NATIONAL BUREAU OF STANDARDS REPORT

9465

Progress Report

INDUCED ACCELERATED DETERIORATION OF PORTLAND CEMENT CONCRETE

Semiannual Report

by

Raymond L. Blaine

9 January 1907

Chemical Research Laboratory

RESEARCH LABORATORIES

Edgewood Arsenal, Maryland 21010

Contract D010-0-35-A6-02806

Sponsored by

BALLISTISTICS RESEARCH LABORATORIES

Aberdeen Proving Ground, Maryland

21005

NATIONAL BUREAU OF STANDARDS

Washington, D. C. 20234

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

/QJLX ? 5 t/ z.
Distribution Statement

This document is subject to special export controls and each transmittal

to foreign governments or foreign nationals may be made only with prior

approval of the CO, Edgewood Arsenal, ATTM: SMUEA-TSTI-T

Edgewood Arsenal, Maryland 21010

Disclaimer

The findings in this report are not to be construed as an official

Department of the Army position unless so designated by other authorized

documents

Disposition

Destroy this report when no longer needed. Do not return it to the

originator
NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT

421.04-12-4212442

Progress Report

NBS REPORT

9465

INDUCED ACCELERATED DETERIORATION OF PORTLAND CEMENT CONCRETE

Semiannual Report

by

Raymond L. Blaine

9 January 1967

This document is subject to special export controls and each transmittal to

foreign governments or foreign nationals may be made only with prior approval

of the CO, Edgewood Arsenal, ATTN: SMUEA-TSTI-T , Edgewood Arsenal, Maryland

21010

Chemical Research Laboratory

RESEARCH LABORATORIES

Edgewood Arsenal, Maryland 21010

Contract DQ18-0-35-A6-02806

Sponsored by

BALLISTISTICS RESEARCH LABORATORIES

Aberdeen Proving Ground, Maryland

21005

NATIONAL BUREAU OF STANDARDS

Washington, D. C. 20234

IMPORTANT NOTICE NATIONAL BUREAU OF STAN

for use within the Government. Be and review. For this reason, the pi whole or in part, is not authorize* Bureau of Standards, Washington, I the Report has been specifically pr<

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST) on October 9, 2015

recounting documents intended

ijected to additional evaluation

ting of this Report, either in

ffice of the Director, National

le Government agency for which

js for its own use.

U.S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

FOREWORD

The work described in this report was sponsored by the U.S. Army Ballistics

Laboratories, This work was started in October 1965 and will continue for

18 months. Experimental data are contained in Vol. 1 of notebook dated

October 1, 1965 assigned to R. L. Blaine.

Notices

Reproduction of this docuuaent in whole or in part is prohibited except with

permission of the CO, Edgewood Arsenal, Maryland 21010; however DDC is

authorized to reproduce the document for United States Government purposes.

The information in this report has not been cleared for release to the general

public

.

Acknowledgments

This research was supported by the US Army Ballistics Research Laboratories

and was monitored by Edgewood Arsenal Research Laboratories, under Contract

D018-0-35-A6-02806,

- 3-
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DIGEST

Measurements and observations were continued during the second six-month

period of the effect of various chemical solutions on mortar bars made

of two portland cements. Measurements were also made of the effect of

the more aggressive chemicals on concrete cylinders made of these

cements, and studies were continued on the induced electrochemical

corrosion of reinforcing steel in concrete.

Some of the mortar specimens immersed in the various chemical solutions

failed in less than 2 weeks, whereas others indicated no weight loss,

cracking, or reduction in fundamental resonance frequency in 6 months.

The type of cement used, the proportions of cement to sand, and the

moisture content of the specimens at the start of the test all appeared

to be significant variables. Although the ammonium salts appeared to

be the more aggressive, most, but not all, of the sulfates were deleterious

to the specimens made of the Type I cement but had little effect on the

specimens of the Type II cement.

A series of mortar specimens was placed on end in shallow concentrated

salt solutions. The absorbtion, evaporation, and crystal formation in

the portions of the specimens exposed to the air caused cracking and

disintegration in some instances. Ammonium acetate had the most severe

effect

.

Some of the 3x6 inch concrete cylinders placed in some of the salt

solutions failed in 2 weeks, whereas others indicated little or no effect

after 24 weeks of immersion. The ammonium salts appeared most aggressive. The type of cement, quality of the concrete, and the moisture

content of the specimens at the time of test also appeared to be significant variables.

Some of the 3x6 inch concrete cylinders with reinforcing rods inserted

in the major axis exhibited cracks in less than 24 hours to 4 or 5 days

when a 110-volt direct electric current was used to corrode the reinforcing

rods. Two of the 7 specimens did not crack in 3 weeks but exuded corrosion

products where the steel rod entered the cylinder. With 55 volt direct

electric current, up to 7 days were required to form the cracks in the

cylinders

.

