strength development

The concrete was transported by

rotary-drum truck from a ready-mix

plant 16 kilometers from CRREL. The

concrete was mixed using unheated

aggregate with heated water (82°C).

The ingredients were added into the

truck’s drum, mixed a few minutes,

and then transported 15–20 minutes

to the construction site. The mix proportions are

given in Table 15. The truck took about 15 minutes to discharge its load, and finishing operations took another 30 minutes. Table 16 gives properties of each mixture as delivered to the site.

Results of the strength tests from the field-cured

pullout cylinders taken out of each concrete section are presented in Figure 4. The target slump

was 10 cm.

Control, admixture-free concrete was not mixed

during this experiment. The control curves included in Figure 4 correspond to concrete of similar mix proportions made with aggregates and

cement from the same sources. These values were

derived from previous laboratory data. As can be

seen, all field samples performed well. They exceeded minimum strength requirements. In addition, the concrete was estimated to have attained

at least 12 MPa before it reached –5°C. The concrete was able to resist freezing at that strength,

shown by the fact that no ice damage was detected in core samples removed from the bin in

May.

FIELD APPLICATION OF

DEVELOPED ADMIXTURES

Soo Locks slabs

Objective

To demonstrate the practicality of using antifreeze admixtures under field conditions.

Description

Three on-grade slabs were cast. One slab was

made of admixture-free concrete to act as a control. It was protected with a heated shelter. A second slab was made with concrete containing the

14
antifreeze admixture code-named DP, which was

developed in this project. A third slab contained

the admixture PolarSet (PS), a low-temperature

accelerator newly marketed by WRG. The admixtured slabs were cast and cured in the open

without shelter. The prototype application in New

Hampshire provided some experience in dealing with these admixtures in cold weather. The

slabs at the Soo Locks provided an opportunity to

apply the new admixtures in a realistic cold

weather setting with conventional equipment and

conventionally trained labor.

Each reinforced slab on grade measured 5.5 m

wide by 6.1 m long by 15.2 cm thick. The slabs

were cast 15–17 March 1994. The Corps’ Soo Area

Office had scheduled 39 sections of concrete to be

replaced because of their advanced stage of freeze–

thaw deterioration. The work area was located on

the southwest pier, which borders the ship canal

of the Soo Lock, the largest of four locks operated

and maintained by the Corps of Engineers, Sault

Sainte Marie, Michigan. Inspection and repair of

the locks themselves is normally done during the

winter months, January through March, when

shipping is stopped. Other repair work, such as

the replacement of the slabs described here, is

also most conveniently done during the winter

nonshipping season, making this test particularly

relevant.

The temporary heated enclosure erected over

the control slab provided a comparison between

conventional and antifreeze concrete operations.

The two admixtured slabs were placed on a cold

gravel bed. After consolidation and finishing operations were conducted conventionally, the fresh

slabs were covered with a plastic sheet. The concrete was exposed to ambient air and was in direct contact with the cold gravel base course, which

was placed directly on frozen ground. No insulation, shelter, or heater was used on the admixtured

slabs. The plastic sheet was placed over the two

exposed concrete sections for seven days to minimize water loss because no curing water was

added. The concrete in the heated shelter was left

uncovered for the seven-day curing period.

Observations and results

Workability

The concrete stayed workable longer than it

did in the prototype application in New Hampshire. The mixtures were 3–6°C colder in Michigan.

Finishability

The concrete workers indicated that the two

mixes, DP and PolarSet, finished quite easily. The

DP did seem to stiffen right at the end of the

finishing operation, about two hours after water

was first added to the mix. However, the concrete

that was left over in a wheelbarrow from the

sample-making procedure was still workable. The

DP contained a different water reducer than that

used in New Hampshire; WRDA-19 was used in

New Hampshire, while AA1D was used in Michigan. The first is a commercial product of WRG

while the second was still in research there.

Thermal records

Four thermocouples were equally positioned

through the thickness of the PolarSet and DP slabs

at about 2.5 m from the edge. One thermocouple

monitored air temperatures.

Figure 5 shows a 22-day record of

air temperature beginning at 9:50 a.m.,

16 March. The air temperatures from

16–17 March were quite cold, averaging –10°C, with a low of –16.5°C at

6:45 a.m. on the 17th. Steady winds

created wind chills of –28°C. The air

temperature averaged only –0.5°C for

the next seven days. The overall average air temperature for the first nine

days was –1.6°C.

The control concrete was cast on

15 March. This slab was cast in a shelter that was heated for the first seven

days; the heater was then turned off,

but the shelter stayed in place for

about a month. Nineteen days of temperature records from four positions

0 5 10 15 20 25

20

10

0

–5

–10

–15

–20

Days

Temperature (°C)

15

5

Figure 5. Air temperatures at the construction site.

15
through the thickness of the slab are given in Figure 6. The position 1.9 cm below the bottom of the

slab was colder than the slab itself the first 2 1/2

days. Over that same 2-1/2-day period, the top

surface was slightly warmer than the middle,

which was slightly warmer than the bottom of the

slab. Thereafter all temperatures throughout the

slab were essentially the same. The heat was

turned off in the control shelter by midafternoon

on 22 March. By 10 a.m. on the 23rd, the control

concrete had equilibrated to ambient conditions.

The PolarSet and DP sections were cast on 17

March. A malfunction in the data recorder prevented temperatures from being recorded past

midnight, 18 March. Consequently, a two-day temperature record of four positions through the thickness of each slab is given in Figures 7 and 8. Both

mixes were relatively warm during this short period, averaging 6.7°C and 6.3°C for the PS and DP,

respectively. Neither mix is expected to have

dropped below –5°C through 23 March. By then it

would have been able to resist frost damage. Except for the heat of day when the sun was shining,

each slab was of uniform temperature throughout

its thickness. Based on tests conducted previously,

it is expected that the temperature of the PS and

the DP slabs tracked that of the air temperature

after day 4. The surface may have gotten a few

degrees warmer than the air during midday.

Microscopic evaluation of

the hardened concrete

Core samples were cut from both slabs in July

1994 and examined for evidence of ice crystal imprints. No icing was found. Similarly, no ice was

found in the 7.6- × 15-cm core samples that were

0 5 10 15 20 25

25

10

0

–5

–10

–15

–25

Days

Temperature (°C)

20

15

5

–20

 1.27 cm Below Top Surface

 Middle of Slab

 2.54 cm Above Slab Bottom

1.9 cm Below Slab

Figure 6. Concrete temperatures at various depths for the heated control slab.

0 5 10 15 20 25

20

15

5

0

–5

–10

Days

Temperature (°C)

10

1.27 cm Below Top Surface

Middle of Slab

2.54 cm Above Slab Bottom

1.9 cm Below Slab

Figure 7. Concrete temperatures for the slab containing PolarSet.

16
stored unprotected next to the slabs. Air-void

parameters were not determined.

Strength development

Concrete cylinders were cast during construction. For the heated control slab, the cylinders

were stored for curing on the ground near the

slab and on an overhead shelf. For the admixtured

concrete slabs, the cylinders were stored for curing partially embedded in cold gravel at the edge

of the concrete slabs. Also, a second set of cylinders for each admixtured concrete was stored on

an overhead shelf in the heated enclosure. The

cylinders were 7.5 cm in diameter by 15 cm in

length. Figure 9 shows their compressive strengths

at various ages. The strengths of the concrete cylinders containing the admixtures, stored heated

and unheated, exceeded the strength of 28-day

control concrete cured under the heated condition. The mixture proportions are given in Table

17, placement time of the concrete in Table 18, and

the properties of fresh concrete in Table 19.

