The program of research on building materials and structures, carried on by the

National Bureau of Standards, was undertaken with the assistance of the Central Housing Committee, an informal organization of Government agencies concerned with

housing construction and finance, which is cooperating in the investigations through a subcommittee of principal technical assistants.

CENTKAL HOUSING COMMITTEE

SUBCOMMITTEE ON TECHNICAL RESEAECH

Walter Junge, Chairman. A. C. Shire, Vice Chairman.

Federal Housing Administration. United States Housing Authority.

Sterling R. March, Secretary.

Albert G. Bear,

Veterans' Administration.

Pierre Blouke,

Federal Home Loan Bank Board

(Federal Loan Agency).

Carroll W. Chamberlain,

Public Buildings Administration (Federal Works Agency).

Joseph M. DallaValle,

Public Health Service (Federal Security

Agency).

John Donovan,

Farm Security Administration (Agriculture).

George E. Knox,

Yards and Docks (Navy).

Vincent B. Phelan,

National Bureau of Standards (Commerce).

Edward A. Poynton,

Office of Indian Affairs (Interior).

George W. Trayer,

Forest Service (Agriculture).

Elsmere J. Walters,

Construction Division (War).

CHAIRMEN OF SECTIONS

Specifications Materials Maintenance

Carroll W. Chamberlain Elsmere J. Walters John H. Schaefer

Mechanical Equipment Methods and Practices

Robert K. Thulman

NATIONAL BUREAU OF STANDARDS

STAFF COMMITTEE ON ADMINISTRATION AND COORDINATION

Hugh L. Dryden, Chairman.

Mechanics and Sound.

Phaon H. Bates, Gustav E. F. Lundell,

Clay and Silicate Products. Chemistry.

Hobart C. Dickinson, Addams S. McAllister,

Heat and Power. Codes and Specifications.

Warren E. Emley, Henry S. Rawdon,

Organic and Fibrous Materials. Metallurgy.

The Forest Products Laboratory of the United States Department of Agriculture is cooperating with both committees on investigations of wood constructions.

[For list of BMS publications and how to purchase, see cover page III.]
UNITED STATES DEPARTMENT OF COMMERCE • Harry L. Hopkins, Secretary

NATIONAL BUREAU OF STANDARDS • Lyman J. Briggs, Director

BUILDING MATERIALS

and STRUCTURES

REPORT BMS38

Structural Properties of Two "Dunstone" Wall Constructions

Sponsored by the

W. E. Dunn Manufacturing Co.

by HERBERT L. WHITTEMORE, AMBROSE H. STANG,

and DOUGLAS E. PARSONS

ISSUED FEBRUARY 7, 1940

The National Bureau ot Standards is a tact-finding organization;

it does not "approve" any particular material or method ot construction. The technical findings in this series ot reports are to be construed accordingly.

UNITED STATES GOVERNMENT PRINTING OFFICE • WASHINGTON

FOR SALE BY THE SUPERINTENDENT OF DOCUMENTS, WASHINGTON, D. C. • PRICE lO

1940

CENTS
Foreword

This report is one of a series issued by the National Bureau of Standards on the

structural properties of constructions intended for low-cost houses and apartments.

These constructions were sponsored by industrial organizations within the building

industry advocating and promoting their iise. The sponsor built and submitted the

specimens described in this report for participation in the program outlined in BMS2,

Methods of Determining the Structural Properties of Low-Cost House Constructions.

The sponsor, therefore, is responsible for the design of the constructions and for the

description of the materials and of the method of fabrication. The Bureau is responsible for the method of testing and for the test results. This report covers only the load-deformation relations and strength of the structural elements of a house when subjected to conipressive, transverse, impact, concentrated, and racking loads by standardized methods simulating the loads to which the

element would be subjected in actual service. It may be feasible later to determine

the heat transmission at ordinary temperatures and the fire resistance of these same

constructions.

The National Bureau of Standards does not "approve" a constiniction, nor does it express an opinion as to the merits of a construction, for the reasons given in reports

BMSl and BMS2. The technical facts presented in this series provide the basic data

from which architects and engineers can determine whether a construction meets desired

performance requirements.

Lyman J. Briggs, Director.

[iiJ
Structural Properties of Two "Dunstone" Wall Constructions

Sponsored by the W. E. Dunn Manufacturing Co.

by HERBERT L. WHITTEMORE, AMBROSE H. STANG, and DOUGLAS E. PARSONS

CONTENTS

Page

Foreword ii

I. Introduction 1 II. Sponsor and product 2

III. Specimens and tests 2

IV. Wall CF . 3

1. Description 3

(a) Four-foot wall specimens 3

(b) Eight-foot wall specimens 5

(c) Fabrication data 5

2. Compressive load 5

3. Transverse load 6

4. Concentrated load 7

5. Impact load. 7

ABSTRACT

For the program on the determination of the struc- tural properties of low-cost house constructions the W. E. Dunn Manufacturing Co. submitted 24 speci- mens representing 2 designs of their "Dunstone"

constructions for walls. The specimens were subjected to compressive, transverse, concentrated, impact, and racking loads. For

each of these loads three like specimens were tested. The deformation under load and the set after the

load was removed were measured for uniform increments

of load, except for concentrated loads, for which the

set only was determined. The results are presented

in graphs and in a table.

