NATIONAL BUREAU OF STANDARDS REPORT

4839

_ n-n . _* or, Building System” Masonry

Tests of ’’Precision Duiiuiug j

by

J. 0. Bryson, L. P. Skoda, and D. Watstein

Report to

Federal Housing Administration

U. s. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
U. S. DEPARTMENT OF COMMERCE

Sinclair Weeks, Secretary NATIONAL BUREAU OF STANDARDS

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

The scope of activities of the National Bureau of Standards at its headquarters in W ashington,

D. C., and its major field 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 reports and publications, appears on the inside back cover of

this report.

W ASHINGTON. D. C.

Electricity and Electronics. Resistance and Reactance. Electron Tubes. Electrical Instru- ments. Magnetic Measurements. Process Technology. Engineering Electronics. Electronic

Instrumentation. Electrochemistry.

Optics and Metrology. Photometry and Colorimetry. Optical Instruments. Photographic

Technologv. Length. Engineering Metrology.

Heat and Power. Temperature Measurements. Thermodvnamics. Cryogenic Physics.

Engines and Lubrication. Engine Fuels. Atomic and Radiation Physics. Spectroscopy. Radiometry. Mass Spectrometry. Solid State Physics. Electron Physics. Atomic Physics. Nuclear Physics. Radioactivity. X-rays.

Betatron. Nucleonic Instrumentation. Radiological Equipment. AEC Radiation Instruments. Chemistry. Organic Coatings. Surface Chemistry. Organic Chemistry . Analytical Chemistry.

Inorganic Chemistry. Electrodeposition. Gas Chemistry. Physical Chemistry. Thermochemistrv. Spectrochemistry. Pure Substances.

Mechanics. Sound. Mechanical Instruments. Fluid Mechanics. Engineering Mechanics.

Mass and Scale. Capacity, Density, and Fluid Meters. Combustion Controls.

Organic and Fibrous Materials. Rubber. Textiles. Paper. Leather. Testing and Specifications. Polymer Structure. Organic Plastics. Dental Research.

Metallurgy. Thermal Metallurgy . Chemical Metallurgy. Mechanical Metallurgy. Corrosion.

.Mineral Products. Ceramic Engineering. Porcelain and Pottery. Glass. Refractories.

Enameled Metals. Concreting Materials. Constitution and Microstructure.

Building Technology. Structural Engineering. Fire Protection. Heating and Air Conditioning. Floor, Roof, and Wa 1 1 Coverings. Codes and Specifications.

Applied Mathematics. [Numerical Analysis. Computation. Statistical Engineering. Mathematical Physics.

Data Processing Systems. Components and Techniques. Digital Circuitry. Digital Systems.

Analogue Systems. Applications Engineering. • Office of Basic Instrumentation • Office of W eights and Measures

BOULDER, COLORADO

Cryogenic Engineering. Cry ogenic Equipment. Cryogenic Processes. Properties of Materials.

Gas Liquefaction.

Radio Propagation Physics. Upper Atmosphere Research. Ionospheric Research. Regular

Propagation Services.

Radio Propagation Engineering. Frequency Utilization Research. Tropospheric Propagation

Research.

Radio Standards. High Frequency Standards Branch: High Frequency Electrical Standards.

Radio Broadcast Service. High Frequency Impedance Standards. Microwave Standards Branch:

Extreme High Frequency and Noise. Microwave Frequency and Spectroscopy. . Microwave

Circuit Standards.
NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT NBS REPORT

1000-30-4880 September 5> 1958 4^39

Tests of "Precision Building System" Masonry

by

J. 0. Bryson, L. F. Skoda, and D. Watstein

To

Federal Housing Administration

<NBS>

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

The publication, |

unless pehmission 25,D.C, Such p

cal ly prepared If

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST)

on October 9, 201 5.

)r In part, Is prohibited

Standards, Washington

report has been speclfireport for its own use.

