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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es along a centimeter scale. Before starting the test, the centimeter scale is ad-justed to the pointer at zero. Power is then applied by the worm-gear pulling fromleft to right at the uniform rate of 5 cm. (1.969 inches) per minute. The distance, in centimeters, registered by the pointer on the scale at the time ofrupture of the thread of asphalt cement shall be taken as the ductility of the asphaltcement. 31. STANDARD METHOD FOR THE DISTILLATION OF TAR AND TAR PRODUCTS. (A. S. T. M. Standard Method, Serial Designation: D 20-18.) (1) The sample as received shall be thoroughly stirred and agitated, warming, ifnecessary, to insure a complete mixture before the portion for analysis is removed. (2) If the presence of water is suspected or known the material shall be dehydratedbefore distillation. About 500 c. c. of the material are placed in an 800-c. c. copperstill provided with a distilling head connected with a water-cooled condenser (see SAMPLING AND TESTING HIGHWAY MATERIALS. 49 I 1
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29465°—21—Bull. 949 4 50 BULLETIN 949, U. S. DEPARTMENT OF AGRICULTURE. fig. 27). A ring burner is used, starting with a small flame at the top of the still andgradually lowering it, if necessary, until all the water has been driven off. The dis-tillate is collected in a 200-c. c. separatory funnel with the tube cut off close to thestopcock. When all the water has been driven over and the distillate has settled outthe water is drawn off and the oils returned to the residue in the still. The contentsof the still shall have cooled to below 100° C. before the oils are returned, and theyshall be well stirred and mixed with the residue. (3) The apparatus shall consist of the following standard parts (see fig. 28):(a) Flash.—The distillation flask shall be a 250-c. c. Engler distilling flask, havingthe following dimensions: Diameter of bulb 8. 0 cm. Length of neck 15. 0 cm. Diameter of neck 1.7 cm. Surface of material to lower side of tubulature 11.0 cm. Length of tubulature 15.0 cm

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