UNITED STATES DEPARTMENT OF AGRICULTURE 



m^m BULLETIN No. 691 



•55j||>i'^|^ Contribution from the Office of Public Roads and Rural % 



^J^'^^^ Engineering, LOGAN WALLER PAGE, Director J^?^'^^U 



WASHINGTON, D. C. T July 10, 1918 



TYPICAL SPECIFICATIONS FOR BITUMINOUS ROAD 



MATERIALS. 



By Pbevost Hubbaed, Chemical Engineer, and Chaees 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 



