NATIONAL BUREAU OF STANDARDS REPORT

6523

Study of the Properties of Rubber Base Calking Materials

(Progress Report No. 1)

by

Arthur Hockman

Report to

the Departments of

the Air Force, the Army, and the Navy

<^>

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
THE NATIONAL BUREAU OF STANDARDS

Functions and Activities

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NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT NBS REPORT

1001-12-10413 August 20, 1959 6523

Study of the Properties of Rubber Base Calking Materials

(Progress Report No. 1)

by

Arthur Hockman

To

the Departments of

the Air Force, the Army and the Navy

NATIONAL BUREAU OF ST

intended for use yvithln the

to additional evaluation and i listing of this Report, either the Office of the Director, N< however, by the Government

to reproduce additional copii

IMPORTANT NOTICE

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST)

on October 9, 201 5.

>rogress accounting documents

rmally published it is subjected

reproduction, or open-literature

sion is obtained in writing from Such permission is not needed,

prepared if that agency wishes

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
f ox • .[ opi

elfii . .

. 5 • q s*3 • bud 8

. c '-jr .:.rxBc- ;-C( art j,
Identification of Samples

of Rubber Base Calkings

(Tri-Service Project)

Sample

No.

Producer Type Color

1-

Pecora Paint Company Polysul f ide

Thiokol

Neutral

1-B II T! f! II Aluminum

1-C I! If II II Brown

1-D t! II II II Gray

1-E *1 !l IT II Black

1-F II II M 11 Neutral

1-G It II II II Aluminum

1-H II II II 11 Black

2-

Parr Paint and Color Co. Polysulfide

Thiokol

Aluminum

2-B II II II II II II Gray

2-C II It II II II 1? Tan

2-D II II II II II II Black

2-E II II II II II 11 Aluminum

2-F II II II It M II Tan

2-G II 71 II II II 11 Black

3-L. Sonneborn Company Polysulfide

Thiokol

Aluminum

3-B II II 11 Gray

3-C II II 11 Tan

3-D II II 11 Black

3-E II II 11 Aluminum

3-F II II 11 Black

3-G II II 11 Gray

3-H II II 11 Tan

3-1 II II II Aluminum

3-J II II 11 Gray

3-K II II 11 Tan

3-L II II 11 Black

Class

Non- sag

Non- sag

Non- sag

Sample

No.

Producer . Type Color Class

4-

A

A. Co Horn Company Polysulfide

(Thiokol)

11

Gray Non- sag

!! 1! 11 11 Non -sag (hard;

4-B

IT u n

1! Aluminum Non- sag

4-C

ft II II

11 White 11 4-D 11 B 1 ack

11 4-E

n ii n

11 Red 1! 4-F 11 Aluminum 1! 4-G

n ii 11 M Gray

It 4-H

4-1 M n ii 11 Black 11

5-A Steelcote Mfg. Co.

ii " "

Polysulfide

(Thiokol)

11

Tan

Gray :al

Non- sag

Non- sag

5-B

ii ii ”

11 Aluminum 1? 5-C

5-D

n ii "

11 Black 11

6-

A

Products Research Co.

ii ii "

Polysulfide

(Thiokol)

11

Neutral

11

Non-sag

Flow

6-B

ii " "

11 Gray Non-sag

6-C

ii " "

11 1? Flow

6-D

ii " "

11 Aluminum Non- sag

6-E

ti I' "

11 Black 11 6-F

ii " "

11 Black Flow

6-G

ii " " u Neutral Non- sag

6-H

it 'I "

11 Aluminum 1! 6-1

ii " "

11 Gray

1! 6-

J

11 Black 1? 6-K

it it "

11 Gray

1? 6-L

ii " "

11 Aluminum 11 6-M

ii " "

?! Neutral 1? 6-N

ii I' "

1! Black 11 6-0

6-P

ii " "

11 Gray Flow

7-A Atlas Mineral Products Polysulfide

(Thiokol)

Black Non- sag

8-A Tremco Mfg. Co. Polysulfide

(Thiokol)

Aluminum Non- sag (soft)

11 1! Non-sag (hard)

8-B

11 11 M

1? Brown Non- sag (soft)

8-C

11 11 H

1! Black Non - s ag (soft)

8-D

8-E

n ii ”

11 11 Non- sag (hard)

Sample

No.

Producer Type Color Class

9-A Presstite-Keystone Co. Polysulfide Aluminum

(Thiokol)

Non-sag

9-B II " Tan 11 9-C II " Aluminum II 9-D II II If Flow

9 -E II " Tan 11 9-F II " Black II

10-

A

David E. Long " Gray Non- sag

10-B II II II II 10-C 1! " Aluminum „ ( 10-D II " Black If 10-E II II II Pourable

10-F 1

1

!? Gray Non-sag

11-

A

Dicks- Armstrong Pontius ii it II 11-B 1

1

ii ii Flow

11-C II " Tan Non- sag

1 1-D If " Black II 11-E II " Gray II 11-F II " Aluminum II 11-G II " Tan II 11-H II " Black II

12-

A

Coast Pro-Seal Co. " Gray II 12-B " Tan 1

1

12-C II " Black 1

1

12-D II If II Flow

12-E II " Tan Non- sag

12-F II " Black 1

1

12-G If " Aluminum II 12-H II " Gold II

13-

A

Minnesota Mining and

Manufacturing Co.

" Tan 1

1

13-B II " Gray 11 13-C II " White 11 13-D II Aluminum 1

1

13-E II " Light Gol d

13-F II " Black II 13-G II " Green II 13-H II " White II 13-1 II " Gray If 13-

J

Aluminum 11

4.

Sample

No.

Producer Type Color

14-

A

Servicised Prod. Co. Polysulfide

(Thiokol)

White

14-B II II Gray

14-C II II Black

15-

A

Armstrong Cork Co. II Aluminum

15-B 1

1

II II 15-C ! 1 II Black

15-D 1 1 II II 15-E II II Aluminum

16-

A

Gera Manufacturing Co. II II 16-B 71 II Black

17-A Dow Corning Silicone

Rubber

Pink

17-B 1

1

II White

18-

A

Sika Chemical Corp. Epoxy Resin Tan

19 - A Stay-Tite Products Co. Neoprene

Rubber

Aluminum

20-B Pittsburgh Plate Glass Co. Butene Rubber Black

US-COMM-NBS-DC

Study of the Properties of Rubber Base Calking Materials

(Progress Report No. 1)

Arthur Hockman

A study of the properties of rubber base joint sealers (calking

compounds) for use in buildings and other types of structures is in

progress at the National Bureau of Standards. For this purpose 130

samples from 19 producers have been obtained to date. These include

125 samples of the polysulfide synthetic rubber base, 2 silicone

rubber, and 1 each of neoprene rubber, butene rubber and epoxy-resin

formulation.

Description of test specimens, procedures, results, and discussion are given for the following properties: 1) staining effects

and color changes, 2) slump, 3) hardness, 4) application life, 5)

bond-ductility, 6) effect of outdoor exposure.

Of 74 samples (17 producers) tested, 937o stained mortar or marble

or both. In the polysulfide group no stain appeared where mortar was

absent. Fifty seven percent developed color changes varying from minor

to extreme, such as light tan or dark brown. Of 65 non-sag type sam- ples from the above group, 21% slumped 1/8 to 5/16 in. when tested in

a trough 4- by 1- by 3/8-in. at 122°F. Nine percent slumped 3/8 in. or more. Shore A hardness values obtained on 53 samples from 17 producers ranged from 10 to 58 at 74°F, with an average of 34. The average hardness increased by 56% when tested at 0°F, and 8.8% at 158°F.

Residual increase in the hardness after the 0°F treatment was 2.9%

and after 158°F it was 29.5%.

Application life tests made with the Brookfield Viscometer indicated 41% of the 29 samples tested as relatively rapid curing compounds

(less than 3 hr pot life). Bond-ductility tests made on 28 samples

from 12 producers with 4 accessory materials (concrete, concrete block,

brick, and wood) showed an exceptionally high degree of failure for

primed brick. Results showed no significant differences between primed

and unprimed concrete or block; there were no significant differences

either between compounds of different colors.

Seventy four samples from 17 producers were exposed outdoors for

nine months in primed and unprimed concrete joints. Joints were

stretched every three months to a total of 33% of the original width.

Thirty six samples developed at least one bond break including twelve

which leaked under 1 in. head of water. Primed joints generally showed

somewhat poorer performance than the unprimed joints. Bond failures in

outdoor exposure tests showed good correlation with laboratory hardness

tests and fair correlation with bond-ductility test results.
.

'
2 .

The investigation will be continued with emphasis on the performance and durability properties such as bond-ductility, hardness

and effects of outdoor exposure. The width-depth ratio of the joint

in the bond test will be increased to produce a lower incidence of

bond failure for all samples, and new accessory materials such as aluminum, glass, steel, and ceramic coated metals will be added. A

purchase specification will be written after enough dependable laboratory test data is compiled.

