NATIONAL BUREAU OF STANDARDS REPORT

3325

REPORT ON

INSPECTION AND TESTS OP PLASTER

ALASKA NATIVE SERVICE HOSPITAL AND QUARTERS BUILDINGS

by

NOLAN D 0 MITCHELL

for the

BUREAU OF INDIAN AFFAIRS

U e S, DEPT, OF THE INTERIOR

II. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
U. S. DEPARTMENT OF COMMERCE

Sinclair Weeks, Secretary NATIONAL BUREAU OF STANDARDS

A. V. Astin, Director

THE NATIONAL BUREAU OF STANDARDS

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cover of this report.

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and Lubrication. Engine Fuels. Cryogenic Engineering.

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Chemistry. Organic Coatings. Surface Chemistry. Organic Chemistry. Analytical Chemistry.

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and Scale. Capacity, Density, and Fluid Meters. Combustion Control.

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#Office of Basic Instrumentation ^Office of Weights and Measures.
NATIONAL BUREAU OF STANDARDS REPORT

ms PROJECT nbs report

1000-30-4731 June 2^, 1954 3325

REPORT ON

INSPECTION AND TESTS OF PLASTER

ALASKA NATIVE SERVICE HOSPITAL AND QUARTERS BUILDINGS

by

NOLAN D„ MITCHELL

for the

BUREAU OF INDIAN AFFAIRS

UoS. DEPTo OF THE INTERIOR

<NBS>

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

The publlcatloi

unless eermtss

25, D. C. Sucl

cal ly prepared

Approved for public release by the 8 or ln P

aft' is prohibited Director of the National Institute of °fStandards ' Washin s<°" Standards and Technology (NIST)

are P° r,hasbeensP

eclfi -

ar report for its own use, on October 9, 2015.

REPORT OF

INSPECTION AND TESTS OF PLASTER

ALASKA NATIVE SERVICE HOSPITAL AND QUARTERS BUILDINGS

ANCHORAGE, ALASKA

by

NOLAN D, MITCHELL

SUMMARY

Visits to the buildings of the Alaska Native Service

Hospital, Bureau of Indian Affairs Projects 501-228 and 501=

228a, were made by the Chief, Chemistry of Mineral Products

Section, and two members of the Building Technology Division

of the National Bureau of Standards, for the purpose of examining the buildings for structural soundness and the condition

of the plaster to determine, if possible, the cause of plaster

cracking, Specimens of the plaster and plaster materials were

obtained for tests.

Character and Location of Cracks

Approximately 99 percent of the cracks observed were in

plaster applied to metal lath of partitions, furring, and suspended ceilings. The warped surfaces of the plaster adjacent

to the cracks, as well as the patterns of the cracking, indicated that the white finish had shrunk. Some of the wider

cracks were found to extend through the base coat plaster to

the lath, indicating that the base coat plaster had also shrunk.

The few cracks found to have resulted from structural defects

were in plaster applied to monolithic concrete which had cracked

from shrinkage.

Plaster Materials and Plaster

The materials used in the plaster and plaster bases were

- 2 -

analyzed and,, except for the sand and water, were found to

be of the quality specified. The colorimetric test indicated

an excessive amount -of organic material in the sand and

the sand was finer than permitted by the specifications. A

settling test indicated that, at times, there was an excessive

amount of silt in the water used.

The proportion of the aggregates in the base coat plaster

of six of the seven specimens taken from the partitions of the

hospital building ranged from 2 1/2 to 4 1/2 ft- per bag ( 100

lb) of gypsum cement plaster . The vermiculite ranged from 2*0

to 3*9 ft and the sand ranged from 0.12 to 0*70, the averages

being, respectively, 3*0 ft^ and 0*40 ft3„ The other specimen

had 3*0 ft^ of vermiculite aggregate per bag of gypsum cement

plaster and no sand.

The proportions of hydrated lime in the white finish

plaster ranged from 40 to 175 lb to each 50 lb of plaster of

Paris (gauging plaster), the average being 95 lb of . lime to

50 lb of gauging plaster. The wide variations in the proportions

of materials indicated a lack of concern for following the specifications, The white finish plaster was stronger than the base

plasters.

The weakening effect of sand added to a vermiculite gypsum

cement plaster mix was shown by tests reported on September

17* 1952. In those tests, the tensile strength of a mixture

of 1,7 ft~ of vermiculite and 0,4 ft^ of sand to 100 lb of

gypsum cement plaster was 115 lb/in, 2

, whereas, the strength

of the plaster without the sand was 200 lb/in, 2

. The addition

- 3 -

of sand to vermiculite aggregate was not in accordance with

the specifications.

Job Conditions

Letters of the Project Engineer to the Contractor written during the application of the plaster indicated that

better ventilation had been needed in the hospital building

to accomplish proper drying of the plaster. There was also

evidence in the building that water had coursed down the face

of some of the plastered walls., probably from moisture con=

densed from the air. Under such conditions * the base coatplaster was not as strong when dry as it would have been

had the drying been at a normal rate. At the time of the visit

in February 1953^ the moisture meter indicated that the plaster

was then normally dry.

Plastering Practices

It is known in plastering practice that white finish plaster has a tendency to shrink on drying and that to avoid

shrinkage cracking the finish should be applied over a strong

base coat that has sufficient suction to withdraw excess water

by capillarity, and, in addition, an after troweling should

be performed while the gauging plaster is setting. Variations

in the proportions of hydrated lime to gauging plaster of the

white finish indicated that the amounts of materials were not

measured or that the ingredients were not thoroughly mixed.

Much cracking of plaster results from lack of thorough mixing

of lime putty and gauging plaster, especially where the after

„ 4 “

troweling is not done under proper conditions and at the

proper time. Too rapid drying of white finish over wet base

coat also tends to overstrain the surfacing material. It is

possible that such causes were operating to some extent in

both the hospital and quarters buildings to induce initiation

of cracking.

In summary , it can be stated that a number of factors

were involved in the cracking of the plaster. The relative

effect of the known factors in causing the conditions found

in the hospital and quarters buildings could not be definitely

determined. Some of the factors were common to both buildings.

The gypsum cement plaster was retarded to give slow set

when combined with aggregates; 5 1/4 hr with Alaska sand,, 11

hr with Alaska sand and vermiculite mixture , 12 hr with

vermiculite^ and 10 1/2 to 24 hr with Ottawa sand. The consistency index of the neat gypsum cement plasters tested was

in the range 50 1/2 to 52 1/2; and that of the two samples of

gauging plaster 46 and 49* these quantities indicating that

the water requirements for workability were 2 1/2 to 3 times

that required for complete set of the plasters. The volumetric

shrinkage of 2-in. cubes of these plasters ranged from 2.0 to

3»0 percent. The shrinkage was doubtless largely the result

of the retarder used for slow set and the amount of water required for consistency.

- 5 -

Expanded vermieulite aggregate 9 likewise 9 requires a

large amount of water to secure workability , The wafer glaze

on the plaster keys of some of the specimens of lath and plaster from the hospital building gave evidence that the vermieulite-sand gypsum plaster had been applied very wet, It is

known that vermieulite gypsum plasters are low in strength

and must be applied and cured under closely controlled conditions if cracking of white finish plaster is to be avoided.

