CBR value of sandy subgrade blended with coarse aggregate

Abstract

In several parts of India, soil deposits consist of a matrix like soil with inclusions of coarser aggregates of various sizes. The CBR test is used for the design of sub grade for highways&pavement. Therefore in the present investigation, the CBR tests were carried out on the sand blended with coarse aggregates of various sizes and proportions. To strengthen the sub grade strata, coarse aggregates of 10mm and 20mm sizes were mixed in the sand, in various proportions. The soil samples were prepared and tested first without coarse aggregates, then by mixing coarse aggregates in varying percentages by weight, starting from 5% to 30%. The results of CBR tests shows that with the increase in the percentage of coarse aggregates, the CBR value of the soil increases. It is observed that the percentage improvements in the CBR values ranges from 20.99 % to 115.83% and 31.30% to 151.94% for 10mm and 20mm coarse aggregates respectively at OMC. In soaked condition, this improvement ranges from 23.20% to 202.48% and 31.35% to 233.17% for 10mm and 20mm coarse aggregates respectively.