1. INTRODUCTION

At the request of the member agencies of the Tri- Service Program, the

National Bureau of Standards is investigating the properties of rubber base

calking materials for sealing joints in concrete, brick, stone and other

types of masonry construction. The study will include the development of

laboratory test methods which will be eventually incorporated in a purchase

specification.

The new type of rubber base calking (also referred to as sealer,

sealant and elastomer) differs from the "conventional" oleo-resinous base

plastic compound in that it consists mainly of a synthetic rubber base

liquid combined with suitable fillers and with little or no volatile com- ponent. The base material is mixed with an accelerator immediately before

application. The application or pot life normally varies from 2 to 6 hr.

For the past ten years polysulfide synthetic rubber base compounds

have been used by the aircraft industry for sealing integral fuel tanks.

The compound proved effective by maintaining good adhesion to the aluminum

frame-work and by remaining flexible over the temperature range of -65°F

to + 180°F. It also has been used to seal wooden decks of aircraft carriers.

The successful use of this type of mastic in aircraft suggested its use as a joint sealer in masonry structures around windows, between panels

in curtain wall and concrete construction, for sealing flashing and expansion joints, and in any joint where some movement is expected and watertightness is required. For the past few years the polysulfide synthetic

rubber compounds have been used by private industry in curtain wall con- struction and to a lesser extent by Government agencies in sealing masonry

structures

.

One of the primary purposes of this study is to develop new laboratory test methods and, if feasible, apply certain existing test methods

which will successfully predict the behavior of the joint sealers in actual

service. Since it is expected that a rubber base joint sealer should function effectively for a minimum of ten years, the performance and durability

tests are being designed with this goal in mind.
• .
3.

The properties investigated thus far and described in this progress

report are as follows: 1) staining effects and color changes, 2) slump or flow, 3) hardness, 4) application life, 5) bond-ductility, 6) effect of

outdoor exposures.

For this portion of the investigation the accessory building materials

used in the various tests of the calkings were restricted to the porous

types only such as concrete, concrete block, brick, and wood. White marble

was used for staining and color change tests.

In view of the fact that some of the tests described herein are some- what exploratory in nature it will be necessary to make changes in procedures, as well as add new ones as the investigation progresses.

2. DESCRIPTION OF SAMPLES

To date, 130 samples of rubber base calkings have been obtained from

19 producers. Of this group, 125 samples are of the polysulfide synthetic

rubber base (Thiokol) type, 2 silicone rubber, 1 butene rubber, 1 neoprene

rubber, and 1 epoxy-resin formulation.

At the start of the study an attempt was made to buy the samples

directly from the producers since no retail outlets were available. About

half of^the total samples were obtained in this way. Later it was found more advantageous to both producer and the Bureau to have the samples submitted without charge. In this way samples were delivered more promptly

than when purchased.

All samples, except the neoprene and butene base compounds, consisted

of two separate components, generally referred to as base and accelerator,

activator, or curing agent.

All samples were classified by the producers as either non-sag or

flow; the latter type specified for horizontal joints only. Some producers submitted samples labeled "hard" or "soft" designating the relative

hardness of the cured rubber.

The polysulfide samples (in the cured state) consisted of several

colors including white, natural (or neutral), aluminum, gray, tan, brown,

red, and black. Most producers had at least three colors available and

black was sold by all producers of the polysulfide type. The two sili- cone rubber compounds were white and pink, respectively; the neoprene

was aluminum colored, epoxy-resin, tan, and the butene rubber, black.

For report purposes each sample was given a laboratory designation

in the form of a number and letter, the number specifying the producer and

the letter, the compound. Some producers submitted as many as 16 compounds

over a year's period, although many of them are duplicate formulations.

4.

3.1 3. PHYSICAL TESTS

Staining and Color Changes 3.1.1

Test Specimens and Procedure

This test was made on 74 samples of calkings submitted by 17 producers. The sample distribution by type, class, and color, is given in

Table 1.

Each test specimen consisted of a calked joint, approximately

1 1/2 to 2 in. long, 1/2 in. deep and 3/8 in. wide placed between two

3- by 2- by 1-in. white marble blocks (either Georgia or Vermont marble

was used for this test). The calking was backed by a layer of white

cement mortar and below the mortar was a 2- by 1/2- by 3/8- in. aluminum

spacer cemented between the two blocks. (Figure 1).

In preparation of the test specimen, a workable mortar mixture made

of white cement, hydrated lime and standard graded Ottawa sand (1:0. 5:3,

by volume) was placed in the bottom of the joint, above and in contact

with the spacer. After allowing the mortar to set for 4 hr at 74°F the

remaining top portion of the joint was filled with freshly mixed calking.

A duplicate test specimen of each sample was made, omitting the mortar backing. Ten to fourteen days after filling, the test specimens were

fastened to an aluminum rack and placed in a vertical position on the

cylinder wall of a standard type Atlas Weatherometer (machine described

in ASTM Standard D529-39T, 1958, part 4). One half of the joint (calking

and marble) was covered with a sheet of aluminum, the latter shielding

that portion of the joint from the light rays. (Figures 2, A, B). During

the test each specimen was exposed to 500 hr of light from the carbon arc and periodic water spray (water, 9 min in each hr). The air temperature

at the specimen during the test was 140° ± 5°F and the water temperature

maintained at 75 ± 2°F.

3.1.2

Test Results

Table 2 summarizes the results obtained on the 74 samples after 500 hr

in the Weatherometer.

All stains formed on the specimens during the exposure, were shades

of red, or brown or mixtures of the two colors, and were rated as slight,

moderate or deep. (Figure 1, A, B). Sixty seven of the 72 polysulfide

calking specimens developed stains in the mortar but only 43 of these

specimens developed stains in the marble.

No stains appeared in the marble blocks containing polysulfide calking without mortar.
- > : v. -
5.

Of the two silicone rubber samples, one developed a deep oily stain

in the marble with no stain in the mortar. The second sample did not

stain either the marble or mortar.

Table 2 also summarizes the color change effects in the calkings

after the 500 hr exposure test.

Of the 74 samples tested, 42 showed noticeable changes in color when

the latter was compared with the original color of the covered half of

the calking joint. (Figure 2, A). Eleven of the 42 compounds turned

lighter and the remaining 31 turned darker including such changes as from

light tan to dark brown, and from white to dark gray. After examination,

the test specimens were placed on the roof of the Mineral Products Building for further observations.

3.2 Slump or Flow Test

3.2.1 Test Specimens and Procedure

This test was made on the same samples as those tested for staining

effects and color changes (except the flow type compounds). A portion of

the freshly mixed sample was placed in an aluminum trough 4-in. long, 1-in

deep and 3/8 in. wide. The trough was immediately suspended in a vertical

position in an oven for 24 hr at 122°F ± 2°F. At the end of this period

the amount of slump was measured from the lower end of the trough to the

lowest point assumed by the compound. Measurements were made to the nearest 1/16 inch.

3.2.2 Test Results

Table 2 includes the results of the slump tests for each of the 65

samples tested. The distribution of the values obtained are shown in

Table 3.

Of the six samples with slump ratings over 3/8 in., three were re- garded as "complete" failures. In such cases portions of the calking mate

rials dropped out of the trough during the test.

3.3 Hardness

3.3.1 Test Specimens and Procedure

This test was made on 53 samples obtained from 17 producers. The instrument used for making the determinations was the Shore Durometer (Model

A) described in Federal Test Method for Rubber No. 601, Method 3021, and

also in ASTM Standard D676-55T, 1958, part 9. All readings were taken by

the instantaneous method.
-
6 .

The test procedure was as follows: A portion of a freshly mixed com- pound was placed into a polyethylene mold with inside dimensions of 4- by

1 1/2- by 1/4-in. After striking off the top surface with a spatula, the

specimen was stored in the laboratory at 74°F. (At least two specimens

were made for each sample). When the compound lost its tackiness (usually

two or three days), it was removed from the mold, placed on a 3- by 6-in.

thin aluminum plate and allowed to cure for a total of 10 to 14 days.

(Figure 4, A).

After the curing period. Shore hardness values were obtained on two

specimens of each sample, at 74°F. An average of eight readings were

taken on the two specimens, and this value was regarded as the "original

value" listed in Table 4. One specimen was then exposed in an oven at

158°F for 72 hr and the other in a freezer at 0°F for the same period.

At the end of the cold and hot exposure periods hardness values were determined at the respective temperatures and also after a recovery period

for 3 hr at 74°F.

3.3.2 Test Results

Table 4 gives the hardness values obtained on all samples at 74°F,

0°F, and 158°F. The recovery values and respective percentage changes

from the original values after the cold and hot exposures are also given.

Figures 5 and 6 illustrate the distribution of hardness values for the

three temperatures for all samples.

It follows from the data given in figure 5 that the average hardness

value at 0°F was 567, higher than the average at 74°F. However, the residual increase in hardness after recovery to 74°F was only 2.97o.

On the other hand, the data in figure 6 show that the hot treatment

(158°F) caused an immediate increase in hardness of only 8.870 over the

original but was followed by a residual hardness, after recovery, of

29.57c.