I. INTRODUCTION

In order to provide technical facts on the

performance of constructions which might be

used in low-cost houses, to discover promising new constructions, and ultimately to determine the properties necessary for acceptable

performance in actual service, the National

Bureau of Standards has invited the cooperation of the building industry in a program of research on building materials and structures

suitable for low-cost houses and apartments.

The objectives of this program arc described

in report BMSl, Research on Binlding Materials

and Structures for Use in Low-Cost Housing,

and that part of the program relating to strucPage IV. Wall Cf—Continued.

6. Racking load 8

V. Wall CG 8

1. Description 8

(a) Four-foot wall specimens 8

(b) Eight-foot wall specimens 10

(c) Fabrication data 10

2. Compressive load 10

3. Transverse load 10

4. Concentrated load 11

5. Impact load 11

6. Racking load 12

VT. Sponsor's coniinonts 13

tural properties in report BMS2, Methods of Determining the Structural Properties of LowCost House Constructions.

Masonry constructions and wood constructions of types which have been extensively

used in this country for houses were included

in the program because their behavior imder

widely difi'erent service conditions is known

to btulders and the public. The reports on

these constructions are BMS5, Structural Properties of Six Masonry Wall Constructions, and

BMS25, Structural Properties of Conventional

Wood-Frame Constructions for Walls, Partitions, Floors, and Roofs. The masonry speci- mens were built by the Masonry Construction

Section of this Bureau, and the wood-frame

specimens were bialt and tested by the Forest

Products Laboratory at Madison, Wis.

The present report describes the structural

properties of two wall constructions sponsored

by one of the manufacturers in the building

industry. The specimens were subjected to compressive, trans\erse, concentrated, impact,

and racking loads, smiidating loads to which

the walls of a house are subjected. In actual

service, compressive loads on a wall are produced b,v the weight of the roof, second floor and second-story walls if any, fiu'niture and

occupants, and snow and wind loads on the

roof. Transverse loads on a wall are produced

[1]
by the wind, concentrated and impact loads

by furniture or accidental contact with heavy

objects, and racking loads by the action of the

wind on adjoining walls. The deformation and set under each increment of load were measured, because the suit- ability of a wall construction depends in part on its resistance to deformation under load and

whether it retui'ns to its original size and shape

when the load is removed.

II. SPONSOR AND PRODUCT

The specimens were submitted by the W. E.

Dunn Manufacturing Co., Holland, Mich., and

represented two wall constructions sponsored

by this company and marketed under the trade

name "Dunstone." The "Dunstone" concrete blocks were made under franchise by the Silver

Hill Brick Corporation, Washington, D. C. The blocks were laid to form a hollow wall. The specimens were built with cement-lime

mortar.

HI. SPECIMENS AND TESTS

The concrete blocks used as headers, which

tied the two faces of the wall together, were

vertical for one construction and horizontal for the other. The wall construction with vertical

headers was assigned the symbol CF; the construction with horizontal headers, the symbol

CG; and the specimens were assigned the designations given in table 1. Table 1.

S-pechnen designations, walls CF and CG

Specimen designation

CI, Ct, C3.^.

Tl, T2, TS... P1,P2, PS K.

II, K, 13 .... Rl. m, R3...

Load

Compressive..

Transverse Concentrated. Impact

Racking

Load applied

Upper end. Either face. Do.

Do. Near upper end.

» These specimens were undamaged portions of the transverse speci- mens.The specimens were tested in accordance

with BMS2, Methods of Determining the

Structural Properties of Low-Cost House Constructions, which also gives the requirements

for the specimens and describes the presentation

of the results of the tests, particularly the loaddeformation graphs.

For the transverse and impact loads, only

three specimens were built, because the specimens were symmetrical about a vertical plane

midway between the faces; and the results for transverse and impact loads applied to one face

should be identical with those obtained by

applying the loads to the other face. The

concentrated loads were applied to onl}^ three

specimens, because the inside and outside faces

of the specimens were similar.

The compressive loads were applied over the

entire thickness of the walls along a line distant

from one face by one-third this thickness. The

shortenings and sets were measured by means

of compressometers attached to the steel loading

plates through which the load was applied to the specimen, not attached to the specimen as described in BMS2.

Measurements of the lateral deflections under

compressive loads and deflections under trans- verse loads were made with a deflectometer of fixed gage length. This deflectometer consists

of a light (duralumin) tubular frame having a

leg at one end and a hinged plate at the other.