- 5 -

TABLE OF CONTENTS

Introduct ion 9 Tests Conducted During the Second 6-Month Period 9 Mortar Bars Stored in Chemical Solutions 10

Results of Tests of Mortar Specimens Stored in 10

Solutions

Mortar Bars Stored on End in Chemical Solutions 11

Results of Tests of Mortar Bars Stored on End in 11

Chemical Solutions

Concrete Cylinders Stored in Chemical Solutions 11

Results of Tests of Concrete in Chemical Solutions 12

Electrochemical Corrosion of Reinforcing Steel in 13

Concrete

Plans for Future Work 16

Table 2-1 Time for Failure or the Change in Re- 17 sonance Frequency in 6 Months of 1:3 (cement

to sand) Mortars Made of Type I Cement When

Stored in Solutions of the Various Reagents.

Table 2-2 Time for Failure or the Change in Re- 18 sonance Frequency in 6 Months of 1:5 (cement

to sand) Mortars Made of Type I Cement When

Stored in Solutions of the Various Reagents.

Table 2-3 Time for Failure or the Change in Re- 19 sonance Frequency in 6 Months of 1:3 (cement

to sand) Mortars Made of Type II Cement When

Stored in Solutions of the Various Reagents.

Table 2-4 Time for Failure or the Change in Re- 20 sonance Frequency in 6 Months of 1:5 (cement

to sand) Mortars Made of Type II Cement When

Stored in Solutions of the Various Reagents.

Table 2-5 Time for Failure, or Change in Dynamic 21

Modulus in 18 Weeks of Mortars Made of Type I Cement When Stored on End in Shallow Concentrated

Solutions of the Various Reagents.

Table 2-6 Time for Failure, or Change in Dynamic • 22

Modulus in 18 Weeks of Mortars Made of Type II

Cement When Stored on End in Shallow Concentrated

Solutions of the Various Reagents.

Table 2-7 Time for Failure, or Change in Re- 23 sonance Frequency in 24 Weeks of 3x6 inch Concrete Cylinders Made of Type I Cement When Stored

in Solutions of the Various Reagents.

Table 2-8 Time for Failure, or Change in Re- 24 sonance Frequency in 24 Weeks of 3x6 inch Concrete

Cylinders Made of Type II Cement When Stored in

Solutions of the Various Reagents.

Table 2-9 Time of Cracking of 3x6 inch Concrete 25

Cylinders Having 3/8 inch Reinforcing Rod in

the Principal Axis With an Applied Direct Electrical Current.

- 7 -
TABLE OF CONTENTS

Distribution List

Document Control Data - R&D, BB Form 1437, With

Abstract and Keyword List

Page

~27
INDUCED ACCELERATED DETERIORATION OF PORTLAND CEMENT CONCRETE

INTRODUCTION

The need for further information on the relative aggressiveness cf different chemicals on portland cement concrete was presented in the previous semiannual progress report, together with a description of the

tests used in the present study. These consisted of a series of screening

tests of the effect of various chemical solutions on mortar specimens

made of two types of portland cement, each with two proportions of

cement to sand, and each of these tested while still moist and after

air-drying. Most of the specimens were completely covered with the

solutions, but some were placed on end in 3 or 4 cm of more concentrated

solutions of the various salts. Concrete specimens were also made for

test after curing. Information on the chemical and physical properties

of the cements, the proportions and properties of the mortars and

concretes were presented in the first progress report together with the

test methods employed.

The results obtained when immersing the mortar-bar specimens in the more

aggressive solutions for six weeks were presented in the previous report.

It was reported that ammonium salts appeared to be the most aggressive,

and specimens made of the Type II cement were more resistant to attack

than those made of Type I cement. The mortars with the greater proportions of cement appeared more resistant to attact than the leaner mortars.

Exploratory test results were also presented on the use of direct

electric current to corrode reinforcing steel in concrete.

Tests Conducted During The Second 6-Month Period

During the second six-month period, the measurements of the 4x4x16 cm mortar specimens stored in solutions of the variotxs chemicals have been

continued on a less frequent basis. A few additional reagents were obtained and their effects evaluated.

Measurements were continued on the effect of selected concentrated salt

solutions on mortar speciments placed on end in 3 to 4 cm of the solutions allowing evaporation from the upper parts of the specimens.

The 3x6 inch concrete cylinders were placed in various salt solutions and

measurements made of the amount of deterioration. A few additional tests

have been made of the electrochemical corrosion of reinforcing rods in

concrete cylinders.