The samples of group 6 had a hardness value of 20 which was the lowest original value. Except for the epoxy-resin sample 18 A, with a hardness of 53, the samples of groups 9 and 10 had the highest original values

of 50.

7.

3.4 Application or Pot Life

3.4.1 Test Specimens and Procedure

This property was determined on 29 samples of calkings (non-sag type)

submitted by 9 producers. A Brookfield Viscometer, model RVF fitted with

a No. 7 spindle, rotating at 2 rpm was used to make the determinations.

(Figure 7). The test procedure was as follows:

After mixing thoroughly about 300 g of base and accelerator of the

sample under test, the compound was placed into a gill capacity can (with

friction rim removed), slightly overfilling the can. The calking was struck off flat with the edge of a spatula. The spindle was slowly brought

down (by means of rack and pinion arrangement) into the compound to the

level of the standard immersion mark indicated on the spindle. Any voids

immediately around the spindle were filled in with the aid of a small

spatula. The viscometer motor was turned on and readings on the scale

(0 to 100) were taken every minute for the first 5 min and at 5, 10, or

20 min intervals thereafter. The motor was stopped either at the end of

3 hr, or when the pointer reached the 100 mark depending on which came

first. (No attempt was made to translate the readings into absolute viscosity values).

3.4.2 Test Results

For 12 of the 29 samples tested the pointer reached the scale limit

of 100 before the 3 hr time limit, indicating relatively rapid curing com- pounds. For the remaining 17 samples, the test ran the full three hours.

At this stage of the investigation it seemed desirable to have a single numerical value (or factor) which could be used as a measure of the

application life of each sample, using the data obtained with the viscometer. For this purpose an index, P, was calculated as follows:

t where, P = application life factor

V = scale reading at end of test (either 100, or specific reading at 3 hr)

t = duration of test in hours (3 hr or less).

The formula indicates that the factor P of a sample is less than

100 when the pointer fails to reach 100 within 3 hours. In such a case

t = 3, and P = V.
' r • - ..

y '
8 .

The factor P is greater than 100 when the pointer reaches 100 in

less than 3 hours. In such case v = . t The smaller the P factor the longer is the application life.

Table 5 gives the minimum and maximum viscometer scale readings,

duration of test in hours and the P factor for the 29 samples tested.

The P factor ranged from 30 to 1500 with an average of 194 for all

samples. The results indicate that one producer had consistently

higher than average P factors such as No. 3-E, F, G, H, and L. All

samples of producers 1, 2, 11, 14, 15, and 18 had P factors smaller than

average. Values for sample group 6 ranged from 49 to 428 and values for

group 12 ranged from 63 to 196.

Figures 8, 19, 10, and 11 show graphically the relationship between

viscometer readings and time over a 3 hr period for 25 samples from 9

producers. The curves indicate that in 11 tests, viscometer readings

reached the limit of the scale in less than 3 hours. These tests included 5 samples with test duration of less than 1 hour.

This test, designed to evaluate the calking compounds for use in

joints where movement is expected, was made on 28 compounds submitted

by 12 producers. Twenty six samples were polysulfide rubber base, 1 silicone rubber, and 1 epoxy resin formulation.

A joint sealer stretching machine accommodating three test speci- mens was used to make the tests. The machine, with some changes in design, is similar to the one described in Fed. Spec. SS-R-406C, Road and

Paving Materials, Method 223.11. (Figures 12, 13).

The test specimens, shown in figure 14-A, were prepared with calking,

accessory masonry materials and aluminum spacers. The accessory materials

used thus far in this study were brick, concrete, concrete block and wood

with the following descriptions:

3.5 Bond-Ductility

3.5.1 Test Specimens and Procedure

24 hr absorption,

%

Concrete Prepared in accordance with

Fed. Spec. SS-R-406, Method 223.11

Sanford Center Tunnel Kiln, Smooth

Expanded slag, high pressure

steam cured

Douglas fir 1 in. plywood

6.6

Brick 8.0

Concrete block 9.0

Wood no test
-
9.

The accessory blocks, except concrete, were cut to the standard size

of 3- by 2- by 1-in. The concrete blocks were fabricated in brass gang

molds

.

The test joint was prepared by first making a "sandwich" of two

similar blocks separated by two aluminum spacers and held together by

rubber bands or a clamp. Freshly mixed calking was carefully placed between the spacers forming a filled joint 2- by 1- by 3/8 in. After a curing period of at least 14 days the spacers were separated from the calking

but left in place between the blocks until they were tested.

The tests were made in triplicate with accessory materials both primed

and unprimed, except in the case of the wood which was tested primed only.

The primers used were those submitted by the producerSt If the producers

submitted no primer for his samples, another producer's primer was used.

A total of 21 test specimens were prepared for each sample.

The bond-ductility tests were combined with a heating, soaking and

freezing cycle in the following sequence:

(a) Test specimens were heated for 16 to 24 hr at 158°F (with the

aluminum spacers between the blocks).

(b) Cooled to room temperature (74°F).

(c) Soaked in distilled water for 3 to 5 hr.

(d) The saturated specimens frozen at 0°F for a minimum of 24 hr.

(e) The joint extended 507o of its original width at the rate of

1/8 in. per hr at 0°F.

(f) The joint held in the stretched position with 9/16 in. spacers

for 16 to 24 hr at 0°F, followed by 4 hr at 74°F.

(g) Test specimens placed with original 3/8 in. spacers in oven and

the cycle repeated until a total of 5 cycles were completed.

3.5.2 Rating of Failure in Bond-Ductility Test

After step (f) in the cycle was completed, the 3 test specimens

(with spacers removed) were examined for bond or cohesion breaks and an estimate made of the loss in bonded area, in square inches, for each of

the 3 specimens. The loss in bonded area of each specimen was estimated

as the sum of the losses on both sides of a given joint.
.

•
10 .

Almost all of the failures occurred as bond breaks. A complete bond

failure in a specimen was defined as a failure resulting in area loss of

2 sq in., regardless of whether this figure represented the loss on a single side or the combined loss on both sides of a joint. When two or three of the specimens showed complete bond failure (total loss of 4 or

6 sq in., respectively) the test was stopped regardless of the number

of cycles completed. In all other cases, the tests were continued through

five cycles.

The following formula for rating bond (or cohesion) failure was used

which evaluated area of bond loss as well as the number of cycles com- pleted :

Bond Loss Factor (Ll) = A (6-C)

where, A = bond loss for each specimen in sq in.

C = number of cycles completed

For example, when the three specimens showed complete bond failure

after the first cycle, the Bond Loss Factor was calculated as follows:

Ll = A (6-C) = 2 (6-1) = 10

For three specimens, L = 3 x 10 = 30

In a second example where complete bond failure occurred on all

three specimens after the fourth cycle, the Bond Loss Factor was calculated as follows:

Ll = A (6-C) = 2 (6-4) = 4

For three specimens, L = 4 x 3 = 12

3.5.3 Test Results

Table 6 gives the bond loss factors obtained on 27 samples submitted

by 12 producers.

The results indicate that the specimens fabricated with primed brick

gave the highest bond losses (average 26.1) among all samples tested. This

is in contrast to the average bond loss factor of 12.0 obtained on the finprimed brick specimens.

Priming of the concrete and concrete block specimens apparently did

not cause any significant changes in bond failure, compared to the un- primed specimens.
.
11 .

The average bond loss factors (exclusive of the unpriraed brick) for

all specimens and all accessory materials ranged from 10.7 (primed wood)

to 13.7 (unprimed concrete).

Table 7 lists the bond loss factors in relation to various colors

of the compounds (white not included). The differences obtained among

the four color groups do not appear significant at this stage of the investigation.

Table 8 lists the bond loss factors in relation to producer groups.

The results show an exceptionally low average bond loss factor for the

samples of group 6. However, it should be noted (table 6) that there

were numerous air bubbles present in the calking of the concrete speci- mens of this group which were not included in the calculation of the

bond loss factors.

3.6 Outdoor Exposure Tests of Calkings in Concrete Joints

3.6.1 Test Specimens and Procedure

This test was devised to obtain information on performance and

possibly on the durability properties of the calkings under natural

weather conditions.

For this purpose reinforced concrete troughs were fabricated, each

14 in. long, 8 in. wide and 1 3/4 in. deep and containing two joints,

each 11 in. long 3/4 in. deep and 3/8 in. wide. (Figure 15, A). The

troughs were so designed that T in. head of water could be placed over

the filled joints to test them for leakage.

After the two joints were thoroughly cleaned with a stiff fiber

brush and methyl ethyl ketone, one joint was given a coat of primer and

the latter allowed to dry. Freshly mixed calking was then placed into

the joints, the surface struck off with a putty knife and the compound

left to cure for at least 14 days in the laboratory. Following the curing period, saw cuts 3/32 in. wide were made in the concrete at the ends

of the joints making it possible to place aluminum wedges in the saw cuts

which stretched the joints to any desired width. In this manner each of

the two joints was stretched 1/32 in. and then placed on the coping of

the roof of the Mineral Products Building and exposed to the weather for

nine months (Figure 15, B)

.

