CEMENT--RETARDED SETS,
500
Dyckerhoff Portland Cement.
RETARDED SET SERIES.
Samples taken out at 2-hour intervals, first and last hours excepted. Main batch of cement allowed to rest undisturbed in the mixing bed between the times of taking out samples, or when regauging. Age when tested, 31 days.
Pounds.
213
2*8.6 per cent= 61
Original quantities:
Cement........
Water.........
Water added to the main batch as follows:
Water used.
Pounds.	Per cent approximate.
61.0	28.6
1.0	29.1
2.0	30.4
2.0	31.3
2.5	34.4
. 0.75	34.4
0.5	35.8
1.0	37.5
Interval after mixing, hours.
Initial mixing
4...............
12..............
14£.............
16..............
18..............
20..............
24..............
	Dimensions.			Sectional area.	First crack.	Compressive strength.		
Hours.	Height.	Compressed surface.				Total.	Per square inch.	Remarks.
0	Inches. 6.00	Inches. 6.01	Inches. 5.92	Sq. inches. 35.58	Pounds. 126,300	Pounds. 126,300	Pounds. 3,549	Age, 32 days.
1	6.00	6.08	5.93	36.05	129,800	132,200	3,667	Do.
2	5.99	6.04	5.92	35.75	112,500	122,000	3,412	Do.
4	6.01	6.05	5.99	36.24	123,300	123,300	3,402	Do.
6	6.03	6.07	6.02	36.55	97,800	98,200	2,686	
8	6.02	6.04	6.00	36.24	88,400	88,400	2,439	
10	6.00	6.03	6.08	36.67	84,800	84,800	2,312	
12	6.00	6.10	6.08	37.09	70,400	70,400	1,898 1,745	
14	5.98	6.10	6.04	36.84	64,300	64,300		
16	6.05	5.99	6.02	36.05	62,800•	63,400	1,758	
18	5.98	6.07	6.00	36.42	60,000	60,700	1,666	
20	5.98	6.03	6.03	36.37	61, 500	61,500	1,690	
22	6.00	6.01	6.03	36.24	55,900	56,900	1,570	
24	5.97	6.00	6.04	36.24	56,200	57,300	1,581	
25	6.05	6.00	6.00	36.36	56,900	57,400	1,578	
25	6.04	5.98	6.01	35.93	54,900	57,200	1,591	
25	4.04	4.05	4.07	16.49	26,600	26,600	1,613	Do.
25	1.94	2.02	2.10	4.24	5,860	5,860	1,382	Do.
25	1.93	2.01	2.10	4.22	5,960	5,960	1,412	Do.
25	2.01	1.92	2.13	4.09	5,180	5,180	1,266	Do.