- 9

-
Mortar Bars Stored in Chemical Solutions

The chemical reagents used in these tests are listed in Table 2-1. Some

reagents are in addition to those listed in the previous report. The

oleic acid was used as received and was not diluted. The 3-pound quantity

used did not cover the specimens. With the other reagents,, 1 pound was dissolved in about 2700 ml of water, and 8 specimens (one from each of

the variables) were placed in each of the solutions. Measurements were

made of the fundamental resonance frequency prior to, and at various times

after storage in the solutions for periods up to 6 months. The fundamental resonance frequencies of the specimens stored in the solutions

of the reagents listed in the previous report have also been determined,

some for a period of 9 months. When obvious failure occurred prior

to these times, these specimens were removed from the solution and

water added to cover the remaining specimen. This caused the solution

to be more dilute than at the start of the test. Another factor

causing dilution was the tendency of some of the salts to crystallize

on the sides of the containers and the crystals force themselves out

of the container.

Results of Tests of Mortar Specimens Stored in Solutions

A tabulation of the results obtained up to the time of the 24 week

measurements (20 weeks in 5 instances) of mortar specimens stored in

the solutions are presented in Tables 2-1, 2-2, 2-3, and 2-4. The

solutions of ammonium slats appeared to be the most deleterious. The

richer 1:3 (cement to sand) mortars were generally more resistant to

attack than the leaner 1:5 (cement to sand) mortars. The specimens

made of the Type II cement were more resistant to attack than those

made of the Type I cement. This was especially true with the sulfate

salts. All of the sulfate salts were not equally aggressive. There

were a number of instances where the air-dried specimens had greater

resistance to the salt solutions than those placed in the solutions

when moist. The reactive sulfate solutions usually caused checking and

cracking of the surfaces of the specimens and in some instances

noticable expansions especially with the Type I cement mortars. Some

badly checked specimens had very little reduction in the resonance

frequency. The citric and lactic acids had a severe surface attack

on the specimens and mold-like materials formed on top of the solutions

in the containers. Voluminous quantities of white reaction products

were formed. The reaction of the oleic acid was not so severe but

there was considerable attack and the acid became very viscous.

- 10»
In some instances there was a more or less regular reduction in the re- sonance frequency with time whereas in other instances very little

effect was noted until large cracks occurred in the specimens. In some solutions the specimens sloughed badly whereas in others there was no evidence of surface attack but the resonance frequency decreased.

Mortar Bars Stored on End in Chemical Solutions

Mortar bar specimens were stored on end in 3 or 4 cm of selected chemical solutions allowing evaporation of solutions and crystal growth on the upper portion of the specimens exposed to laboratory air. For

these tests, the selected reagents listed in Table 2-5 and 2-6 were

used. One pound of each reagent was mixed in 500 ml water and 8 speci- mens (one of each of the variables) placed on end in each of the solutions. Only 4 specimens, all air dried, were placed in the ferric

ammonium sulfate solution. Measurements were made of the fundamental

resonance frequency just prior to, and at intervals after being placed

in the solutions. Observations were also made of cracks in the specimens

Results of Tests of Mortar Bars Stored on End in Chemical Solutions

A tabulation of the results obtained up to 18 weeks on the mortar bar

specimens stored on end in_3-4 cm solutions are presented in Tables 2-5

and 2-6. In some instances the specimens readily absorbed the solutions

and large quantities of crystals were formed on the specimens. In other

instances the specimens appeared moist for la very limited distance from

the tops of the solutions, and some specimens Appeared to be attacked

only in the solutions. The action of the ammonium acetate .appeared to

be the most severe. Some of the mortar .specimens in concentrated

ammonium sulfate, ammonium nitrate and. calcium chloride solutions also

failed in relatively short periods. The differences -in effectiveness

of the different salts when the speciemsn were completely Immersed

(Tables 2-1, 2-2, 2-3, and 2-4), and when placed on end in the solutions

of these chemicals (Tables 2-5 and 2-6) may be attributed in part to

the crystal growth within the specimens, and in part to the fact that

the latter solutions were more concentrated. The differences in

chemical composition of the cements did not appear to have so great an effect when specimens were placed on end in solutions as when they were

completely, immersed.

Concrete Cylinders Stored in Chemical Solutions

The 3x6 inch concrete cylinders made of the 2 types of cement and of

two qualities were stored in 95 to 100% RH for 28 days. Half of each

of the specimens made of mix A and mix B was then transferred to laboratory air at 50% RH. The mix C specimens remained in the high humidity

- 11-
storage until tested. At the age of about 4 months for specimens made

of mixes A and B and 3 months for specimens made of mix C the cylinders were placed in solutions of various chemicals listed in Table 2-7. The

solutions consisted of 1 lb of the reagent in approximately 2700 ml. water. Three specimens were placed in each container. Water was added

from time to time to replace that lost by evaporation. The weight and

fundamental resonance frequency was determined prior to, and at intervals after immersion in the various solutions. Only six of th« cylinders

were immersed in the ammonium acetate solution, the other 3 being placed

in a shallow (3 to 4 cm) concentrated solution of the slat.