During the nine months exposure period each joint was extended 1/32

in. every three months following the initial extension of 1/32 in. This

made a total extension of 1/8 in. or 337, of the original width. At the

end of nine months, thfc total length of bond breaks (or cohesion) regardless of depth, was measured and each joint tested for leakage.
.
12 . 3.6.2 Outdoor Exposure Test Results

Table 9 gives the results of observations and tests made on 74 sam- ples of calkings exposed to the weather for nine months.

Figures 16 to 20 illustrate some of the bond and cohesion failures

obtained in both primed and unprimed joints after six months exposure.

As shown in Table 9, 497, of the samples developed at least one break in either the primed or unprimed joint. Almost all breaks were

in bond. Of this group 12 samples developed leakage through either one

or both joints when tested with 1 in. head of water.

The results in Table 9 also show a total of 135 in. of bond breaks

in the primed joints as compared with 93 in. in the unprimed joints.

3.7 Discussion of Results

3.7.1 Staining and Color Changes

It is obvious from the test results that staining of mortar and

light colored masonry in contact with mortar is characteristic of most

polysulfide rubber base (Thiokol) calkings. It is not known if the

staining affects in any way the performance or durability of the sealer

itself. However, it is an established fact that extensive stains, caused

by calking, can seriously mar the appearance of a marble, limestone or concrete facade of a building. Such examples are the United Nations Building in New York City and the Arlington Amphitheater in Virginia, both badly

stained by polysulfide rubber base calkings in the joints. Several other

instances of staining caused by calkings have come to the attention of the

National Bureau of Standards.

To date no method has been found to remove such stains from the

masonry. Some observations made at NBS on stained marble test specimens

indicate that the stains tend to lighten, and in some cases disappear

entirely after the specimens have been exposed to the sun's rays over a period of six months.

It has also been observed in a limited number of tests that a coat

of primer applied to the surfaces of a joint, including the mortar backing,

prevents staining. However, the primer itself if applied carelessly can cause a yellowish stain on the masonry.

The "Rubber and Plastic Adhesive and Sealant Manufacturers Council"

in a proposed specification for rubber base sealers, suggests a staining

test that is simple and effective. Briefly, it consists of placing a mortar mixture in the form of a 3 in. diameter ring (doughnut shape) on

a glass plate and a pat of freshly mixed calking over and in contact with
> *
13.

the mortar. After being suspended over water in a closed desiccator for

14 days, the test specimen is examined for stains. No marble or other

accessory material is required for the test.

All staining tests made at the National Bureau of Standards with polysulfide calkings have shown that no stain occurs when there is no cement

mortar in contact with the calking.

Although the test results indicated some extreme color changes after

500 hr in the Weatherometer this effect is not as serious as staining.

In installations where white or neutral calkings are required, a test for

color change should be a requirement in a specification.

3.7.2 Slump

Slump or flow in a rubber base calking is an important handling

property of the material. On the job, a slumping compound, applied to

a vertical joint can cause poor workmanship, unsightly appearance and delay in installation.

The slump test results reported herein are significant only for the

specific size of trough, period of exposure, and the temperature used in

these tests.

In future studies troughs of other dimensions will be used such as

6- by 3/4- by 3/8 in., and 6- by 1/2- by 1/2 in. before a standard test

is developed.

3.7.3 Hardness

The main objective of the study of the hardness properties of the

rubber base compounds is to accumulate enough data on this property which

would form the basis for a laboratory durability test.

Experience has shown that hardness is of relatively minor importance

in a calking installed in a joint in which there is little or no movement.

This has been demonstrated by the behavior of various fillers installed

in joints of an experimental concrete panel structure on the NBS grounds.

After two years exposure to the weather, the joints that were filled with

cement mortar prevented leakage of rain water as effectively as the rubber

base calkings.

However, in installations where large movements are expected the

stresses developed in the bond between calking and masonry may be directly

related to the hardness (or modulus of elasticity) of the joint filler.

14.

The test results obtained thus far indicate (with some exceptions)

that relatively high hardness values tend to cause bond failures. Sample groups 9 and 10 which had the highest average hardness values

(except sample 18-A) also had the highest average bond loss factors.

Furthermore, the seven samples of groups 9 and 10 developed bond breaks

in the exposure test totaling 44.5 and 53.5 in., respectively.

In the case of the epoxy-resin sample, 18-A, the high hardness

value of 82 at 0°F, caused failure in the bond test, by breaking the

accessory blocks when the joints were stretched.

Nevertheless, all bond failures were not caused by excessive hardness of the calking. This is shown by sample 14-A which developed com- plete bond failure on both primed and unprimed specimens after six months

exposure in concrete joints. The sample had an initial hardness value of

36.

The study of hardness properties will be continued in the investigation. An attempt will be made to develop an accelerated test which can predict the extent of hardening of a calking with time. The use of heating and freezing cycles as well as exposures in the Weatherometer will be

tried. These test results will be correlated with the results obtained

on specimens exposed to the weather.

3.7.4 Application Life

The application or pot life of the two part rubber base calkings may

be regarded as the most important of the handling properties. It can sometimes be the single factor causing failure in a calking installation

when an attempt is made to force a rapidly curing compound into a joint.

The use of the Brookfield Viscometer proved to be an accurate laboratory method for determining the rates of curing of the calkings over a

3 hr period at constant temperature. Unfortunately the tests were made

without control of relative humidity. However, a repeat test made on a sample at two different relative humidities of 20 and 40% did not produce

significant differences in the results.

Another method for measuring this property, as suggested by the

Rubber and Plastic Adhesive and Sealant Manufacturers Council, involves

the use of a standard "Semco" cartridge or equivalent, operated at 50

psi. The maximum application life is reached when the time required to

discharge 6 fluid oz exceeds 1 min for flow type compounds and 2 min for

the non-sag type.

In continuing the study of application life, some tests will be made

by the method described above, and the results compared with those obtained

with the Viscometer.

15.

3.7.5 Bond-Ductility

The results in Table 6 give the impression that most of the calking

samples tested would be ineffective sealers in calking installations

where the joints were subjected to large movements. This high incidence

of failure shown in the bond-ductility test might be due to the relatively deep joint used in the test, or more specifically, the low widthdepth ratio of the calking , .38, in this case.

W. H. Kuenning-^ in his study of joint sealers for concrete pavements

also found a high degree of bond and cohesion failures of rubber base calkings tested with low width-depth ratios. The number of failures in the

tests were reduced by lessening the depth of the calking in the joint (in

effect, increasing the width-depth ratio).

Studies of bond-ductility will be continued in this investigation.

The test joints will be made up in various width-depth ratios ranging from

0.5 to 1.0 to determine the optimum width-depth ratio.

Heretofore, the bond-ductility test procedure included stretching of

the joint with recovery to its original width. In future tests, it is

planned to study the effect of compression of the calking along with ex- tension.

The effect of accessory materials such as aluminum, steel, glass and

ceramic coated materials on bond will also be studied.

3.7.6 Outdoor Exposure Tests

The outdoor exposure tests afford an excellent opportunity to observe

the over-all performance of the calkings in concrete joints' under natural

weather conditions. For this reason, the< exposure tests will be continued

on the 74 samples reported and on as many new samples as possible.

As in the bond-ductility tests, the results of the exposure test indicated that priming of the concrete joints, generally, did not improve

the performance of the calkings, although several exceptions are noted in

Table 9.

Of the 74 samples exposed to the weather only 14 were included in the

bond-ductility tests. An attempt was made to correlate the bond loss

factors (concrete) of these 14 samples with the length of bond breaks

occurring after nine months exposure in the concrete joints. The results

obtained for the 14 samples are given in Table 10.

1J

Kuenning, William H., Laboratory Tests of Sealers for Sawed Joints,

Highway Research Board, Bulletin 211, (1959).
,

*
16 .

As indicated in Table 10, eight of the fourteen samples show good

correlation between the two tests. It is possible that by increasing

the width-depth ratio in future bond-ductility tests, better correlation

between the bond loss factors and the bond losses in the outdoor exposure

tests will be obtained. In the tests reported, the width-depth ratio of

the joints in the exposure test was .50 as compared to .38 in the bondductility test.

As mentioned in section 3.7.3 in the discussion of hardness results,

the two sample groups 9 and 10 with the highest average hardness values

developed exceptionally large bond breaks in the exposure tests. The

study of the relationship between outdoor exposure effects and hardness

will be continued on the old as well as new samples.

USCOMM-NBS-DC
-
Table 1. Distribution of samples in staining, color

change and slump tests.