Cost comparison between

conventional and antifreeze concrete

As previously mentioned, a heated shelter was

used for the control concrete. This provided an

opportunity to compare costs between normal

winter concreting to those using antifreeze admixtures. Based on these field tests, it is apparent

that the main difference between normal concrete

and antifreeze concrete is the heat, shelter, and

labor needed to protect normal concrete compared

to the chemicals needed to protect antifreeze concrete. The cost to erect, heat, and dismantle the

temporary shelter at Soo was estimated to be

1.27 cm Below Top Surface

2.54 cm Above Slab Bottom

1.9 cm Below Slab

0 5 10 15 20 25

20

15

5

0

–5

–10

Days

Temperature (°C)

10

Middle of Slab

Figure 8. Concrete temperatures for the slab containing admixture DP.

Control 

(est) Control Site

Control Ceiling

PS Site

DP Site

Control +5°C

6000

4000

1000

0

0 7 14 28

Concrete Age (days)

Compressive Strength (psi)

21

5000

3000

2000

Figure 9. Compressive strength of cylinders (some cured in the heated

shelter and some next to open slabs).

Control (est)

Control Site

Control Ceiling

PS Site

DP Site

Control +5°C

17
$1070. Heating accounted for nearly 15 percent of

this expense. Because antifreeze admixtures are

still prototypes, their market price has not been

determined. However, based on the estimate developed for the shelter in this project (Table 20),

the break-even cost of the antifreeze admixtures

would be $5.51 per liter.

POTENTIAL APPLICATIONS OF

ANTIFREEZE ADMIXTURES

The current standards were written under the

assumption that concrete cannot develop strength

at acceptable rates when the temperature is lower

than 5°C. Current testing methods are designed

for warm environments. Antifreeze admixtures

open new possibilities and the challenge to adapt

standards accordingly.

Antifreeze admixtures offer potential use in

various applications. In building construction,

floor slabs and wall sections can be placed without the need for temporary shelter. However,

whether or not the method of antifreeze admixtures may be advantageous over conventional

thermal protection depends on the specific job

circumstances. For some jobs, building a construction shelter may be useful for worker comfort, at

least during work periods.

Because of the ability to place concrete in the

cold and let the concrete be cold while developing

acceptable strengths, antifreeze mortar and concrete can be safely placed on cold substrates. This

option allows for applications such as joints in

precast concrete structures, repair of dams, tunnels, foundations, etc., where a massive structure

is cold.

Winter paving operations can benefit greatly.

With antifreeze admixtures, the concrete does not

need to be thermally protected, and it can be placed

directly on cold granular bases. From the standpoint of worker comfort, the highly mechanized

operation of paving makes this type of work possible at even lower temperatures than for vertical

building construction. Thus, there is ongoing need

to search for admixtures that work at very low

temperatures.

In general, summer construction is less expensive, but there are applications where the job must

be done in the winter and against cold substrates.

Table 20. Winter cost estimate.

Shelter

Erect shelter

(6 men, 1/2 day @ $23/hr) $552.00

Heat shelter: 1 day prior to pour and 7 days after

(8 days @ 81 L propane/day @ $0.206/L $133.54

Dismantle shelter $276.00

Materials: Assume 9 reuses (Total cost

estimated at $1062) 118.00

Total estimated cost of shelter $1079.54

Antifreeze admixture

Volume of concrete placed inside shelter 5.12 m3

Dosage of admixture per kg of cement 98 cm3

Amount of cement per m3 of concrete 391 kg

Amount of admixture per 5.12 m3 of concrete 196 L

Cost of admixture to equal cost of shelter $5.51/L

Table 17. Mixture proportions per cubic meter, Michigan.

Coarse Portland Admixture dosage

aggregate cement (wgt active ingredient

(19-mm) Sand Type IA w/c per cement wgt)

Mixture (kg) (kg) (kg) ratio (%)

Control 1045 772 391 0.41 0

PolarSet 1045 772 391 0.43 5.2

DP 1045 772 391 0.41 5.2

Table 18. Concrete placement

time, Michigan.

Mixture Date Start

Control 15 Mar 11:00 am

PolarSet 17 Mar 10:50 am

DP 17 Mar 1:10 pm

Table 19. Properties of fresh concrete, Michigan.

Air Unit Concrete

Slump content weight temperature

Mixture (cm) (%) (kg/m3) (°C)

Control 5 3.2 2309 12

PolarSet 11 5.3 2293 8

DP 13 8 2164 7

18
There are other operations where work is best

done during the winter when more workers are

available and construction is less disruptive.

CONCLUSIONS

The experimental results of this project show

that it is possible to place concrete at temperatures significantly below the freezing point of

water and obtain acceptable structural strength.

The test results also show that accelerating admixtures, such as Daraset, do not provide acceptable strengths in freezing temperatures. PolarSet,

an accelerating admixture designed for cool temperatures, was developed and tested during this

project. It performed very well at temperatures

below 5°C, the current low-temperature limit for

admixture-free concrete, provided the concrete

was prevented from freezing. It was unable to

provide protection down to the –5°C goal of this

project. That required that a new admixture be

developed.

A new prototype admixture code-named DP

was developed in this project. DP was tested in

the laboratory for compressive strength at various curing temperatures, and for several other

relevant concrete properties. The laboratory tests

indicate that this admixture met the pre-set requirement of causing concrete to gain strength at

–5°C equal or higher than its equivalent, admixture-free concrete cured at 5°C. The tests also indicate that this admixture has no known detrimental side effects for concrete. It does not contain

chlorides or alkalis, and therefore it does not induce corrosion or cause alkali-silica reaction. DP

did not interfere with the function of an airentraining agent known by the trade name

Daravair.

Although DP needs to be tested prior to its use

with other admixtures to ensure compatibility, so

far there is no indication of compatibility problems. The strength of concrete containing DP and

cured at 20°C was slightly enhanced compared to

that of equivalent admixture-free concrete. DP was

successfully applied to a winter field construction

as described earlier. This field application indicated that concrete containing DP displayed adequate workability, adequate set regime, and adequate strength. The field application indicates

that DP can be successfully applied without special equipment or specialized labor. The laboratory tests show that DP can be safely used with

concrete cured at –5°C. This temperature is the

internal temperature of concrete, not just the ambient temperature.

Caution must be used when comparing this

temperature limit with the limits presented in the

promotional literature of some commercial admixtures that present low-temperature limits of

the ambient instead of the internal concrete temperature. In many cases, the ambient temperature

may be below 0°C, but the internal concrete temperature may be above 0°C because of the heat of

hydration and the presence of insulation. With

those admixtures, the key to success is to keep the

internal concrete temperature above freezing. With

DP, the ambient temperature can be lower than

–5°C, as long as the internal concrete temperature

remains at about –5°C or higher. Neither Daraset

nor PolarSet met the –5°C strength requirement

that was preset at the beginning of this project.

DP did. Daraset and PolarSet are excellent products for concrete temperatures above 0°C.*

Knowledge of the processes of ice formation in

fresh and hardened concrete was advanced. Current winter practice assumes that concrete is automatically damaged if frozen before developing a

compressive strength of 3.4 MPa. Experiments

with antifreeze concrete showed that some ice in

concrete does not necessarily cause damage, as

long as certain minimum unfrozen water content

is maintained. This added knowledge will be useful for future research in the areas of low temperature concrete and masonry. In the past, the

temperature frontier for placing and curing concrete was at 5°C.

There are obstacles when introducing a new

admixture to the market. The existing standards

for concrete admixtures are not applicable to lowtemperature admixtures because they evaluate the

admixtures at higher temperatures. Not having

industry standards discourages concrete practitioners from using a product because doing so

would increase liability.

Admixture manufacturers must find a largeenough market to dilute the cost of promotion,

storage, transportation, and distribution of a new

admixture. Current winter concrete operations are

relatively small because of the added cost of build-

*The manufacturer (Jeknavorian et al. 1994) has published

information showing that concrete mixed with PolarSet at

22°C may not gain appreciable strength when cured at –5°C,

but is able to regain strength when the concrete is warmed to

22°C. The 28-day strength for concrete cylinders treated in

this manner is comparable to a control concrete cured at 22°C

for 28 days.