Results of Tests of Concrete in. Chemical Solutions

A tabulation of the results of the tests on the concrete cylinders

stored in the various chemical solutions up to 24 weeks are presented

in Tables 2-7 and 2-8. A reduction in fundamental resonance frequency

of 1600 cps was used as an Indication of failure. Some of the specimens, especially those made of the Type I cement stored in the sodium,

potassium or ammonium sulfate solutions, failed by spalling. ‘The

bottom edges of the cylinders expanded and curled outward and in some instances the pieces broke away from the cylinder. 'The resonance

frequency could not be determined accurrately after this condition

occurred. The effects of the solutions of the various reagents on the

concrete cylinders were, in most but not all instances, similar to the

effects on the mortar specimens which were immersed in the solutions.

The three concrete cylinders placed on end in 3 to 4 cm concentrated

ammonium acetate solution became soft below the top level of the solution

and some material sloughed off within a few days. Crystals formed on

the sides of the cylinders and in one week the crystals of the Type I cement, B mix had reached the top of the cylinder. The crystals were

about half way up on the cylinders made of the A mix and Types I and II

cement. The crystals and soft spongy concrete was scraped off and

returned to the solution and this was repeated the second week. Judged

by weight loss and appearance, the more porous M B mix” specimen had the

most severe damage, but this appeared limited to the surface of the

cylinder and the core appeared fairly firm. After these measurements,

the cylinders were returned to the solution and crystals again formed

on the parts of the cylinders above the solution. Water was added

from time to time taking care not to wash any of the salt crystals back

into the solution. There was not apparent further action whan the

crystals were not redissolved.

- 12 -
Electrochemical Corrosion of Reinforcing Steel in ConCr ete

A number of exploratory tests were made to test the feasibility of

using direct electric current to cause sufficient corrosion of the

reinforcing steel in concrete so that splitting or cracking of the

specimens would occur.

Some preliminary tests were made using 2x4 inch mortar cylinders made

of 1:3 cement to sand. Small reinforcing rods were placed in the

principal axis of the cylinders when made. These rods were inserted

to about two thirds of the depth of the mortar and extended 2 inches

or more above the tops of the cylinders.

Concrete cylinders (3x6 inches) were also made of the Types I and II

cements using mixes A, B and C as previously described. The rods were vibrated into place as above, and cured in moist air, after which some cylinders were dried in laboratory air. Some 6x12 inch concrete cylinders were made using the Type I cement and mix A. Two different sizes of reinforcing rods were used in these cylinders.

In making the tests, the positive lead of the dc potential was connected

to the reinforcing rod at the top of the cylinder, and the negative lead

connected to a bronze screen wire or to another reinforcing rod in the

liquid in which the cylinder was placed. Under these conditions,

oxygen ions go to the reinforcing rod in the concrete (the anode) and

the hydrogen to the cathode in the liquid or electrolyte outside the

specimens. Potentials of 110, 55 and 1.8 volts were used. Because of

the electrical resistance of concrete it was at first believed necessary

to add salts to the surrounding water ‘and to have the solution within a half inch to 1 inch from the top of the specimen. Later tests were made using only tap water with no added electrolytes, and in some instances with lesser depth of immersion of the specimens. Some measurements were made of the amount of current at different times. Observations were also made of the time of cracking and of the extrusion of the

corrosion product. Some of these observations are presented to indicate

more clearly some of the variables involved and the problems associated

with the corrosion of the steel

.

The first tests were made on 1:3 (cement to sand) cylinders with 1/4 inch

and 3/8 inch reinforcing rods. With 110 volts direct current, a moist

cured cylinder in NaCl solution in a small beaker formed a hair-line

crack in about 1 hour. The crack extended from the rod on top of the

cylinder and down one side. The temperature of the electrolyte went up

to 95°C. The crack did not open appreciably with an additional 5 hours

of applied voltage. The cylinder was split open, and the brown corrosion

*

- 13 -
product was found in the crack in the cylinder as well as on the reinforcing rod and in the mortar in the opposite side of the cylinder

from that where the crack appeared.

Another wet 2x4 inch cylinder with a 3/8 inch reinforcing rod was placed in NaCl solution and HOv dc used. Gas and water bubbled out

of the top of the specimen near the reinforcing rod and later a yellowish brown corrosion product. The temperature of the electrolyte

went up to 98°C and after 2 hours it was down to 80®C. The specimen

cracked in less than one hour. The current was turned off, and the

following morning again turned on. The corrosion product came out

into the electrolyte and the crack opened to about 1 ram on one side of

the cylinder.