1

r

i

' i

Type

I

I Number of samples tested

I

t

1

1 Total Non-sag

t Flow Color1

1

1

i

f Polysulfide Rubber

f

f 72

I

' 66 8

!

| Black 22

1

I

| | | Gray - 16

Alum. - 15

t Tan - 12

White - 4

t Brown - 2

i 1 I Red - 1

1

! Silicone Rubber 1 2 ' 2 none ' White - 11

1 ! I

' Pink - 1

1

Table 2. Staining, color

of 74 joint

change

sealers

and

1 /

slump properties

Sample

No.-

* 1 Color

(mix)

t 1

1 1

After 500 hr in Weatherometer

1 Slump

Stain 3/ ' Calking » rating

122°

Mortar

1

, Marble

' color i

' change i

1-

A

Light tan Moderate Moderate Lighter

in.

1/8

I-B Aluminum do do do 1/8

1-C Brown do do Darker 1/8

1-D Gray do do Lighter 1/4

1-E Black do do None 1/4

2-

A

Aluminum Moderate Moderate Lighter None

2-B Gray do do do do

2-C Tan do do Darker do

2-D Black do Slight None 1/8

3-

A

Aluminum Moderate Moderate None None

3-B Gray do do Lighter 1/8

3-C Tan do do Darker None

3-D Black do do None do

4-

A

Cray

Gray—7 Moderate Moderate Lighter 1/16

4-B do do Brownish 1/16

4-C Aluminum do Slight

gray

None 1/8

4-D White Slight do Tan None

4-E Black do None None 3/16

4-F Red do Slight Darker 1/16

5-

A

Tan Moderate Moderate Brown None

5-B Gray do None Brownish do

5-C Aluminum do do

gray

Darker do

5-D Black do do None do

6-

A

Light tan , Light tanNone None Brown None

6-B do do Dark brown No test

6-C Gray

Gray -

Slight Slight None None

6-D None None Darker No test

6-E Aluminum Slight do None 1/16

6-F Blacky . BlackNone do do None

6-G Slight do do No test
.
Table 2. Staining, color change and slump properties

of 74 joint sealers. (Continued)

“

"T‘ Sample 1 No.- t

Color

(mix)

1

f After 500 hr in Weatherometer

r Slump

1 Stain 3/ rating

"

J

„ C.a IkinP

1

1

f Mortar ? Marble

' color

• change

, 122°

f

in.

7-

A

Black Moderate Slight None None

8-A

4/

Aluminum,

,

Aluminum—'

Moderate Moderate None 1/16

8-fi do Slight do None

8-G Brown

Black 6/

do Moderate Lighter do

8-D do do None do

8-E Black it! Slight None None 1/16

9-A Aluminum Slight None Brownish gray None

9-B Tan Moderate Slight Dark brown 1/16

9-C Black , Aluminum—

do do None None

9-D do Deep Brown No test

9-E Tan U do Moderate Dark brown No test

9-f Black —‘

'

do Slight None No test

10-

A

Gray Moderate None Grayish tan None

10-B

Aluminum—

Slight do Dark gray do

io-b Moderate do None Complete

10-D Black

Black 1>

Slight Slight do 1/8

10 -E Moderate Moderate do No test

10 -F Gr ay Slight None Dark gray None

11 -A Gray

GraySlight None Grayish brown None

11-B Moderate do Darker No test

11-C Tan Slight do Dark brown None

11-D Black do do None do

12-

A

Gray Slight Slight Darker None

12-B Tan do None Dark brown do

12-C Black , Moderate do None 1/16

12-D r Black—7 do Slight do No test

13-

A

Tan Moderate None Dark brown None

13-B Gray Moderate Slight Darker 1/16

13-C White None None Dark gray None

13-D Aluminum Moderate Moderate Lighter 1/16

13-E Light tan Moderate None Darker 3/8

13-F Black Slight Deep None 3/8

13-G White Slight None Dark gray None

Table 2. Staining

of 74 j

color change

oint sealers.—1 / and slump properties

(Cont inued)

»

l After

I 500 hr in Weatherometer I

_ |

1

, Sample

' No. y

i

, Color

, (mix)

f

' Stain - Calking

Slump

rating

' 122°

-

f

1

»

, Mortar

?

, Marble • color

change

t

1 in

.

14-

A

White None None Buff None

14 -B Gray Moderate Slight Brownish gray None

14-C Black Slight None None None

15-

A

Aluminum Slight None Lighter Complete

15 -B Aluminum Moderate Moderate do 3/16

15 -C Black do do None 3/8

15 -D Black do do do Complete

16-

A

Aluminum Moderate Moderate None None

16-B Black do do do do

17-

A

. 7/ Pink -, / Whiter

None Deep (oily) None 1/8

17-B do None do None

1 / Samples are polysulfide rubber base compounds, non-sag type, unless

specified in a footnote.

2/ NBS sample designation: the number represents a producer, and the

letter, an individual sample.

3/ Color of stain is shade of red or brown or mixture of both unless

specified in a footnote.

4/ Designated by producer as "hard" type.

5/ iFlow type compound. No slump test made on these samples.

6/ Designated by producer as "sdft" type.

7/ , Silicone rubber compound.

Table 3. Distribution of slump ratings,

(slump in inches)

' None

'

V—rr

i 1/16 .

1 1/8

f

. 3/16

I

f 1/4

I

• 5/16

f

i »

' 3/8 or'

' or < 1/16'

i '

f

1

i i more

i i

1 1 1

' No. of '

I - f ^ • » samples

t 10

t 8

!

I

, 2

1

I

1

t

t

2

i

i

, 2

f

f !

i r

i 6 i

Table 4. Shore "A" Hardness Values

Sample

No.

1-F

1-G

1-

H

Avg.

2-

E

2-F

2-

G

Avg.

3-

E

3-F

3-G

3-H

3-1

3-J

3-K

3-

L

Avg.

4-

G

4-H

Avg.

6-

A

6-H

6-J

6-K

6-L

6-M

Avg.

Specimen 1 (cold exposure)

t Specimen (hot exposure)

Orig.

value

74°F

Exposure, 3 da>s Recovery 'Orig.

1 Exposure, 3 days Recovery

0°F

1

1

' Change ,

' 7°

r To

74 °F , Change

%

value

| 74°F

i

' 158°F

t

, Change

7

i /o To

74 °F

( Change

7 i /o

32 51 +59 40 +25 32 32 0 40 +25

32 52 +63 36 +12 32 32 0 44 +38

34 59 +73 36 + 6 34 34 0 42 +24 __ —..... , — - . . i — — 33 54 + 65 37 +14 33 33 0 42 +29

42 55 +31 41 - 2 42 42 0 47 +12

38 50 +32 40 + 5 38 32 -19 39 + 3

34 51 +50 35 + 3 34 38 + 12 43 +26

38 52 +38 39 + 2 38 37 - 2 43 +14

32 49 +53 32 0 32 24 -25 41 +28

33 53 +61 34 + 3 33 35 + 6 40 +21

46 56 +22 41 -11 46 44 - 4 43 - 7 33 51 +55 34 + 3 33 41 +24 46 +39

30 61 +103 33 +10 30 38 +27 48 +60

38 56 + 47 36 - 5 38 39 + 3 46 +21

31 56 +81 34 +10 31 36 +16 46 +48

25 48 +92 26 + 4 25 29 +16 42 +68

34 54 + 64 34 + 2 34 36 + 8 44 +35

39 64 +64 46 +18 39 40 + 3 51 +31

22 56 +155 35 +59 22 39 +77 46 +109

30 60 + 110 41 + 39 31 40 +40 49 + 70

15 40 +167 16 + 7 15 7 -53 16 + 7 20 37 + 85 20 0 20 15 -25 24 +20

16 34 +112 22 +38 16 12 -25 16 0

16 43 +169 19 +19 16 12 -25 20 +25

16 53 +231 18 +12 16 15 -6 22 +37

35 58 + 66 34 - 3 35 27 -23 37 + 6

20 44 +138 22 + 12 20 15 -26 23 + 16

Table 4. Shore "A" Hardness Values (Continued)

Sample

No.

Specimen 1 (cold exposure) Specimen

l (hot exposure)

- ’ Orig.

"value

'74°

!

1

'Exposure, 3 days Recovery

1 'Orig. Exposure, 3 days ' Recovery

»

, 0°F

1

f

' Change

• 1

' To

' 74°F

1

»

t Change

7 i >°

value

1 74°F

!