The distance between points of support was

7 ft 6 in. A dial micrometer was attached to the deflectometer at midlength. The micrometer was graduated to 0.001 in., and the readings were recorded to the nearest tenth of a

division. The deflectometer was attached to the specimen in a vertical position by clamping the hinged plate to the upper end of one

face. There were two deflectometers on each

specimen, one near each edge. This method

of measurement was used instead of the taut- wire and mirror-scale method, as described

in BMS2.

The deformations under racking loads were measured by a dial micrometer which was

fastened to one end of a rigid right angle biult

up with a steel channel and a steel angle

braced to form a rigid connection. In use,

this deformeter was attached to the specimen

by resting the channel along the top of the

specimen. Two pins driven through this channel into the top of the specimen prevented

relative motion between them. The steel angle was then in a suspended vertical position in the plane of the specimen with the dial at

its lowest point and the spindle of the dial bearing directly on the specimen. This deformeter was used instead of the system of taut wires

and mirror scales, as described in BMS2.

[2]
The tests were begun March 6, 1939, and

completed March 20, 1939. The specmiens were tested 28 days after they were built. The

sponsor was notified when the tests woidd be

started but found it impossible to have a

representative present.

IV. WALL CF

1. Description

(a) Four-Foot Wall Specimens

The 4-ft wall specimens with vertical headers were 8 ft b}{ in. high, 4 ft 2){ in. wide, and 8}^ in. thick, and had 12 courses of blocks. The

blocks formed an all-rolok in Flemish bond

wall, as shown in figure 1. Each course conFiGURE 1.

Four-foot wall specimen CF.

A, 1-core block as stretcher; B, 3-core block as stretcher; C, 2-core block

as bonding header; D, mortar 2 in. thick; E, concrete fill; F, expanded

metal; G, 1-core block for end of concrete form.

sisted of 1-core blocks, A, and 3-core blocks, B,

as stretchers with 2-core blocks, C, as bonding

headers. The details of the blocks are shown

in figures 2 and 3. The bed joints and head

joints were completely filled with mortar and

were cut flush with the surface of the wall.

Figure 2." Dunstone" concrete blocks.

1-core and 2-core blocks.

Figure 3."Dunstone" concrete block.

3-core block.

The space between the blocks of the first course was filled with mortar, D, to a height of about

2 in. above the bottom of the wall to support

the first course during construction. The top

course was filled with concrete, E. The bottom

form for the concrete was made by placing a

length of expanded-metal corner bead, hammered flat, F, in the bed joint and filling the

openings in the expanded metal with mortar.

Two 1-core blocks, G, laid in the space between

the blocks of the top course served as the end

forms for the concrete. The concrete was

poured on the day foflowing the completion of

the specimen.

[3]
Figure 4. — Wall specimen CF-Cl under compressive

load.

The price of this construction in Washington,

D. C, as of July 1937, was $0.20/ft-. Concrete blocks.—The materials for the blocks were portland cement and washed bank sand

(passed K-in. sieve). The blocks were made by

the Silver Hill Brick Corporation in the proportions of 8 parts of sand to 1 part of portland

cement by volume. The blocks were made on a standard Dunbrik-Dunstone machine manufactured by the W. E. Dunn Manufacturing Co.

The physical properties of the concrete

blocks, determined by the Masonry Construction Section of the National Bureau of Standards, in accordance with the ASTM Standard

C 90-36,^ are given in table 2.

Table 2.Physical properties of the concrete blocks,

ivalls CF and CG

Block

Compressive

stren<rth,» gross area

Water absoriition, 24-hr cold im- mersion Dry weight

By

weight

Per cubic

foot of concrete

Per

block

Per cubic

foot of concrete

1-core.

lb/in:' 1,330

2, 060

1, 730

Percent

11.0

fi. 2

7. 4

lb

12. 7 9.3

y. 7

lb3.81

9. 78

13. 90

lb 116 129

125

2-core 3-eore . _

« Loaii applied in direction of longer dimension of core.

Mortar.—The materials for the mortar were Medusa Cement Co.'s "Medusa" portland ce- ment, lime putty made by slaking Standard

Lime and Stone Co.'s "Washington" powdered

quicklime, and Potomac River building sand.

