OFFICE OP PUBLIC ROADS. 875 



Tatt.or County. W. Va. — During May, 1912, at the request of the county 

 authorities, a highway engineer from this office made a study of conditions in 

 this county relative to a proposed bond issue of $400,000 for improved roads. A 

 system of radial highways from the town of Grafton was projected. The pro- 

 posed system involves a total of 32 miles of new work, of which 18 miles is of 

 bricli. Recommendations were submitted for 12 miles of bricli road 14 feet 

 wide and 6 miles of single tracli briclc road 9 feet wide. Fourteen miles of the 

 system were planned as macadam road. The worli in this county also included 

 a thorough study of local soils, sources of road material, investigations of the 

 use of convict labor, and general suggestions as to the proper method of carrying 

 out the proposed improvement. The present system of road management and 

 revenues was investigated and recommendations were made concerning them. 



INA'ESTIOATIONS OF ROAD MATERIALS. 



During the fiscal year 1912 there were received 669 samples of road 

 materials to be tested in the physical and chemical laboratories. 

 These samples included road-building rocks and gravels, sand, clay, 

 marl, cement, concrete, iron-ore tailings, soil, shells, slag, oils, 

 tar^ etc. 



PHYSICAL TESTS. 



The work of the testing laboratories, as in the past, has included 

 research investigations, as well as the routine testing of road ma- 

 terials. 



The road-building rocks tested included 115 samples of limestone, 

 71 of gravel, 41 of sandstone, 39 of dolomite, 32 of granite, 29 of 

 trap, and 144 miscellaneous samples, including gneiss, schist, shale, 

 slate, etc. These samples were received from 37 States and Terri- 

 tories, as well as from Canada, Porto Rico, and Wales. The States 

 sending the greatest number of samples were: Virginia, 55; Penn- 

 sylvania, 46; Texas, 25; Ohio, 24; North Carolina, 21; Maryland, 

 20; and New York, 18. 



Research work on concrete included the testing of a large number 

 of full-sized arch culvert sections, to obtain data of value in their 

 design. Strains were measured, enabling the overstressed portions 

 to be determined, and finally the maximum or breaking load for each 

 section of arch was obtained. The study of the expansion and con- 

 traction of concrete has progressed and has created much interest 

 among concrete workers. This experiment will be continued, both 

 in the laboratory and in the field. The field measurements will em- 

 brace the investigation of a concrete roadway made with different 

 kinds of aggregate. For fine measurement in concrete investigations 

 a new instrument has been designed and built in the office. Other 

 investigations were started to determine the effect of concentrated 

 loads on reinforced concrete slabs. This is a problem of importance 

 in the design of bridges by this office. 



The work in oil-mixed concrete is being continued for the most 

 part in making long-time strength tests on samples of this material.* 

 Several papers, technical in nature, concerning results obtained in the 

 research work of the testing laboratories, were presented before engi- 

 neering societies at Wa.shington, New York, Cleveland, and Indian- 

 apolis. The subjects included oil-mixed Portland cement concrete, 



> For complete information see Bulletin 46, Office of Public Roads, United State* 

 Department of .^Kiiculture. 



