CONTENTS. 



Introduction 5 



Important physical and mechanical properties of road materials 7 



Hardness 7 



Toughness 8 



Cementing or binding power 9 



The causes of the deterioration of roads 10 



Mechanical agencies 10 



Chemical agencies 11 



Physical agencies 1 '1 



Service tests 14 



Historical review of road material tests 16 



Tests of road materials in France 17 



The Deval machine 17 



Compression test 19 



The Dorry test 20 



Impact test ". 21 



Tests on wood paving blocks 21 



Tests of road materials in Portugal 22 



History of paving brick tests 23 



Methods and tests of the Road Material Laboratory 25 



Tests for rock and gravel 25 



Abrasion test L'"> 



Cementation test 27 



Test for toughness 33 



Absorption test 35 



Specific gravity and weight per cubic foot 36 



Test for hardness 36 



Compression and tensile strength tests 36 



Tests for paving brick 36 



Rattler test 36 



Absorption test 38 



Cross breaking and compression tests 



Tests for cement 38 



Classification of materials '!' 



Petrographic analysis 39 



Chemical analysis 40 



The application of laboratory results to practice 41 



APPENDIX. 



Met hods of chemical analysis 47 



TABLE A. Results of laboratory tests 52 



TABLE B. Percentage of mineral constituents in road-making rocks 58 



Forms for reporting results of tests, etc 74 



3 



