501
CEMENT--RETARDED SETS,
Dyckerhoff Portland Cement.
RETARDED SET SERIES.
Samples taken out at 2-hour intervals, first hour excepted. Main batch of cement kept in a state of agitation in the mixing bed until put into the molds. Age when tested, 31 days.
Original quantities:	Pounds.
Cement........................................................... 207
Water.......................................................29.5 per cent= 61
Water added to the main batch as follows:
Per cent approximate.
Pounds.
Interval after mixing, hours.
29.5
30.0
30.0
31.0
61.0 1.0 0.25 0.12
Initial mixing
10..............
16..............
20..............
Hours.	Dimensions.			Sectional area.	First crack.	Compressive strength.		Remarks.
	Height.	Compressed surface.				Total.	Per square inch.	
	Inches.	Inches.	Inches.	Sq. inches.	Pounds.	Pounds.	Pounds.	
0	5.99	6.06	6.06	36.72	104,500	109,200	2,973	
1	6.00	6.10	6.05	36.90	119,900	120,400	3,262	
2	6.07	5.98	6.01	35.93	107,900	114,500	3,186	
4	6.07	5.98	6.14	36.71	102,200	102,200	2,783	
6	5.98	6.10	6.26	38.19	104,400	104,400	2,733	
8	5.99	6.10	6.02	36.72	98,900	98,900	2,693	
10	5.97	6.03	6.14	37.02	83,400	83,400	2,252	
12	5.98	6.05	6.15	37.20	69,600	71,800	1,928	
14	5.98	6.02	6.08	36.60	62,900	62,900	1,718	
16	5.98	6.01	6.07	36.49	65,800	65,800	1,803	
18	6.05	6.00	6.06	36.36	64,600	64,600	1,776	
20	5.98	6.04	5.50	33.22	57,100	57,100	1,718