The effect of soil grading on compaction test results of base course layers

A base course is the layer immediately underlying the highway’s wearing surface, subjected to severe trafficloading. Its material must be of extremly high quality, and proper construction procedures must be carefully adhered to. The material’s quality as specified is controlledthrough standard tests, these includes gradation, plast-icity, Los-Anglos etc. The two basic requirements for the materialwhen placed as a base layer are its thickness and density. The requirement for granualar base density isattained through determining moisture-density relationship in the laboratory followed by proper compaction in thefield.The results of laboratory compaction tests for the base layer materials are affected by a number of factors. Theseincludes the material’s type, gradation, maximum grain size, percentage of coarse portion, and method and amount of compaction energy applied to the sample. The objective ofthis study is to investigate the effect of these factors on the results of laboratory compaction tests for the Egyptian base materials.