Tests of "Precision Building System" Masonry

b y

J. 0. Bryson, L. P. Skoda, and D. Watstein

Abstract

Masonry walls of precision molded hollow concrete masonry units constructed by a grouting

method were tested for compressive strength,

drying shrinkage, heat transfer properties and

water permeability. The concrete masonry units

known as "Precision Block" contained expanded

shale aggregates.

The average compressive strength of three walls

was 37.1 kips/ft or 387 psi on the gross area

of the walls. The average drying shrinkage of

a grouted wall 8 ft long was 0.0103 percent

while the shrinkage of a similar wall having

conventional mortar joint was 0.0057 percent.

The thermal transmittance u was 0.25 and the

corrected thermal transmittance U was 0.28.

(See text for definitions of u and U)

.

A specimen of Precision Block masonry subjected

to a water permeability test received a rating

of "Very Poor." The method of test and the rating

system were those described in BMS Report 95*

1. INTRODUCTION

Whenever new materials or methods of construction are

introduced, it is important that the relative properties of

their end products as regards to present standards be

examined. One such new method of construction has been intro

duced by the Precision Building System, Inc., of Canton, Ohio

This method makes use of precision molded concrete masonry

units of lightweight aggregate so designed that when set up

as a wall the units interlock and provide a continuous system

of vertical and horizontal apertures to receive a grout mix

which serves to bond the units in the wall.

At the request of the Federal Housing Administration, testing of "Precision Building System" masonry walls was performed

by the Structural Engineering Section of the Division of Building

Technology. The test program included the following:

3 compressive strength tests,

2 shrinkage tests,

1 water permeability test.

A test of the heat transfer properties of one wall was also

made in the laboratories of the Heating and Air Conditioning

Section.

2. MATERIALS

The Precision Building System, Inc., furnished all materials

and constructed the wall specimens with the exception of one

shrinkage specimen which was constructed with 3/8 in. mortar

joints by a qualified mason 0 Precision Block with expanded shale aggregate were used in

construction of all wall specimens. The general features of the

8- by 8- by 16-in. block are shown in figure 1, and the physical

properties are given in table 1. The properties of the blocks

were determined in accordance with Federal Specification SS-C-621,

and the blocks met the requirements for load-bearing units.

A grout of creamy consistency containing air-entraining

Portland cement, hydrated lime and a mortar sand "A" was used in

bonding the test walls. The grout was proportioned by volume

in the ratio of 1:0.!?: 3 and had a water- cement ratio of approximately 0.75. The sieve analysis of the sand "A" used in the

grout mix is given in the following table:

Sieve Analysis of Sand "A"

Sieve No. Percent Passing

4 100

8 100

16 91

30 77

50 58

100 34

200 19

It is noted that the fineness modulus of sand "A" was 1.14*

2 k
'

*
A sample of the grout mix was taken during the grouting

of each wall specimen and the properties of the grout in the

respective walls are given in table 2. The dry densities and

compressive strengths of the grout were determined with 2 in.

cubes. The grout cubes were aged under the same conditions

as the corresponding wall specimens and were tested at the

age of 28 days.

The mortar which was used in the construction of a shrinkage wall specimen having conventional 3/8 -in. joints

was proportioned in the ratio of 1 : 0 . 15>: 3 » by weight, but

the sand was a coarser sand designated as sand ”B M

. The

sieve analysis of sand n B

M was as follows:

Sieve No, Percent Passing

8 100

16 86

30 69

50 37

100 10

The consistency of the mortar used in the conventional

wall was adjusted in accordance with the mason’s wishes. The

water-cement ratio in this mix was 0.48 and the average compressive strength was 2080 psi.

3. CONSTRUCTION OF WALL SPECIMENS

The dimensions and the numbers of the various test walls

constructed are given in the following table:

Description of Test Wall

Dimensions, in.

1

I l

f

' Thickness

( Height{ _

jj

Length

2 - thermal transmittance c test t

i compression test t

s drying shrinkage test, » grouted construction t

5 drying shrinkage test,*

conventional joints ?