The mortar was 1 part of cement, 0.42 part of

hydrated lime, and 5.1 parts of dry sand, by

weight. The proportions by volume were 1 part

of cement, 1 part of hydrated lime, and 6 parts

of loose damp sand; assuming that portland

cement weighs 94 Ib/ft^, dry hydrated lime 40

Ib/ft^, and that 80 lb of dry sand is equivalent

to 1 ft^ of loose damp sand. The materials for each batch were measured by w^eight and mixed

for not less than 2 minutes in a batch mixer

having a capacity of % ft^. The amount of

water added to the mortar was adjusted to the

satisfaction of the mason. The following properties of the mortar materials and of the mortar and concrete were determined by the Masonry Construction Section. The cement complied with the requirements of Federal Specification SS-C-191a,

Cement; Portland, for fineness, soundness, time

of setting, and tensile strength. The lime putty

contained 40 to 45 percent of dry hydrate, by

weight, and had a plasticity of over 600, measured in accordance with Federal Specification

SS-L-351, Lime; Hydrated (for) Structural

Purposes. The sieve analysis of the sand in

the mortar is given in table 3.

ASTM Standards, pt. 2, 168-171 (1936).

[4]
Table 3.

Sieve analysis of the sand in inorlar, walls CF and CG

U. S. standard

Sieve number

Passing, by

weight

Percent

8 100

]6 98 30 81 50 23 100

The average water content of the mortai- was 23.9 percent by weiglit of the dry materials.

Samples were taken from at least one batch of mortar for each wall spechnen, the flow determined in accordance with Federal Specification

SS-C-181b, Cement; Masonry, and six 2-in. cubes made. Three cubes were stored in water

at 70° F and three in air near the wall specimen.

The compressive strength of each cube was

determined on the day the corresponding wall

specimen was tested. The physical properties

of the mortar are given in table 4.

Table 4.Physical pi'operties of the mortar and of the concrete, wall CF

[The compressive strengths were determined on the liay the corresponding wall specimens were tested |

Mortar

Compressive Concrete, Specimen strength compressive Flow strength Air stor- Water

age storage

CI

Percent Ib/inJ IbliiiJ 109 560 740 2, 790 C2 108 595 720 3, 970 C3 100 580 760 2, 830

Tl_. 102 755 745 3, 250 T2 108 495 660 2. 700 TS 109 470 640 2, 700

11 107 545 745 2, 790

12 106 BOO 765 3, 970

IS 108 590 715 3, 970

f 110 490 645 3, 180 Rl \ 105 540 680 3, 180

[ 108 590 595 2, 380 R2 r 113 630 545 2, 380

\ 120 655 600 3, 390 R3 114 665 770 3,390 Average . 109 580 690 3. 130

Concrete.—The materials for the concrete

fill in the top course of the wall were Medusa

Cement Co.'s "Medusa" portland cement,

Potomac River concrete sand, and Potomac

River gravel (maximum size % in).

The concrete was 1 part of cement, 2.1 parts of dry sand, and 3.7 parts of dry gra vel, by weight. The proportions by volume were

1 part of cement, 2.5 parts of loose damp sand,

and 3.5 parts of gravel.

A 6- by 12-in. cylinder was made by the

Masonry Construction Section from the concrete for each wall specimen and stored in ait- near the specimen. Tlie compressive strength

of each cylinder was determined on the day the

correspontling wall specimen was tested. The

compressive strengths of the concrete cylinders

are given in table 4. Expanded metal.—The expanded metal used

for the bottom form of the concrete fill was a galvanized corner bead of expanded metal,

2% in. on each side, hammered flat. The metal was 0.025 in. thick (No. 24 U. S. Std. Gage).

The corner bead weighed 0.21 lb/ft.

(b) Eight-Fuot Wall Specimens

The 8-ft wall specimens were 8 ft 5/4 in. high, 8 ft % in. wide, and 8)8 in. thick, having

12 courses of blocks. The specimens were

similar to the 4-ft wall specimens.

(c) Fabrication Data

The fabrication data, determined by the

Masonry Construction Section, are given in table 5.

Table 5.Fabrication data, walls CF and CG

[The values per square foot were computed, using the face :)rea of the specimens]

Construction symbol CF CG

Thickness of bed joints, in ,._ . 0.37 0. 36 Thickness of head joints, in_ .40 .39

1-core blocks, number/ft*-.- .68

2-core blocks, number/ft*-.- L02

3-core blocks, number/ft'- _ 2.04 3. 08 Mortar materials: Cement, Ib/tt^ 1. 14 1. 18 Lime, drv hydrate, lb/ft' 0. 477 0.495 Sand, dry, Ih/ft' 5. 78 6.02 Mason's time, lir/ft'- „ 0. 073 0. 082

2. Compressive Load

Wall specimen CF~C1 under compressive

load is shown in figure 4. The results for wall

specimens CF-Cl, C2, and C3 are shown in table 6 and in figures 5 and 6.

[5]
Table 6.

Structural properties of "Dunstone" wall constructions CF and CG

[Weight: Wall CF, 52.6 Ib/tti; wall CG, 54.8 Ib/ft^, based on the face area)

Con.structinn symbol

Compressive

Speci- men

Maxi- mum

load

Transverse

Speci- men

Maxi- mum

load

Load

Concentrated

Speci- men

Maxi- mum

load

Impact t

Speci- men

Maxi- mum

height

of drop

Racking

Speci- men

Maxi- mum

load

CF.