A wet 3x6 inch concrete cylinder made of the Type I cement, mix A, was placed in NaCl solution with 18 volts dc potential. The current was

0.13 amperes at the start but decreased to 0.10 amps in 2 hours and

0.06 amps in 8 days. No visible cracks were found in 2 weeks. The

corrosion product all came out at the top of the cylinder near the

reinforcing rod and, being rather fluid, ran into the electrolyte. At

14 days the electrolyte was filtered and 7 grams dried blackish brown

solids recovered.

In another test, a 3x6 inch concrete cylinder in CaClg solution had a very rapid electrolytic reaction at the start but the action had come

to a complete stop in 3 hours. The cathode had become coated with a white materials, (possibly lime) and when replaced, the action became

rapid again. In this cylinder, the corrosion product came out in two

laces on the side of the specimen. No crack could be seen at the

che test was stopped. The cylinder was broken open and path of the

corrosion product from the rod to the outside of the cylinder noted.

A 3x6 inch cylinder in an ammonium chloride solution, and using an 18

volt potential, had a current of 0.14 amps at the start of the test.

Two days later, the current was 0.09 amps after which it increased to

0.13 amps. The cylinder was not removed until 10 days after the test was started. At that time horizontal cracks were noted near the

bottom of the cylinder. Twelve grams of corrosion product in the

electrolyte in the container was recovered by filtration.

With a 3x6 inch cylinder in calcium chloride solution, and using an 18

volt potential, the cathode became coated and the current, originally

0.14 apms, went down to 0.06 amps. Replacing the cathode caused an increase in the current to 0.09 amps. At 7 days, horizontal cracks in

the cylinder were observed.

- 14-
Other sal. ts such as Na 2HPO^_,

^

3?©^, NH4NO3 , Na.HG03 and NH/+Ac were also

used as electrolytes with no outstanding effects noted. It appeared

that with the use of the chlorides or nitrates that there was an excessive quantity of liquid corrosion product which escaped either

around the reinforcing rod or through places of weakness or porous

parts of the specimens. This liquid which was light yellow or brown

when it came out, became darker brown or black when exposed to the air

or in the electrolyte. Even with the use of an electrolyte the amount

of electric current decreased with time. The formation of cracks in

the specimens did not appear to result in an increase in the current.

The corrosion product on the reinforcing rod may therefore inhibit

or restrain the rate of further corrosion.

A second series of tests was conducted in which, the 3x6 inch cylinders

were placed in tap water with no added salts or elctrolyte. Both 110

and 55 volts direct electric current were used. A tabulation of the

results are presented in Table 2-9.

With a wet 3x6 inch cylinder made of Type I cement, mix A, and llOv dc,

approximately 4 or 5 days were required to cause a crack in the specimen. The electrolytic action was rapid to start and the current

decreased with time.

Using tap water, 110 volts, and a wet stored 3x6 inch cylinder made of

Type I cement and the B mix, a slight crack was noted at about 50

hours. The crack did not open appreciably in 4 weeks. At 8 weeks

the reinforcing rod had corroded and broke off even with the top of

the cylinder when the specimen was moved.

With the Type II cement made of the A mix the wet cylinder was found

to be cracked in 24 hours at 110 volts in tap water with no added

electrolyte.

When dry cylinders made of Types I and II cements, mix A were placed

in tap water and 110 volts potential applied, it took about 1 hour

for the gas to start coming off the cathode. At 7 hours there was a current of about 0.12 amps for the Type I cement cylinder and 0.50

amps for the Type II cement cylinder. Both cracked in less than

24 hours.

Using only 55 volts and specimens made of Types I and II cements A

mix, and tested before drying out, 7 days were required to produce

a crack when using only tap water. The current was about 0.33 amps

at the start and 0.08 amps at one week. At 3 weeks the cracks had

opened up to 1.5 to 2 mm on the surface of the cylinders.

- 15-
When the specimens made of these cements using the B mix were tested

before drying the Type I cylinder cracked in 7 days in tap water and

the Type II cylinder in less than 24 hours both with 55 volts potential

The current was about 0.4 amps to start and for the Type I cement speci men only 0.02 amps at 3 weeks although the crack was about 3 mm wide

at the surface of the cylinder.

One pair of specimens made of the Types I and II cements, B mix, and

air dried were placed in tap water and 110 volt potential applied.

No cracks developed in 3 weeks, and the current, which was about 0.13

amps at 24 hours, was only about 0.01 amps after 3 weeks. In these

tests a rather large quantity of liquid corrosion product came out near the reinforcing rod of the cylinder made of the Type II cement.