1

158°F Change

7/o

' To

' 74°F

Change

L

7-

A

49 60 + 22 48 - 2 49 48 - 2 56 +14

8-

A

10 37 +270 10 0 10 12 +20 24 +140

8-B 27 52 + 92 29 + 7 27 34 +26 48 + 78

8-D 16 44 +175 13 -19 16 15 -:6 21 + 31

8-E 47 61 + 30 47 0 47 53 +13 54 + 15

Avg. 25 49 +142 2.5 - 3 25 29 +13 37 + 66

9-A 49 59 + 20 52 + 6 49 50 + 2 53 + 8

9-B 45 56 + 25 44 - 2 45 45 0 50 + 11

9-C 50 60 + 20 49 - 2 50 52 + 4 54 + 8

9-F 55 59 + 7 52 - 5 55 56 + 2 58 + 5

Avg. 50 59 + 18 49 - 1 50 51 + 2 54 + 8

10-

A

36 57 + 58 36 0 36 36 0 42 + 17

10-

B

58 67 + 16 5,7 - 2 58 58 0 62 + 7 10-D 57 63 + 10 64 +12 57 60 + 5 60 + 5

Avg. 50 62 + 28 32 + 3 50 51 + 2 55 + 10

11-

A

33 54 + 64 24 + 3 33 47 +42 53 + 61

litE

40 58 + 45 37 - 8 40 46 +15 51 + 28

U-F 17 46 +171 16 - 6 17 32 +88 40 +135

11-G 41 57 + 39 41 0 41 43 + 5 52 + 27

1I-H 44 60 + 36 46 + 5 44 50 +14 58 + 32

Avg. 35 55 + 71 35 - 1 35 44 +33 51 + 57

12’-E 41 54 + 32 42 + 2 41 44 + 7 50 + 22

12-F 39 56 + 44 37 - 5 39 40 t 3 47 + 20

12-G 28 52 + 86 32 +14 28 35 +25 46 + 64

12-H 45 60 + 33 46 + 2 45 48 + 7 57 + 27

Avg- 38 56 + 49 39 + 3 38 42 +11 50 + 33

Table 4. Shore "A" Hardness Values (Continued)

Sample

No.

1

( Specimen 1 (cold exposure) Specimen (hot exposure)

?'Orig.

'value

' 74°F

r

'Exposure, 3 day^

1 t Recovery

1'Orig.

Exposure ,3 days Recovery

I

1

, 0°F

f

J

i Change

7

1

t /o

»

To

74°F

f

1 Change

• 7,

value

' 74°F

J

1 158°F>

1

Change

%

; to

74°F T

t

i Change

, %

13-1 24 54 + 125 26 + 8 24 30 +25 43 +79

13-

J

21 42 +100 20 - 5 21 28 +33 36 +71

13-K 24 44 + 83 26 + 8 24 33 +37 43 +79

Avg. 23 47 103 24 + 3 23 30 + 32 41 + 76

14-A 36 56 + 56 36 0 36 31 -14 41 +14

15-B 46 57 + 24 46 0 46 48 + 4 51 +11

15-E 41 54 + 32 52 +27 41 46 +12 40 - 2 15-F 16 42 +162 15 - 6 16 26 +62 36 +125

Avg. 34 51 + 73 38 + 7 34 40 +26 40 + .45

17-C 40 40 0 40 0 40 44 +10 42 + 5

18-

A

53 92 + 74 55 + 4 53 64 +21 82 +55

19-A 20 26 + 30 25 +25 20 21 + 5 35 +75

Table 5. Results of application life tests with the

Brookfield Viscometer.

f

f

I

1

t

Sample No.

Viscometer Readings

, (0-100 scale)

1 Time (t)

f

f

' "P" factor

f

1

I

t

f

1

? Miniraum

?

I

i Maximum ' (hr)

1

t

1 1-F

i

' 49.0

»

' 56.5

!

' 3

1

' 56.0

1

1

t 1-G - 55.4 ' 81.0 - 3 • 81.0 I

1 1-H • 80.7 ' 92.7 - 3 ' 93.0 1

1 2-E • 48.0 ' 98.2 < 3 » 98.0 f

? 2-F • 41.4 • 100 ' 2.75 • 109 1

J 2-G ' 53.0 ' 100 • 2.33 - 129 1

1 3-E • 46.0 100 • 0.97 > 212 f

1 3-F . 70.0 . 100 .57 • 525 1

? 3-G . 50.7 . 100 - .47 . 638 1

1 3-H . 69.8 . 100 . .20 . 1500 1

1 3-L . 77.7 . 100 . .25 . 1200 1

I

1 6-H

f

i 51.5 . 100 2.50 . 120 I

» 6-1 . 37.0 . 49.2 . 3 . 49 I

1 6-

J

i 60.6 . 100 • .70 . 428 1

t 6-K . 45.5 . 100 . 1.33 . 226 1

I 11-E ' 63.0 ' 82.8 ' 3

' 83 1

1 1 1-F ' 58.0 ' 61.9 ' 3

' 62 f

t 1 1-G ' 53.0 ' 61.0 ' 3

' 61 1

1

1 11-H ' 67.51

' 100

f

' 2.08

1

' 144

I

1

1

f 12-E ' 55.3 ' 62.8 ' 3

' 63 1

» 12-F ' 57.0 ' 70.5 ' 3

' 71 I

1 12-G ' 54.8 ' 60.5 ' 3 61 r

f

f 12-H ' 23.3

1

' 76.2

!

' 1.53

f

' 196

1

t

i

f 14 -H ' 51.7 ' 59.0 ' 3 59

i

1 14-1 ' 34.9 ' 51.3 ' 3

' 51 t

1

1 14-

J

' 52.7

1

' 60.4

I

' 3

1

' 60

1

t

i

1 15-E ' 24.7 ' 29.5 ' 3

' 30

i

1

1 15-F ' 46.5

1

' 84.4

t

' 3

!

' 84

1

f

f

1

f 18-

A

' 30.5

1

' 50.5

1

' 3

t

' 51

1

i

?

Table

6.

Results

of

Bond-Ductility

Tests

X

O

O£

PiO

O

r-H PQ

d

Od

O

cU

pin

CO

CO0

P

1 X)do

PQ

PiU

-Hd

PQ

X)

a>b

•Hd

Pd

1X3 CUs

•Hd

a

dP

X

CUb

•Hd

fd

XI

<Ubua

d

p

x

<ob

CU d

a)du

•rdO

o

d

Pd

X

0)b

•Hd

CXd

x

a

B

cu co

d

co rd| co X cu CO cu cn o o o d o in o d o o m m O m m r-H • O CM in o m O o o CN m O in o o o O • CN • rH d CO r-H rH d rH CN CN

IN

CO

cu m

O d id O O

d

m vo

CO O O

d

COQJ d <t m <r O H id r—

I

d h

d d d

'

CO I M

O CN

CNO' o m cn

CO0000MO o

cn

m

o

o o cn m

d cn

oo m oo o

ClCN

d

CO

CU 00 00 d cn m

o cn o

cn cn cn

O' O sf

o o o o

O O

d

00 o cn

vO 0s

* CN <t O O

O O

o o o

co <o in

cn oo d o

o

oo

-M <N| tn oo

cn o o

CN

O O O id

mo o

m

CNd| m|

<J

CN o o o o

cn cn cn cn o o o

o o

cn cn

CN | o o o o

o o o o

cn cn m cn

ocn

o o

o n o ocn

id|CN|

00 o

o o

cn cn o oo o o

cn

-JON cn i—

i

lOm

o cn di m

o di cn vo

H| U

CO CN O CN

• 4J co

CN | cn|cn| in -j cn m id cn o o

X

a)s m o CO CTs o O CN o

^ 1 00 CN 18

* d X <)• <j <o o m CO i“H o

fd CM rH r-H CN CO r-H CN CN r-H

cn o o o o

\ CN|

CN | MO <t MO

CN rd CN o

CN | O id o

cn

co o o rd cn

O O rd

ni|

O

H| CN|

a

cd C

cs e B B lU B g § u d P P P d P P P o d d d d d d

r-H d -H prf •H Pi! •H p*; d -h Pi Pi •H •H Pi Pi o ,c b u B O B u -d B o o §

s CJ CJ o oo d cu d P d cU P cu oo P cu cu cU p p CU CU •H r-H r-H cd rH cU id id d •rH r-H d id rH r-H id r-H r-H P <c pp H < H PQ < pa p < O PQ PQ < < PQ PQ

00

CU CU lO vfl 00 N cu 00 d d O O <N m CN O d id o • • • « • • • • • o o o o o o O O CN o O

d d cn d cn

00m

cn

00

nO'- ni

a PC

1

C_) rd P CD . < p • 33 Id X . < < PQ p w .

| i 00 1 i i i 00 1 i 00 1 1 1 1 00 1 i 1 i 1 00 rH r-H r-H $

CN CM CN CN $

CO cn $

vO X MO M> 3

00 00 CO 00 £

Table

6.

