UNITED STATES DEPARTMENT OF AGRICULTURE 
H BULLETIN No. 691 { 
► Contribution from the Office of Public Roads and Rural 
jfC^'^^L Engineering, LOGAN WALLER PAGE, Director 1&P*^SU 
WASHINGTON, D. C. ▼ July 10, 1918 
TYPICAL SPECIFICATIONS FOR BITUMINOUS ROAD 
MATERIALS. 
By Peevost Hubbakd, Chemical Engineer, and Chares S. Reeve, Chemist. 
CONTENTS. 
Page. 
Introduction 1 
Specifications 4 
Page. 
Methods of testing 47 
Samples and sampling 58 
INTRODUCTION. 
Since public attention was first attracted to the use of bituminous 
materials in road treatment and construction the Office of Public 
Roads and Rural Engineering has received increasingly numerous 
requests for specifications which will describe suitable types and 
grades of such materials for the various uses required in highway 
engineering. It was early realized that the preparation of standard 
specifications of any value would be extremely difficult if not impos- 
sible, owing to the widely varying characteristics of the materials 
which should be covered and to the many local factors, such as cli- 
mate, traffic, and character of available non-bituminous road mate- 
rial, which largely control service results and which should govern 
the selection of suitable bituminous material. Therefore, attempts 
were first made to consider every request as an individual prob- 
lem and to furnish specifications only after certain information 
relative to local conditions and proposed methods of treatment or 
construction had been secured. 
Gradually, as the result of its own experimental work as well as 
observation of the work of others, the Office was able to prepare cer- 
tain specifications which though not considered as standards were 
found to be in most cases serviceable for general use in well estab- 
lished types of construction and maintenance. Such specifications 
were called typical specifications and were furnished, upon request, 
on typewritten or mimeographed sheets. As additional information 
55478°— 18— Bull. 691 1 