There are relatively few examples where good results have

been achieved when the plaster base was expanded metal lath

on furring channels or on metal studs, Vermieulite plasters

are also susceptible to relatively large volumetric changes

as the result of changes in the relative humidity of the atmosphere , The sand which was used as the only aggregate of the base

coat plaster of the quarters building and as an additive to

the vermieulite aggregate of the base coat plaster of the

hospital building was finer in size than permitted by the

specifications and was indicated by test to be unsuited for

plaster aggregate. The resulting base ©oat plasters were low

in tensile strength, and in tests of 2-in, cubes had 0,6 percent volumetric shrinkage. The proportions of aggregates to

gypsum cement plaster were in excess, of. those usually found

in good plastering practice.

The plaster base consisting of expanded metal lath and

- 6 -

either lightweight metal studs or strip steel channels did

not have sufficient rigidity to hold the weak base coat plaster in position when subjected to the shrinkage effects cf

both the base coat and the white finish plasters* especially

after cracking of the white finish plaster had been initiated.

In the hospital building* the measured thickness of plaster

on metal lath was rather uniformly 3<A in. as specified* but

in many locations in the quarters building the thickness was

not more than two-thirds the thickness specified.

The evidence of long-continued dampness in the hospital

building leads to the conclusion that during the application

and curing of the base coats and white finish plaster the

careful control of conditions necessary to prevent the cracking of vermieulite plaster on metal lath was lacking. The

continuation of the damp condition probably caused the formation of the compounds ne squehon± te (MgCO-- ^S^O) and epsom

salts (MgS02i°7H20) within the white finishs compounds that

are found in efflorescence of plaster and that could account

for the excess of combined water found in analyses of the dried

white finish plaster specimens taken from the third* fourth*

and fifth stories.

There was evidence that high temperatures and rapid circulation of air were maintained, for part of the time that the

plastering operations were under way in the quarters building. Such a condition could lead to the too rapid drying of

white finish plaster over damp base coat plaster with the result that cracking would be almost inevitable* particularly

if the white finish plaster were stronger than the base coat.

- 7 -

The two extremes of long- continued dampness of plaster

in the hospital building and the rapid drying of plaster in

the quarters building by means of forced circulation of hot

air were both contrary to accepted good practice in plastering. It is not known to what extent the practices employed

by the plastering contractor were influenced by the specification requirement;

"Every precaution shall be taken to prevent too

rapid drying of the plaster and to that end windows

shall be closed as soon as the plaster is applied.*

if necessarys and the under coats of plaster shall

be sprayed with water as soon as partially set and

as often as required,,"

The specified precaution for spraying with water was doubtless

inserted to guard against possible dry-outs or the too rapid

drying of sanded gypsum plaster 0 This is not wholly compatible

with the best practice when vermieulite aggregate is used5 for that aggregate carries a large excess of water and holds

it rather tenacious ly.

- 8 -

1, INTRODUCTION

In April 1952* the Bureau of Standards was requested to

investigate the cracking of plaster in the Alaska Native Service Hospital then under construction at Anchorage* Alaska.,

Dr. Lansing S. Wells* Chief* Chemistry of Mineral Products

Section* was assigned to make the investigation. He visited

the project on April 25 and 26* 1952* and besides examinations

of the condition of the plaster* took samples from the set

plaster on the wall and conferred with the architect and representatives of the contractor* the Bureau of Indian Affairs*

and the producers of the vermiculite plaster aggregate. The

results of the investigation made at that time and subsequent

tests of materials were reported In a letter dated June 16*

1952* to Mr. Edward A. Poynton* Chief* Branch of Buildings and

Utilities* Bureau of Indian Affairs* and National Bureau of

Standards Report 9*>8/G-10015 dated September 17* 19£2* to the

Bureau of Indian Affairs* Department of the Interior* both

signed by Lansing S. Wells* Chief* Chemistry of Mineral Products

Section.

A further request from the Bureau of Indian Affairs* Department of the Interior* dated February 13* 1953* asked that

a team of three be sent to Alaska to make inspections and tests

to determine the cause of plaster cracking. The team consisting of Lansing S. Wells* William C, Cullen* and Nolan D.

Mitchell arrived in Anchorage* in the forenoon of February 21*

- 9

-

and proceeded at once to make the inspections requested and

to take samples of lath and plaster from the walls of the

hospital building (Project No, 501-228) and the quarters

building (Project No, 501-228A) . Containers of samples of

the gypsum plaster and lime bearing the dates of approval were

requested to be forwarded to the National Bureau of Standards

for test.

The members of this team were present at a conference

held by representatives of the general contractors for the work

and those of the Bureau of Indian Affairs on February 23 , 1953

.

The General Contractor, Boespf lug~Kiewit~Morrison, was represented by Messrso DeGarmo, Miller and Edsall, and the Bureau

of Indian Affairs was represented by Messrs* Finley, Halvorson,

Reimer, Featherstone, Burn, and others*

National Bureau of Standards Report 2585 "Report of Inspection of Plaster Work at Alaska Native Service Hospital and

Tests for Quality and Characteristics of Plaster Materials"

on inspections by Messrs* Wells, Cullen, and Mitchell and tests

on plaster and aggregates, was submitted to the Bureau of

Indian Affairs on June 19, 1953* Certain tests of materials

were continued beyond the date of that report. The results

of the tests, as well as a review of the previous inspections,

are incorporated in this report.

cii ! 1 ilia ' lo t oi 2 » EXAMINATION OF PLASTER, 1952

On April 25, 1952, a group which included Messrs. Harold

B. Foss, Architect^ Edward A„ Poynton, Chief, Branch of Buildings

- 10 -

and Utilities! Harry Halvorson, Area Construction Engineer;

V. P. Reimer, Project Engineer; J. C. Boespflug, representing Boespf lug-Kiewit-Morrison, General Contractor; William

Miller, Contractors General Superintendent; Lansing S. Wells,

Chief, Chemistry of Mineral Products Section, National Bureau

of Standards; Melvin Quayle, Zonolite Company; and others

inspected the plaster in various parts of the hospital building to observe its condition with respect to cracking. Dr*

Wells reported on June 16, 1952, that;

"From the inspection of the plastering it was

evident that the cracking was general throughout

the building where the plaster had been applied

to metal lath. This condition had not occurred

on the ceilings and other locations where plaster

was applied to concrete. The cracks extended

through the white coat and base coat to the metal

lath* With the possible exception that some of

the cracks radiated from the section where the

metal lath was overlapped, there did not seem to

be any definite pattern to the cracking. Cracking

appeared to be more prevalent in the corridors and

hallways than in the rooms, but appeared to be continuing, especially in the rooms."

Based on Dr. Well's knowledge of the properties of plaster and supplemented by conversations with those familiar

with what had occurred on the job, he reported as follows;

"The plastering contractor apparently attempted

to give a good job. However, he elected to use

vermiculite in lieu of sand, on the basis that,

in his opinion, the sand in the vicinity of

Anchorage was not particularly well suited for

plastering; only later to put some of this sand

in the mixture of gypsum plaster, vermiculite,

and water* The addition of sand seems to have

been made because the plaster mix without sand

tended to 'roll' under the trowel. In my opinion,

this tendency arose primarily from the fact that

- 11 -

initially too much water had been added to the

mix. Thus* the mix was a combination of gypsum

plaster, vermiculite, sand, and, apparently, too

much water. ..... "From what could be learned at the Hospital at

Anchorage, it is my belief that conditions were

far from ideal for the satisfactory drying of the

plaster. Although the building was heated so that

no freezing occurred, nevertheless, the' building

was not adequately ventilated to remove moisture

from the building during the drying period.

