[Trade Journal]
Publication: Engineering Bulletin Purdue University
Lafayette, IN, United States
vol. 20, no. 5, p. 5,11,15-17, col. 1
RESEARCH SERIES NO. 55
ENGINEERING EXPERIMENT STATION
REPORT
OF THE
RESEARCH AND EXTENSION
ACTIVITIES
OF THE
ENGINEERING SCHOOLS AND DEPARTMENTS
FOR THE SESSIONS OF
1935-1936
A A. POTTER
Director
Engineering Experiment Station
Engineering Extension Department
W. A. KNAPP
Secretary
Engineering Experiment Station
Engineering Extension Department
PURDUE UNIVERSITY
Lafayette. Indiana
SEPTEMBER, 1936
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RESEARCHES CARRIED ON BY THE ENGINEERING
EXPERIMENT STATION
AND THE ENGINEERING SCHOOLS AND
DEPARTMENTS
July 1, 1935, to June 30, 1936
Engineering researches was carried on by the Engineering Experiment Station and the several schools and departments and by undergraduate and graduate students.
A. Researches of the Engineering Experiment Station included:
(a) Station research
(b) Co-operative research — direct with the industry
(c) Co-operative research — through the Purdue Research Foundation.
(d) Service and commercial tests.
B. Researches of the schools and departments included:
(a) Staff researches
(b) Graduate researches
(c) Undergraduate researches.
The report that follows includes brief progress reports on all active research investigations carried on by the Engineering Experiment Station and by the several engineering schools and departments for the period of July 1, 1935, to June 30, 1936. The reports are grouped under the several divisions of the Engineering Experiment Station corresponding to the teaching divisions of the engineering schools and departments. Researches caried on under the direct supervision of the Director of the Engineering Experiment Station are reported under the Administrative Division.
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CIVIL ENGINEERING DIVISION
W. K. Hatt in charge
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Hollow Glass Block Research (Project C-29). Co-operative research for the Owens-Illinois Glass Company, started in July, 1935. Investigators, R. B. Crepps, R. E. Mills, and W. K. Hatt.
Progress Report. Hollow glass blocks as manufactured by the Owens-Illinois Glass Company of Muncie, Indiana, were submitted to the Testing Materials Laboratory for test and study. The several qualities considered in these tests were (a) compressive strength, (b) adhesion of mortar joints, (c) air-pressure tests on glass block panels, (d) transmission of heat, and (e) transmission and diffusion of light.
Compressive strength tests were conducted upon: (a) two types of individual blocks — No. 101, 4 7/8" x 3 7/8", and No. 201, 5 3/4" x 5 3/4" x 3 7/8"; (b) piers representing both blocks which were laid up (5 blocks high) with mortar joints; and (c) panels approximately 2' x 4' representing both blocks and laid up with mortar joints. All of the piers and panels were laid up by experienced brick masons. Average strength values for the individual blocks ranged from about 1,250 to 2,000 lb. per sq. in,; for the piers from about 275 to 500 lb. per sq. in.; and for the panels from about 375 to 415 lb. per sq. in.
Adhesion tests of the mortar joints were conducted in direct tension and in shear. Average strength values for these tests showed about 16 to 27 lb. per sq. in. for direct tension and about 52 to 80 lb. per sq. in. for shear. The composition of the sand coating on the glass blocks seemed to have considerable effect upon the results.
Air-pressure tests were conducted upon a 7'-3" x 8'-7" glass block panel and a 7'-3 1/8" x 8'-6 3/4" standard steel sash glazed with 30 lights of double-strength glass. Both of these test units were mounted on a concrete sill and supported on either side by a 12 1/2" square common brick column. The top of each test panel was supported by two angle iron lintels. The air pressure was applied through the medium of a rubberized bag. This bag, which was placed against one side of the test panel, was supported on the back by a rigid wooden wall. Inflation of the bag produced a uniform pressure against one side of the test panel; as the air pressure was increased, the panel deflected outward until failure developed. The maximum pressure carried by the glass block panel was 161 lb. per sq. ft., while that carried by the steel sash was 52 lb. per sq. ft.
Heat transmission tests were conducted by W. T. Miller, School of Mechanical Engineering. The tests indicate that the glass block panel transmitted about 69% less heat than a steel sash of corresponding size.
Transmission and diffusion of light tests were conducted by G. W. Sherman, Jr., Department of Physics. The tests show that the design of the blocks, the color, etc., have a very marked effect upon the transmission light. Some of the clear glass blocks showed a light transmission percentage of about 80.
Additional tests are now under way in the laboratory to determine the thermal coefficients of expansion of glass block panels and to study the adhesion qualities of a number of commercial masonry cements.
Later investigations were expanded to include (f) standard tests of thirteen different brands of masonry cement, (g) consistency and strength of masonry mortars, (h) thermal coefficients of expansion of glass block masonry, and (i) modulus of elasticity of glass block masonry.
Tests were conducted to determine the physical properties of thirteen different brands of masonry cement as selected from several sections of the United States. These tests showed a wide range of results, with the weaker cements developing only about one-third the strength of the stronger cements. The importance of selecting masonry cements of a high degree of strength is shown by the fact that all the strength exhibitions of the glass block masonry were increased when the stronger masonry cements were used.
Adhesion tests of the mortar joints were conducted in direct tension and in shear. One hundred eighty specimens representing the strength range of the masonry cements were included in these tests. Average values show that mortars having high compressive strength exhibit correspondingly high values in shear and tension.
Average values show a thermal coefficient at 80 increased. Thermal coefficients of expansion were determined for both the glass block masonry and small mortar beams. For all tests the coefficients were found to vary somewhat with the brand of cement, and to increase slightly as the temperatures degrees F. of about .00000453 for the glass block masonry and about .00000538 for the masonry mortar.
Modulus of elasticity values were determined for glass block masonry representing several different brands of masonry cement. Average values show that the modulus of elasticity increased proportionately to the strength of the masonry mortar. The values ranged from 552,000 to 940,500.
A complete report of these tests was submitted to the Owens-Illinois Glass Company in May, 1936.
Additional tests are now under way in the laboratory to determine the strength of panels and piers and to study the moisture-resisting qualities of glass block masonry.
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