19
ing with conventional methods according to existing specifications, and the lack of standards for

the new low-temperature admixtures. Therefore,

it becomes a somewhat negative cycle: users wait

for commercially available admixtures and standards; admixture manufactures wait for the market to grow.

The U.S. Army Corps of Engineers is the largest civil engineering organization in the world.

The Corps has provided leadership in many areas

of civil engineering technology. The antifreeze admixtures technology presents both a challenge and

an opportunity for the Corps to lead the way by

developing the needed standards for working in

the winter with concrete that is not heated. A proposal for changes to a Corps guide specification is

included in Appendix C.

RECOMMENDATIONS

Daraset and PolarSet are two commercial admixtures that were evaluated during this project.

Both of these are excellent admixtures for the range

of temperatures for which they are specified. Neither of these admixtures met the minimum

strength requirements set at the beginning of this

project for concrete cured at –5°C. That necessitated the need to search for a new admixture. The

admixture DP, developed in this project, met the

preset requirements. Therefore, DP is recommended for use in winter concrete applications in

which the internal temperature of concrete may

be allowed to drop down to –5°C. The air temperature may be at even lower temperatures as

long as the internal concrete temperature stays at

–5°C. DP is not currently commercially available

off the shelf. The investment needed to bring such

a new admixture through the distribution channels, including storage tanks, advertising, technical advisor training, etc., is significant. At this

point, WRG has decided not to make this investment until the winter concrete market grows.

However, WRG is willing to supply this admixture upon request for significant projects.

The antifreeze admixture KC1 was patented by

the U.S. Army. This admixture is made of two

generic chemicals usually supplied in powder

form. They can be purchased from any chemical

supplier. KC1 is made of three weights of sodium

nitrate (sodium nitrite works as well) and one

weight of sodium sulfate. The recommended dosages vary from 6 to 8% by weight of cement. KC1’s

major disadvantage is that it adds alkalis to the

concrete mix. This may pose a problem if reactive

siliceous aggregates are used. Alkali-silica reaction is not an issue with calcareous aggregates

such as limestone. Natural sand is made of siliceous mineral, but it is chemically inert, and therefore does not react with alkalis. Consequently, KC1

should be safe for use in mortar and grouts that

have only natural sand as aggregate. For combat

engineering applications and for emergency construction, where the short-term goals are predominant, KC1 would be recommended.

Much work is needed in promoting standards

for antifreeze admixtures to encourage their demand. Admixture manufacturers must consider

many factors in assessing the convenience of

launching a new admixture into the market.

Some of these factors are beyond technical control. Tort liability concerns discourage private

construction industry in the United States from

trying new materials for which industry standards are not available. Industry standards are

difficult to set without extensive product application. Admixture producers would like to have

the market demand before investing in a new

product. The U.S. Army Corps of Engineers may

be a catalyst for the implementation of this new

technology. It is recommended that the Corps

use the information in Appendix C to update its

specifications. The information does not identify acceptable chemicals but, rather, identifies

how they should perform when used at low

temperature.

The return in federal research and development investment in a new technology, such as

antifreeze admixtures, may be slow because of

the standards, liability, and marketing considerations described above. However, the economic

opportunity to increase the construction season in

a significant portion of the United States is a real

possibility that should not be ignored.

The U.S. Army could benefit from adding the

antifreeze admixture method to its menu of options

for winter operations. The experience in military

construction could provide confidence in the use of

antifreeze admixtures in the civilian sector.

TECHNOLOGY TRANSFER

AND MARKETING PLAN

Objective

To disseminate and publicize the findings of

the research project, and develop a marketing strategy as appropriate.

20
Technology transfer

Transfer of information is being achieved

through the publication of technical reports, papers, and articles in professional journals, newsletters, and other engineering publications.

WRG has integrated the laboratory results and

experience gained from this project into its technical and marketing literature.

Six publications were produced from this

project (see the first six references in this report’s

“Literature cited” section).

Marketing plan

Market analysis

No comprehensive study of the market potential for freeze protection admixtures (also called

antifreeze admixtures) has been carried out, but

several pieces of information can be used to make

a convincing case that a substantial market does

exist. More detailed analysis is clearly required to

more accurately define the opportunity for these

kinds of admixtures.

To obtain an estimate of the current amount

of concrete construction taking place under conditions that warrant freeze protection, monthly

cement shipments on a state-by-state basis were

matched with monthly average daily temperature data for the major markets within each state.

Assumptions were then made concerning average amounts of cement per cubic meter of concrete, as well as the proportion of cement that

goes to ready-mixed concrete construction.

Using this methodology for the 1992 calendar

year, it is estimated that roughly 19 million cubic

meters of ready-mixed concrete were placed in

conditions where freezing conditions exist (approximately 10% of the U.S. total ready-mixed

concrete). It is assumed from industry knowledge

that only a small portion of this concrete was

placed in environments that are heated for reasons other than providing adequate working/curing conditions. It is further estimated from company data that accelerators (both chloride and

nonchloride) would have been used to treat anywhere from two to four million cubic meters of

this total to provide accelerated set and strength

development as well as some measure of freeze

protection.

Based on these data and these assumptions,

the statistics shown in Table 21 are derived. No

work has been done as part of this project to survey the market and determine the amounts of

money being spent on freeze protection. Previous

estimates of $800 million per year for freeze protection have been published. The magnitude of

this number matches well with the magnitude of

the numbers presented in Table 21 ($600 million

for current practice potential market using freezeprotection admixtures).

Economic viability of new admixtures

It is the opinion of the industry partner in

this project that the products developed through

this CPAR project definitely represent a positive advancement in the development of freezeTable 21. Market estimate.

Freeze protection available and potential market

Current practice Future practice

Available market Potential market Potential market

(million m3) ($ million) (million m3) ($ million) (million m3) ($ million)

2–4 22–38 15 600 29 1,140

Notes:

1. Available market is defined as the amount of concrete where admixtures are already being used

to deliver some degree of freeze protection.

2. Average price of $9.81/m3 (to the concrete producer) for admixtures currently used in marginal

freeze protection environments is assumed (dominated by inexpensive calcium chloride).

3. Current practice potential market merely assumes that all of the concrete currently protected

from freezing through external or internal heating insulation could make use of an admixture to

provide freeze protection.

4. Average price of $39/m3 is assumed for freeze protection of more than just a marginal nature.

5. Future practice potential market assumes that the availability of reliable freeze protection

technology would make concrete construction during subfreezing weather more easily accomplished than it is now. The rate at which concrete is used where average daily temperatures are

between 4°C and 16°C was applied for the amount of time that average daily temperatures are

below 4°C to determine this potential. (This assumption resulted in a 90% increase versus

current cement usage in freezing conditions.)

21
protection admixtures, also referred to as antifreeze admixtures. These new admixtures do not

adversely affect the long-term durability of concrete. The admixtures developed through the joint

efforts of WRG and CRREL provide satisfactory

strength performance down to –5°C, exceeding

the strength performance of untreated concrete

cured at 5°C. There is limited use of chemical

admixtures below 0°C. At any concrete curing temperature in excess of 0°C, PolarSet (WRG’s new,

premier nonchloride accelerator prescribed for air

temperatures as low as –7°C) matches the strength

of the new admixtures developed under the CPAR

project. PolarSet also provides longer set times at

its working temperature range. Therefore, the

advantage band provided by the new antifreeze

admixture is relatively narrow compared to

PolarSet, and it may economically justify its use

only for large projects where the job weather

conditions can be fairly predicted.

Plans for commercialization

Bringing a new product to the market involves

developing manufacturing facilities and protocols,

implementing storage containers, increasing inventory costs, developing technical and promotional literature, and incurring training and other

expenses. The advantage provided by the new

product must justify the investment. In the case of

the new admixtures developed under this CPAR

program, the advantage was clear but not extensive enough to justify the cost of marketing a new

product. The new admixture extends the concrete

curing temperature approximately 5°C lower than

that possible with WRG’s existing accelerator,

PolarSet.

