BULLETIN 9-49, U. S. DEPARTMENT OE AGRICULTURE. 
Grimes, J. F., Kentucky. 
Hinderlite, H. B., North Carolina. 
Hutchinson, G. W., Delaware. 
Jackson. F. H.. Bureau of Public Boads. 
Lang. F. C. Minnesota. 
Leavitt. H. Walter, Maine. 
Maddocks, Frederick T.. California. 
Martin, W. D., Ohio. 
Milbum. Heniy M.. Bureau of Public 
Boads. 
Punington. W. F.. New Hampshire. 
Bea ; A. S., Ohio. 
Boman, F. L.. Illinois. 
Bossell. F. C, Maryland. 
Saunders, B. L.. Connecticut. 
Seaton. B. A., Kansas. 
Smith. E. B., Bureau of Public Boads. 
Terrell. D. V.. Kentucky. 
Llman, Malcolm H., Pennsylvania. 
Withe v. M. 0.. Wisconsin. 
The important recommendations which resulted from the confer- 
ence are due largely to the painstaking and effective work of the 
testing engineers who participated. 
Standard methods of sampling and testing the materials employed 
in highway construction were adopted, as set forth in this bulletin. 
It will be noted that the standard methods adopted by the American 
Society for Testing Materials have been accepted so far as the field 
has been covered by that society. In some of the methods minor 
revisions of the A. S. T. M. standards have been made, and where 
that has been done, the notation that follows the title of the test or 
method indicates that there has been such revision. 
For tests that have not been standardized by the American Society 
for Testing Materials, the methods of testing set forth in Bulletins 
314. 347. and ooo of the U. S. Department of Agriculture, contributed 
by the Bureau of Public Roads, have been adopted for the most 
part. Several new tests and revisions of old tests are suggested for 
trial, to be adopted later if they prove to be satisfactory. 
It will be noted that for the convenience of testing departments. 
there is given the full text of all tests usually employed in a highway 
department testing laboratory. This has been done because it is 
believed it will save time and avoid confusion to have all of this 
material available in a single volume. 
The tests set forth in this bulletin are recommended as official 
standards by the committee on tests and investigations of the Amer- 
ican Association of State Highway Officials, and this recommenda- 
tion is concurred in by the Bureau of Public Roads. 
The recommendations of the conference were assembled and 
arranged by T. R. Agg. chairman of the committee on tests and 
investigations of the American Association of State Highway Offi- 
cials, and A. T. Goldbeck. engineer of tests of the Bureau of Public 
Roads. 