"It was observed in many instances that the base

coats of plaster were still damp below the white

coat, which appeared to be surface dry, and often

had been painted. This suggests that the white

coat had been applied to base coats that were too

wet. Although it is not necessary to wait until

the base coats are 'bone dry’' (for then they must

be slightly wetted) before applying the white coat,

nevertheless they should be at least partially

dry o ..... "An examination of the sample of set plaster shipped

to the Bureau revealed imprinted rust marks in excess of those normally seen on hardened sanded

plaster applied over metal lath. This is a further

indication that the plaster was moist for a longer

period of time than is usual in the case of sanded

gypsum plaster.

"Incidentally, it should be mentioned that this

sample was taken from an area over which the flat

metal lath had been overlapped and from which there

had been radiating cracks. It is my belief that

this radiation of the cracks from the overlapped

area of the metal lath can be explained on the

basis that over this overlapped area the plaster

is thinner than in adjoining areas. Consequently,

the plaster over the overlapping dried sooner than

that over the thicker plaster over the adjoining

areas and, therefore, the shrinkage cracks firstformed there and radiated from foci within the

overlapped area.

"As stated previously, there was little or no cracking of plaster over the areas where the plaster had

been applied to the underside of the reinforced concrete floor slabs. It was stated that the concrete

- 12 -

in the building had been poured for a considerable

period of time before the plastering was undertaken, and that the concrete had dried well, lb

is suggested that the dry concrete absorbed enough

water from the very wet plaster to reduce the moisture content of the plaster after it had been

applied and before it had set to reduce the shrinkage on further drying very greatly. Furthermore.,

the probability of cracking would be reduced on a

solid plaster base such as concrete, as compared

with a more flexible base such as metal lath."

3. EXAMINATION OF PLASTER, 1953

The examination of plaster on February 21, 22, and 23*

1953* was made by Messrs, Wells, Mitchell, and Cullen, The

condition was essentially the same as revealed by figures 1

to 11, inclusive, which show the pattern of the cracking of

plaster applied on metal lath. The cracks observed on suspended ceilings of plaster applied on metal lath were of the

same pattern but fewer than those in partitions having metal

lath on metal studs as the plaster base. The cracking of

plaster in the hospital building was more extensive than

found in the quarters building. The direction of the cracks

in the hospital, figures 1 to 8, was observed to be of a more

random pattern than in the quarters building figures 9 to 11.

In the quarters building the cracking of wall plaster was

ordinarily more vertical in direction than otherwise. It

was likewise observed in the hospital building that where

sand was mixed with the vermiculite aggregate, the cracks

appeared to be closer spaced than where vermiculite alone

was used as the plaster aggregate. There was no evidence

in the quarters building of the plaster having
.
13 -

remained in a wet condition for an extended period* as was

evident in the hospital building where streaks remained* indicating that water had condensed on the partition and coursed

down the surface.

3.1 Inspection of Quarters Building Plaster,

Inspection of the quarters building (Project 501-228A)

was begun on February 21* 1954, and continued during the forenoon of February 22$ 15 of 20 rooms visited and the corridors

in the helps' quarters were found to have cracks in the plaster applied on metal lath. Plaster applied on reinforced

concrete* apparently had no cracks except where the concrete

was cracked. Cracks were observed in rooms Nos. 200* 201*

207 , 209, 212* 214* 215, 217, 303, 309, 311, 321, 325, 329,

331, and in the walls of the corridor in the vicinity of

room 303. A number of the cracks extended from the corners

of the electrical outlet boxes* and the direction of the

major wall cracks* as previously mentioned* was usually more

or less vertical. Several of the larger cracks were intersected by smaller cracks extending laterally from the larger

ones. There were some examples of cracks in random direction

forming a pattern known as "map cracking." In a few of the

rooms and at some places in the corridors of the quarters

buildings* figures 9 and 11* horizontal cracks indicated

the height at which the plastering operation from the scaffold stopped.

Not only were there cracks in the plaster on metal

- 114. -

lath but a number of the ceramic tiles in the wainscots of

bathrooms were found to be broken; and, in a number of places,

wall tiles were found to be loose from the backing of portland cement plaster on metal lath, A tier of the wall tiles

was removed from the wainscot in one location and three

horizontal cracks in the cement plaster base were observed

to be spaced about a foot apart in the height of the wainscot* These cracks extended through the neat cement setting

mortar and the mortar base course made of Portland cement and

hydrated lime. The cracking of the base course of mortar for

the tile wainscot was attributed to shrinkage,

3 ,2 Inspection of Hospital Building and Plaster.

The inspection of the hospital building (Project 501-228)

and plaster was begun on February 22 and continued on the 23rd

and 2i|.th. An inspection of the exterior of the monolithic

concrete building walls was made before the inspection of the

condition of the plaster was begun. Thin cracks were seen

below the first-story windows. Several of the cracks extended

through the window sills or extended downward from the corner

of the window opening. Nearly all of the cracks seen were on

the south and west walls of the building. There were a few

cracks in the east wall, but these appeared to be smaller than

those seen on the south and west sides. The cracks in the

exterior walls are doubtless the result of shrinkage of the

monolithic concrete. There was no discernable evidence of

unequal settlement of the foundation.

15 -

Approximately :6C percent of the rooms and all the

corridors were visited. Cracks were found in almost all of

the metal lath and plaster partitions inspected. There were

also cracks in the lath and plaster furring for pipe spaces.

A very large proportion of the plastered walls had been paint

ed. In some instances* the painting had been done after the

plaster had cracked. Many of the cracks* however, appeared

to have occurred subsequent to the application of the paint,

indicating that the cracking had been progressive.

Figures 1 to 8, inclusive, show the typical pattern of

cracking of the plaster in the hospital building. In some

instances, the principal cracks were in long curves (Fig. 4),

many reaching to the metal electrical outlet boxes, (Figs.

5, 6, and 7). It is likely that many of these cracks started

at the outlet boxes.

Samples of plaster for analysis were taken without lath

from the basement corridor and from one room in each of the

six stories. Other plaster samples for stability measurements were removed from the walls and included the metal lath

and plaster keys back of the lath, as shown in the figures 12

13, and 14. These specimens were about 16 in. square and the

presence or absence of water glaze showed that the water content of the plaster mix varied considerably. The differences

in water content were also indicated by differences in the

length and appearance of the plaster keys. Five of the lathand-plaster specimens were sawed into 3-in„ wide strips to

determine changes in length that might occur when they were

- 16 -

exposed in atmospheres having high or low humidity; and also

how they were affected by changing from high to low humidity;

and vice versa.

During the conference among -/‘representatives of the contractor and the Bureau of Indian Affairs , Mr, DeGarmo cited

the increases in the number of visible cracks in each of

several rooms between October 15, 1952, and February 23, 1953*

the time of the conference. This information indicated that

the cracking rate, which had increased during the winter

months, was aggravated by the low relative humidity which,

on February 23, ranged from 17 to 28 percent in various parts

of the building. As examples of the increase of cracking,

Mr, DeGarmo stated that on October 15, 1952, room 507 had 3

cracks and on February 23, 19 j that on October 15, 1952,

room 511 had 1 crack, and on February 23, 16. The progress

of cracking in several other rooms was reported to be of

about the same order,

4. TESTS OF MATERIALS, 1952 SERIES

Materials collected for tests in 1952 consisted of sand

from Anchorage, Alaska, recovered from the project site, and

a piece of plaster taken from the wall of the fifth story

corridor, south wing, of the hospital building. Other materials from the project were U, S, Gypsum Company's Red Top

gypsum cement plaster^ f ibered; Boulder Canyon Miracle Lime,

produced by U. S, Lime Products Corporation, Henderson,

Nevada; and expanded vermiculite, produced by Vermiculite

- 17 -

Northwest, Inc, at Portland, Oregon, The gypsum cement plaster, hydrated lime, and sand were tested for conformity with

the requirements of appropriate specifications.

