Identifier: standardtentativ949unit (find matches)
Title: Standard and tentative methods of sampling and testing highway materials : recommended by the Second Conference of State Highway Testing Engineers and Chemists, Washington, D.C., Feb. 23-27, 1920
Year: 1921 (1920s)
Authors: United States. Bureau of Public Roads Second Conference of State Highway Testing Engineers and Chemists (1920 : Washington, D.C.)
Subjects: Road materials
Publisher: Washington, D.C. : U.S. Dept. of Agriculture
Contributing Library: U.S. Department of Agriculture, National Agricultural Library
Digitizing Sponsor: U.S. Department of Agriculture, National Agricultural Library

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e individual and the average toughness of three test specimens shallbe reported when no plane of structural weakness is apparent. In cases where a planeof structural weakness is apparent, the individual and average toughness of the threespecimens in each set shall be reported and identified. Any peculiar condition of atest specimen which might affect the result, such as the presence of seams, fissures,etc., shall be noted and recorded with the test result. 5. TESTS FOR APPARENT SPECIFIC GRAVITY AND ABSORPTION OFSTONE OR OTHER COARSE MATERIALS. (1) The apparent specific gravity shall be obtained by weighing the water dis-placed by a sample of the material weighing approximately 1,000 grams, broken intopieces about \\ inches in diameter. The vessel to be used is shown in figure 7. Itconsists of a galvanized-iron cylinder closed at one end and measuring 5 inches indiameter by 8 inches high. A brass spout \ inch in diameter is soldered into 8 BULLETIN 949, U. S. DEPARTMENT OF AGRICULTURE.
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Fig. 6.—DetaiLs of Page impact testing machine. SAMPLING AND TESTING HIGHWAY MATERIALS. 9 the side of the cylinder 6 inches from the bottom. The spout is inclined at an angleof 2° with the horizontal and is 2h inches long. A notch is filed across its lower end,as shown, to stop the drip from the displaced water. To determine the specificgravity, the dried and cooled sample shall he weighed to the nearest 0.5 gram andimmersed in water for 24 hours. The pieces shall then be surface-dried individuallywith a towel, the sample reweighed and immediately placed in the cylinder, whichhas been previously filled to overflowing with water at room temperature. (2) The weight of water displaced by the sample shall be used to calculate itsapparent specific gravity. The difference between the original weight of the sampleand its weight after 24 hours shall be used to determine the absorption. Zl Galvanized Iron ^ r r5D. Note: Notch is filed acrosslower end of spout +/g; (2°)to prevent drip.z=. )

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