54 BULLETIN 555, TJ. S. DEPARTMENT OF AGRICULTURE. 



Methods of testing materials: Page. 

 Abrasion test (per cent of wear, or French coefficient) stone, stone block, 



and slag 30 



Abrasion test, suggested for gravel 30 



Toughness test, stone 31 



Hardness test, stone and stone block 31 



Specific gravity and absorption tests, stone 31 



Weight per cubic foot test, slag 32 



Mortar strength test, screenings and sand 32 



Test of size, or grading, of coarse aggregate, stone, slag, and gravel 32 



Washing test and mechanical analysis, road gravel 32 



Elutriation test, sand or fine aggregate 32 



Mechanical analysis, sand or fine aggregate 33 



Mechanical analysis and tests of physical properties of semi-gravel, top-soil, 



and sand-clay aggregates 33 



Specific gravity, road oils, asphalt cements, and tars 36 



Flash point, road oils and asphalt cements 36 



Melting point, asphalt cements, refined tars, and tar residues 36 



Ductility, asphalt cements 36 



Penetration, asphalt cements 36 



Float test, road oils, oil residues, and refined tars 36 



Specific viscosity, road oils and tars 36 



Total bitumen, and organic and inorganic matter insoluble in carbon 



disulphide, road oils, asphalt cements, and refined tars 36 



Bitumen insoluble in naphtha, road oils and asphalt cements 36 



Volatilization test (loss at 163° C. or other temperature), road oils and 



asphalt cements 36 



Distillation test, tars 36 



Fixed carbon, asphalt cements 36 



Dimethyl sulphate test, tars 36 



Percentage of residue of penetration, road oils 36 



Tests of Portland cement 37 



Tests of Portland cement concrete field samples 37 



Tests of steel reinforcing rods 37 



Rattler test, vitrified paving brick 37 



Forms for test results: 



Rock or slag 38 



Gravel or sand 39 



Semi-gravel, top soil, or sand clay 40 



Petroleum and asphalt products 41 



Tars 42 



Portland cement 43 



Vitrified paving brick 44 



Standard methods for sampling: 



Broken stone 45 



Broken slag 45 



Stone block 46 



Gravel 47 



Sand 47 



Semi-gravel, top soil, and sand clay 48 



Bituminous materials 49 



Portland cement 50 



Portland-cement concrete 51 



Paving brick 51 



