20 



BULLETIN 555, U. S. DEPARTMENT OF AGRICULTURE. 



Methods of The sand shall be sampled in accordance with the method de- 

 grading, scribed on page , paragraphs , of these specifications ; 



and the grading shall be determined in accordance with the 

 methods described or referred to on page of these specifi- 

 cations, tests Nos. 



Note. — It is recommended that volumetric analyses be reported 

 by the laboratory to facilitate field control. 



SPECIFICATION FOR SAND FOR FINE AGGREGATE FOR PORTLAND-CEMENT 

 CONCRETE WEARING SURFACE. 



General. 



Grading. 



M o r t t t 



strength test. 



Methods of 

 sampling and 

 grading. 



The sand shall consist of clean, hard, durable, uncoated parti- 

 cles, preferably siliceous, free from lumps of clay and all organic 

 matter. 



It shall be well graded from coarse to fine, and when tested by 

 means of laboratory screens and sieves shall meet the following 

 requirements : Per cent. 



Passing ^-inch screen 100 



Passing 20-mesh and retained on 50-mesh 



sieve to 



*Total passing 50-mesh sieve not more than 



tPassing 100-mesh sieve not more than 



Not more than per cent by weight shall be removed by 



the elutriation test. 



When the sand is mixed with Portland cement in the proportion 

 of 1 part of cement to 3 parts of sand, by weight, according to 

 standard methods of making 1 : 3 mortar briquets, the resulting 

 mortar at the age of 7 and 28 days shall have a tensile strength 



of at least % per cent of that developed in the same time 



by mortar of the same proportions and consistency, made of the 

 same cement and Ottawa sand. 



Preliminary acceptance samples shall be subjected to both 7 

 and 28 day tests, and acceptance based thereupon. Samples tested 

 during the progress of the work will be accepted on the basis of 

 the 7-day test. 



The sand shall be sampled in accordance with the method de- 

 scribed on page , paragraphs , of these specifications ; 



and the grading shall be determined in accordance with the meth- 

 ods described or referred to on page of these specifications, 



tests Nos. 



Note. — It is recqjnmended that volumetric analyses be reported 

 by the laboratory to facilitate field control. 



SPECIFICATION FOR GROUTING SAND. 



General. The sand shall consist of clean, hard, durable, uncoated par- 



ticles, preferably siliceous, free from lumps of clay and all or- 

 ganic matter. 



* It is recommended that 25 per cent be specified as the amount per- 

 mitted to pass a 50-mesh sieve, and in localities where practicable that 

 a smaller figure be used. 



t It is recommended that 5 per cent be specified as the quantity per- 

 mitted to pass. 



$ It is recommended that the strength ratio be 100 per cent for this 

 purpose. 



