■878 NEW YOKK STATE MUSEUM 



Specifications 



The specifications tinder whicli tlie cements intended for nse on 

 the canal improvements were submitted, were, from 1896 to 1899, 

 as follows. 



Portland cement mnst be of the best quality and of snch fine- 

 ness that 95^ of the cement will pass through a sieve of 2500 

 meshes to the square inch, and 90 fo through a sieve of 10,000 

 meshes to the square inch. Portland cement when mixed neat 

 and exposed one day in air and six days in water, shall with- 

 stand a tensile strain of not less than 400 lb to the square inch; 

 and when mixed in the ratio of 3 lb clean, sharp sand to 1 lb 

 of cement, and exposed one day in air and six days in water, it 

 shall withstand a tensile strain of not less than 125 lb per square 

 inch. 



E'atnral hydraulic cement must be of the best quality, and of 

 such fineness that 90/^ will pass through a sieve of 2500 meshes 

 to the square inch, and 80^ through a sieve of 10,000 meshes to the 

 square inch. Briquets, made of equal parts of natural hydraulic 

 cement and crushed quartz, immersed in water as soon as they 

 are sufiiciently hard to sustain a gV inch wire Aveighted with 

 1 lb, must show a tensile strength of 65 lb to the square inch at 

 the expiration of seven days; but briquets showing less than such 

 strength will be held until 28 days have elapsed, when, if they 

 then show such strength as to sustain as many pounds to the square 

 inch above 125 as the seven day test shows them to have fallen 

 below 65, they will be deemed to have passed this test. 



Briquets made of neat cement must not set so as to support a 

 iV iiich wire with a load of J lb in less than 15 minutes. Briquets 

 •of neat cement must not show checks or cracks when immersed 

 in water for seven days after mixing. 



Portland and natural cements manufactured in this state will 

 be given the preference for this work, provided they satisfactorily 

 pass the tests called for by these specifications. 



The specifications at present in use are the following. 



28 Requirements hydraulic cement. American Portland cement 

 or American natural cement, as may be specified, shall be used 

 and shall be of a brand known by prior use on extensive, works 

 to be of the best quality. Any cement not so known may be 

 declined without testing. 