8 t 108

1

I

? 64

3

- 8 t 96

t

1 40

!

?

t 41

f

t

? 48

1 - 8

!

t

t 96

1 - 8

f

t

1 98

1 - permeability test t 8 I 48

1

t 40

t !

3 .
.* '

.

.
The general procedure for constructing the wall specimens

‘by the Precision Building System method called for the first

course of the wall to be laid in a full bed of mortar. After

the mortar in the base course hardened, the remaining courses

were set up to the specified height, and sheet metal channels

were placed over the ends of the wall and held in place with

metal strapping. The grout was then pumped into the walls

through holes provided in the top course. A view of the grouting operation and the view of sheet metal bulkheads are shown

in figures 2 and 3.

The shrinkage specimens illustrated in figure 4 were constructed so as to permit unrestrained shrinkage in each of

their five courses (see HHPA Research Paper 34 Tor a detailed

description of the unrestrained shrinkage walls). The thermal,

compression and permeability specimens were constructed on

12-in. channels to facilitate handling and were transported to

the appropriate laboratories by means of an electric fork lift

truck.

The thermal specimens were faced on the cold surface with

two coats of cement base paint. The base coat consisted of

high-early strength portland cement and sand passing a No, 40

sieve. The mix was proportioned in the ratio of 1:2 l/2, by

weight. The second coat consisted of a cement-water paint proportioned in the ratio of 1 part cement to 0.6 parts of water,

by weight. Both coats were applied with a fender brush.

In the preparation of the permeability specimen, a mortar

parging approximately 3/8 in, thick was applied on top and on

each end of the wall to prevent the escape of an appreciable

amount of air or water through these surfaces.

The Precision Block which were used in the construction

of both shrinkage test walls were conditioned in a constant temperature room in which the shrinkage tests were nconducted, for

a period of 20 days. During this period the relative humidity

varied from 22 to 35 percent. The moisture content in the units

was checked at intervals and at the time the walls were constructed the moisture content was 14-1 percent of total absorption in

the grouted wall units and 13.2 percent in the conventional wall

units. These two walls were constructed on March 29 and April

4, 1956, respectively. Prior to the construction of the shrinkage wall specimens, the end blocks for each course of the walls

were selected for the establishment of reference points to

measure the linear changes of the walls along each course. The

units were selected from a group stored in the constant temperature laboratory. A hole, approximately 1 in. in diameter and

2 to 3 inches deep, was drilled at the center point of the

appropriate end of each unit using a masonry drill. Cold

rolled steel and brass bars, 3/4 in. i n diameter and 5 inches

long were cemented in the holes with a neat cement paste.

After the installation of the gage plugs the units were, returned to the constant temperature laboratory for conditioning with the rest of the Precision Block.

4. TESTING PROCEDURE AND RESULTS

4.1 Compressive test

The specimens were tested at the age of 28 days in a 600,000 lb capacity hydraulic testing machine. A plaster

cap was placed between the platen of the machine and the

steel channel at the base of the wall to insure a full bearing area. The loads were applied to a steel plate covering

the top of the specimen. The top course consisted of

specially cut blocks having a flush surface. A plaster cap

was used between the top of the wall and the steel plate.

The load x^as applied uniformly through a 1- by 1- by 5>0~in.

steel bar placed between the steel plate and the loading

beam along a line parallel to the inside face, and one-third

the thickness of the specimen from the inside face.

The specimens were alternately loaded and unloaded, the

load increments being 5 kips up to a load of 10 kips, 10 kip

increment up to a load of 20 kips, and 20 kip increments

thereafter until failure occurred. Readings of all gages

were taken at each load and succeeding zero load. Figure 5

shows a specimen in the testing machine prior to test.

The apparatus used to measure the vertical shortening

consisted of four compressometers attached to the face of

the specimen near each corner. The lateral deflection was

measured at each end of the specimen with a dial gage

attached to a free hanging straight edge that was restrained

from lateral motion at the bottom. The measuring devices

used in the compressometers and defle ctome ters were 0.001-in.

micrometer dial gages. The measuring devices can be seen in

place in figure

5 .