Ip • 1 Gypsum Cement Pl&ster

The gypsum cement plaster was tested in accordance with

Federal Specification SS-P-1+02 with additional tests for

tensile strength of plaster mixes (using normal consistency

determined under Federal Specification SS-P-I4.02)

.

Table 1, Analysis of gypsum cement plaster

(Fines, 96,81 percent of total)

[Basis, sample dried at 1+5>°C]

Fines Composition

Calculated

compounds

Percent Percent

CaO 37 . 14-2 - -

CaSO^'-gi^O calculated from CaO _ - 96.92

so

3

lj- 9 ,66 - - CaSO^gf^O calculated from SO^ _ _ 89 088

E^O combined 5.83 - - CaSO^gl^O calculated from t^O - - 93,92

CaSOj^gl^O of sample (89,88 x 0.9681) - 87,01

- 18 -

Table 2 . Characteristics of plaster

Composition of mix Normal

consistency,

water

Time

of

set

Tensile

Aggrega te Plaster Water strength

Kind Weight Weight Volume

Ottawa sand

Ottawa sand

Anchorage

sand

Vermiculite

Vermiculite

,

Anchorage sane

E.

225

200

225

17

17)

4.0)

75

100

75

100

100

ml

60

58i

78i

89-1

Percent

16

20

i9i

67

57

hr.

12

5i

12

11

lb/in.

24-5

200

115

Ij.. 2 Aggregates,

Tests of sand from Project 501-228, Anchorage, Alaska, The

sand was tested by the methods of the specif Ications indicated

beside each test:

Specific gravity and absorption (ASTM Designation- C128-4-2)

Specific gravity 2.65

Absorption 1*8 percent

Organic impurities (ASTM C35-52T56 and CI4.Q-I4

. 8 ) Color of hydroxide solution: Jet black, indicated as

unsuitable for use in interior plaster because of high

percentage of organic impurities.

19 -

Table 3 . Sieve analysis of sand

(ASTM Designation C 136-Ij. 6 )

Sieve Passing Retained

No. Percent Percent

3/6 in. 100 0

k 100 0

8 95 5

16 90 10

30 80 20

50 k-3 57

100 11, 89

200 s

1 95

^Determination made in accordance with the method of ASTM

Designation C117-[|_9.

Table l\.. Soundness of sand

(ASTM Designation C88-I4.6)

(Solution, magnesium sulfatej

Sieves

Passing Retained Corrected loss

No. No. Percent

TT nr 0.2

8 16 0.2

16 30 0*6

30 50 2^

Total 3.5

Sands finer than No 50 sieve were not subjected to the soundness test*

Tests of vermiculite aggregate* The bulk density 11*22

lb/ft3 of vermiculite aggregates was determined by the jigging

method, l/lO ft3 measure (ASTM Designation C29 -4- 2 ). (Note:

The bulk density of this specimen was 10 percent greater than

for the samples received later.)

- 20 -

l\. „3 Hydrated Lime

The hydrated lime was tested in accordance with methods

in Federal Specification SS-L-351 with additional tests for

free CaO+MgO and autoclave expansion and was found to meet

the requirements for type S hydrated dolomitic lime„

Table 5>o Analysis of hydrated lime

(Ba$is, sample dried' at ij- 5

0 C)

Characteristics

Fineness: Percent

Passing sieve No „30 100 o0

Passing sieve No o 200 91 o 4

Oxides

co

2

0 o 10

H2° 27 c 08

CaO W.76

MgO 28o88

Si°

2 0*20

R

2°3 O0I4.I

Total 100 olt3

Compound composition

CaC0

3

0 0 23

Ca( OH) 2 57.65

Mg( OH)

1|1o78

h2

o O0I6

Si°2

0 o 20

r

2°3 0*41

Total 100 0 43

Computed constituents

CaO+MgO (anhydrous basis) 99 0 00

C 02 (anhydrous basis) 0.34

CaO+MgO unhydrated OoOO

Linear expansion

Expansion in autoclave-^- 0 o 07

Plasticity

Index i Determination, by ASTM CllO-lj.9 l4.Bo~

-L The autoclave expansion bar was fabricated of lime and

Portland cement in the ratio of 1 to 1 and tested according to Federal Specification SS-C- 158C

- 21

4„4 Tests of Plaster Mixes

A piece of finished plaster with keys broken,, but otherwise intact* was stripped from the lath of the corridor wall*

fifth floor* south wing* of the hospital building on April

2 6 * 1952o It was 8-= by in size and 3/4 in„ thick e Linear changes from wetting and dryings The specimen

was prepared for test by drilling holes into which reference

points for a 5~in„ Whittemore strain gage were cemented with

Densite plaster,, The specimen plaster was moistened at the

holes before the reference-point pins were cemented into

place,, The specimen thus prepared was exposed to drying in

the air of the laboratory for 24 hr before the initial measurement with the Whittemore gage was made, After the initial

measurement of length between gage points was made* the specimen was subjected alternately to soaking in a saturated solution of calcium sulfate (CaSO^) and drying in an oven at

50°C e Measurements were made at the end of each half of each

wetting and drying cycle* when the specimen had reached constant weight. The linear changes of the gage length of the

specimen* based on the initial measurement* were as shown in

table 6 0

- 22 -

Table 6. Dimensional changes of set plaster specimen

(Minus quantities indicate shrinkage)

Condition of specimen

Linear change of gage length

k Total

change

Differences,

reading to reading

Air dried for 24 hr (Base Percent Percent

length 5 in.

)

0 . 000 - - Dried to constant weight

at 50°C. -0.060 -0.060

Wet - 0.004 +0.056

Dry, 2nd cycle -0.080 -0.076

Wet -0.022 +0.058

Dry, 3rd cycle -0.088 -0 . 066

Wet -O.O36 +0.052

Dry, 4 th cycle -0.102 -0.066

This plaster specimen showed continued shrinkage superimposed

on the alternate shrinkage and expansion of the drying and

wetting cycle. The specimen was only 0.024 percent longer

in the wet condition at the end of the third cycle , than

when in the dry condition at the end of the first drying at

50°C, although the change of length between the wet and dry

condition averaged about 0.067 percent.