The amount of corrosion product extruded when no electrolyte was added to the tap water appeared to be less than when an electrolyte

was added.

Plans for Future Work

Additional tests of electrolytic corrosion of reinforcing steel in

6x12 concrete cylinders will be performed. A few reinforced concrete

beams will be made, cured, and tested when the facilities in the new laboratory are operational.

“ 16 “
Table 2-1 - Time for failure or the change in. resonance frequency in 6 months

of 1:3 (cement to sand) mortars made of Type I cement when stored

in solutions of the various reagents.

Condition of Specimen

at Start of Test Moist Moist Dry Dry

Time for Change in resonance Time for Change in resonance Reagent failure , weeks

frequency.. cps failure

,

weeks frequency

cps

none __ 4- 50 -- + 150

Na 0 SO. 18 — - 100 MgS0

4

-- - 430 - + 190 Stearic acid -- + 30 -- -!- 110

(NH

4

) 2 S0

4 • 18 -- 18 -- NH . NO, 4 _ _ • 3 --

4 3 Na„ S.,0„ + 10 __ + 250

2 2 3 Cane sugar -- + 180 -- + 120

NaHSO, 22* ‘ -- 24* K

2 S0 4 24* -- 24* -

(NH.

)

0 SO, FeSO. 4/4 4 22* -- - 30

(NH

4

) 2

S 2°8 5 -- 3

...

KAc + 10 -- + 40 nh

4

ci 3 — 6 --

Na

2 S0

3 -- + 180 + 300 NH

4Fe(S04

) 2 24* - 24* 1

Citric acid ** - ** --

NaHSO^ 24* — -- -1020 NH

4Ac -- - 990 22 -

NaAc -- + 40 __ -t- 130

Fe

2

( S0 4) 3 — - 100 -- + 50

KA1 (S0 4

) 2 -- - 130 -- + 120

khso

4

-- -1290 -- - 330 CuS0

4

-- + 70 -- + 190

(NH

4

> 2 S0

4 & sugar - - 210 — + 60 KA1(S0

4

) 2 & sugar -- + 100 -- + 200

CaCl

2 -- - 220 + 70 Lactic acid*** -- - 880 -- - 460

K- S.O *** 22 -- -- - 120

2 2 5

- 80 PDGA (Monsanto)*** — - 260 Oleic acid*** -- ** **

* Cracks in specimens noted prior to these measurements.

** Surface attack was the dominant feature, causing loss of weight. *** Measurements made at 5 months, the 6 month values not available

at time table was prepared.

- 17 -
Table 2-2 - Time for failure or the change in resonance frequency in 6 months

of 1:5 (cement to sand) sorters made of Type I cement when stored

in solutions of the various reagents

Condition of Specimen

at Start of Test Moist Moist Dry Dry

Reagent

Time for Change in resonance Time for Change in resonance

failure

,

frequency failure, frequency

weeks cps weeks cps

none — + 20 — + 310

Na

2 S°4

6 - 7 -- MgS0

4 22 -- - + 490 Stearic acid -- - 10 — h 260

( NH

4

) 2 S0

4

2 — 6 --

NH HO. 2 -- 2 4 3 Na„ S-O. - 190 -- + 170

2 2 3 Cane sugar -- + 130 -- + 140

NaHSO,

4 18 — 18 -- V°4 4 — 5 --

(NH

4

) 2 S0

4FeS04 22* -- -- + 190*

(NV2S 2°83 — 3 --

KAc -- - 280 -- + 40 NH.C1 3 — 5 —

Na

2 S0

3 22 — 24 —

NH

4Fe(S0

4

) 2 18 — 24* —

Citric acid ** — ** --

N aH SO

^ 18 — 18 --

NH

4Ac 4 — 4 —

NaAc -- - 120 — + 60 Fe

2 (S°

4

) 3 — - 100 — + 320 KA1(S0

4

) 3 22 -- -- + 470 KHS0

4

12 — 24 --

CuSO.

4 — 0 — + 380

(NH4

) 2 S0

4

fit sugar 7 - -- - 40 KA1(S0

4

) 2 & sugar -- - 130 -- + 350

CaCl

2 -- - 270 -- + 190 Lactic acid*'** -- - 960 -- - 220 K2

S 2°5*** 12 -- 16 —

PDGA (Monsanto)*** -- - 320 -- - 180 Oleic acid*** — ** **

* Cracks in specimens noted prior to these measurements.

** Surface attack was the dominant feature, causing loss of weight. *** Measurements made at 5 months, the 6 month values not available

at time table was prepared.

