CEMENT---SET AT DIFFERENT TEMPERATURES.
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same age in the air at 70° F. are not here shown to be conspicuously unlike, notwithstanding the different durations of the preceding intervals of exposure in the freezer at zero temperature.
Diagrams follow showing the curves of strength for each of the three groups, which set in air at 0°, 39°, and 70° F., respectively. There are also diagrams which show the strength acquired by specimens which set various intervals at zero and at 39° F., after they were removed from the cold storage warehouse and set additional intervals at 70p F. temperature.
Cements which Set in Air at Different Temperatures.
MEAN RESULTS WITH 2-INCH CUBES.
[Where figures are given in two columns showing the time of setting the cement was first exposed to the lower temperature, then to the higher, the indicated intervals prior to testing.]
Brand.	Class.	Composition.			Time of setting in air at temperature of—						Compres- sive strength per square inch.
		Ce- ment.	Sand.	Water.	0° F.		39° F.		70° F.		
				Per ct.	Mos.	Days.	Mos.	Days.	Mos.	Days.	Pounds.
				23.4		31					
				23.4		31				7	
				23.4		31				30	
				23.4	3					1	
				23.4	3					7	2,690
				23.4	3					14	3,300
				23.4	3					30	3,620
				25.7				29			2,980
				25.7				29		7	3,550
				25.7				29		30	4,200
				25.7			3				3,350
				25.7			3			7	4,090
				25.7			3			14	4,280
				23.4						29	4,350
				23.4						32	4,570
				23.4						36	
				23.4						38	4,820
				23.4					2		4,840
				23.4					2		4,830
				23.4					3	14	4,410
				24.6					4		4,100
		1	1	36.1		5				1	287
				36.1		5				7	846
				36.1		14				1	321
				36.1		14				7	1,000
				36.1		21				1	337
				36.1		21					1,010
				36.1		31				1	'383
				36.1		31				7	981
				36.1		31				30	1,400
				36.1	2					1	'416
				36.1	2					7	981
				36.1	2					14	1,250
				36.1	3					1	497
				36.1	3					7	1,010
				36.1	3					14	l’310
		1	1	32.0				15			1,710
				32.0				15		7	2^710
				32.0				31			l’960
				32.0				31		7	2,720
				32.0				31		21	S, 050
				32.0			2				2'460
				32.0			2			7	3,270
				32.0			2			14	3,220
		1	1	32.0						15*	1,970
				32.0						22	2,290
				32.0						31	2,330
				32.0						38	2,320
				32.0					2		2; 490