4.5 Expansion Test Bars.

Bar specimens made of plaster mixes of gypsum cement

plaster and vermiculite and others made of gypsum cement

plaster, vermiculite, and Anchorage sand were cast in steel

molds described in ASTM Designation C 227- 52 T, figure 2 , with

- 23 -

inset stainless steel reference points , The specimens were

1 in„ square by 11 3/8 in 0 long with 10 in 0 length between

the inner ends of the reference points „ The bare specimens

were measured as soon as removed from the molds and at intervals thereafter * as shown in table 7. They were stored in

the laboratory maintained at 73°F (23°C) with relative hu°

midity at 50 percent until the interval immediately preceding the last reading* in which latter interval the

relative humidity of the container in which the bars were

stored* was 30 percent* the temperature remaining 73°P

(23°C) 0

214-

Table 7 « Length changes of expansion test bars of

gypsum plaster mixes

(Minus quantities Indicate shrinkage)

Composition of Bar identification

plaster mixes 1 1A 2 2A

Gypsum -cement plaster, g 200 200 200 200

Vermiculite ( expanded),

g

34 34 34 34

Water, ml 78 156 90 177

Sand (Anchorage), g

- 80 80

Linear change s relative to original

Age of specimen 10 in,

points

length between reference

Days Percent Percent Percent Percent

1

- 0,000 - 0.000

2 0,000 0.004 1 0,000 0.004

3 0,007 0.003 0,001 -0,003

4 0,013 “ 0.019 .007 - .017

5 ,016 1 - .020 ,oi4 - .-18

6 ,007 - ,019 ,oi4 - .017

7 - ,008 “ .021 ,008 - .018

8 - ,012 -- - .010 —

9 - ,010 - ,008 , -- 10 - .020 „ — i e oH—1 14 - ,006 -- - .002 —

17 - .014 - .010 „ -- 18 - .015 - ,019 - ,011 - ,017

28 -- - , 022 -- - ,020

38 *

, ““ - .022 . -- - .019

5i 2 " ,015 „ -- “ .011

56 - ,022 - .027 “ .018 - ,023 •

^Bars 1A and 2A stored 18 days in a container the relative

humidity of which was held at 30 percent after this reading*

pBars 1 and 2 stored 5 days in 30 percent relative humidity*

- -

5. TESTS OF MATERIALS * 1953 SERIES

5.1 Materials.

Specimens of materials received from Projects 501=228

and 501“ 228a included approved samples of fibered gypsum

cement plaster* gypsum cement plaster* not fibered* medium

set gauging plaster and hydrated lime. Other materials from

the projects included sand from a lot delivered to the job*

seven specimens of plaster taken from six rooms and one corridor for determinations of proportions of aggregates and

plaster mixes* six specimens of lath and plaster cut from

the walls of the hospital building and two from the walls of

the quarters building. Visual examination and a settling

test indicated that large quantities of silt were present in

the water available on the site. Additional materials for

test were purchased from dealers in Seattle* Washington* who

had supplied plaster* lime* and aggregates for the project.

These materials included U. S, Gypsum Company 8 s Red Top fibered gypsum cement plaster* gypsum cement plaster* unfibered*

and Red Top gauging plaster ; U 0 S. Lime Products Corporation's

Miracle hydrated lime; and sand from a dealer in Anchorage*

Alaska.

5.2 Tests of Plasters.

jment plasters, fibered and unfibered. The speei=

mens of approved plaster samples were tested and analyzed to

determine whether they conformed to the requirements of Federal

Specification SS-P-402 and for other characteristics.

- 26 -

Table 8. Characteristics of U.S. Gypsum Red Top plasters and plaster mixes

(Basis, sarrples dried at 45 °C; proportions by weight)

Sample designation Typel Con- Time Con- 'Tensile Two-inch cubes Neat nlaster

sistency

of

set

sistencystrength Compressive

strength

Shrinkage

GaSOl^-gl^O Insoluble

Gypsum cement,

hr Psi psi percent percent percent

plaster, fibered, 1- 1;2 Ottawa sand

N 20 24 190 90.0

Gypsum cement

plaster, unfibered,^

ls2 Ottawa sand

N 19* 10J *"** 225 90.3 OB0

Gauging plaster,

medium set G 46 Si - 540 - - 93.0 -

Gauging piaster^ 3 >£/ G 49 2 - 540 2470 2.00 98.3 -

Gypsum cement

plaster, fibered,? 240

ls2 Ottawa sand

N isi Ti 2ii 1190 92.8 U3«S5

Gypsum cement

5i 0.6

2.1

plaster, 1 s 2

Alaska sand ?

Gypsum cement

N 21 23-1 185 1030

plaster, Red.

Spec. SS-P-401j>5

N 5<4 8 50* 350 1930

(avg. 0,

2.3

: two lot s)

Gypsum cement

plaster, 150g 365

needle for con- sistency 5

N 5Si 1880 3.0

1 Retained sample of plaster approved for project 50l~228. ^ Sample purchased from dealer who supplied material for project.

3 All of 25g sample of gauging plaster passed through No. 100 sieve,

h

'Average of 5 determinations, namely, 3° 73s 3*80, 3»S5 C 3»^9 and 3.98 percent.

^ Cubes ipade from the four plasters and plaster mixes showed decided shrinkage.

- 27 -

5*3 Tests of Aggregates

Sand, Two lots of sand were received from Alaska, The

sieve analyses were as shown in table 9*

Table 9. Sieve analyses of two lots of sand and pro

portions as recombined for use in

plaster specimens

Sieve

Retained on sieve

Lot 1 Lot 2 Recombined lot

No. Percent Percent Percent

8 5.9 6 ,

9

£.0

10 12,1 11.9 5.0

30 23.5 27.35 10,0

50 39*7 39*7 lj.0,0

100 18®8 13.9 4.0,0

The sand from the two lots received from Alaska were

separated by sieving and recombined to give approximately the

same gradation as the sample taken from the project in April,

1952* (See table 3*) The magnetic content of the sand found

by making six determinations was approximately 4- percent®

Vermiculite

One bag ( I|_ ft3

) of expanded vermiculite was

received from Vermiculite Northwest, Inc® This material was

checked for bulk density by filling a 10-gal measure® It

was found by two determinations to weigh 10.1 lb/ft3 and its

magnetic content, as determined by means of an Alnico magnet,

nil®

The sand as recombined for size and vermiculite of the

above lot were used to make plaster specimens for expansion

bars and specimens to show the flexing of lath and plaster

under various conditions of relative humidity®

- 28 -

5.4 Tests of Hydrated Lime

Samples from projects . Two cans of hydrated lime submitted by the Contractor for approval of the Project Engineer

were received from Anchorage * Alaska . Notations on one of

the cans, indicated that the material had been approved for

use

.

Sample from dealer , A bag of Miracle Brand hydrated

lime 5 manufactured by U, S, Lime Products Corporation*

Henderson* Nevada* was received from Pioneer Sand and Gravel

Company* 901 Fairview North* Seattle* Washington* This was

the same brand of hydrated lime as was used for the white coat

finish of both the hospital building and the quarters building*

These three lots of lime were analyzed for conformity

with the requirements of Federal Specification SS-L-351 with

the results shown in table 10,

5.5 Proportions of Aggregates in Base Coat Plasters

Specimens of plaster removed from the metal lath plaster

base at the project* after having the white finish removed*

were analyzed for the proportions of aggregates with the results shown in table 11, After having the plaster dissolved

by ammonium acetate the residue was washed* dried* and weighed.

The magnetic content of the residue was separated by the use

of a magnet* and weighed. From the known insoluble content

of the gypsum cement plaster and the magnetic content of the

aggregate* it was possible to compute the volumes of vermiculite and sand in relation to the gypsum cement in the setplaster samples.

- 29 “

Table 10. Characteristics of U. .S. Lime Products Corporations 5 s "Miracle"

lime, used in white finish plaster for Alaska Native Service

Hospital, Anchorage, Alaska.

