7 1 t 2s i:w fOBK B i All: MUSI I M 



parts tre lime and alumina, and the grinding of the vitrified 

 materia] to a fine powder. 



1 Packing and weights: As a rule Portland cement is to be 

 packed in standard barrels of l sn kilograms (397 pounds), gross 

 weight, and about 170 kilograms (374 pounds), uet weight, and 

 in half Btandard barrels of 90 kilograms i i'- ,y> pounds), 

 weight and about s -" kilograms (133 pounds), net weight. The 

 to be marked on the barrels. If the cement is 

 called for in bags or barrels of other weight, the gross weight of 

 the same must be clearly marked upon the packages. Lose 

 and variations in weight of the single packages up to 2& of the 

 same will l>e allowed. Barrels and sacks, in addition to the 

 weight shall Bhow in legible writing the name and trade mark 

 of the manufacturer. 



S ow or quick setting cement may he called 

 for according to the use for which the cement is to he put Ce- 

 ments which do not set in less than 2 hours, are to be considered 

 slew Betting cements. 



3 Constancy of volume: Portland cement shall be of constant 

 volume. As a preliminary test, admitting of forming a rapid 

 opinion, the heating test is recommended. The decisive test shall 

 he that a paste of neat cement made on a glass plate protected 

 against drying and placed under water after 24 hours, shall not 

 show after the lapse of a longer period of time any blowing cracks, 

 or change of shape. 



4 fineness of grinding: Portland cement shall be so finely 

 ground that a batch of the same shall not leave a residue of more 

 than l«»v upon a Bieve of 900 meshes per square centimeter (5806 

 meshes per square inch). The thickness of the wire of the sieve 

 shall equal half the space between the wires. For test 100 grams 



ounces »ment -lull be used. 



:, Tests of strength: The cohesive power of Portland cement 

 shall be determined by the testing of a mixture of cement and 

 sand. The tests -hall be both tensile and compressive, made 

 according t<> a uniform method, with test pieces of the same form 

 and <•]•■ tion, and with the same apparatus. At the same time 



a determination of the strength of the neat cement is to be recom- 

 mended. 



rensile and compressive Btrength: Oood slow setting cement, 

 in the proportion of three parts by weight of Btandard Band to 

 one part of cement -hall have when tested, after l )x days' hard- 

 ening i«-ne in air and 27 in water), a minimum tensile strength 