- 18-
Table 2-3 - Time for failure or the change in resonance frequency in 6 months

of 1:3 (cement to sand) mortars made of Type II cement when stored

in solutions of the various reagents

Condition of Specimen

at Start of Test Moist Moist Dry Dry

Time for Change in resonance Time for Change in resonance

Reagent failure

,

frequency failure

,

frequency

weeks cps weeks cps

none -- + 240 -- + 140

Na SO,

L 4

-- + 190 -- + 180 MgS0

4

-- + 40 — + 210 Stearic acid -- + 70 -- + 160

(nh

4

) 2 s°

4

-- - 300 — + 30

NH

4N03 -- - 570 -- - 580

Na

2 S

2 0

3 -- + 100 — + 140 Cane sugar -- + 140 -- + O' o NaHSO. -- - 110 -- + 20 K

2 504

-- + 110 -- + 200

(NH

4

) 2 S0

4FeS04

-- - 20 — + 90

(nh4

) 2

s

2 o

8 — - 744 -- -1020 KAc -- + 10 -- - 10 NH.C1 12 -- -- - 960

Na

2 S0

3 -- + 207 -- + 200 NH

4Fe(S0

4

) 2 24* -- 24* --

Citric acid ** -- ** -- NaHS0

3 -- + 20 -- + 100

NH, Ac -- - 890 -- - 520 NaAc — + 10 — + 60

F e

2 (S°4

) 3 -- + 130 — + 120 KFe(S0

4

) 3 -- + 10 -- + 190

KHSO, __ - 400 -- - 70

CuSO, -- + 130 — + 180

(NH4

) 2 S04

St sugar — - 200 -- + 40 KA1(S0

4

) 2 & sugar -- + 130 -- + 280

CaCl

2 *** -- - 120 -- + 30 Lactic acid *** -- - 500 -- - 420 K

2 S 2°5 *** -- - 50 — + 130 PDGA (Monsanto) *** -- - 240 -- - 100 Oleic acid *** — **

1 **

* Cracks in specimens noted prior to these measurements.

** Surface attack was the dominant feature, causing loss of weight. *** Measurements made at 5 months the 6 month values not available

at time table was prepared

- 19-
Table 2-4 - Time for failure or the change in resonance frequency in 6 months

of 1:5 (cement to sand) mortars made of Type II cement when stored

in solutions of the various reagent3

Condition of Specimen

at Start of Test Moist Moist Dry Dry

Time for Change in resonance Time for Change in resonance

Reagent fa ilure

,

frequency failure

,

frequency weeks cps weeks cps

none -- + 100 -- + 220

Na

2 S0

4

-- + 160' -- + 370 MgSO^ — + 340 — + 470 Stearic acid -- + 60 -- + 160

(nh

4

) 2 S0

4

5 -- — - 410 NH

4N03 -- - 720 — - 730

Na

2 S

2 0

3 -- - 70 -- + 90 Cane sugar -- + 100 — - 30 NaHSO, -- + 30 — + 170 k

2 so4

-- + 230 -- + 370

(NH

4

) 2 S°

4

F e s°

4 — + 50 -- + 180

(NH

4

) 2

S 2°8 — - 780 — - 150

KAc -- - 260 — + 60 NH.Cl 2 -- 3 —

Na

2 S0

3 -- + 240 — + 380 NH

4Fe ( S04

) 2 24* — 24* --

Citric acid ** -- ** -- NaHS0

3 -- - 754 -- + 268

NH

4Ac 2 -- 4 --

NaAc -- - 130 -- - 120

Fe

2 (SV3 -- + 100 — + 200 KF e(S0

4

) 3 — + 180 — + 300

KHSO. -- - 110 -- - 50 CuSO,

q

-- + 150 -- + 240

(NH

4

) 2 S0

4 & sugar 8 — — - 540 KA1(S0

4

) 2 & sugar — + 120 -- + 180

CaCl

2*** -- - 210 — + 60 Lactic acid *** -- - 790 -- - 240

K.,S o 0, *** - 190 + 250

2 2 5 PDGA (Monsanto) *** -- - 170 -- - 210 Oleic acid *** -- ** --

* Cracks in specimens noted prior to these measurements.

** Surface attack was the dominant feature, causing loss of weight. *** Measurements made at 5 months, the 6 month values not available

at time table was prepared.

