20 “BULLETIN 704, U. S. DEPARTMENT OF AGRICULTURE. 
Definition. 
Chemical 
Limits. 
Specific Gravity. 
Fineness. 
Soundness. 
Time of 
Setting. 
Tensile 
Strength. 
Packages and 
Marking. 
Storage. 
Inspection. 
SPECIFICATION Ct-1. 
Portland Cement. 
(1) Portland cement is the product obtained by finely pulverizing 
clinker produced by calcining to incipient fusion an intimate and prop- 
erly proportioned mixture of argillaceous and calcareous materials, with 
no additions subsequent to calcination except water and calcined or un- 
calcined gypsum. 
I. CHEMICAL PROPERTIES. 
(2) The following limits shall not be exceeded: 
Per cent. 
sO SS ONY TNT ETO ar a ee Ea Ne ae re a Be EE ees 4.00 
Insoluble sresiducm ee ee Mine ge Pui bainines Reh yet ey dane & yl , 85 
Sulphuriceanhydride- (S03) 2222 ee a ee 2.00 
Magnesia (MgO) 2.284. 22525255 ie ee ee SE ee 5. 00 
II. PHYSICAL PROPERTIDS. 
_ (3) The specific gravity of cement shall be not less than 3.10. Should 
the test of cement as received fall below this requirement, a second test 
may be made upon an ignited sample. The specific-gravity test will not 
be made unless specifically ordered. ‘ 
(4) The residue on a standard 200 mesh sieve shall not exceed 22 per 
cent by weight. ia 
(5) A pat of neat cement shall remain firm amd hard, and show no 
signs of distortion, cracking, checking, or disintegration in the steam 
test for soundness. 
(6) The cement shall not develop initial set in less than 45 minutes 
when the Vicat needle is used, or 60 minutes when the Gillmore needle 
is used. Final set shall be attained within 10 hours. 
(7) The average tensile strength in pounds per square inch of not less 
than three standard mortar briquets composed of 1 part cement and 3 
parts standard sand, by weight, shall be equal to or higher than the 
following: 
Tensile 
Age strength 
at Storage of briquets. per 
test square 
inch 
Days. Pounds 
(.\ Wd ayanimoistiain WOid ays nS walter ema sac e sais eter oerees 200 
28 |-liday- insmoistiair.27, day Siiltawater =p eee eee see ee see ee ae 300 
(8) The average tensile strength of standard mortar at 28 days shall 
be higher than the strength at 7 days. 
III. PACKAGES, MARKING, AND STORAGE. 
(9) The cement shall be delivered in suitable bags or barrels with the 
brand and name of the manufacturer plainly marked thereon, unless 
shipped in bulk. A bag shall contain 94 pounds net. A barrel shall 
contain 376 pounds net. 
(10) The cement shall be stored in such a manner as to permit easy 
access for proper inspection and identification of each shipment, and in a 
suitable weather-tight building which will protect the cement from 
dampness. 
IV. INSPECTION. 
(11) Every facility shall be provided the purchaser for eareful sam- 
pling and inspection either at the mill or at the site of the work, aS may 