Average _

CG.

Avera.ei'

CIC2

C~S

Kipslft 38.9

40. 2

42. 7

TlTi

TS

mm

36. 0

29. 1

2fi. 0

PIPS

lb d 1, 000

<i 1, 000

J 1, 000

2. 5

2. 5 3.0

40.6 30.4 d 1, 000 2.7 CIC2

CS

35.9

38.3 38.7

TlT2

T3

24. 0

(') 26.0

PIP2

PS

<1 1. 000

<! 1, 000

1 1, 000

2.0

2.0

2. 0

37.6

RlRS

RlR2

RS

'Kipn/ft

1.81 1.93

2. 28

2. 01

2. 00

2. 18

3. 56

2. 58

» The compressive loads were applied 2.71 in. from one face of the spec- imen on wall CF and 2.09 in. from one face of the specimen on wall CG. Span 7 ff 0 in.

A kip i> l.iinii lb. d Tesi ilisciinlinued. Specimen did not fail.

» This siifcitiic'ii had an initial crack. 40

A

J)

I

O

30

20

10

0^

• • • o 9 O

• o cr o

o P

° 7

o pD

/ o f"

op •1/ Cf

0 0.02 0.04 0,06 0.08

shoHen'inc^ in/8ff

Figure 5.Compressive load on wall CF.

Load-shortening (open circles) and load-set (solid circles) results for specimens CF-Cl, C2, and CS. The load was applied one-third the thickness (2.71 in.) from one face. The loads are in kips per foot of actual width of specimen. At loads of 32.0 and 39.6 kips/ft stretchers, at one edge on the face nearer the load line and

near the top, cracked vertically in specimens

Cl and C2, respectively. Specimen Cl col- lapsed at the maximum load, failinp,' by cracking

of the stretchers on the inside face near the top.

Specimen C2 failed by breaking of all the headers midway between the two faces. Specimen

C3 failed by breaking of the headers at one edge

near the top.

3. Transverse Load

The results of the transverse load are shown

in table 6 and in figure 7 for wall specimens

CF-TU T2, and TS. 40

20

in

(n

J!I 10 8

) o o

o o / o -1

m • o o/ o

1

r

o c

7 °

f

c )

i» on u

o

•ogo

T CF 0 0.04 0.08 0.12

laferal deflecfion in. Figure 6.

Compressive load on wall CF.

Load-lateral deflection (open circles) and load-lateral set (solid circles) results for specimens CF-Cl, C2, and CS. The load was applied one- third the thickness (2.71 in.) from one face. The loads are in kips per

foot of actual width of specimen. The deflections and sets are for a gage length of 7 ft 6 in., the gage length of the deflectometers.

[6:
50

I

in I

10

|»o

t

1 1

ft

ff

iT11

CF

O.OF OM 0.06

defleciion in. Figure 7. —Transverse load on wall CF.

Load-defleetion (open circles) and load-set (solid circles) results for specimens CF-Tl, T2, and T3 on the span 7 ft 6 in. The deflections and sets are (or a gage length of 7 ft 6 in., the gage length of the deflectometers. Each of the specimens Tl, T2, and T3 failed

by rupture of the bond between the mortar and

the concrete blocks at a bed joint between

loading rollers.

4. Concentrated Load

The results of the concentrated load on wall

specimens CF-Pl, P2, and P3 are shown in

table 6 and in figure 8. Wall specimens CF-Pl, P2, and PS, loaded on a stretcher block near the center of the wall,

showed no measurable indentation after a load

of 1,000 lb had been applied and released.

5. Impact Load

The results of the impact load on wall speci- mens CF-Il, 12; and IS are shown in table 6 and in figure 9. In each of the specimens II, 12, and IS a bond crack appeared in a bed joint near midspan on the face not struck at a height of drop

of L5 ft. In each case failure occurred at this bond crack, which extended to the face struck.

Wall specimen CF-Il during the impact test

is shown in figure 10.

1000

^ 800

is

o

o0

600

400

200

0

CF 0 0.0^ 0.04 0.06

indenfailon in. Figure 8.

Concentrated load on wall CF.

Load-indentation results for specimens CF-Pl, P2, and PS.

2

I

0 ^

r* '

• •

1

c 9' o —V

—o—

o

—o

r

CF

0.^ 0.4 0.6 0.8

defleciion in. Figure 9.

Impact load on wall CF.

Height of drop-deflection (open circles) and height of drop-set (solid cir- cles) results for specimens CF-Il, 12, and IS on the span 7 ft 6 in.

[7]
6. Racking Load

The results of the racking load on wall speci- mens CF-Rl, R2, and R3 are shown in table 6 and in figure 11. The deformations and sets shown in figure 1

1

were computed from the deformeter readings.