- 20-
- 21 -

Table

2-5

-

Time

for

failure,

or

change

in

dynamic

modulus

in

18

weeks

of

mortars

of

Type

I

cement

when

stored

on

end

in

shallow

concentrated

solutions

of

the

various

reagents.
22

Table

2-6

-

Time

for

failure,

or

change

in

dynamic

modulus

in

18

weeks

of

mortars

made

of

Type

II

cement

when

stored

on

end

in

shallow

concentrated

solutions

of

the

various

reagents.
23-

Table

2-7

-

Time

for

failure,

or

change

in

resonance

frequency

in

24

weeks

of

3x6

inch

concrete

cylinders

made

of

Type

I

cement

when

stored

in

solutions

of

the

various

reagents.
- 24-

Table

2-8

-

Time

for

failure,,

or

change

in

resonance

frequency

in

24

weeks

of

3x6

inch

concrete

cylinders

made

of

Type

II

cement

stored

in

solutions

of

the

various

reagents
Type of

cement

Concrete

mix

Condition at

Start of Test

Applied

vol tage

Time at which

crack was noted, j days

i

1 A moist 110

f 5

I B moist 110 2

II A moist 110 1

1 I A dry 110 1 II A dry 110 1

I B dry 110

II B dry 110 -*

I A moist 55 7 11 A moist 55 7

I B moist 55 7 II B moist 55 1

1

* No cracks had developed in 3 weeks.

Table 2-9 - Time of cracking of 3x6 inch concrete cylinders having

3/8 inch reinforcing rod in the principal axis with an applied direct electrical current

DISTRIBUTION LIST

a. Twenty copies of the report shall be forwarded to Defense Documentation Center Headquarters, Attention: DDC-IRS, Cameron Station, Alexandria,

Virginia 22314.

b. Twenty- three copies of the report shall be forwarded to Commanding

Officer, U. S. Army Edgewood Arsenal, Attention: SMUEA-RCRP, Research

Laboratories, Mr. Gordon N. Jarman, Project Officer, Edgewood Arsenal, Maryland 21010.

-2 7-
UNCLASSIFIED

Security Classification

DOCUMENT CONTROL DATA - R&B

(Securi ty classification of title, body of abstract and indexing annotation must be entered when the overall report is classified)

1 ORIGINATING ACTIVITY ( Corporate author) NATIONAL BUREAU OF STANDARDS , Washington, D. C,

20234

2a. REPORT SECURITY C i_ ASS IP 1 C A T I ON

UNCLASSIFIED

Zb GROUP

N/A

3. REPORT TITLE INDUCED ACELERATED DETERIORATION OF PORTLAND CEMENT CONCRETE

4 DESCRIPTIVE NOTES (Type of repoff end inclus i ye dates) Semiannual Report - July-December 1966

5 AUTHOR(S) (Las( name, first name, initial)

i Blaine, Raymond L. i

6. REPO RT DATE

9 January 1967

7 a. TOTAL NO. OF PAGES

(complete)

7 b. NO. OF REFS

None

8a. CONTRACT OR GRANT NO. D018-0-35-A6-02806

b PROJECT NO. US Army Ballistics Research

c Laboratories

d

9a. ORIGINATOR’S REPORT NUMBER(S)

SEMIAPR, NBS Report 9465

9 b. OTHER REPORT NOfS) (A ny other numbers that may be as si gned

this report) None

10 A V A IL ABILITY/LIMITATION NOTICES

This document is subject to special export controls and each transmittal to

foreign governments or foreign nationals may be made only with prior approval of

the CO. Edgewood Arsenal. ATTN: SMUEA-TSTI-T Edeewood Arsenal. Md . 21010 1 11 SUPPLEMENTARY NOTES

Mortars

12 SPONSORING MILITARY ACTIVITY

US Army

Ballastics Research Laboratories

Aberdeen Proving Ground, Maryland 21008 8 13 ABSTRACT

Measurements made of the effects of various salt solutions on the fundamental

resonance frequencies of mortar and concrete specimens made of two portland

cements indicated that ammonium salts appeared most aggressive when specimens were completely immersed. The specimens made of the Type II cement were more resistant

to attact (especially by the sulfates) than those made of the Type I cement, and

the richer mixes were more resistant than the leaner mixes. Some specimens failed

in some solutions in 2 weeks but in other solutions comparable specimens were

stronger after 6 months of storage than at the start of the test. Ammonium acetat

caused the most rapid deterioration on mortars stored on end in a shallow con- centrated solution. Other salts also caused fairly rapid deterioration of the

mortar specimens with this test condition. Using 110 volt direct electric current

to cause corrosion of reinforcing steel, caused cracking of 3 x 6 inch concrete

cylinders in less than 24 hours to 7 days even without the use of an electrolyte.

In some instances the corrosion product was extruded and no cracking occurred.

The amount of current decreased with time of application of the applied potential.

DD FORM

1 JAN 6« 1473

Security Classification
14. KEYWORDS

Deterioration

Concrete cylinders

Mortar bars

Corrosion

Reinforced steel

Aggressive chemicals

Electrochemical corrosion

Portland cement concrete

Acceleration

Cement 1 Absorption

Evaporation

Crystal formation

Disintegration

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