UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 348 



Contribution from the Office of Public Roads and Rural Engineering 

 LOGAN WALLER PAGE, Director 



Washington, D. C. 



PROFESSIONAL PAPER 



April 4, 1916 



RELATION OF MINERAL COMPOSITION AND 



ROCK STRUCTURE TO THE PHYSICAL 



PROPERTIES OF ROAD MATERIALS 



By 

 E. C. E. LORD, Petrographer 



CONTENTS 



Introduction 



Examination and Classification of Rocks 

 for Road Making 



Mineral Composition of Rocks for Road 

 Making 



Physical Properties of Road Materials . 



Page 



General Relation Between the Physical 

 Properties of Rocks and Their Mineral 

 Composition and Structure 11 



Effect of Secondary Minerals on the 

 Physical Properties of Rocks for Road 

 Building 13 



Summary and Conclusion 24 



WASHINGTON 



GOVERNMENT PRINTING OFFICE 



1916 



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