620
STEEL BARS IN CONCRETE.
Adhesive Resistance of Steel Bars Embedded in Concrete.
Steel rods X embedded in concrete prisms 6" X 6" by 18" long. Material submitted by Mr. H. A. Carson, chief engineer Boston transit commission.
Test No.				Depth rod is embedded.	Surface	Adhesive resistance.	
	Marks.	Brand of cement.	Age.		in contact.	Total.	Per square inch.
11416	P.22	Vulcanite		Days. 30	Inches. 2	Sq. inches. 4	Pounds. 1,170	Pounds. 293
11417	P. 41		30	4	8	1,335	167
11418	P.42		30	4	8	920	115
11419	P. 61		30	6	12	920	77
11420	P. 62		30	6	12	2,850	237
11421	P.81		30	8	16	1,860	116
11422	P. 82		30	8	16	3,920	245
11423	P. 101		30	10	20	5,100	255
11424	P. 102		31	10	20	5,920	296
11425	P. 121		31	12	24	5,870	245
11426	P.122		30	12	24	4,720	197
11437	R.8		30	8	16	3,850	241
11438	R. 10		30	10	20	5,830	292
11439	R. 12		30	12	24	8,560	357
Compression Tests of the Concrete Prisms in which the i" X Steel Rods were Embedded, of the Preceding Tests.
Test No.	Marks.	Brand of cement.	Age.	Dimensions.			Sec- tional area.	First crack.	Ultimate strength.	
				Height.	Compressed surface.				Total.	Per square inch.
				Inches.	Inches.	Inches.	Sq. ins.	Pounds.	Pounds.	Pounds.
11416 a	P. 22		31	17.77	6.08	6.04	36.72	78,800	78,800	2,150
11417 a	P. 41		31	17.55	5.99	6.30	37.74	101,600	101,600	2,690
11418 a	P. 42		31	17.68	6.02	6.29	37.87	93,000	93,000	2,460
11419 a	P. 61		31	17.58	6.06	6.23	37.75	81,400	81,400	2,160
11420 a	P. 62		31	17.62	6.04	6.15	37.15	94,100	94,100	2,530
11421 a	P. 81		31	17.50	6.02	6.32	38.05	85,700	85,700	2,250
11422 a	P. 82		31	17.73	6.04	6.25	37.75	80,500	80,500	2,130
11423 a	P. 101		31	17.63	6.04	6.30.	38.05	88,500	88,500	2,330
11424 a	P. 102		31	17.60	6.09	6.30	38.37	81,400	81,400	2,120
11425 a	P. 121		31	17.55	6.06	6.26	37.93	76,100	76,300	2,010
11426 a	P. 122		31	17.70	6.05	6.25	37.81	84,200	84,200	2,230
11437 a	R. 8		35	17.60	6.25	6.05	37.81	153,500	153,500	4,060
11438 a	R. 10		35	17.58	6.15	6.05	37.21	160,500	160,500	4,310
11439 a	R. 12		35	17.62	6.19	6.03	37.33	159,200	159,200	4,260