The product as developed in this CPAR project

will be further studied to see if it warrants commercialization on a very limited scale. It is currently anticipated that, if the product were to be

brought through WRG’s product authorization

procedure, and then just kept on the shelf, it would

be available on a specific project-by-project basis

where its particular performance characteristics

may be needed. Also, developments from this program are currently being investigated further to

determine whether the performance of existing

accelerator products can be enhanced. It is very

difficult at this time to project future sales volumes for a product that is commercialized in this

manner.

Given the magnitude of the market potential

(even allowing for the cursory nature of the analysis), WRG views this as an exciting new opportunity for growth, and one that will be pursued

further.

LITERATURE CITED

American Concrete Institute (1988) Cold Weather

Concrete. Detroit, Michigan: ACI 306-388.

Borland, S. (1994a) Pushing the winter concreting

envelope. ASCE New Hampshire Section Newsletter,

15(10): November.

Borland, S. (1994b) Researchers awarded patent

for admixture. Concrete International Magazine,

American Concrete Institute, December.

Korhonen, C.J. (1990) Antifreeze admixtures for

cold weather concreting: A literature review. U.S.

Army Cold Regions Research and Engineering

Laboratory, Special Report 90-32.

Korhonen, C.J., E.R. Cortez, B.A. Charest, and

C.E. Smith, Jr. (1994a) Low-temperature admixtures for concrete. In Proceedings of the Seventh International Specialty Conference on Cold Regions Engineering, Edmonton, Alberta, Canada, p. 87–96. New

York: American Society of Civil Engineers.

Korhonen, C.J., B.A. Charest, E.R. Cortez, and

C.E. Smith, Jr. (1994b) Pushing the winter concreting envelope. The Military Engineer, 86(565).

Alexandria, Virginia: The Society of American

Military Engineers.

Korhonen, C.J., B.A. Charest, and K. Romisch

(1995) Developing new low-temperature admixtures for concrete. In Proceedings of Corps of Engineers Structural Conference, San Antonio, Texas.

Jeknavorian, A.A., Berke, N.S., and Shen, D.F.

(1994) Performance evaluation of set accelerators

for concrete. In Proceedings of the Fourth CANMET/

ACI International Conference on Superplasticizers

and Other Admixtures, Montreal, 1994.

22
APPENDIX A: PHASE 1 TEST RESULTS

Table A1. Compressive strength.. Task 1A cured at various temperatures.

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 N/A N/A 106

2 76 19 212

3 56 9 193

4 1 3 80

5 N/A N/A N/A

6 24 43 278

7 43 28 273

8 56 59 323

9 N/A N/A N/A

10 24 56 71

11 0 13 28

12 7 16 21

13 N/A N/A N/A

14 0 30 19

15 17 24 33

16 3 12 24

17 N/A N/A N/A

18 0 16 21

19 384 408 603

20 189 409 652

d. –20°C

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 4691 5293 5603

2 5955 6401 6923

3 6280 6106 6682

4 6813 6955 7026

5 5186 5870 6494

6 6130 6188 6791

7 7945 7827 8333

8 6342 6636 7533

9 4611 5186 5758

10 4385 4821 5857

11 5234 6130 6564

12 5568 6566 7432

13 4286 5057 5541

14 5021 5823 6060

15 5639 6318 6319

16 5677 6707 4803

17 4743 4951 5635

18 4677 5163 5588

19 4894 5352 5883

20 4583 5151 5494

a. 20°C

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 103 183 377

2 700 844 1160

3 1602 1973 1627

4 858 1317 2033

5 N/A N/A N/A

6 726 839 1028

7 1980 2053 2565

8 933 1200 1495

9 N/A N/A N/A

10 355 459 646

11 457 702 863

12 236 497 844

13 N/A N/A N/A

14 429 556 556

15 749 1296 1115

16 582 1075 2098

17 70 198 292

18 1589 1699 1926

19 3503 4347 5032

20 3489 4286 4838

b. –5°C

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 58 80 189

2 306 367 462

3 246 392 622

4 41 131 472

5 N/A N/A N/A

6 241 298 434

7 227 414 745

8 240 360 594

9 N/A N/A N/A

10 169 194 212

11 67 129 208

12 89 161 236

13 N/A N/A N/A

14 187 269 292

15 246 357 478

16 150 290 544

17 42 60 129

18 518 706 797

19 2072 2602 3065

20 2635 3791 3999

c. –10°C

23
Table A2. Chemical composition of admixtures tested in Phase 1, Task A.

Mix % Solids Dosage Slump

 no. Antifreeze admixture formulation in sol. (% CWT) w/c Ratio (cm) Remarks

1 Control 0 0 0.48 5.7

2 Daraset 30 2 0.48 N/A

3 Daraset 30 3 0.48 N/A

4 Daraset 30 4 0.48 N/A

5 Control 0 0 0.48 2.5

6 ACL 33 2 0.48 N/A

7 ACL 33 4 0.48 N/A

8 ACL 33 6 0.48 N/A

9 Control 0 0 0.48 4.5

10 X1B 50 2 0.48 N/A

11 X1B 50 4 0.48 N/A

12 X1B 50 6 0.48 N/A

13 Control 0 0 0.48 5.7

14 A-2 35 2 0.48 N/A

15 A-2 35 4 0.48 N/A

16 A-2 35 6 0.48 N/A

17 Control 0 0 0.48 7.6

18 KC1 25 2 0.48 N/A

19 KC1 25 6 0.48 N/A

20 KC1 25 8 0.48 N/A

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 4336 4810 5456

2 4687 4774 5461

3 4678 4822 5838

4 4357 4963 5352

5 4744 4805 5876

6 5112 5899 6107

7 6281 6550 6880

8 5725 5946 6486

9 4885 5340 6126

10 5470 6165 6909

11 5828 6719 7074

12 5390 5635 6842

13 5050 5570 6456

14 5102 5871 6593

15 5708 6166 6578

16 5913 6236 5956

17 4093 4774 5216

18 5083 6000 6611

19 5800 5965 6626

20 5607 6342 7008

a. 20°C

Table A3. Compressive strength. Task 1B cured at various temperatures.

b. –5°C

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 131 239 406

2 1339 1532 1608

3 3192 3923 4574

4 3040 4027 4574

5 N/A N/A N/A

6 1057 1448 1679

7 1415 2579 3103

8 967 1641 2325

9 N/A N/A N/A

10 726 1141 1344

11 1429 2551 2891

12 1325 2150 2089

13 N/A N/A N/A

14 1030 1141 1415

15 1841 3282 3824

16 1830 3183 3518

17 N/A N/A N/A

18 1806 2461 2938

19 2381 3674 4485

20 2164 3169 3933

24
Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 0 0 71

2 45 66 170

3 260 535 877

4 254 677 1240

5 N/A N/A N/A

6 122 85 141

7 71 38 42

8 80 39 42

9 N/A N/A N/A

10 71 0 71

11 47 31 28

12 42 25 28

13 N/A N/A N/A

14 67 91 156

15 20 52 127

16 17 52 203

17 N/A N/A N/A

18 51 81 146

19 31 41 57

20 25 39 75

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 41 60 113

2 376 600 722

3 1386 2091 2363

4 1549 2457 2994

5 N/A N/A N/A

6 191 277 335

7 227 173 307

8 226 225 396

9 N/A N/A N/A

10 161 184 311

11 90 164 274

12 226 278 382

13 N/A N/A N/A

14 203 371 509

15 251 579 981

16 361 723 1269

17 N/A N/A N/A

18 287 401 472

19 213 546 1042

20 283 665 1070

d. –20°C

Table A3 (cont’d).

c. –10°C

Mix % Solids Dosage Slump

 no. Antifreeze admixture formulation in sol. (% CWT) w/c Ratio (cm) Remarks

1 Control 0 0 0.48 5 Mix water at 9°C. Concrete temp at 23°C.

2 KC1 30 2 0.48 10

3 KC1 30 6 0.48 11

4 KC1 30 8 0.48 13

5 Control 0 0 0.48 8

6 CNN 35 2 0.48 6

7 CNN 35 4 0.48 6

8 CNN 35 6 0.48 4 Unworkable at 22 min.

9 Control 0 0 0.48 4

10 CCT 33 2 0.48 4

11 CCT 33 4 0.48 3

12 CCT 33 6 0.48 3

13 Control 0 0 0.48 8

14 CCSD 35 2 0.48 5

15 CCSD 35 4 0.48 5

16 CCSD 35 6 0.48 3

17 Control 0 0 0.48 3

18 CCSN 33 2 0.48 3

19 CCSN 33 4 0.48 4

20 CCSN 33 6 0.48 3

Table A4. Chemical composition of admixtures tested in Phase 1, Task B.