Results

of

Bond-Ductility

Tests

(Continued)

Pi!OO

X r— ^ 1 1

a> 43

H CM 4-J "O e O o o oo CO o nO o r-* o CO o •H CD • • • CD • • « • • CD • o O 4* o o rH u o o 00 CM 4-J o 3 Pm CO O CO CO CO rH rH rH rH

Mi

O o - - -

PQ 0 0 X

CD 4-J e CO •H o 00 <t NO o o LO 00 o CD CD 44 o

Mi 4-J 44

O • a o CM LO ON rH o o o CN o O O rH 0 CM cn tH rH CO CO CN CO o 1m iH rH X 0 43 43 oo — —

tH

CQ

4-J 4-J

X CO CO

CD o o o co o o o NO nO CD CD CM e 4-1 4-J • •H o Q o CO o o o CM CN o u mi r—1

CO CO eg CO CO CM o o rH o Pm 0 0

•uo — - —

CO pH

CO

X

CO CD 44 o a CO hJ •H o o CN <J* LO o o LO 00 O CD CD 44 o

Mi 4J 4*: CJ • nD a o o t—1 O rH o o o rH o o O CM c 4*i c ro CO <N co CO CM CO o Mi H rH o O pa 0 43 43

pa

u - —

PQ

4-)

X CO

CD

O o O

O o o o o o o o CD

H e 4J • •H O o O O rH o o o o o NO

Ml CO <-o CO CO CN CO CO CM CO CO CO o CN

PM 0

13

CD 4-J e CO •H o ON LO 00 NO o o CN nO 00 CD CD 44

Mi 4-J 44

U • 0) CD o NO CM o lO ON CO CM O O co

4-1 c CO r—1 CM <N CO CM rH CM o Mi rH rH

CD pa C3 43 43

CiO

—— co N • a ^ 1 4-J CD X CO Ml CD CM rH o o LO o LO CN nO LO (D ro 0 • e 4-J • rH 00

•H rH rH o 00 CM o CO rH rH CO CN •H 0 c C\J ro H rH CM CO CN rH o rH co •H

PM 0 mh 44H 0 CO o u

•H >N CO 0

CO CD •iH

B Ml 43

u 0 oc

O CO o 0 CO CJ CD rH •H 4rf 4-J 4P CD CD CD rH o e o >N 43 U 4-J 4-J 00 XI 4a 0 0 CO CO 00 CO CO *H •H 0 CO 0 43

rH co rH Ml •H rH Ml ri CO Mi CO 0 < H pa e> hJ pa u 3 3 H (D 43 > X

<C 0 Mi <d O •H rH X pa <!

(X < w Pm • < pa

Q • < < pa < 0 e 1 1 00 1 1 1 00 1 1 1 1 cO ON ON ON > O o o > rH 00 Mi cn < rH rH rH < rH rH rH rH O rH 1TM

Table 7. Bond loss factor in relation to color

(Polysulfide type compounds)

1

1'No. of

' samp les

1

' Concrete

1 _ 1 Brick ' Block

'

> Wood

Primed

1

f

I

!

, Color

t

' Primed

1

* Unprimed 1

i i Primed 1

1 Unprimed 'PrinEd^" '

' 'primed i

, Averages

1

t

1

1 Aluminum

f

»

1 7

1

I

1 f 15.3

?

i i

i i 15.3

f 1

! 21.7

I 13.0

1

'll.

7

1

» i

i ? 8.4

f i 13.2

f

14.

1

I

1

I

1

| Tan

\

, 5! 9 • 2

I f

, 8.0 , 28.2 | 10.2 ! 8 * 5

t i

, 6.0, 0.3 | 10.0

1

1

.Gray

t 4 1 | 10.71 1

. 9 " 1

, 27.8 | 8.4 ! 8 * 2

f f

, 8.7, 6.7 | 11.4

r

i

t Black

1

, 9

J

' 13.4

»

! !6.5

t f 26.7 |

1

11.9 ' 11.6

f

» !

, 13.5,

f f

15.0 \ 15.5

I

!

1

I

Table 8. Bond loss factors in relation to producer groups

I

' Producer Group

f

t

1

1/

Number ofsamples tested

J

i Bond Loss Factor

i (average)

I

f

t

1

1 3 11.4

1

. 2 1 4 » 15.3 !

' 3

1 2

' 10.9 ,

V

f f ' 2/ »

. 6 J 4 , 4.7 -f

' 7

» 1 ' 25.6 1

r 8

f

1 4I 8.3

T

1

' 9

t 3 • 23.6 1

! 10

t

t 3 20.2

1

f

' 11 1 1 ' 8.6 1

14

?

1 1 16.8

I

t

' 17 I 1 ' 18.5 f

_1 / Includes tests with different accessory materials: concrete, brick,

block and wood.

2/ Many air bubbles were observed in the calking of the concrete

specimens. These were not included in the calculation of bond

loss factor.

Table 9. Results of 9 months' exposure to weather

of 74 calkings in concrete joints .—

1'

1

t

1

1 Total loss in bond 27

to concrete (inches)—

i

F

1 Sample f Primed joint Unprimed

1 joint I

t

1 No. 1

I Top

1

I Bottom ' Top Bottom

F

1

f

. 1-A

I Nonef Nonef f None 3/16

F

1-B None 1 None None

1-C None None None None

1-D None None None None

1 1-E

I None 1 None None 1 t None »

1 2-

A

1 None f None ' None ' None F

1 2-B 1 1/4 1 None 1 None ' None F

I 2-C I None 1 None ' None ' None F

I 2-D 1 None 1 3/4 ' None ' None F

1

1 3-A

1

1 3

I

I 1/2

F F

, None , None

t

F

f 3-B F None I None , None , None »

f 3-C f None 1 None , None , None F

1 3-D 1 None » None , None , None 1

I 4-

A

1 None1 None

? F None None

F 4-B None None None None

1

»

4-C

4-D

4-E

1

I

5/8

1/4

None

None—'

1

1

None

6

None

None

' 5 5/ ’ None

'

None , 5 None

f

F

I

t 4-F Ff

1

1 None None —/

'

F F None F

F

I

1

1

5-

A

5-B

5-C

T

t

f

None

1/2

None

I

1

!

None

None

1 1/2

: i/

:

i None i

None

None

None

F

F

F

1 5-D 1 None I None i None i None I

I 6-

A

6-B

I None . 3 —

3 y

M

6 / None—

1 None .

l y

M

6/ None—

F F None None

F None None

6-C

4/ 6-D

None None F None None

6-E None 1/4 None None

6-F 2 1/2 3/4 None None

6-G None None None None

1

1 7-

A

f

f None !

1 6 i y \

F F s y F

F
.
Table 9. Results of 9 months' exposure to weather of

74 calkings in concrete joints. U (Continued)

1—

t

' Total loss in bond 2 / to concrete (inches)-

1

1 Sample

1 Primed joint Unprimed

f joint

f

1

No

.

' Top

?

1

| Bottom Top Bottom

1 8 -A

1 j

I

( None

f

, None

I 1

, None

3 / 4 -

None

8 ~ B

8 / 8 -C

8 -D

8 -E

, None , None None

, None , None , None , None

None , None , None , None

1 , None , 9 , None , None

I 9-A

1 None» None c

,

' 5 2/

I f None 1/2

f 9 -B ' 9 5/ None None

1 9 ' C

4/

9

- D

!/

9 - E r/ 9-F -

' 4

' 3' 2 None

I

t

1

None

: ;

3 /

| 1 1/2

None

' 8 5/

None c /

’ 3 1/2 T

' '3 5 /

'

1 f

None c/

2 —

7

7 ~

10-A

10-E

g/

10-C -

10-D 4/

10-E -

10-

F

U- A

4/

11-

B -

11-C

11-

D

12-

A

12-B

12-C 4/

12-

D ~

13-

A

13-B

13-C

13-D

13-E

13-F

13-

G

14-

A

14 -B

14 -C

V'h

None

Complete—

None

None

None

None

None

None

None

None

None

None

None

None

1/2 2/ None

1/4

None

„

. 5/ CompleteNone

None

Noner

/

1 -

None

^

, Complete—7 None

None

2 1/2

None

None

None

1/4

None

None

None

3 1/2

None

1/2 l!

None

None

None

CompleteNone

None

None

9 None

1/4

None

None

None

None

None

None

None

None

None

None

None

None

1/4

1/4

None

None

None

Complete'

None

None

5/

3/

5/

None 5/ 3 -

None

1/2

None

3/4

2 None

None

None

None

None

None

None

None

None

None

None

None

None

None

Comp leti

None

1 1/2

5/

Table 9. Results of 9 months' exposure to weather of

74 calkings in concrete joints, i/ (Continued)

1

1

I

1 Total loss in bond to concrete (inches) 2J

1

I

? Samp le

No

Primed joint Unpriroed

t joint t

1

1 I Top

I

, Bottom ' Top

I

1 Bottom

1

1

1

!

f 15-

A

None 5 /

I

1 None

?

1 None

f

1 None

1

1

1 15-B ' 3 1/2 “

' 2 5/ ' 5 5/ 1 6 5 I

1 15-C None ' None ' None 1 1/4 »

I 15-D None ' None ' None I None 1

f

1

f 16-A , None

T

, None

1

, None

f

f None

1

t

» 16-B , None , None , None » None I

» 10/,

17 ~A To/,

17-B — I

None

f None

t Nonef None

1

1 None None

1 None

t ? None

!

1/ Calkings are polysulfide rubber base, non-sag type, except

where specified in a footnote.

2/ Figures (in inches) denoting loss of bond are for bond

breaks, except where specified by a footnote.

3/ Cohesion (or ductility) break.

4/ Flow type compound.

5/ Joint leaked.

6 / Small air holes on surface.

2/ Compound classed as "hard" by producer.

8 / Compound classed as "soft" by producer.

