UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 949 
Contribution from the Bureau of Public Roads 
THOMAS H. MacDONALD, Chief 
J>\fr'<&J-U 
Washington, D. C. 
October 10, 1921 
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. 
CONTENTS. 
Introduction 
Tests for non-bituminous road materials. 
Tests for bituminous road materials 
Tentative tests 
Page. 
.. 1 
.. 3 
.. 36 
.. 62 
Page. 
Recommended standard methods of sampling. 69 
Miscellaneous matter 75 
Forms for recording and reprinting results 79 
INTRODUCTION. 
In connection with the administration of Federal appropriations 
for highway construction, conferences have been held from time to 
time, between representatives of the Bureau of Public Roads and 
of the various State highway departments, for the purpose of formu- 
lating policies relative to matters of mutual interest. In accordance 
with this general plan, a conference of testing engineers of the State 
highway departments was deemed advisable in order to standardize 
the work of the State highway department laboratories and the 
bureau laboratories. 
The conference held at the Bureau of Public Roads, Washington, 
was called by the committee on tests and investigations of the Ameri- 
can Association of State Highway Officials and the following repre- 
sentatives of State highway departments and of the Bureau of 
Public Roads were in attendance, for all or a part of the conference : 
Agg, T. R., Iowa. 
Anderton, B. A., Bureau of Public Roads. 
Begg, R. B. EL, Virginia. 
Bragg, J. G., New Jersey. 
Carmick, L. G., Bureau of Public Roads. 
29465°— 21— Bull. 949 1 
Cooper, W. F., Louisiana. 
Dayton, R. B., West Virginia. 
Dean, A. W., Massachusetts. 
Gage, R. B., New Jersey. 
Goldbeck, A. T., Bureau of Public Roads. 
