206 ANNUAL REPORT 
25.. Cement for Inspection and Tests.—The contractor must submit the 
cement for inspection and testing at least ten (10) days before using, and 
such inspection and tests will be made only from samples obtained by the 
Inspector from cement delivered on the work. The inspector shall be noti- 
fied of each delivery of cement. All cement must stand the following tests: 
26. Checking and Cracking.—Two cakes, three inches in diameter and 
one-half mch thick, with thin edges, will be made. One of these cakes as 
soon as set will be placed in water and examined from day to day. If the 
cake exhibits checks, cracks or contortions, the cement will be rejected. The 
other cake described will be used for setting and color tests. 
27. Beginning of Set,—The time will be noted when the cake has become 
hard enough to sustain a wire one-twelfth inch in diameter loaded with one- 
fourth pound. When the wire is sustained, the cement has begun to set, 
and this time shall not be less than forty-five (45) minutes. 
28. End of Set.—When the cake will sustain a wire one twenty-fourth 
inch in diameter loaded with one pound, the set is complete, and this time 
must not be less than two (2) hours nor more than six (6) hours. 
29. Color.—The cake used for setting test will be preserved, and when 
examined from day to day must be of uniform color, exhibiting no blotches 
or discolorations. 
30. Fineness, —-The cement must be evenly ground, and when tested with 
the following standard sieves, must pass at least the following percentages. 
No. 50 sieve, having 50 meshes per lineal inch, 98 per cent; No. 74 sieve, 
having 74 meshes per lineal inch, 94 per cent; No. 100 sieve, having 100 
meshes per lineal inch, 90 per cent. The diameter of wire for the sieves 
being respectively: For No. 50 sieve, No. 85 Stub’s wire gauge; For No. 74 
sieve, No. 37 Stub’s wire gauge; For No. 100 sieve, No. 40, Stub’s wire gauge. 
33. Mixing Test Cement.—All cement for test briquettes, will be mixed 
with barely sufficient water to make a stiff mortar. The neat briquettes to be 
pressed into the molds by hand and the sand briquettes to be compacted 
by light tapping. 
32. Strength,—The required tensile strength per square inch shall be 
as follows: 
Neat eement: 
One day—till set in air, remainder time in water............ 150 Ibs. 
One week—one day in air, six days in water .................. 400 Ibs. 
Cement one part, and sand three parts: 
One week—one day in air, six days in water................ 140 Ibs. 
33. Covering Briquettes.-—Briquettes for seven (7) day tests will be 
covered for the first twenty-four (24) hours with a damp cloth. 
SAND. 
34, Sand for Concrete.—The sand for concrete shall be clean, sharp 
silicious sand. It shall be free from clay or other mineral impurities, loam or 
organic matter, and shall be thoroughly screened. 
35. Sand for Finish Coat.—The sand for cement tests, and for the finish 
coat of the walk, will be crushed quartzite of such fineness that all will pass 
a sieve of 10 meshes per lineal inch, and none of it a sieve of 50 meshes 
per lineal inch. 