9/ Lar£e closed air pockets.

10/ Silicone rubber.
*
Table 10. Relationship between bond loss factor

and exposure test results.

1

1

1

1 Sample r No. .

Bond-Loss \J , Exposure Test (9 mo.),

Factor (Avg.) ° , „ , T .1/ ,

' -Bond Loss, in.— ' Correlation

»

1

!

»

1

1

1

» 2-C 1 23

1

f 0

» Poor

1

1

1

1 3- A ' 12.2 ' 3.5 Good 1

t

1 3-D I .2

r 0

t Good

1

f

1 7-A ' 24.2 ' 15 (leaked) Good f

t

1 8- A \ 4.0

f

, 0 Good

»

1

1 8-B ' 16.0 ' 4 Good f

1

1 8-D | 0

t 0 Goodf

1

f 9-A ' 25.6 ' .5 Poor 1

1

! 9-E | 9.0 ! 6.5 (leaked) t Poor

»

1

t 10- A ' 10.3 ' 4.5 Poor f

1

1 10-B | 26.2

1

, 17 ( leaked) Good

f

1

1 10-D 27.5 ' 11 (leaked) ' Good f

1

1 11-A | 2.4 ! 4.5 Poor

f

!

1

1 14-A

1 12.2 1 complete

' failure

(leaked) ' Poor f

f

1/ Results are the values obtained on primed and unprimed specimens.

Stained Area

Calking

Marble Mortar

Spacer

Fig. 1. Staining of marble and mortar caused by contact

with Thiolol base calking compounds:

(A) Example of stain (appears red) on white marble

after 5>00 hours exposure in a Weatherometer

.

Calking joint is 1 l/2 in. long, l/2 in. deep

and 3/8 in. wide, backed by 3/4 in. white

cement mortar and l/2 in. aluminum spacer.

(B) End views of 4 specimens of different calkings

with mortar and spacers as in (A)

,

showing

prominent- stains ( red and brown) in mortar after

500 hours exposure in the Weatherometer.

Pig. 2. Test specimens of rubber base calkings fabricated

like those in Pig. 1, for study of staining of

masonry and color changes in the calkings.

(A) Examples of color changes in calkings after 500

hours in Weatherometer . Top half of joint was covered during test.

(B) After exposure in the weatherometer, specimens

are exposed on the roof of the building with one half of each joint covered by a strip of aluminum.

Fig. 3 . Laboratory test of slump or flow property of rubber

base calkings . Freshly mixed compounds are placed in

aluminum troughs, l|. in. by 1 in. by 3/8 In. and are suspended for 2l\ hrs at er-£4-^P6-.- 122 ± 2° F. The eight specimens on the right side show varying

degrees of slump while those on the left show none.

Pig. 4* Calking specimens used for the determination of

Shore A hardness.

(A) Hardness specimens, 4 in. by 1 l/2 in by l/4 in. are placed on aluminum panels and tested 10 to

14 days after compounds are mixed.

(B) Hardness specimens exposed on the roof of the

building for future study.

15

10

5

0

25

20

15

10

5

0

15

10

5

0

1 1 171 1 1 1

1

14

Original - 74° F

mean: 34

8

9

5

10

29

72 hr Exposure

at 0°

F

mean; 53

9

8

15

10 20 30 40 50 60

3 hr Recovery

at 74° F

mean ; 35

70 80 90

SHORE 'A' HARDNESS VALUES

5 DISTRIBUTION OF SHORE 'A' HARDNESS VALUES

OBTAINED ON 53 SPECIMENS OF RUBBER BASE

CALKINGS.

100

15

10

5

0

15

10

5

0

20

15

10

5

0

t r

14 Original - 74° F

mean: 34

17

15 72 hr Exposure

at 158° F

mean: 37

—

6 6 6

1 2

24

14

3 hr. Recovery

at 74°

F

mean: 44

10 20 30 40

SHORE 'A' HARDNESS VALUES

50 60 70 80 90 100

6 DISTRIBUTION OF SHORE 'A' HARDNESS VALUES

OBTAINED ON 53 SPECIMENS OF RUBBER BASE

CALKINGS.

Fig. 7. Application or "pot" life of the calkings was measured with a Brookfield Viscometer fitted

with no. 7 spindle rotating at 2 rpm. Readings

were taken periodically and test was stopped when

pointer reached the limit of the scale (100) or after 180 minutes- whichever came first.

001

Time,

min

Relationship

of

viscometer

readings

with

elapsed

time

obtained

in

the

determination

of

application

life

of

calking

samples.

00i

o

co

1

o

in

O

c\j

O

<7>

O

Oro

O

sbuipoay j0j.aiuoos!A

Time,

min.

Fig

9

Relationship

of

viscometer

readings

with

elapsed

time

obtained

in

the

determination

of

application

life

of

calking

samples.

001 o

goO

inO

C\J O

G>O

IDO

roO Er CDE

hTD

CDco toCD xio

Q.E

a; o E

too>c

TD

CD

1st:

if) o

Q. o O

cd *—o

-C CD * « 5

toCO

c.o C

TJ o O o

cd

k_ "o. Q.

k_

O

CD Hcd o Eo c o o

to +-

’> o

<*— c o E

k_ CL CD J=

to CD c TD oo

CD XI

CD q: c O

o>

1001 o

coO

LDO

(Vi O

<T> O

CDO

ro

CP

Time,

min.

Relationship

of

viscometer

readings

with

elapsed

time

obtained

in

the

determination

of

application

life

of

calking

samples.

ig. 12. Joint material extension machine used in the

bond-ductility tests. Joint is stretched 5

0

%

of its original width at 0 deg P, at the rate

of 1/8 in. per hour.

Pig. 13. Bond-ductility test specimens in joint material

extension machine.

(A) Specimen with joint, 2 in. by 1 in. by 3/8 in.

before extension.

(B) Specimen after extension of 50$ of its original

width.

mm

Pig. 14. Bond-ductility test specimens. (A) Typical specimens

before test: brick, concrete block, concrete and

wood, (B) Examples of complete bond failure after

test. (C) Failure caused by combination of high

hardness of calking and strong adhesion resulting

in breakage of the accessory blocks
I

.

'

.

1

-
Fig. 15 . Calked joints used in outdoor exposure studies.

(A) Typical concrete trough containing two joints

11 in. by 3/4 in. by 3/8 in., primed and unprimed, and filled with the calking under test.

(B) Troughs exposed to the weather on the coping of

the Mineral Products building. Joints are stretched 1/32 in. every 3 months.

NO PRIMER

'

l. P

[ PRIMED JOINT ' * sv r

Pig. 16 . Effect of six months exposure to the weather

on calkings in concrete joints. Joints were

stretched total of 3/32 in.

(A) Sample 9-B shows several bond breaks in

primed joint and none in unprimed joint.

(B) Sample 1 ip— A shows complete bond failure

in both primed and unprimed joints.

Pig. 17. Effect of 3 ix months exposure to tne weatner on

two samples of calkings in concrete joints.

Joints were stretched a total of 3/32 in.

(A) Sample 10-D shows complete bond failure in

the primed joint and almost no failure in

the unprimed joint.

(B) Sample Ip-D shows about 3 in. of bond breaks

in the unprimed joint and about I/I4

. in break

in the primed joint.

Pig. 18. Effect of six months exposure to the weather on

a sample of calking in concrete joints (No. 1%-B)

(A) Top surface of trough showing bond breaks in

primed and unprimed joints.

(B) Under side of same trough showing more extensive

bond breaks in unprimed joint and only about 1/4

in. break in primed joint.

Fig. 19. Effect of six months exposure to the weather on

a sample of calking In concrete joints (No. 6-B)

Joints were stretched a total of 3/32 in.

(A) Top surface of trough showing about 4 l/2 in.

of bond breaks in the unprimed joint and none

in the primed joint.

(B) Under side of same trough with slightljr more

extensive breaks in the unprimed joint and

none in the primed joint.

Fig. 20. Effect of six months exposure to the weather on

calking sample No.. 8-B. Joints were stretched a total of 3/32 in.

(A) Top surface of trough shows some ductility

breaks in unprimed joint and none in primed

joint

.

(B) Bottom surface of trough shows no breaks in

both joints.

U.S. DEPARTMENT OF COMMERCE

Kn ilfiii k II. Murllrr. Secrelury NATIONAL BUREAU OF STANDARDS

A. V. Amin, Director THE NATIONAL BUREAU OF STANDARDS

The scope of activities of the National Bureau of Standards at its headquarters in Washington, D.C., and its major

laboratories in Boulder, Colorado, is suggested in the following listing of the divisions and sections engaged in technical work. In general, each section carries out specialized research, development, and engineering in the

field indicated by its title. A brief description of the activities, and of the resultant publications, appears on the

inside of the front cover. WASHINGTON, D.C.

• Electricity and Electronics. Resistance and Reactance. Electron Devices. Electrical Instruments. Magnetic Measurements. Dielectrics. Engineering Electronics. Electronic Instrumentation. Electrochemistry.

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