EUHAL ENGINEERING. 685 



Information for bidders: Specifications, proposal, contract, and bond for 

 grading and road improvement, A. D. Williams (W. Va. Dept. Agr. Bui. 12 

 (19U), pp. U). 



Information for bidders: Specifications, proposal, contract, and bond for 

 macadam road improvements, A. D. Williams (W. Va. Dept. Agr. Bui. IS 

 (1914), pp. 66). 



Information for bidders: Specifications, proposal, contract, and bond for 

 brick road improvement, A. D. Williams (IF. Va. Dept. Agr. Bui. 15 (1914), 

 pp. 56, fig. 1). 



Standard specifications for superstructures of steel highway bridges, R. P. 

 DA^^[S (W. Va. Dept. Agr. Bui. 8 (1914), pp. 29, figs. 2).— This bulletin contains 

 a form of contract and specification. 



Standard specifications: Proposal, contract, and bond for superstructure 

 of concrete highway bridges, R. P. Davis (W. Va. Dept. Agr. Bui. 9 (1914), 

 pp. 20, figs. 2). — A form of tender, contract, and bond, and specifications for the 

 superstructure of concrete highway bridges are given. 



National Association of Cement Users: Proceedings of the eighth annual 

 convention, 1912', edited by E. E. Kkauss (Proc. Nat. Assoc. Cement Users, 8 

 (1912), pp. 819, pis. 6, figs. 293). — Among other reports and special articles are 

 the following: 



The Design of Concrete Flat Slabs, by F. J. Trelease; The Practical Design 

 of Reinforced Concrete Flat Slabs, by S. E. Thompson ; The Design of Concrete 

 Grain Elevators, by E. L. Heidenreich ; Aggregates for Concrete, by W. M. Kin- 

 ney ; Comparative Tests of the Strength of Concrete in the Laboratory and in 

 the Field, by R. J. Wig ; Flat Slab Concrete Bridges, by W. H. Finley ; Concrete 

 Highway Bridges, by W. S. Gearhart ; Standard Specifications for Concrete 

 Roads and Street Pavements ; Recommended Practice for Plain Concrete Drain 

 Tile; Method of Testing Drain Tile, by A. N. Talbot and D. A. Abrams; The 

 Manufacture and Use of Cement Drain Tile, by C. E. Sims; Concrete Fence 

 Posts, by W. J. Towne ; and Concrete Fence Posts, by L. J. Hotchkiss. 



Effect of controllable variables upon the penetration test for asphalts and 

 asphalt cements, P. Hubbard and F. P. Peitchakd (U. S. Dept. Agr., Jour. Agr. 

 Research, 5 (1916), No. 17, pp. SC5-SiS).— Experiments with four types of oil 

 asphalt, produced from (1) steam-refined Calfornia petroleum, (2) steam- 

 refined Mexican petroleum, (3) refined blended petroleum, and (4) blown 

 petroleum, are reported. The purpose was to determine what effect apparently 

 slight differences in laboratory conditions and variations in (1) the method of 

 preparifig melted samples for testing, (2) temperature, (3) load, and (4) time 

 will produce in the results of the penetration test for asphalts and asphalt 

 cements. The more important conclusions reached as a result of these investi- 

 gations are as follows : 



" Melted samples should be cooled for not less than 2 hours prior to test, 

 and should be tested upon the same day that they are melted, preferably after 

 2 or 3 hours. Samples should be maintained at the testing temperature for 

 not less than 1 hour, and preferably for 1.5 hours prior to test. 



" Upon standing in the air, prepared samples show a decreasing penetration, 

 but no definite end point or set is produced up to 28 days. In ordinary labora- 

 tory work there is no apparent advantage in cooling samples in ice or ice water 

 prior to determining their penetration at higher temperatures. . . . Samples 

 should be maintained and tested within 0.1° C. of the desired temperature for 

 accurate work, as a variation in temperature of less than 0.5° may produce a 

 decided difference in results. Tests at 4° are not the practical equivalent of 

 properly made tests at 0°. When making tests at 0°, samples should not be 

 packed in crushed ice, but should be immersed in a brine bath. 