25
a. 20°C

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 4480 N/A 5659

2 4522 N/A 5324

3 4225 N/A 4989

4 4169 N/A 5060

5 4404 N/A 5725

6 4220 N/A 5036

7 4385 N/A 5347

8 4055 N/A 4838

9 4560 N/A 5673

10 4951 N/A 6084

11 5792 N/A 6719

12 5626 N/A 6823

13 4338 N/A 5446

14 3843 N/A 4824

15 4305 N/A 5045

16 4272 N/A 5329

17 4110 N/A 5347

18 4824 N/A 6705

19 5807 N/A 7026

20 5368 N/A 6988

c. –10°C

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 0 N/A 0

2 284 N/A 438

3 1211 N/A 2556

4 1649 N/A 3654

5 N/A N/A N/A

6 0 N/A 0

7 0 N/A 0

8 0 N/A 0

9 N/A N/A N/A

10 0 N/A 0

11 0 N/A 0

12 0 N/A 24

13 N/A N/A N/A

14 0 N/A 0

15 0 N/A 0

16 0 N/A 0

17 N/A N/A N/A

18 0 N/A 0

19 0 N/A 0

20 0 N/A 0

b. –5°C

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 0 N/A 0

2 1000 N/A 1451

3 2593 N/A 4145

4 2391 N/A 4084

5 N/A N/A N/A

6 131 N/A 602

7 91 N/A 985

8 86 N/A 870

9 N/A N/A N/A

10 442 N/A 1035

11 336 N/A 1898

12 331 N/A 1280

13 N/A N/A N/A

14 189 N/A 703

15 75 N/A 1238

16 80 N/A 511

17 N/A N/A N/A

18 568 N/A 1437

19 165 N/A 1976

20 354 N/A 1393

d. –20°C

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 0 N/A 0

2 0 N/A 0

3 0 N/A 556

4 0 N/A 842

5 N/A N/A N/A

6 0 N/A 0

7 0 N/A 0

8 0 N/A 0

9 N/A N/A N/A

10 0 N/A 0

11 0 N/A 0

12 0 N/A 0

13 N/A N/A N/A

14 0 N/A 0

15 0 N/A 0

16 0 N/A 0

17 N/A N/A N/A

18 0 N/A 0

19 0 N/A 0

20 0 N/A 0

Table A5. Compressive strength. Task 1C cured at various temperatures.

26
Table A6. Chemical composition of admixtures tested in Phase 1, Task C.

Mix % Solids Dosage Slump

 no. Antifreeze admixture formulation in sol. (% CWT) w/c Ratio (cm) Remarks

1 Control 0 0 0.48 4 Concrete temp at 18°C

2 KC1 30 2 0.48 4 Concrete temp at 18°C

3 KC1 30 6 0.48 7 Concrete temp at 18°C

4 KC1 30 8 0.48 9 Concrete temp at 18°C

5 Control 0 0 0.48 4 Concrete temp at 18°C

6 CCNDD-5 33 2 0.48 3 Concrete temp at 18°C

7 CCNDD-5 33 4 0.48 4 Concrete temp at 20°C

8 CCNDD-5 33 6 0.48 4 Concrete temp at 21°C

9 Control 0 0 0.48 3 Concrete temp at 18°C

10 CC-SONI/NMP 33 2 0.48 2 Concrete temp at 18°C

11 CC-SONI/NMP 33 4 0.48 3 Concrete temp at 21°C

12 CC-SONI/NMP 33 6 0.48 3 Concrete temp at 21°C

13 Control 0 0 0.48 3 Concrete temp at 18°C

14 CCD-NMP 33 2 0.48 2 Concrete temp at 18°C

15 CCD-NMP 33 4 0.48 2 Concrete temp at 18°C. Too-fast set.

16 CCD-NMP 33 6 0.48 4 Concrete temp at 18°C. Too-fast set.

17 Control 0 0 0.48 3 Concrete temp at 18°C

18 CC-NMP 33 2 0.48 3 Concrete temp at 18°C

19 CC-NMP 33 4 0.48 3 Concrete temp at 18°C

20 CC-NMP 33 6 0.48 1 Concrete temp at 23°C. Too-fast set.

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 4691 5293 5603

2 N/A N/A N/A

3 2855 5800 3489

4 3815 4178 4366

5 N/A N/A N/A

6 N/A N/A N/A

7 3230 5564 6437

8 5079 6163 6432

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 N/A N/A N/A

2 N/A N/A N/A

3 1893 3249 3131

4 2613 4494 4866

5 N/A N/A N/A

6 N/A N/A N/A

7 2490 4419 5116

8 1570 3725 4593

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

a. 20°C b. –5°C

Table A7. Compressive strength. Task 1D cured at various temperatures.

27
Table A8. Chemical composition of admixtures tested in Phase 1, Task D.

Mix % Solids Dosage Slump

 no. Antifreeze admixture formulation in sol. (% CWT) w/c Ratio (cm) Remarks

1 Control 0 0 0.48 5

2 K2CO2 + lignosulfonate 30 6/0.5 0.43 7 10% water reduction.

3 K2CO2 + lignosulfonate 30 6/1.5 0.43 19 10% water reduction.

4 K2CO2 + lignosulfonate 30 6/1.5 0.38 1 20% water reduction.

5 Control 0 0 0.48 5

6 Ca(NO2)2 + NaNO2 30 1.5/1.5 0.48 5

7 Ca(NO2)2 + NaNO2 30 3/3 0.48 6

8 Ca(NO2

)2 + NaNO2 30 5/5 0.48 4

9 N/A N/A N/A N/A N/A

10 N/A N/A N/A N/A N/A

11 N/A N/A N/A N/A N/A

12 N/A N/A N/A N/A N/A

13 N/A N/A N/A N/A N/A

14 N/A N/A N/A N/A N/A

15 N/A N/A N/A N/A N/A

16 N/A N/A N/A N/A N/A

17 N/A N/A N/A N/A N/A

18 N/A N/A N/A N/A N/A

19 N/A N/A N/A N/A N/A

20 N/A N/A N/A N/A N/A

Table A7 (cont’d). Compressive strength. Task 1D cured at various temperatures.

c. –10°C

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 N/A N/A N/A

2 N/A N/A N/A

3 0 1325 1438

4 1307 2726 2895

5 N/A N/A N/A

6 N/A N/A N/A

7 355 1261 2165

8 0 1038 2320

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

d. –20°C

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 N/A N/A N/A

2 N/A N/A N/A

3 664 247 98

4 162 126 667

5 N/A N/A N/A

6 N/A N/A N/A

7 0 39 123

8 0 0 691

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

28
d. –20°C.

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 N/A N/A N/A

2 N/A N/A N/A

3 N/A N/A N/A

4 N/A N/A N/A

5 N/A N/A N/A

6 N/A N/A N/A

7 N/A N/A N/A

8 N/A N/A N/A

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

c. –10°C.

