8 DEPARTMENT BULLETIN 1216, IT. S. DEPT. OF AGRICULTURE 
Table 1. — Percentage of water for standard mortars 
Percentage 
Percentage 
Percentage 
Percentage 
of water for 
of water for 
of water for 
of water for 
neat cement 
1 cement, 
neat cement 
1 cement, 
paste of 
3 standard 
paste of 
3 standard 
normal con- 
Ottawa 
normal con- 
Ottawa 
sistency 
sand 
sistency 
sand 
15 
9.0 
23 
10.3 
16 
9.2 
24 
10.5 
17 
9.3 
25 
10.7 
18 
9.5 
26 
10.8 
19 
9.7 
27 
11.0 
20 
9.8 
28 
11.2 
21 
10.0 
29 
11.3 
22 
10.2 
30 
11.5 
DETERMINATION OF SOUNDNESS 5 
38. A steam apparatus, which can be maintained at a temperature between 
98° and 100° C, or one similar to that shown in Figure 2, is recommended. 
The capacity of this apparatus may be increased by using a rack for holding 
Ihe pals in a vertical or inclined position. 
39. A pat from cement paste of normal consistency about 3 inches in diam- 
eter, one-half inch thick at the center, and tapering to a thin edge, shall be 
made on flat clean glass plates about 4 inches square and stored in moist air 
lor 24 hours. In molding the pat, the cement paste shall first be flattened on 
the glass and the pat then formed by drawing the trowel from the outer edge 
toward the center, then flattening the top. The pats used for the time of 
setting tests by the Gillmore method may be used for soundness teste 
49. The pat shall then be placed in an atmosphere of steam at a temperature 
between 98 and 190° C, upon a suitable support 1 inch above boiling water 
for five hours. 
Note. — It is important that the specimens be 24 hours old when placed in steam, 
since variations in their age will produce differences in the results of the steam tests. 
Particularly noticeable are the effects of steaming pats too soon, for many specimens 
steamed when only 10 or 12 hours old give apparently satisfactory results, while 
failure would be observed if they were not placed in steam until 24 hours old. 
41. Should the pat leave the plate, distortion may be detected best with a 
straightedge applied to the surface which was in contact with the plate. 
DETERMINATION OF TIME OF SETTING 
42. The following are alternate methods, either of which may be used as 
specified: 
43. The time of setting shall he determined with the Vicat apparatus de- 
scribed in section 35. (See fig. 1.) 
44. A paste of normal consistency shall he molded in the ring G as. described 
in section 36 and placed under the rod B, the smaller end of which shall thea 
he carefully brought in contact with the surface of the paste, and the rod 
quickly released. The initial set shall be said to have occurred when the needle 
ceases to pass a point 5 millimeters above the glass plate in one-half minute 
after being released, and the final set when the needle does not sink visibly into 
the paste. The test pieces shall be kept in moist air during the test. This 
may be accomplished by placing them on a rack over water contained in a pan 
and covered by a damp cloth, kept from contact with them by means of a wire 
screen ; or they may be stored in a moist closet. Care should be taken to keep 
the needle clean, as the collection of cement on the sides of the needle retards 
the penetration, while cement on the point may increase the penetration. The 
time of setting is affected not only by the percentage and temperature of the 
5 Unsoundness is usually manifested by change in volume which causes distortion, 
cracking, checking, or disintegration. Pats improperly made or exposed to drying may 
develop' what are known as shrinkage cracks within the first 24 hours and are not an 
indication of unsoundness. These conditions are illustrated in Plate 1. The failure of 
the pats to remain on the idass or the cracking; of the «;lass to which the pats are 
attached does not necessarily indicate unsoundness. 