4. 1.1 Results

The results of the compressive tests are presented graphically in figures 6 and 7. It is noted that the data in these

figures are given only up to loads of 120 kips; the measuring

devices were removed after this load to avoid damage to the

apparatus. The compressive strengths of the three walls tested

were 140, 134* and 171 kips. The average for the three walls

was 37.1 kips per foot, or 387 psi on the gross area of the

walls. Wall No. 1 was .0547 in. at 120 kips with a shortening

set of .0056 in. The average lateral deflection was .0736 in.

at 120 kips with a lateral set of .0242 inches.

In the test of Wall No. 1, cracks on the tension side of

the specimen were first seen at a load of 120 kips. Failure

was evidenced at 140 kips when the load began to fall and

cracks were noticed at the second course from the top on the

compression side of the west end. Upon destruction, an examination of the wall was made, and it was found that a single air

space was filled with grout to a height of six courses from the

bottom at the east end of the wall. Similar filling of an air

space was noted at the west end of the wall to a height of four

courses from the bottom.

The average shortening of Wall No. 2 was .0715 in. at 120

kips with a shortening set of .0119 Inches. The average lateral

deflection was .0913 in. at 120 kips with a lateral set of

.0408 inches. Spalling cracks were visible in the top two

courses at the 120 kip load. Upon destruction and examination

of this wall no grout was noticed in any of the air spaces.

The average shortening of Wall No. 3 was .0922 In. at 120

kips with a set showing an elongation of .0011 inches. The

average lateral deflection was .0621 in. at 120 kips with a lateral set of .0179 inches. Cracking was first noticed on

the tensile side of the specimen at 4^ kips with compression

spalling first seen at 115 kips. The top four courses were completely sheared off on the compression side at failure as shown

In figure 8. Upon destroying this wall a visual examination revealed that three of the four air spaces on the west end were

filled with grout to a height of five courses. It is believed

that the filling of these air spaces with grout accounts for

the significantly greater strength attained by Wall No. 3 compared with the other two walls.

4.2 Shrinkage tests

The shrinkage test consisted of comparing the drying shrink

age of two walls five courses high and about 8 ft long. One

6 .

wall was constructed by the grouting method and the other was

constructed with conventional 3/8 in. mortar joints. Both

wails, constructed 6 days apart, were exposed to the same drying condition in a constant temperature room. During the first

54 days of exposure, the relative humidity varied from 24 to

36 percent, while the temperature was maintained at 75 - 3° F.

During the remainder of the drying period of 120 days, the controls of the temperature and humidity in the laboratory were

somewhat erratic and the relative humidity fluctuated from 33

to 49 percent.

In addition to the drying shrinkage measurements on the

two 8 ft walls, shrinkage was also determined on three individual units from a saturated condition to equilibrium with

air in the same laboratory. These auxiliary tests were made

in order to estimate the effective increase in the moisture

content of the masonry units resulting from the excess water

in the grout being absorbed by the masonry.

The masonry units used in the wall specimens were conditioned for about 20 days in the laboratory. At the time of

construction, moisture contents of 14.1 percent of total absorption for the grouted wall and 13.2 percent for the conventional

wall were determined.

4.2.1 Instrumentation in measurement of shrinkage

The instrument used in the measurement of length changes

in the walls is shown in figure 9. The instrument consists

essentially of a frame equipped with a pointed support of

hardened steel at one end and a 0.0001-in. micrometer dial

gage at the other end. The frame consisted of two 2 l/2 in.

thin wall steel tubes joined rigidly with a welded brace at

one end and held together with an adjustable bracp at the

other end. The pointed leg at one end of the comparator was

seated in a l/l6 in. hole drilled in a suitable steel or brass

reference point embedded in the end block of each course. The

other end of the comparator carried a micrometer dial which

made contact with a machined face of a steel or brass reference

point embedded in the other end block of each course. The dial

gage had a spherical contact point. In order to secure coincidence of the gage contact point with the center point of the

reference plug and to assure reproducible readings with the instrument, provision was made to support the comparator in the

same position relative to each reference plug by means of a yoke which bore on the reference plug and cradled the two tubes

of the comparator. A partial view of this arrangement is shown

in figure 4* The comparator was checked against a standard bar

7 .
,
mad© of a steel tube. The length changes in the individual

masonry units were measured with a 10-in, Whittemore gage. Two

gage lines were installed on each unit.

