BUREAU OF PUBLIC EOADS. 519 



distilled petroleum residuals" was prepared and presented at the last 

 annual meeting of the American Society for Testing Materials. 



The work done on the study of the asphalt content of road oils 

 during the preceding year was worked up and ])resented in the form 

 of a paper at the last meeting of the American Society for Testing 

 Materials. 



ROUTINE CHEMICAL TESTING AND INSPECTION. 



vSeven hundred and eighty-three samples were examined in the 

 chemical laboratory. This represents an increase of 197 per cent 

 as compared with the ])rece(ling fiscal year. Of the samples examined 

 365 were bituminous materials, 406 metal, and 12 miscellaneous. In 

 addition, analyses of 40 samples of smelter slags and 29 samples of 

 blast-furnace slags were-made. 



CONFERENCE OF STATE TESTING ENGINEERS AND CHEMISTS. 



In February the second conference of State highway testing engi- 

 neers and chemists was held at the bureau. Representatives of prac- 

 tically all the State highway department laboratories w^ere in attend- 

 ance. Standards for use in the making of tests for Federal-aid work 

 were adopted by this conference and will be published by the bureau. 



STANDARDIZATION OF METHODS OF TESTING NONBITUMINOUS ROAD MATERIALS. 



Research work on proposed modifications of the standard abrasion 

 test for rock was completed and a paper on this subject presented at 

 the twenty-third annual meeting of the American Society for Testing 

 Materials.^ The study of methods of testing the quality of granite 

 ])aving block in the laboratory was completed and a paper on the 

 subject prepared for publication in the technical press. 



Methods of soil analysis adapted to a study of road subgrade mate- 

 rials were developed for use in connection with a systematic study of 

 the bearing power of soils to be undertaken during the coming year. 



Experiments in developing apparatus adapted to the rapid testing 

 of road materials in the field were continued. 



STANDARDIZATION OF METHODS OF TESTING BITUMINOUS ROAD MATERIALS. 



Cooperation with the American Society for Testing Materials \yas 

 continued through the committee on road materials. The following 



c 



& 



investigations will be of direct beneiit in the standardization work 

 of the bituminous section of committee D-4 : 



Methods of making penetration test. 



per 

 Methods of making float test. 

 Standardization of viscosity test for road oils. 

 The work on "asphalt content" will also be of direct use in the 

 standardization work of the committee. 



FEDERAL-AID WORK. 



Of the samples examined in the physical, chemical, and petro- 

 graphic laboratories, 875 were materials for use in Federal-aid 

 construction, as compared with 355 samples examined for similar 

 use during the precednig year. 



Test reports, numbering 2 1,985, submitted by laboratories tlu'ough- 

 out the country on samples of material used in Federal-aid road 