The gage length of the deformeters was 7 ft 2 in. Stepwise cracks through the bed and head

joints appeared in specimens Rl and R2 at a

load of 1.5 kips/ft and in R3 at a load of 1.2 kips/ft. Each of the specimens failed by rupture of the cracked bed and head joints approximately along a diagonal between the point of

application of the load and the stop.

V. WALL CG

1. Description

(a) Four-Foot Wall Spiximens

The 4-ft wall specimens with horizontal

headers were 8 ft 3% in. high, 4 ft 2% in. wide,

and SKe in. thick, and had 18 courses of blocks.

The blocks formed an ali-rolok wall, every

other course being a header course with the

Figure 10. —Wall specimen

CF-Il during the impact

test.

[8]
blocks laid flat, as shown in figure 12. Tlu-ee- core blocks (shown in fig. 3) laid on edge, A,

were used in the stretcher courses and the same

size blocks laid flat, B, were used in the header

courses. Blocks, C, 1 K-core, were used to stagger the head joints. The bed joints and the

> i.e

>^ o.s

0.4'

0

1

1 >

-o—

1

^ —•

1/

f/

1

o

i

f

CF 0 0.04 0.08 OIZ

oleformaiion in./8ff Figure 11.

Racking load on wall CF.

Load-deformaf,ion (open circles) and load-set (solid circles) results for specimens CF-Rl, R2, and R3. The loads are in kips per foot of actual width of specimen. head joints were completely filled with mortar

and were cut fiush with the surface of the wail.

After the first course was laid, about 2 in. of mortar, D, was spread in the cavity to support

the blocks laterally. The uppermost stretcher course was filled with concrete, E. A 1-core

block, F (shown in fig. 2), laid inside this course,

ser\ ed as the end form for the concrete. The

top header course was placed after the concrete was poured.

The price of this construction in Washington, D. C, as of July 1937, was $0.20/ft\

The concrete blocks, the mortar, and the concrete fill had the same proportions in wall

CG as in wall CF and were made, sampled,

and tested using the same methods.

For wall CG the average water content of the

mortar was 24.0 percent by weight of the dry

materials. The physical properties of the

mortar and of the concrete are aiven in table 7.

Table 7.

Physical properlies of llic niorlar and of the concrete, wall CG

(The c()mi)r('Rsiv(> stronpths were determined on the day the eorrcspondine: wall specimens were tested]

.Mortar

Specimen

CICS

riT2

T3

//12

IS

RlR2

R3

Average

Flow

Percent

109

108

107

108

107

108

108

108

106

108

116 114 112

113

114

Compressive

strength

Air

storage

III /in."

.555 530

680

470

600 585

525 570

610

585

495

590

550 490

555

Concrete, compressive strength Water

storage

lb/in.'715 750

710

730

730

665

740

715 765

705

630

700

700

675 720

lb/in.'

3, .390 4,020

4, no

4,020

3, 540

3, 2.50

2, 830

3, 390

4, 020

3, 290

3, 290

3, 330

3, 330

3, 180 3,180

3,480

Figure 12.

Four-foot wall specimen CG.

A, 3-core block as stretcher; B, 3-eore block as header: C, IJ-i-core block: D, mortar 2 in. thick; E, concrete fill; F, 1-core block for and of concrete

form.

[9]
(b) Eight-Foot Wall Specimens

0 OM 0.0^

5hof^ienin<^ in./Sff

Figure 13.

Compi-essive load on wall CG.

Load-shortening (open circles) and load-set (solid circles) results for specimens CG-Cl. CZ, and C3. The loads were applied one-third the thickness (2.69 in.) from one face. The loads are in kips per foot of actual width of specimen.

0 O.OF 0.04 0.06

laferal deflecflon in. Figure 14.

Compressive load on wall CG.

Load-lateral deflection (open circles) and load-lateral set (solid circles) results for specimens CG-Cl, C2, and CS. The load was applied one- third the thickness (2.69 in.) from one face. The loads are in kips per

foot of actual width of specimen. The deflections and sets are for a gage length of 7 ft 6 in., the gage length of the deflectometers.

The 8-ft wall specimens were 8 ft 3% in. high, 8 ft bYt in. wide, and SKe in. thick. The

specimens were similar to the 4-ft wall speci- mens.

(c) Fabrication Data

The fabrication data, determined by the

Masonry Construction Section, are given in

table 5.

2. Compressive Load

The results of the compressive load on wall

specimens CG-Cl, C2, and C3 are shown in

table 6 and in figures 13 and 14. In specimen Cl, a block on the face nearer

the load line at one end near midheight crushed

at a load of 34.5 kips/ft. Failure occurred by

the crushing of blocks and mortar in the two

adjacent courses on the face nearer the load

line and near midheight. Specimens C2 and

C3 failed by breaking of the headers at the inner

surfaces of both faces, each header breaking in

two places. Specimen C2, at the maximum

load, collapsed suddenly without warning.