4.2.2 Results of shrinkage tests

The shrinkage- time relationship of the two wall specimens

is shown in figure 10, and each value of shrinkage plotted is

the average of the shrinkage on each course of the respective

walls. It will be noted that the grouted wall expanded about

0.001 percent and remained close to that value for several days

before exhibiting any shrinkage, whereas the conventional wall

Indicated shrinkage by the first length change measurement.

The first set of readings with comparator was obtained when

each wall was one day old. The maximum recorded values of

shrinkage were 0.0103 percent and 0.0057 percent for the grouted

and conventionally constructed walls, respectively. Comparison

of the drying shrinkages of the two walls shows that the excess

water in the grout causes the grouted wall to shrink 0.0046

percent more than the conventionally constructed wall.

The results obtained with individual units are shown in

figures 11 and 12. The drying shrinkage of the block from a saturated condition (3 days in water at 73° - 2° F) to equilibrium in the laboratory air, was 0.033 percent. Figure 12

gives the relationship between moisture content and shrinkage.

It is noted that the shrinkage of the individual units dried

in an oven at 220° P for 4^ hr was 0.0694 percent,

4.3 Thermal transmittance test

The heat transfer measurements were made in the NBS

Rotatable Guarded Hot-Box apparatus. The hot box apparatus

conforms substantially to the requirements of ASTM 0-236-54^*

f, Method of Test for Thermal Conductance and Transmittance of

Built-Up Sections by Means of the Guarded Hot Box” (Tentative).

One specimen designated as thermal Wall No. 2 was tested

in a vertical position. Thermocouples were attached to each

face at ten points for measurement of the surface temperatures

over the central area of the wall, 32 in. wide and 60 in. high.

A layer1 of caulking compound about l/4 in. deep and approximately 1 l/2 in. wide was placed along the periphery of this

area to assure an air tight seal with the gaskets of the metering box of the test apparatus.

8 .
,* .
During a test, heat flowed from the metering and guard

boxes, (see fig, 13) which were heated electrically to the same

temperature, to the cold box which was cooled by a refrigerating machine. The electric energy supplied to the metering

box was closely equivalent to the heat energy transferred

through the area of the specimen covered by the metering box.

The energy so supplied was measured with an integrating watthour meter; and this measurement, converted to Btu and divided

by the time, the area, and the temperature difference, yielded

the heat- transfer coefficient for the specimen.

By means of the guard box, the space surrounding the

metering box was maintained at substantially the same temperature as its interior. This minimized heat exchange to or

from the metering box except through the specimen and subjected the face of the specimen not covered by the metering box

to air at the same temperature as that in the metering box.

The measured heat input to the metering box was corrected for

any actual small heat interchange that occurred, during the

test, between the metering box and the surrounding guard box

by utilizing an apparatus calibration factor and the measured

difference of temperature, as determined from 10 seriesconnected differential thermocouples with the junctions of

each pair cemented opposite each other in grooves in the surfaces of the metering box.

The top, two vertical, and bottom edges of the specimen

projection beyond the guard, and cold boxes, were heavily insulated to minimize heat gain or moisture condensation from the

laboratory air.

To promote uniformity of temperature, the air within the

boxes was circulated through the baffle spaces adjacent to the

test specimen, by means of electric fans. The air velocities

were about IpO to 90 ft/min on the warm and cold sides, respectively. The energy used by the fan in the metering box was

included in the measurement of the total energy supplied to

the metering box„

Air and specimen- surf ace temperatures were measured by

copper- constantan thermocouples in conjunction with a potentiometer, A recording potentiometer was used for approximate

measurements of the interior temperatures of the boxes and the

surfaces of the test specimen during the period preceding each

test when the apparatus was being brought to the steady temperature conditions required for the test.