(Basis, samples dried at room temperature)

Analyses

Characteristics Sample designation!

Lot 1 Lot 2 Lot 3

Fineness: Percent Percent Percent

Passing sieve No. 30 100.0 100.0 100.0

Passing sieve No. 200 95.1 93 .2 93 “2

Oxl des

C02 0.50 OT69, 1.85

h2o 26.47 26.51 25 . 5O

Si02+R20^ 0.85 0.63 O .69

CaO 42.8? 43.31 43.32

MgO 2^ 0 6s 29.44 28.39

Total 100.37 100 . 5S 99-75

Compound C opposition

CaCO^ 1.14 1-57 4.21

Ca( OH)

g 55. 80 56.06 54.12

Mg (OH) 2 In. 77 41.70 39.95

MgO 0.81 0.62 0.7S

S

i

02+R20

^ 0.85 0.63 O .69

Total 100.37 100.58 99.75

Computed Constituents

CaO+MgO, nonvolatile basis 99-3 99.0 98.7

C 02 , nonvolatile basis 0.70 0.94 2.55

MgO on basis of CaOtMgO 40.9 40.5 39.6

MgO, hydrated 97-3 97°9 97.3

CaOtMgO, unhydrated 0.81 0.62 0.78

, Linear expansion

Expansion in autoclave - O .03

Plasticity

Index Index Index

Determination by ASTM C110-49 480 580 430

1

Tile can containing material of lot 1 was labeled; "General Contractor—

Boespflug-Kiewit-Morrison; Subcontractor—Steeves & Wilson; Subject—

Anchorage Hospital Project 501-228 ; Manufacturer—U. S. Lime Products Corp.;

Material—Miracle Lime."

The can for lot 2 was labeled "United States Lime Products Corp., Boulder

Canyon Miracle Lime, Dolomitic Pressurized Hydrated Lime; Contr .—Steeves &

Wilson; Quarters Bldg., Alaska Hospital; checked H/13/51 hy H.H." (Probably

Harry Halvorson)

Lot 3 was from a bag of "Miracle" Hydrated Lime purchased from Pioneer Sand

and Gravel Co., Seattle, Washington

Table

11,

Analysis

of

base

coat

plasters,

for

proportions

of

aggregates

by

the

ammonium

acetate

method

and

magnetic

content.

- 30 -

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- 31

5» 6 White Finish Plaster

Analysis of specimens

®

The white finish plaster analyzed

for proportions of lime and gauging plaster had been removed

from the specimens used in making determinations of the proportions of plaster and aggregates of the base coat plaster®

The results of the analyses are given in table 12® There

were wide variations in the proportions , but in no case was

the proportion of lime putty to gauging plaster excessive c The computation was made on the assumption that 1 ft^ of

lime putty contained 45 lb of dry hydrated lime and 1 ft-' of

dry gauging plaster weighed 65 lb®

An examination of the compound composition in table 12

in which an excess of H20 is reported for the plaster specimens from the three upper stories of the hospital building,,

which were among the first plastered,*, has led to the conclusion that in the continued presence of excessive moisture

nesquehonite (MgCO^* 3H20) and epsom salts (MgS02j.°7H20) had

been formed® Such reactions have been described in National

Bureau of Standards Research Paper RP1538 ’'Function of Carbon

Dioxide in Producing Efflorescence on Plaster and Cement Products" (May 1943)o
,* .

.
- 32

Table 12. Analysis of white finish plaster from hospital building

(Basis, material dried at 45°C)

Analyses

Sample designations^- B Hall N12 E106 N245 E316 S43S W504

Oxides

Percent Percent Percent Percent Percent Percent Percent

C02

l 11.87 10.02 11.52 10.02 10.62 12.22 4.4i

H20 (combined) 21.16 16.47 17.54 18. 27 23.34 17.47 21.01

S i Op+Bp 1.12 1.21 0.60 0 . 6l 2.18 1.09 0.70

CaO 35.62 34.95 36087 32.70 34.58 34.51 32.24

MgO 18.02 10.57 14.89 14.83 16.86 12.44 12.77

S0

3

12.49 27.23 is. 99 23.69 12.70 22.38 29.03

Compound composition

CaSOty” 2H2 0 26.86 40.84 50*94 27.31 48.13 62743

CaC 26.99 22.79 26.20 22.79 14.15 27.27 10.03

Ca( OH) 2 15.52 4.11 11.74 4.4i 26.06 5.00 8.31

Mg ( OH) 2 26.07 10.42 19.88 21.16 24.39 18.00 is. 47

MgO 3.72 3*37 1.15- 0.20 0 00 0.00 pO.OO

HpO excess 0.00 0.00 0.00 0.00 6.19 U .62 0.22

SiOp+RoO? 1.12 1.21 0.60 0 o 61 2.18 1.09 0,7.0

Total 100.28 100.45 ioo.4i 100.11 100.28 100.11 100.16

MgO of lime

Proportion;

MgO

CaOfMgO 4l.4 4o.o 38.7 3 47-9 39.6 39-S 3 5i-7

Hydrated 79 A 68.1 92°3 98°7 100.0 100.0 100.0

Lime putty in mix

Proportion of putty Ratio Ratio Ratio Ratio Ratio Ratio Ratio

to CaS04*'gH20 3-5 O .95 2.0 1.3 3*3 1.4 0.81

White finish plaster

\ in. in. in. in. in. in. in.

Thickness 1 1 1 3 1 1 1 1 1 1 1 1

UT T5 IS 32 32 IS 32 32 lS IS W " TE

Letters in sample designations signify, respectively s B, basement; N, north;

E, east; S, south; W, west, and figures denote room numbers as given on the

architectural plans

The excess H2O may be attributed to nesquehonite (MgCOyj^O) » epsom salts

(MgSOty^^O) , or the unidentified mineral s. 5 Samples N245 and W504 shown apparently abnormally high percentages of MgO in

the lime. Possibly some vermiculite from the base coat was carried into the

white finish plaster in the troweling. If so, this would upset the validity

of the calculations which were based on the assumption that the white finish

plaster consisted wholly of lime and gypsum.

- 33 -

There is a high degree of probability that the same reactions had occurred in other stories of the building., but

in the calculations of compositions the evidence is masked

as long as any magnesium oxide (MgO) appears to remain unhydrated o This type of reaction would occur in the more

favorable locations * rather than uniformly throughout the

white finish plaster* and may account for initiation of

cracking and. the closer spacing of plaster cracks near the

floors.

5o7 Expansion Tests

Expansion of test bars. Bar specimens of plaster mixes

consisting of 20 parts gypsum cement plaster* 8 parts vermiculite* and 5 parts Alaska sand by weight were cast with stainless steel reference points in the ends in steel molds as

described and shown in figure 2 of ASTM Designation C227-52T.

The length of the bars between reference points was 10 in.

