.\<;KHl'LTl'RAL. APPUOPRIATION' BILI, IWI. 355 



results. Also trstiiif; j'n^inorrs frnin thr hiimni vi»il tin* State 

 lalxirntorios and tlir Statr testing <'H^iiH't'rs visit lln» lal)orntori«»^ of 

 the l)iin'aii. Ill this way a lUMCsmiry result is Immh^ ^radiiully 

 secured whirh we mav call (he Htandardixation of t««stin^ lahonitorint. 

 Af^airi. the hurcati )ias in procc'ss n l«>n;r s«'ri«»s of tests and r- 'i 



stutiics on hitiiininous materials. Tnder that an a major ii<..<;i..^' 

 we are studying; the shovinj; of bituminous {>av(>ments and other 

 properties (»f hituminous surfa<es. \Vc are workin«; on tcwtM for thi? 

 volatilization of petroleum products, the <'onsistencv of tars, and other 

 tests which we are trying to hrin;.; down to the pomt of slandaniuu- 

 tion for fxeneral use all over the country. Most of this work is in 

 conjuncti«)n with the A. S. T. M. These are oidy imlicalive (»f the 

 ^reat man\' paths there are to follow durinj; thi>^ perioil of dcvelop- 

 miMit of modern road huiidinj;. The researches of the hureau on non- 

 bituminous materials an<l methods of testinj; jure extensive and include 

 the studies of the resistance to wear of concrete a»;^re<;ates. the deter- 

 minati<m of deleterious substances in concrete a^}.jre^ates. the ai-tion 

 of alkali upon concrete, the use of blast-furmice sla;; for concrete 

 aj^re^ates. and a very extensive study of subfjrach's ajid sub;,'ra<le 

 materials. 



RESE.VRCH STUDIES IN HIOHW.W FNOINKKRINO. 



The bureau has endeavored and is endeavoriiif^ to stimulate re- 

 search in the lield of hiochway engineering, and in this connection has 

 affiliated with the National Research Council, whose activities we 

 are supporting in its efforts to establish a national program of highway 

 research. 



From the National Research Council there is a bulletin ju>t now 

 available which outlines a very long series of tests and researches 

 which are now going forwaril all over the United States in the highway 

 field, a complete census of highway research projects. In most of 

 the maj<»r research projects tlie Bureau of Public Roads is either 

 cooperating or is carrying on the tests independently. The bureau 

 has taken the nosition that there exists in the State highway depart- 

 ments and at the colleges and universities of the country hd)oratories. 

 plants, and e(|uipment which are being used only to a partial capacity, 

 and that without large additions to alreatly existing plants and 

 e(|uipment it is possible to obtain a greater output from these labora- 

 tories. In many of them assistants are available who are not em- 

 ployed during vacation periods or who may be employed only part 

 time with the colleges. In order to stimulate research and to make 

 use of existing facilities the bureau has entered into cooperative 

 agreements wnth a number of universities, including Purdue, Massa- 

 chusetts Institute of Technology, Iowa State College, and other 

 univei-sities: also State highway departments, including the Connecti- 

 cut State Highway Department, the California State IIi;j:hway De- 

 partment, the Illinois State Highway Department, and others. 



It is our judgment that the funds which are being used for research 

 purj)()se'; are perhaps the most productive and that this work should 

 go forwartl on an increased scale continually. It is only lhr<»ugh 

 painstaking and exhaustive research that we shall arrive at tleter- 

 minafions of the best de-igns for highways anil the best u-e- tt> make 

 of materials in their building. 