9 .
,

*

'
In the test, the temperatures in the cold box was approximately 0° P and that in the metering and guard boxes was about

70° P. After a steady state of heat flow was attained, the

heat transmission of the specimen, indicated by the rate at

which electric energy was supplied to the metering box, was observed. The heat transfer measurement was made for an area

32 in. wide and 60 in, high, centrally located on the face of

the specimen covering a representative section of the wall.

Thermocouples on the warm and cold faces of the wall were located so as to measure the temperatures of the surfaces at

points opposite the air cells, near the joints, and opposite

the grout fill.

4.3.1 Results

The heat transfer characteristics of the specimens, based

on the observations, were as follows:

Observed thermal transmittance, u 0.25

Corrected thermal transmittance, U 0.28

Thermal conductance, C 0.3&

Warm surface conductance, f^ 1.32

Cold surface conductance, f 0 2.08

Temperature averages, °P Warm side Cold side

air 72.1 -0.6

surface* 58.4 8.1

-"-Arithmetic average of all ten temperatures on

each surface of tests area.

The definitions of u, U, and C, representing the various

coefficients of heat transmission are:

u = number of Btu per hour transmitted through each

square foot of specimen for each degree P

difference in temperature between the air on

the two sides, as observed under the test conditions , U = u corrected for a l5-mph wind outside and still

on inside by means of the surface conductances n = 1.65 and fQ = 6.00, taken from the ASHAE Guide,

C = number of Btu per hour transmitted through each

square foot of specimen for each degree P difference

in temperature between the surfaces of the two

sides as observed under test conditions.

10 .
-

.
4*4 Water permeability test

The wall specimen subjected to the permeability test is

shown in figure 14 . The specimen was constructed entirely of

Precision Block grouted in the regular manner, except that

the base course consisted of one course of clay building

brick to permit installation of flashings and provide a wall of

proper height. The manner of installation of the flashings,

the testing procedure and the performance ratings are described in Building Materials and Structures Report BMS95>.

4.4*1 Results

The wall specimen was rated "Very Poor” on the basis of

the following ratings of performance:

Excellent (E) - No water visible on back of the wall

(above the flashings) at the end of 1 day. Not more than

25 percent of the wall area damp at the end of 5 days. No

leaks through the wall in 5 days.

Good (G) - No water visible on the back of the wall at

the end of 1 day. Less than £0 percent of the wall area damp

at the end of 1 day. No leaks through the wall at the end of

1 day.

Pair (P) - No water visible on back of the wall during

first 3 hours, but visible at end of 1 day. The rate of

leakage through the wall less than 1 liter/hr at the end of

1 day.

Poor (P) - Water visible on back of the wall in 3 hr or

less and at the end of 1 day. Rate of leakage less than 5> liters/hr at the end of 1 day.

Very Poor (VP) - Rate of leakage through the wall equal

to or greater than 5 liters/hr at the end of 1 day.

The detailed results obtained in the permeability test are

given below:

11 .
'

.
T“ »

t Dura-* Time to fail as

1 r

indicated byvArea t

f ! Maximum leakage t per hour

ttion * !0 f tDamp

ttest * through

, iwall

T*~

i Leak

f through

f wall

t

i Leak

t through

t facing

* damp t

tat end t

t of testt

f t

Through

wall

’ ^Rating*

f Through* * ’facing * *

f ! t

days hr hr hr percent liters liters

1 0.067 0.1 0.1 83 74

Very

18 poor

5* SUMMARY

Specimens of "Precision Building System" masonry were tested

to determine the following properties:"

Compressive strength

Drying shrinkage

Water permeability

Thermal transmittance

The average maximum load supported by the three 4“ by 8-ft

wall tested in compression was 37.1 kips/ft or 387 psi on the gross

area of the walls. The ratio of the compressive strength of the

walls to that of masonry units was 0.276.

