SPECIFIC ATIONS FOR NONBITUMINOUS ROAD MATERIALS. 25 



SPECIFICATION R-1. 



Oranite Block, Oravel, and Sand for Stone-Block Pavement. 



STONE BLOCK. 



The stone block shall be of granite of medium-sized grain, showing an General. 

 even distribution of constituent minerals. They shall be of uniform qual- 

 ity and texture throughout, and free from seams, scales, or disintegrated 

 material. 



Sample blocks shall meet the following requirement : Physical 



French coefficient of wear, not less than 8 Properties. 



Toughness, not less than 7 



The blocks shall meet the following requirements : Dimensions. 



Inches. 



Length on top 8 to 12 



Width on top Si to 4J 



Depth 42 to 5i 



The stone block shall be subjected to inspection subsequent to delivery y£g„j,i 

 at the place of use, prior to and during laying, in order to cull out and Inspection. 

 reject those which fail to conform with the general and dimension clauses 

 and the following requirements of this specification : 



The blocks shall be so dressed that when laid as specified measurement 

 of any joint shall show a width of not more than | inch for a depth of 1 

 inch, or a width of not more than 1 inch in any part of the joint. 



The wearing surface of the blocks shall show no depressions more than 

 I inch deep, and the edges and corners shall be unchipped and unbroken. 



SAND FOR CUSHION. 



The sand shall pass a |-inch laboratory screen, and shall be well Grading. 

 graded from coarse to fine. The material removed by the elutriation test, 

 consisting chiefly of clay and loam, shall not exceed 5 per cent by weight. 



SAND FOR GROUTING. 



The sand shall consist of clean, hard, durable, uncoated stone particles. General. 

 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 Grading. 

 of laboratory screens, shall meet the following requirements : 



Per cent. 



Passing 10-mesh sieve 100 



Passing 20-mesh sieve, not less than 80 



Passing 100-mesh sieve, not mor€ than 10 



Not more than 5 per cent by weight shall be removed by the elutriation 

 test. 



"When the sand is mixed with Portland cement in the proportions of 1 Mortar Strength 

 part of cement to 3 parts of sand by weight, according to standard meth- ^®^t" 

 ods 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 75 per cent of that 

 developed in the same time by mortar of the same proportions and con- 

 sistency, 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. 



GRAVEL FOR FILLER. 



The gravel shall be composed of clean, hard, durable fragments of rock. General. 

 When tested by means of laboratory screens it shall meet the following Grading. 

 requirements : 



Per cent. 



Passing i-inch screen, not less than 95 



Retained on J-inch, not less than 85 



Tests of the physical properties of the block, gravel, and sand shall be Methods of 



XcsLiQsr 

 made in accordance with the following methods : 



1. French coefficient of wear, U. S. Department of Agriculture Bulletin 



347, p. 4. 



2. Toughness, U. S. Department of Agriculture Bulletin 347, p. 15. 



