605
CONCRETE AND MORTAR CUBES.
Marks, 208.
Composition: Alpha Portland cement, 1; sand, 6; f" trap rock, 12. Water used in mortar, 146.7 per cent of cement.
Age, 1 year.
Sectional area, 144.48 square inches.
Gauged length, 5".
Applied loads.		In gauged length.		
Total.	Per square inch.	Compres- sion.	Set.	Remarks.
Pounds. 14,448 28,896 43,344 57,792 72,240 86,688 101,136 115,584 124,300	Pounds. 100 200 300 400 500 600 700 800 860	Inch. 0. .0006 . 0012 .0018 .0026 .0069 .0139 .0280	Inch. 0. .0001 .0001 .0001 . 0005 .0039 .0104 .0235	This specimen had been loaded with 500 pounds per square inch compression before the micrometer observations were begun. E=833,000 pounds per square inch. First crack and ultimate strength.
				
The maximum load was sustained about 8 minutes, during which time failure of the cube slowly progressed, gaining near the end of the test.
Marks, 387.
Composition: Alpha Portland cement, 1; sand, 2; 2£" trap rock, 7. Water used in mortar, 69.3 per cent of cement.
Age, 1 year, 2 months.
Weight per cubic foot, 154.6 pounds.
Sectional area, 145.56 square inches.
Gauged length, 5".
Applied loads.		In gauged length.		Remarks.
Total.	Per square inch.	Compres- sion.	Set.	
Pounds.	Powids.	Inch.	Inch.	
14,556	100	0.	0.	Initial load.
29,112	200	.0009	. 0006	
43,668	300	. 0018	.0012	
58,224	400	.0029	.0019	
72,780	500	.0038	.0025	
87,336	600	.0046	.0031	E=l,667,000 pounds per square inch.
101,892	700	.0055	.0037	
116,448	800	.0063	.0043	
131,004	900	. 0074	.0049	
145,560	1,000	.0082	.0055	1 E=l,667,000 pounds per square inch.
174,672	1,200	.0100	. 0069	
203,784	1,400	.0117	.0080	Ie=2,000,000 pounds per square inch.
232,896	1,600	.0135	.0091	[
262,008	1,800	.0150	.0103	
291,120	2,000	.0162	.0110	
329,000				
376,200	2,584			Ultimate strength.