The drying shrinkage of the grouted wall five courses high

and 8 ft long exposed to laboratory air for a period of about 120

days was 0.0103 percent, while the shrinkage of a companion wall

constructed with conventional 3/8 in. joints was 0.0057 percent.

Visible cracks developed in the vertical joints of the top three

courses of the conventional wall several days after construction

and it is quite probable that the shrinkage of this wall would

have been somewhat greater had the cracks not occurred.

The water permeability specimen received a rating of "Very

Poor" in accordance with the performance ratings described in the

Building Materials and Structures Report BMS95.

The heat transfer characteristics of the 5- by 9- ft wall

having two coatings of cement-water paint on the cold side and

tested in the NBS Rotatable Guarded Hot-Box apparatus, were as

follows

12

Observed thermal transmittance, u

Corrected thermal transmittance, U

Thermal conductance, C

Warm surface conductance,

Cold surface conductance t fg

0.25

0.28

0.36

1.32

2.08

Temperature Averages, °F Warm side Cold side

air

surface#

72.1

58.4

- 0.6

8.1

-“-Arithmetic average of all ten temperatures on

each surface of test area.

The definitions of u, U, and C, representing the various

coefficients of heat transmission, are:

u = number of Btu per hour transmitted through

each square foot of specimen for each degree

F difference in temperature between the air

on the two sides, as observed under the test

conditions.

U = u corrected for a l5-mph wind outside and

still on inside by means of the surface conductances = 1.65 and f = 6.00, taken from

the ASHAE Guide.

C = number of Btu per hour transmitted through each

square foot of specimen for each degree F

difference in temperature between the surfaces

of the two sides as observed under test conditions .

13 .
•

’

••

.
Table

1.

Physical

Properties

of

"Precision

Building

System"

Masonry

Units.

©

bO©pB

•H

Ph P

tow£

•H

Ph p

Ph ft •H © ©

•H

Ph £ P •H

-p©

co

OAOo P ft ©o

•H

O

Ph cm P CM oPoo I P ca 4_> © hO £ © £

ft > © g H £ O © ft O 03

•H

03ft oo

-dxHQ P O

•H

-p p!

&.* O CM

03 4© t>»

«*! ft

©

ft

ft

©

S3 £

bOft o

•h o a © o

I* o

ftl P CO

bO ft »H P > •H o £ 1 1 ca © B co

|2 “ w fe*

v~ — 3 P 1A O © vO P H © • © pj © CM

IS ft £ O* to- CM *“ «M.