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 0 00

2 0 31 178

3 40 91 309

4 43 84 271

5 70 152 348

6 N/A N/A N/A

7 N/A N/A N/A

8 N/A N/A N/A

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

Table A9. Compressive strength. Task 1E cured at various temperatures.

a. 20°C.

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 4291 5546 5899

2 5220 5819 6248

3 4904 5461 5263

4 4649 5210 5843

5 4633 5222 5508

6 N/A N/A N/A

7 N/A N/A N/A

8 N/A N/A N/A

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

b. –5°C.

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 42 119 182

2 910 1783 2370

3 1227 1910 2428

4 927 1594 2211

5 1278 2137 2791

6 N/A N/A N/A

7 N/A N/A N/A

8 N/A N/A N/A

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

29
Table A10. Chemical composition of admixtures tested in Phase 1, Task E.

Mix % Solids Dosage Slump

 no. Antifreeze admixture formulation in sol. (% CWT) w/c Ratio (cm) Remarks

1 Control 0 0 0.48 3

2 CM-42 30 4 0.48 4

3 CM-42 30 6 0.48 3

4 CM-48 30 4 0.48 3

5 CM-48 30 6 0.48 3

6 N/A N/A N/A N/A N/A

7 N/A N/A N/A N/A N/A

8 N/A N/A N/A N/A N/A

9 N/A N/A N/A N/A N/A

10 N/A N/A N/A N/A N/A

11 N/A N/A N/A N/A N/A

12 N/A N/A N/A N/A N/A

13 N/A N/A N/A N/A N/A

14 N/A N/A N/A N/A N/A

15 N/A N/A N/A N/A N/A

16 N/A N/A N/A N/A N/A

17 N/A N/A N/A N/A N/A

18 N/A N/A N/A N/A N/A

19 N/A N/A N/A N/A N/A

20 N/A N/A N/A N/A N/A

Table A11. Compressive strength. Task 1F cured at various temperatures.

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 5899 6149 N/A

2 5630 6055 N/A

3 6078 6375 N/A

4 6319 6427 N/A

5 5541 6218 N/A

6 3551 3810 N/A

7 6602 7267 N/A

8 N/A N/A N/A

9 6814 7545 N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 152 49 N/A

2 870 1352 N/A

3 655 956 N/A

4 648 1266 N/A

5 797 1120 N/A

6 94 0 N/A

7 882 1190 N/A

8 1546 2098 N/A

9 839 1219 N/A

10 1159 1502 N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

a. 20°C. b. –5°C.

30
Table A11 (cont’d).

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 45 0 N/A

2 146 52 N/A

3 168 74 N/A

4 118 0 N/A

5 163 41 N/A

6 0 0 N/A

7 281 278 N/A

8 N/A N/A N/A

9 120 353 N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 0 N/A N/A

2 N/A N/A N/A

3 N/A N/A N/A

4 N/A N/A N/A

5 N/A N/A N/A

6 N/A N/A N/A

7 N/A N/A N/A

8 N/A N/A N/A

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

c. –10°C. d. –20°C.

Table A12. Chemical composition of admixtures tested in Phase 1, Task F.

Mix % Solids Dosage Slump

 no. Antifreeze admixture formulation in sol. (% CWT) w/c Ratio (cm) Remarks

1 Control (with WRDA-19) 0 0.56 0.40 0 Contains 12 fl oz of HRWR/CWT

2 PolarSet (with WRDA-19) 4 0.61 0.40 0 Contains 13 fl oz of HRWR/CWT

3 PolarSet (with WRDA-19) 6 0.70 0.40 0 Contains 15 fl oz of HRWR/CWT

4 PolarSet (with AA1-D) 4 0.56 0.40 0 Contains 13 fl oz of HRWR/CWT

5 PolarSet (with AA1-D) 6 0.56 0.40 0.5 Contains 13 fl oz of HRWR/CWT

6 Control (with WRDA-19) 0 0.70 0.40 0 Contains 15 fl oz of HRWR/CWT

7 DCI (with WRDA-19) 4 0.70 0.40 0 Contains 15 fl oz of HRWR/CWT. Too-fast set.

8 DCI (with WRDA-19) 6 0.70 0.40 0 Contains 15 fl oz of HRWR/CWT

9 DCI (with AA1-D) 4 0.56 0.40 0 Contains 13 fl oz of HRWR/CWT. Too-fast set.

10 DCI (with AA1-D) 6 0.56 0.40 0

11 N/A N/A N/A N/A N/A

12 N/A N/A N/A N/A N/A

13 N/A N/A N/A N/A N/A

14 N/A N/A N/A N/A N/A

15 N/A N/A N/A N/A N/A

16 N/A N/A N/A N/A N/A

17 N/A N/A N/A N/A N/A

18 N/A N/A N/A N/A N/A

19 N/A N/A N/A N/A N/A

20 N/A N/A N/A N/A N/A

31
Table A13. Compressive strength. Task 1Ga cured at various temperatures.

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 1214 1722 N/A

2 N/A N/A N/A

3 N/A N/A N/A

4 N/A N/A N/A

5 N/A N/A N/A

6 N/A N/A N/A

7 N/A N/A N/A

8 N/A N/A N/A

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

a. 20°C.

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 N/A N/A N/A

2 N/A N/A N/A

3 N/A N/A N/A

4 N/A N/A N/A

5 N/A N/A N/A

6 N/A N/A N/A

7 N/A N/A N/A

8 N/A N/A N/A

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

d. –20°C.

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 0 0 N/A

2 1467 2413 N/A

3 875 1590 N/A

4 677 1482 N/A

5 1483 1910 N/A

6 1377 1950 N/A

7 874 1108 N/A

8 950 942 N/A

9 1628 2494 N/A

10 818 1349 N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

b. –5°C.

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 N/A N/A N/A

2 N/A N/A N/A

3 N/A N/A N/A

4 N/A N/A N/A

5 N/A N/A N/A

6 N/A N/A N/A

7 N/A N/A N/A

8 N/A N/A N/A

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

c. –10°C.

32
Table A14. Chemical composition of admixtures tested in Phase 1, Task Ga.

Mix Dosage

 no. Antifreeze admixture formulation (% CWT) w/c Ratio Remarks

1 Control 0 0.45 Mix too fluid.

2 Ca(NO2

)2 /propylene glycol 3/3 0.40 Moderately fast set.

3 Ca(NO2

)2 /propylene glycol 4.2/1.8 0.40 Faster set.

4 Ca(NO2)2 /propylene glycol 1.8/4.2 0.40 Moderately fast set.

5 Urea/Ca(NO2)2 1.5/4.5 0.40

6 Urea/Ca(NO2

)

2 4.5/1.5 0.40 Easely workable.

7 Ca(NO2)2 /Daratard 6/0.26 0.42 Too-rapid set.

8 Ca(NO2)2 /Daratard + microsilica (25%

PC substitution) 6/0.78 0.42 Gritty mix; clay-like: moldable but not bleeding.

9 Ca(NO2)2 /cane sugar 6/0.1 0.40 Soft and workable; not bleeding. Moderate set at 40 minutes.

10 Ca(NO2)2 /latex 6/7.5 0.45 Sticky; too-fast set.

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

Table A15. Compressive strength. Task 1Gb cured at various temperatures.

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 6027 N/A N/A

2 N/A N/A N/A

3 N/A N/A N/A

4 N/A N/A N/A

5 N/A N/A N/A

6 N/A N/A N/A

7 N/A N/A N/A

8 N/A N/A N/A

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 953 N/A N/A

2 1936 N/A N/A

3 1000 N/A N/A

4 1456 N/A N/A

5 851 N/A N/A

6 N/A N/A N/A

7 N/A N/A N/A

8 N/A N/A N/A

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

a. 20°C. b. –5°C.

