Effects of Repeated Loading on Gravel and Crushed Stone Base Course Materials Used in the AASHO Road Test

THIS PAPER PRESENTS THE RESULTS OF A LABORATORY INVESTIGATION OF THE BEHAVIOR OF THE AASHO ROAD TEST GRAVEL AND CRUSHED STONE MIXTURES SUBJECTED TO REPEATED LOADING. APPROXIMATING THOSE THAT WOULD BE FOUND IN THE BASE COURSE OF A HIGHWAY PAVEMENT. THE REPETITIVE LOADINGS WERE APPLIED WITH EQUIPMENT DEVELOPED IN THE LABORATORIES OF THE SCHOOL OF CIVIL ENGINEERING AT PURDUE UNIVERSITY. THE MATERIALS USED IN THE STUDY WERE OBTAINED FROM THE SITE OF THE AASHO ROAD TEST. THE GRAVEL AND CRUSHED STONE WITH GRAIN-SIZE DISTRIBUTION EQUAL TO THAT USED IN THE ROAD TEST AND COMPACTED TO THE MEAN DENSITY LEVELS FOUND IN THE FIELD WERE THE SUBJECT OF PRIMARY INTEREST. VARIATION IN PERCENT FINES AND DEGREE OF SATURATION WERE CONSIDERED TO HAVE A GREAT EFFECT ON THESE BASIC GRADATIONS. THEREFORE, THE PERCENT PASSING THE NO. 200 SIEVE WAS VARIED SO THAT THREE MIXTURES OF EACH MATERIAL WERE OBTAINED. THESE THREE MIXTURES WERE TESTED AT THREE LEVELS OF SATURATION. THE EFFECTS OF THESE VARIABLES ON THE DEFORMATION-REBOUND CHARACTERISTICS OF THE MATERIALS UNDER REPEATED LOADS WERE STUDUED. FROM THESE STUDIES, THE ADVANTAGES AND BASE COURSE MATERIALS, WERE FOUND AND ARE REPORTED IN DETAIL . ALSO, A COMPARISON BETWEEN THE LABORATORY AND FIELD PERFORMANCE OF THE TWO AASHO MATERIALS IS PRESENTED. /AUTHOR/