rH P O HO© o © H 03 V Pi S3 © 1—1

CO ft £ m *» «»* fe- s— *- ft £ o © o • ft © vO © £ H • •H © O i—1

pop C- g. W fe* fe» «» ftPi TP

bO ca

•H • © r— w^ 1 CM' »» fe-l P

ft 1A

ft

O

•H • |S ofe- feu to* (M* •- *- p

ft 1A

bD

O £ • © LA

ft

H

— *- V-,

——

-p£©o£©

ft

-pftBo

ftt I—I • CM CO

03 ft

•H£B

CO£o

ft

©•

03©

ft©£©P

cO ft

03 •HP

ft£

•H

ft©

ft£O

ft©

Ph©

fti—I B

03©£©©

ftO

£5 5

TOP

VIEW

Table

2,

Properties

of

Grout

Mix

'r'Tj©>

•H -P 0 bo

CO P*H

O o O o o o o o 0 ® CO to CM CO o M3 o CO CO p pp. o O O o cr- o MO o

Ph -p i—1 1 1 1 1 1—1 1—1 1 1 1—1 0 g CO Pi P o -P O o •H

Td • -P

p

p co cd

p cd 0 P 0 P2 -H o ® P £ p p POP •H 0 rO 0

Php co -P -p O 0 p p CM ia CM CO CO o CM o Ph T) 0 a3 » O

-p -P O- vO r- MD r— vO vO P 0 p P •H ® Oh o o ) bO-P o 3 CM Pp p p rP rP ® O

•H CO -P > Pc < 0 •rH d p Is rd

Ph 0 0

*-

— *— *-— *“ *** L— t— ft- *- 03 01® 0 -p p

p >3 P

cdp •H 0 p

-p T3 CO vO CO CM CO CO CO o g *ri 0 p P g O -P P CO vO IA rO pi CO O- IA (D rH *H g PH c H 1 1 1 1 1 1 1 1 1—1 1 1 1 1 1 1 -P rH O 1 1 1 1 1 1 1 1 1—1 1 1 1 1 1 1 0 cd 0

<p

p X> 5 Ph

O o 0 * \ 0 Oh ®

[>3,0

— cd

O 0 O

-P rH

U a)

p

p

•H

p 1 1 CO CO cr IA Pt IA IA 0 -p cd

CO CO 01 -P P 0 cO IA cO pi Pt IA pi -P P 0 -P 0 p CM CM CM CM CM CM CM CM hD O d *H P pH ( 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 PP 5 s 0 0

ft-— to- ®** **" C— V- P Td CM

p

-P© =tte cd 0 -p p P H -P ©OH 1 1 CM CO > pH cd rH

Ail

=te >3

•H 0 Is cd 0 p g

p P p -P Ul rH

M

CO

O o o 0 © -P cd 0 1

i—1CM •H •H •H 0 rH bO pi

—1 g Ol 1— CO CO w bO •H 0 a P p HJ

CE i—1 1 1 CO CO 0 d pi P g 0 0

12 cd cd 0 0 0 ,3 aJ 0 O 0 pp s g p p P q 0 > O P EH O q Vh Ph Ph <1

"r—T| "cm} 0

01

®

oi £o £o £o p

At 0

Eh Eh o o o CO CM

a

hO •H

View

of

’’Precision

Building

System”

masonry

units.

Bmmm ( * ^ _

, Ir M\

li' . -Jf . JMHT f f'

: 1 ", wjaf. I

Fi

2

-

View

of

thermal

and

compression

wall

specimens

n

I

+-

VI

(T



Pig.

4

“

Ylflw

of

grouted

and

conventionally

constructed

shrinkage

test

specimens.

View of compressive test specimen in testing machine
II
COMPRESSIVE

LOAD,

KIPS/FT

COMPRESSIVE LOAD

VS.

SHORTENING 8 SHORTENING SET

FIG. 6

COMPRESSIVE

LOAD,

KIPS/

FT

COMPRESSIVE LOAD

VS.

LATERAL DEFLECTION a LATERAL SET

Pig. 8 - Compression Wall No. 3 after failure.

Pig. 9 - Horizontal comparator used in measuring length

changes of shrinkage specimens.

TIME,

DAYS

DRYING

SHRINKAGE

OF

INDIVIDUAL

UNITS

VS. TIME

FIG. II

TIME,

DAYS

MOISTURE

CONTENT

o O o o o o O O o

0> 00 <£> in tj- ro cm —

NOIlddOSS V "IV101 dO 39V±N30d3d ‘1N31N00 3an±siow

FIG. 12

SHRINKAGE,

PERCENT

(@

0 TEST PANEL

(D RUBBER GASKETS

(3) COLD BOX

@ GUARD BOX

® METER BOX

© REFRIGERATING COIL 0 ELECTRIC HEATERS

® AIR COMPOUND THERMOCOUPLES

® SURFACE COMPOUND THERMOCOUPLES © AIR TEMPERATURE THERMOCOUPLES

@ AIR CIRCULATING FANS

(g) BAFFLES

(@> EDGE INSULATION

(@ COMPRESSION SPRING HANDWHEELS © HEATER DUCTS © METER HEAT DIFFUSER

Pie. 13 - Diagram of metering and guard boxes used for the

thermal transmittance determination,,





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 bas»c 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.