A strip of wet cardboard was placed in the bottom, of the mold

to make the bars 1- by 7/8-in. in cross section. Immediately

upon removal from the molds* bars A and B expanded In length

0.03 and 0.02 percent* respectively* as shown in figure 15 . A l/l6-in. thick white finish was applied to the side which

had been molded against the cardboard. After application of

the white finish* the bars were laid horizontally in a humid=

ity chamber on a continuous support and without restraint

other than their own weight. The specimens continued to expand as shown in figure 15 o Under the influence of relative

humidities ranging from 93 to 97 percent* at 72°F* bars A

- 3k

and B had increased in length by 0,130 and 0.156 percent

respective ly* in two weeks. The bars were then placed in a

chamber* the relative humidity of which ranged from 30 to 18

percent* for the next four weeks. During the first two weeks

of this period* the length of the bars decreased by 0.046 and

0.048 percent* respectively. During the next two weeks* the

* shrinkage in length of each amounted to 0,007 percent. The

subsequent changes in conditions of storage and lengths of

bars are shown by the graph* figure 15 • 5,8 Stability of Lath and Plaster from the Hospital Building

Changes in length of specimens. Five of the 16- by 16-

in, specimens of lath and plaster cut from the partitions of

the basement* first* third* and fifth stories of the hospital

building were sawed into 3-in, wide strips and subjected alternately to high-and- low or low-and-high humidity at nearly

constant temperatures. Changes in length between gage points

10 in. apart on p-in. diameter brass discs cemented to the

front and back surfaces of the plaster were measured by means

of an optical comparator. The comparator was calibrated

against a 10-in. invar standard bar at the time each set of

readings was made.

Two chambers having controlled humidity were used for

storage of specimens between readings. The specimens were

transferred from one chamber to the other at the time of

making the measurements. The cycles of storage and the percentages of relative humidity are shown by the graphs at the

top of figures 18 and 19. The length changes from reading

-

to reading are shown as percentages of the 10-in gage length*

Certain anomalies are apparent in the graphs* For example, although the relative humidity of the chamber (Fig.

19) was about 30 percent, the average increase in the lengths

of the specimens was approximately 0.05 percent* An exception to this trend was the shrinkage on the key side of the

specimen marked 7 & 8C which showed a slight decrease in

length* The general trend was for expansion of the plaster

when exposed to high relative humidity, and shrinkage when

the humidity was lowered. Some of the anomalies can be attributed to internal cracking of the plaster when the strains

induced between the plaster and lath could no longer be

resisted by the plaster. There was no decided difference

in the deformations of the specimens cut in horizontal strips,

length-wise of the lath, in comparison with those cut vertically, that is, transversely to the lath. The deformations

on the back or key side of the specimens were usually, but

not always, smaller than those on the finish side.

It will be observed that the lengths of the specimens

were usually increased with increases in relative humidity

and decreased when the humidity was lowered. When dampened

at l8-§- weeks, the expansion brought the length up to approximately the same state as was reached in the earlier stages of

the test under the influence of high relative humidity.

5.9 Plaster from Quarters Building

Examination of plaster specimens. The two 16- by 16-in.

specimens cut from the walls of the quarters building were

- 36 -

examined for friability and thickness of plaster as well as

the condition of the lath. The plaster had been applied in

three coats i scratch* brown* and finish coats* There were

voids in the furrows in some parts of the scratch coat where

the brown coat plaster had not filled the scratch furrows*

and there appeared to be a plane of weakness in one specimen

between the scratch and brown coats. The gypsum plaster seemed to be weak and somewhat more friable than is the ease with

the usual gypsum plaster as applied to metal lath. The white

finish was decide ly stronger than the base coats*

The measured thickness of the base coats plus the white

finish plaster from the face of the expanded metal lath to

the face of the white finish as determined by 20 measurements on the two specimens was 0,54 in. The plaster keys on

the backs of the metal lath varied widely in depth and appearance, Water glaze was apparent on the keys of one of the two

specimens of lath and plaster. The lath from the quarters

building where the plaster had been stripped from it* showed

less corrosion than was found on the lath from the hospital

building.

In addition to the measurements of plaster thickness on

the two specimens obtained from the quarters building* measurements were made by Chief Area Engineer* William Featherstone

in May 1954* hy drilling into the plaster and measuring from

the surface to the lath with a depth gage. The thicknesses

of the plaster of partitions and ceilings as measured by

gages inserted into 101 drilled holes ranged from 1/4 to

- 37 -

1 1/8 in. * the average being 0.66 in. At 68 of the 101

points where the measurements were made* the depth from the

surface to the lath was less than specified* and at 19 points

it was in the range of 1/4 to 1/2 in., the average of the

latter range being 0.44 in. Inasmuch as the strength of the

plaster in resisting bending varies as the square of the

thickness* it can be assumed without question that the deficiency in thickness was a factor in the development of the

plaster cracks.

Sand used in plaster for quarters building. A retained

sample of sand for the quarters building* Project 501-228A*

marked "Submitted by MeDougall-Dixon & Pardue" was subjected

to a sieve analysis with the following results? 0.1 percent

was retained on the No. 8 sieve* 3*2 percent on the No. 16

sieve* 27.3 percent on the No. 30 sieve* and 77*0 percent on

the No. 50 sieve. When subjected to the ASTM Test for Organic

Impurities (ASTM Designation C40~48)* the color of the sodium

hydroxide solution in which the sand was tested was darker

than the No. 5 (darkest) reference color* in fact the color

was almost jet black. A sample of the sand was washed with

running water until the effluent appeared clear and then subjected to the same test. The sodium hydroxide solution on

this sample was slightly darker than the No. 4 reference

color

- 38

The ASTM Specification C35-52.T states that:

"Sand, when subjected to the colorimetric test

for organic impurities, shall develop a color

no darker than the standard, unless it is established by adequate tests that the impurities

causing the color are not harmful to plaster,"

The color of the standard reference No, 2 is that produced

"by adding 2,5 ml» of a 2 per cent solution of

tannic acid in 10 per cent alcohol to 97 <>5 nil,

of a 3 per cent sodium hydroxide solution*"

5,10 Strength of Sanded Gypsum Plaster

Comparison of strengths of plasters with sand aggregates, Tests were made to compare the tensile strengths of

sanded gypsum plasters made with 1 part of fibered gypsum

cement plaster to 3 1/3 parts by weight of sand. One lot

was made with graded Ottawa standard sand and the other with

washed sand from Anchorage, Alaska, The average tensile

strength of the five specimens of the first lot was 150

lb/in, 2 and for the six specimens of the second lot, 125

lb/in, 2

, The strength of the plaster made with the sand from

Anchorage, Alaska, was 5/8 that of plaster made with Ottawa

sand. The minimum permissible strength of sanded scratch

coat plaster under Federal Specification SS-P-402 is 125

lb/in, 2

, Therefore, the mixture used for the tests met the

specification requirements for strength of scratch coat plaster.
4

ft
FIGURE

1°

PROJECT

501—

228.

WALL

SECTION

OF

ROOM

W—

825

(DUN!

NG

ROOM).

THE

CRACK

PATTERN

'9

TYPICAL

OF

STEEL—

STUD

WALL9

*wn

miing

re

II

LINGS

IN

THE

FIRST

STORY.

THE

9-BY

IS-FT.

WALL

AREA

SHOWN

REQUIRED

86

L8NFT.

OF

REPAIR.

FIGURE 2. PROJECT SOS— 228 - WALL OF ROOM W-149 (WAITING ROOM), A TYPICAL STEEU-STUD CONSTRUCTION, THE CRACK PATTERN OF WHICH WAS THE SAME AS IN OTHER AREAS . THE I I—BY 20-FT. AREA SHOWN

REQUIRED 139 UN. FT • OF REPAIR.
•

•
riGURt

3

PROJECT

SOS-228-

NORTH

WALL

OF

ROOM

E-202*

CRACK

PATTERN

AND

CONDITION

TYPCCAL

OF

ALL

STEEL—

STUD

WALLS

ON

SECOND

FLOORTHUS

WALL

REQUIRED

90

LtN«

FT

°

OF

REPAIR

FOR

THE

8-BY

S-FT.