3. Transverse Load

Wall specimen CG-T2 under transverse load

is shown in figiu'e 15. The results of the transverse load on wall

specimens CG-Tl, T2, and T3 are shown in

table 6 and in figure 16. After specimen T2 had been set in place for the transverse test, but before a load had been

applied, it was noticed that a bond crack in the

bed joint below the fourteenth course existed in

both faces. This crack was probably caused

by moving the specimen into position for

testing. The maximum load on specimen T2

was 10.3 Ib/ft^, at which load the initial crack

widened.

In specimen T3, a crack in the bond between

the mortar and the blocks at a bed joint

appeared at a load of 20 Ib/ft^

At the maximum loads each of the specimens

Tl, T2, and T3 failed by rupture of the bond

between the mortar and the blocks at a bed

joint.

[10]
Figure 15. —Wall specimen CG-T2 under transverse

load.

4. Concentrated Load

The results of the concentrated load on wall

specimens CG-Pl, P2, and PS are shown in

table 6 and in figure 17. There was no measurable indentation for any

of the specimens after a load of 1,000 lb had

been applied and released.

5. Impact Load

The results of the impact load on wall speci- mens CG-Il, 12, and 13 are shown in table 6

and in figure 18.

to

12

8

4

0

—

-•—

1

-o

-

1—

o

>•<>

1

1

1

1

1

I CG

0 0.2 04 0.6

defleciion in. Figure 16. —Transverse load on wall CG.

Loart-delloction (open circles) and load-set (solid circles) results for speci- mens CG-Tl, TZ, and TS on the span 7 ft 6 in. The deflections and

sets are for a gage length of 7 ft 1 in., the gage length of the defiec- tometers.

1000

^ 800

I

o

o

600

400

200

CG

0.02 0.04 0.06

indenfafion in.

Figure 17.

Concentrated load on wall CG.

Load -indentation results for specimens CG-P!, F2, and PS.

11
0 0.2 0.4 0.6 0.8

deflecfion in. Figure 18.

Impact load on wall CG.

Height of drop-deflection (open circles) and height of drop-set (solid

circles) results for specimens CG-Il, K, and IS on the span 7 ft 6 in.

A bond crack appeared in a bed joint near midspan on the face not struck in specimens

CG~I1, 12, and 13 at a height of drop of 1.0,

1.5, and 1.0 ft, respectively. In each case, at

failure, this bond crack extended to the face

struck.

6. Racking Load

Wall specimen CG-R2 under racking load is shown in figure 19. The results for wall

specimens CG-Rl, R2, and R3 are shown in

table 6 and in figure 20. The deformations and sets shown in figure

20 were computed from the deformeter readings. The gage length of the deformeters was

6 ft 7 in. Each of the specimens failed by rupture of

the bed and head joints in stepwise cracks approximately along a diagonal between the

point of application of load and the stop. In

addition, in each case the concrete blocks at the toe cracked diagonally at the maximum

load.

I'iGUKE 19. —Wall specimen CG-Ril under racking load.

\\2]
VI. SPONSOR'S COMMENTS

Roinforced-concrete pilasters or columns are formed in the space between the facing and

backing by inserting stops at the desired location and placing reinforcing steel and concrete

2

0

• —•

• 0

0

0

• o

• o

• o •o

-o-»o

uIfO 30

3/D 0

0 0.0^ 0,04 0.06

deformaiion in./Sff

Figure 20.

Racking load on wall CG.

Load-deformation (open circles) and load-set (solid circles) results for specimens CG-Rl , and R3. The loads are in kips per foot of actual width of specimen.

in the enclosed space. Beams and lintels are

also reinforced concrete, formed in the same

manner. The outside of the wall may be finished with

cement paint or may be stuccoed. The inside

of the wall may be finished with plaster, consisting of a K-in. base coat applied directly to the blocks and covered by the usual white

finisli. Tlie total cost of these constructions

in Washington, D. C, as of July 19.37, wlien

weatherproofed with cement paint and plastercid on the inside, is $0.36/ft^.

The "Dunstone" blocks are manufactured

by 96 individually owned plants in different

parts of the country. There are no standardized mixes for the blocks due to the use of

local materials. Each plant has tests made by

the local testing laboratories to insure compli- ance with the requirements of the sponsor and

of the building codes of dift'erent cities. Many other sizes of "Dunstone" blocks than

the three sizes mentioned in this report are

available. They may be obtained in a wide

range of colors, shades, and textures, offering a permanent colored exterior for the building.

The "Dunstone" blocks may be used for other

types of walls than the two described in this

report and for veneering frame constructions.

