CHAPTERS ON THE CEMENT INDUSTRY L 8Y9 



29 Storing. Provision shall be made bj the contractor for 

 storing cement in a dry place and delivery shall not be made 

 until the state engineer has been notified to inspect the cement 

 and to take samples for which all facilities shall be offered by 

 the contractor. The contractor shall replace at his own cost any 

 cement which may be damaged while stored. 



30 Samples. Samples will be taken by the engineer, at once 

 on delivery, from every 10th barrel or from the eqnivalent of the 

 10th barrel, when packed in sacks, and will be numbered con- 

 secutively throughout the progress of the work; each sample shall 

 fill a 4 inch cubical box, and each lot of samples shall be forwarded 

 by express to Albany for separate tests, the results of which may 

 be expected in 10 days. 



31 Tests. These tests will follow the practice recommended 

 by the American society of civil engineers and will be: 1st, for 

 fineness; 2d, for soundness; 3d, for time of initial set; 4th, for 

 tensile strength; 5th, for composition by chemical tests. 



32 Required fineness. Cement shall be ground to such fine- 

 ness that 95^ by weight will pass through a standard sieve of 

 2500 meshes per square inch and 90/^ by weight will pass through 

 a standard sieve of 10,000 meshes per square inch. 



33 Soundness. The cement shall endure the hot water test at 

 125° F for 24 hours without cracking or blowing. Chemical 

 tests. The state engineer may cause chemical tests of cement to be 

 made and may reject any cement which, in his judgment, is not 

 suited to the purpose. 



34 Initial set. Neat cement shall not set to support J lb 

 weight on ^ inch wire in less than 15 minutes for natural cement 

 and 25 minutes for Portland cement. 



35 Required strength — American Portland cement. Briquets 

 of neat cement mixed three minutes, put in the molds with thumbs 

 and trowel, and kept at a temperature of 65° to Y0° for one day 

 in moist air and six days in water shall show a least average tensile 

 strength of 400 lb per square inch. 



Briquets of three parts by weight of standard crushed quartz 

 and one part by weight of Portland cement, mixed in the same 

 manner and kept seven days under the same conditions, shall show 

 a least average tensile strengi;li of 125 lb per square inch. 



Briquets of three parts by weight of standard crushed quartz 

 and one part by weight of Portland cement, mixed in the same 