33
Table A16. Chemical composition of admixtures tested in Phase 1, Task Gb.

Mix Dosage

 no. Antifreeze admixture formulation (% CWT) w/c Ratio Remarks

1 Control 0 0.43

2 DCI 4 0.43

3 DCI/propylene glycol 3.6/0.4 0.43

4 DCI/propylene glycol 3.2/0.8 0.43

5 DCI/propylene glycol 2.8/1.2 0.43

6 N/A N/A N/A

7 N/A N/A N/A

8 N/A N/A N/A

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

Table A15 (cont’d). Compressive strength. Task 1Gb cured at various temperatures.

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 N/A N/A N/A

2 N/A N/A N/A

3 N/A N/A N/A

4 N/A N/A N/A

5 N/A N/A N/A

6 N/A N/A N/A

7 N/A N/A N/A

8 N/A N/A N/A

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 N/A N/A N/A

2 N/A N/A N/A

3 N/A N/A N/A

4 N/A N/A N/A

5 N/A N/A N/A

6 N/A N/A N/A

7 N/A N/A N/A

8 N/A N/A N/A

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

c. –10°C. d. –20°C.

34
Table A17. Compressive strength. Task 1Gc cured at various temperatures.

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 1714 1744 N/A

2 N/A N/A N/A

3 N/A N/A N/A

4 N/A N/A N/A

5 N/A N/A N/A

6 N/A N/A N/A

7 N/A N/A N/A

8 N/A N/A N/A

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

a. 20°C.

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 0 0 N/A

2 1217 1862 N/A

3 1495 2392 N/A

4 1267 2135 N/A

5 1757 2357 N/A

6 N/A N/A N/A

7 659 1189 N/A

8 1261 2543 N/A

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

b. –5°C.

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 0 0 N/A

2 0 0 N/A

3 84 701 N/A

4 520 1017 N/A

5 133 332 N/A

6 N/A N/A N/A

7 N/A N/A N/A

8 569 1337 N/A

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 N/A N/A N/A

2 N/A N/A N/A

3 N/A N/A N/A

4 N/A N/A N/A

5 N/A N/A N/A

6 N/A N/A N/A

7 N/A N/A N/A

8 N/A N/A N/A

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

c. –10°C. d. –20°C.

35
Table A18. Chemical composition of admixtures tested in Phase 1, Task Gc.

Mix Dosage

 no. Antifreeze admixture formulation (% CWT) w/c Ratio Remarks

1 Control 0 0.42 Normal plasticity.

2 Ca(NO2

)2 /propylene glycol 3/3 0.39 Normal plasticity.

3 Urea/Ca(NO2

)2 1.5/4.5 0.42 Less plastic than previous mix.

4 Urea/Ca(NO2)2 4.5/1.5 0.42 Very soft mix; little bleeding.

5 Ca(NO2)2 /cane sugar 6/0.4 0.42 Rapid set.

6 Ca(NO2

)2 /cane sugar 9/0.4 0.42 Excessive rapid set.

7 Ca(NO2)2 /cane sugar + microsilica (25%

cement substitution) 6/0.3 0.45 Too-rapid set.

8 K2CO2 /cane sugar 6/0.4 0.42 Normal plasticity kept by remixing at intervals.

9N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

Table A19. Compressive strength. Task 1H cured at various temperatures.

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 231 254 478

2 2947 4249 5022

3 1912 3150 4186

4 2516 3711 4702

5 1723 3046 4238

6 2964 4183 5043

7 2098 3442 4385

8 N/A N/A N/A

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 5550 6088 6681

2 N/A N/A N/A

3 N/A N/A N/A

4 N/A N/A N/A

5 N/A N/A N/A

6 N/A N/A N/A

7 N/A N/A N/A

8 N/A N/A N/A

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

a. 20°C. b. –5°C.

36
Table A20. Chemical composition of admixtures tested in Phase 1, Task H.

Mix Dosage Slump

 no. Antifreeze admixture formulation (% CWT) w/c Ratio (cm) Remarks

1 Control 0 0.43 6

2 DP 6 0.43 6

3 DP 8 0.43 6

4 DPT 6 0.43 6

5 DPT 8 0.43 5

6 DPTC 6 0.43 5

7 DPTC 8 0.43 5

8 N/A N/A N/A N/A

9 N/A N/A N/A N/A

10 N/A N/A N/A N/A

11 N/A N/A N/A N/A

12 N/A N/A N/A N/A

13 N/A N/A N/A N/A

14 N/A N/A N/A N/A

15 N/A N/A N/A N/A

16 N/A N/A N/A N/A

17 N/A N/A N/A N/A

18 N/A N/A N/A N/A

19 N/A N/A N/A N/A

20 N/A N/A N/A N/A

Table A19 (cont’d).

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 N/A N/A N/A

2 N/A N/A N/A

3 N/A N/A N/A

4 N/A N/A N/A

5 N/A N/A N/A

6 N/A N/A N/A

7 N/A N/A N/A

8 N/A N/A N/A

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

Compressive strength (psi)

Testing age (days)

 Mix no. 7 14 28

1 0 45 110

2 60 93 432

3 112 42 1032

4 41 384 126

5 64 275 766

6 55 87 503

7 162 373 754

8 N/A N/A N/A

9 N/A N/A N/A

10 N/A N/A N/A

11 N/A N/A N/A

12 N/A N/A N/A

13 N/A N/A N/A

14 N/A N/A N/A

15 N/A N/A N/A

16 N/A N/A N/A

17 N/A N/A N/A

18 N/A N/A N/A

19 N/A N/A N/A

20 N/A N/A N/A

c. –10°C. d. –20°C.

37
39

0 2 4 6 8 10 12 14 16 18 20 22

20

15

5

0

–5

–10

–15

–20

Days

Temperature (°C)

10

Surface

Air

0 2 4 6 8 10 12 14 16 18 20 22

20

15

5

0

–5

–10

–15

–20

Days

Temperature (°C)

10

4 cm Below Surface

Air

APPENDIX B: THERMAL HISTORY OF SLAB-WALL PROTOTYPE

Figure B1. Slab.

Figure B2. Slab.

0 2 4 6 8 10 12 14 16 18 20 22

20

15

5

0

–5

–10

–15

–20

Days

Temperature (°C)

10

8.25 cm Below Surface

Air

Figure B3. Slab.
0 2 4 6 8 10 12 14 16 18 20 22

20

15

5

0

–5

–10

–15

–20

Days

Temperature (°C)

10

1.27 cm Below Slab Base

Air

0 2 4 6 8 10 12 14 16 18 20 22

20

15

5

0

–5

–10

–15

–20

Days

Temperature (°C)

10

12.4 cm Below Surface

Air

Figure B4. Slab.

Figure B5. Slab.

Figure B6. Wall.

0 2 4 6 8 10 12 14 16 18 20 22

20

15

5

0

–5

–10

–15

–20

Days

Temperature (°C)

10

South Surface

Air

40
Figure B7. Wall.

0 2 4 6 8 10 12 14 16 18 20 22

20

15

5

0

–5

–10

–15

–20

Days

Temperature (°C)

10

4 cm Into South Side

Air

0 2 4 6 8 10 12 14 16 18 20 22

20

15

5

0

–5

–10

–15

–20

Days

Temperature (°C)

10

8 cm Into South Side

Air

0 2 4 6 8 10 12 14 16 18 20 22

20

15

5

0

–5

–10

–15

–20

Days

Temperature (°C)

10

12 cm Into South Side

Air

Figure B8. Wall.

Figure B9. Wall.

41
0 2 4 6 8 10 12 14 16 18 20 22

20

15

5

0

–5

–10

–15

–20

Days

Temperature (°C)

10

16 cm Into South Side

Air

Figure B10. Wall.

0 2 4 6 8 10 12 14 16 18 20 22

20

15

5

0

–5

–10

–15

–20

Days

Temperature (°C)

10

North Surface

Air

Figure B11. Wall.