The drawings of the specimens were prepared

by E. J. Schell and G. W. Shaw, of the Bureau's

Building Practice and Specifications Section,

under the supervision of V. B. Phelan.

The structm-al properties were determined

by the Engineering Mechanics Section, under

the supervision of H. L. Whittemore and A. H.

Stang, and the Masonry Construction Section,

under the supervision of D. E. Parsons, with the

assistance of the following members of the professional staft': F. Cardile, H. Dollar, M. Dubin,

A. H. Easton, A. S. Endler, C. C. Fishburn,

C. D. Johnson, A. B. Lanham, P. H. Petersen, A. J. Sussman, and L. R. Sweetman.

Washington, August 5, 1939.

o

[13]

BUILDING MATERIALS AND STRUCTURES REPORTS

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BMSl Research on Building Materials and Structures for Use in Low-Cost Housing 10^ BMS2 Methods of Determining the Structural Properties of Low-Cost House Constructions 10^ BMS3 Suitability of Fiber Insulating Lath as a Plaster Base 10^ BMS4 Accelerated Aging of Fiber Building Boards lOji BMS5 Structural Properties of Six Masonry Wall Constructions 15^ BMS6 Survey of Roofing Materials in the Southeastern States 15^ BMS7 Water Permeability of Masonry Walls 10^ BMS8 Methods of Investigation of Surface Treatment for Corrosion Protection of Steel 10^ BMS9 Structural Properties of the Insulated Steel Construction Co.'s "Frameless-Steel" Constructions for Walls, Partitions, Floors, and Roofs lOji BMSIO Structural Properties of One of the "Keystone Beam Steel Floor" Constructions Sponsored by the H. H. Robertson Co 10^ BMSll Structural Properties of the Curren Fabrihome Corporation's "Fabrihome" Constructions for Walls and Partitions 10^ BMS12 Structural Properties of "Steelox" Constructions for Walls, Partitions, Floors, and Roofs

Sponsored by Steel Buildings, Inc 15^ BMS13 Properties of Some Fiber Building Boards of Current Manufacture 10^ BMS14 Indentation and Recovery of Low-Cost Floor Coverings 10^ BMS15 Structural Properties of "Wheeling Long-Span Steel Floor" Construction Sponsored by

the Wheeling Corrugating Co 10^ BMS16 Structural Properties of a "Tilecrete" Floor Construction Sponsored by Tilecrete Floors, Inc 100 BMS17 Sound Insulation of Wall and Floor Constructions 10^ BMS18 Structural Properties of "Pre-Fab" Constructions for WaUs, Partitions, and Floors Sponsored by the Harnischfeger Corporation 100 BMS19 Preparation and Revision of Building Codes 150 BMS20 Structural Properties of "Twachtman" Constructions for Walls and Floors Sponsored by

Connecticut Pre-Cast Buildings Corporation 100 BMS21 Structural Properties of a Concrete-Block Cavity-Wall Construction Sponsored by the National Concrete Masonry Association 100 BMS22 Structural Properties of "Dun-Ti-Stone" Wall Construction Sponsored by the W. E. Dunn Manufacturing Co 100 BMS23 Structural Properties of a Brick Cavity-Wall Construction Sponsored by the Brick Manufacturers Association of New York, Inc 100 BMS24 Structural Properties of a Reinforced-Brick Wall Construction and a Brick-Tile CavityWall Construction Sponsored by the Structural Clay Products Institute 100 BMS25 Structural Properties of Conventional Wood-Frame Constructions for Walls, Partitions,

Floors, and Roofs 150 BMS26 Structural Properties of "Nelson Pre-Cast Concrete Foundation" Wall Construction

Sponsored by the Nelson Cement Stone Co., Inc 100 BMS27 Structural Properties of "Bender Steel Home" WaU Construction Sponsored by The

Bender Body Co 100 BMS28 Backflow Prevention in Over-Rim Water Supplies 100 BMS29 Survey of Roofing Materials in the Northeastern States 100 BMS30 Structural Properties of a Wood-Frame WaU Construction Sponsored by the Douglas

Fir Plywood Association 100 BMS31 Structural Properties of "Insulite" Wall and "Insulite" Partition Constructions Sponsored by The Insulite Co 150 BMS32 Structural Properties of Two Brick-Concrete-Block Wall Constructions and a Concrete- Block Wall Construction Sponsored by the National Concrete Masonry Association. 100 BMS33 Plastic Calking Materials 100 BMS34 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 1 100 BMS35 Stability of Sheathing Papers as Determined by Accelerated Aging 100 BMS36 Structural Properties of Wood-Frame Wall, Partition, Floor, and Roof Constructions with

"Red Stripe" Lath Sponsored by The Weston Paper and Manufacturing Co 100 BMS38 Structural Properties of Two "Dunstone" Wall Constructions Sponsored by the W. E. Dunn Manufacturing Company 10^