SECTION

SHOWN.

FIGURE 4. PROJECT SOI-228. CORRIDOR E-501 ; 99f> OF GRACK9 THROUGH TO LATH. THIS WALL

REQUIRED 73 LIN. FT. OF REPAIR ON 9-BY 1 0—FT • AREA SHOWN.

NORTH

WALL

OF

ROOM

N-5S8

(PRJNTED

REVER3EO)

SHOW

ItNG

CRACKS

GROOVED

f'SURE

6-

PROJECT

500-^228-

SOUTH

AND

CORRCDOR

WALLS

Of

ROOM

N-51'8

(

PR5NTED

REVERSED

)

SHOWING

CRACKS

GROOVED

READY

TO

BE

FiLLEO.

FIGURE 7 . PROJECT 501-228, NORTH WALL OF ROOM 518 NEAR DOORWAY, FIG. 5, SHOWING CRACKS DEVELOPED AFTER HAVING BEEN REPAIRED TWICE PREVIOUSLY. PHOTOGRAPHED OCTOBER 28, 1952*
cjft ^

<p,

®

c\ P <P °V v/& %

P+ C5 ^

'vdl- ' 4 ®o Q> ^ 5>

., <A <j A ©

Q.V <Pr v* <$ o, v I*PPPPPPPPPPPiIPP

c\

CD Vs 
 ,

<A ^ V. C1 r V^v < C1*

• v %

* ^

>oO

\9„ <* %'a %

V) \

* ro ' j?

n

V

I

K

I

I

i

n
r*.GURC

9-

PROJECT

S0I-228A.

PATTERN

OF

CRACKING,

NORTH

WALL

OF

ROOM

E-240,

QUARTERS

BUILDING

ON

NOVEMBER

17,

I9S2.
%c\

%

%

if.

- %.\\<S> %K% %%% %*
w* a I UJ

*- ac

o5 5rAw

kfi ^ ca

- hi (_>

*
•«S

Ji? Of

fi/?0. *»_ ' J9s^tSp ^

S°1

«&C*

UM

*3*4

*1
HGUftE

II.

PROJECT

50I-228A.

PATTERN

OF

CRACKING

IN

TME

WALL

OF

THE

NORTH-WING

CORRIDOR,

SECOND

FLOOR

OF

QUARTERS

BUILDING

ON

NOVEMBER

17,

1952.

THIS

WAS

TYPICAL

OF

CRACKS

IN

THE

CORRIDOR

PARTITIONS.
4-Z &.

e*st w*l2. n0

$RS ^ 'nk

e* to°v.

*****

S01

7' 1953
figure 12 . Project soi-228. specimens of

PLASTER FROM WALLS OF ( I ) ROOM W-318,

(2) Corridor wall of basement between doors

OF ROOMS 7 and 8, (3) ROOM W— 1 9 2 , AND

(4) LINEN CLOSET S523 SHOWING PLASTER KEYS.

flllllllllllllllflllll

FI SURE 13. PROJECT 501-228. SPEC MEN OF LATH AND PLASTER

TAKEN FROM WALL OF LINEN CLOSET N—3 08 SHOWING WHERE KEYS

ARE BROKEN HOW RUST STAINS PENETRATE PLASTER KEYS.

Fi sure 14. Project 501 -228 . edge view of specimen from linen

CLOSET SHOWING CURVATURE OF SURFACE AND THICKNESS OF PLASTER

001

co

>-<Q

yaawvHO isai

dOAliaiWflH 3AI1V13H H19N33 dO lN3Dd3d N0ISNVdX3

FIGURE

15.

EXPANSION

AND

CONTRACTION

OF

BARS

OF

VERM i

CULI

TE—

SAND—

GYPSUM

PLASTER

WITH

CHANGES

IN

THE

HUMIDITY

Of

THE

ATMOSPHERE

OF

THE

STORAGE

CHAMBER.
^u m2 - <*


BER I

I

CHAMBER!!

FIGURE 17. FLEXING OF LATH ANO PLASTER SPECIMENS RESULTING FROM CHANGES IN THE RELATIVE HUMIDITY OF STORAGE CHAMBERS HELD AT 70°F. SEE FIGURE 16 FOR MOUNTING OF SPECIMENS.

FIGURE 13. EXPANSION AND CONTRACTION OF LATH AND PLASTER SPECIMENS FROM HOSPITAL BUILDING AS THE RESULT OF CHANGE IN RELATIVE HUMIDITY AND DAMPENING. THE NUMBERS OF SPECIMENS CORRESPOND TO THE ROOM LOCATIONS SHOWN ON THE BUILDING PLAN.
cl? -
LENGTH

CHANGES

FROM

BASE

READING,

PERCENT

TIME, WEEKS

FIGURE 19. EXPANSION AND CONTRACTION OF LATH AND PLASTER SPECIMENS FROM HOSPITAL BUILDING AS THE RESULT OF CHANGES IN RELATIVE HUMIDITY AND DAMPENING. THE NUMBERS OF SPECIMENS CORRESPOND TO ROOM LOCATIONS SHOWN ON THE BUILDING PLAN. SPECIMENS MARKED 7 AND a WERE FROM TnE BASEMENT CORRIDOR.

THE NATIONAL BUREAU OF STANDARDS

Functions and Activities

The functions of the National Bureau of Standards are set forth in the Act of Congress, March

3, 1901, as amended by Congress in Public Law 619, 1950. These include the development and

maintenance of the national standards of measurement and the provision of means and methods

for making measurements consistent with these standards; the determination of physical constants and properties of materials; the development of methods and instruments for testing materials,

devices, and structures; advisory services to Government Agencies on scientific and technical

problems; invention and development of devices to serve special needs of the Government; and the

development of standard practices, codes, and specifications. The work includes basic and applied

research, development, engineering, instrumentation, testing, evaluation, calibration services, and

various consultation and information services. A major portion of the Bureau’s work is performed

for other Government Agencies, particularly the Department of Defense and the Atomic Energy

Commission. The scope of activities is suggested by the listing of divisions and sections on the

inside of the front cover.

Reports and Publications

The results of the Bureau’s work take the form of either actual equipment and devices or published papers and reports. Reports are issued to the sponsoring agency of a particular project

or program. Published papers appear either in the Bureau’s own series of publications or in the

journals of professional and scientific societies. The Bureau itself publishes three monthly periodicals, available from the Government Printing Office: The Journal of Research, which presents

complete papers reporting technical investigations; the Technical News Bulletin, which presents

summary and preliminary reports on work in progress; and Basic Radio Propagation Predictions,

which provides data for determining the best frequencies to use for radio communications throughout

the world. There are also five series of nonperiodical publications: The Applied Mathematics

Series, Circulars, Handbooks, Building Materials and Structures Reports, and Miscellaneous

Publications.

Information on the Bureau’s publications can be found in NBS Circular 460, Publications of

the National Bureau of Standards ($1.25) and its Supplement ($0.75), available from the Superintendent of Documents, Government Printing Office. Inquiries regarding the Bureau’s reports and

publications should be addressed to the Office of Scientific Publications, National Bureau of

Standards, Washington 25, D. C.