42
0 5 10 15

AAAAAAAAAAAAAA

AAAAAAAAAAAAAA

AAAAAAAAAAAA

AAAAAAAAAAAA

AAAA

AAAAAAAAAAA

AAAAAAAAAAA

AAAAAAAAAA AAAAAAAA

AAAAAAAA

AAAA

AAAA

AAAAAA

AAAAAA

AAAAAA AAAAA

AAA

AAA

AA

AA

AAA

AAA

AA

AA

AA

AA

AAAAA

AA

AA

AA

AA

AA

4 cm Below Surface

8.25 cm Below Surface

1.27 cm Below Slab

12 cm Below Surface

Surface

Slab

9 am

17 Feb 1994

Slab

Noon

17 Feb 1994

Slab

6 pm

17 Feb 1994

Slab

Midnight

17 Feb 1994

Slab

3 pm

18 Feb 1994

Temperature (°C)

Figure B12. Thermal record, 17–18 February.

43
0 5 10 25

AAAAAAAAAA

AAAAAAAAAA

AAAAAAAAA

AAAAAAAAAA

AAAAAAAAAA

AAAAAAAAAAAAAA

AAAAAAAAAAAAA

AAAAAAAAAAAAA

AAAAAAAAAAAA

AAAAAAAAAAAA

AAAAAAAAAAAAA

AAAAAAAAAAAAA

AAAAAAAAAAAAA AAAAAAAAAAAA

AAAAAAAAAAA

AAAAAAAAAAA

AAAAAAAAAA

AAAAAAAAAA

AAAAAAAAAA AAAAAAAAA

15 20

Temperature (°C)

AA

AA

South Surface

4 cm Into South Surface

8 cm Into South Surface

AA

AA

AA

12 cm Into South Surface

16 cm Into South Surface

North Surface

Wall

Noon

18 Feb 1994

Wall

3 pm

18 Feb 1994

Wall

Midnight

18 Feb 1994

Wall

Noon

19 Feb 1994

Figure B13. Thermal record, 18–19 February.

44
APPENDIX C: PROPOSED CHANGES TO USACE GUIDANCE

Example document to be changed: CEGS 03300 (September 1995)

Section: 2.3 Chemical Admixtures

Change #1

Insert “Antifreeze Admixtures” as number 2.3.7 using the text below, and

renumber the section on “Other Chemical Admixtures” to be number 2.3.8.

Suggested Insertion

Antifreeze admixtures

An antifreeze admixture shall be able to promote the strength of concrete cured

at –5°C ±1°C to reach a minimum seven-day strength of 40% of the strength of an

equivalent admixture-free concrete cured at 20°C at the same age, and a minimum

14-day strength of 60% of the strength of an equivalent admixture-free concrete

cured at 20°C at the same age. The test specimens shall be standard cylinders 7.6 cm

in diameter or larger. The concrete shall be mixed and cylinders cast at room

temperature (about 20°C). The specimens to be cured at –5°C shall be brought into

the cold chamber no more than 40 minutes after water has been added to the cement

during mixing. The cold chamber shall be able to cool the center of mass of the

cylinders to 0°C or lower within three hours, and to –4°C within eight hours. The

temperature of the cylinders shall be measured with embedded thermocouples on

replicate specimens. On the day of the compressive strength test, the cylinders shall

be moved from the cold room to a warm room at about 20°C. The temperature at the

cylinders’ center of mass shall be allowed to reach 5°C before being compression

tested. The cylinders shall be compression tested within one hour of reaching 5°C.

Except for the strength requirements, the admixture shall meet the physical

requirements set forth in ASTM C 494 for an admixture Type C.

For cast-in-place concrete, the admixture shall not contain more than 2% of

calcium chloride by weight of cement. For prestressed concrete, the admixture shall

not contain any chlorides, except in trace amounts.

The admixture may add alkalis only to the extent that the total mixture alkali

content does not exceed 0.6% by weight of cement.

Change #2

Rewrite section 3.8.3, “Cold Weather Requirements,” as follows:

There are two possible protection measures that can be used when the ambient

temperature drops below 0°C. The first measure entails thermal protection and the

second method entails chemical protection. Whichever method is chosen, it must be

approved by the Contracting Officer.

Thermal Protection may be chosen if freezing temperatures are anticipated before

the expiration of the specified curing period. The ambient temperature of the air

where concrete is to be placed and the temperature of surfaces to receive concrete

shall not be less than 5°C (40°F). Heating of the mixing water or aggre

45
gates will be required to regulate the concrete placing temperature. Materials

entering the mixer shall be free from ice, snow, or frozen lumps. Upon written

approval, an accelerating admixture conforming to ASTM C 494, Type C or E, may

be used, provided it contains no calcium chloride.

Antifreeze admixtures may be chosen in lieu of thermal protection provided

the concrete temperature, at it coldest section, does not dip below the lowest

protection capability of the admixture. The admixture shall conform to the requirements of section 2.3.7 of this document.

46
1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED

4. TITLE AND SUBTITLE 5. FUNDING NUMBERS

6. AUTHORS

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION

 REPORT NUMBER

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING/MONITORING

 AGENCY REPORT NUMBER

11. SUPPLEMENTARY NOTES

12a. DISTRIBUTION/AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE

13. ABSTRACT (Maximum 200 words)

14. SUBJECT TERMS 15. NUMBER OF PAGES

16. PRICE CODE

17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION 20. LIMITATION OF ABSTRACT

 OF REPORT OF THIS PAGE OF ABSTRACT

NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89)

Prescribed by ANSI Std. Z39-18

298-102

REPORT DOCUMENTATION PAGE Form Approved

OMB No. 0704-0188

Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and

maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information,

including suggestion for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington,

VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188), Washington, DC 20503.

October 1997

Antifreeze Admixtures for Concrete USACE

Construction Productivity

Advancement (CPAR)

Research Program

Charles J. Korhonen, Edel R. Cortez, Timothy A. Durning, and

Ara A. Jeknavorian

U.S. Army Cold Regions Research and Engineering Laboratory

72 Lyme Road Special Report 97-26

Hanover, New Hampshire 03755-1290

Office of the Chief of Engineers

Washington, D.C. 20314-1000

For conversion of SI units to non-SI units of measurement consult ASTM Standard E380-93, Standard Practice for Use of the

International System of Units, published by the American Society for Testing and Materials, 1916 Race St., Philadelphia, Pa.

19103.

Approved for public release; distribution is unlimited.

Available from NTIS, Springfield, Virginia 22161

Antifreeze admixtures, Cold concrete, Cold regions construction, Cold weather

concrete, Concrete admixtures, Freeze-point depression, Low-temperature strength,

Thermal protection, Winter construction

UNCLASSIFIED UNCLASSIFIED UNCLASSIFIED UL

The goal of this project was to develop a chemical admixture that would reduce the need for wintertime thermal

protection of freshly placed concrete. Chemicals were investigated for their ability to promote strength gain in

concrete cured below 0°C. The project was carried out in five phases. Phase 1 evaluated existing and new

admixtures. Phase 2 measured the effect of promising chemicals on concrete properties. Phases 3 and 4 tested the

practicality of using the new technology/admixture in the field. Phase 5 disseminated the findings through an

Army conference and through the development of this report, in addition to normal W.R. Grace advertising

channels. Laboratory strength tests established that two prototype admixtures were capable of protecting

concrete down to –5°C. Results from other laboratory tests show that the chemicals pose no harm to the concrete

or embedded ferrous metals. Concrete containing the prototype admixtures passes standard freeze–thaw tests,

does not shrink unusually, does not contain harmful alkalis, and does not produce irregular hydration products.

Field tests clearly demonstrated that working with these new admixtures requires no new skills. The concrete

can be mixed at lower temperatures, saving energy. The admixtures are easily dosed into the mixing trucks, as is

normal practice today, and concrete is finished in the usual manner. Estimates show that the two prototype

admixtures can extend the construction season by as much as three months in the contiguous United States. The

prototype has proved that low-temperature admixtures are possible. The industry partner sees the need to

develop admixtures that will work to –10°C before going commercial with this technology.

54