CORRELATION OF C. B. R. WITH UNCONFINED COMPRESSIVE STRENGTH OF SOILS

Abstract

among tine varioas methods of designing flexible pavements, the C.b.a. method occupies the molt prominent position because; of its simplicity and the availability of California Irlay Department charts waich provide rairly de rentable values of depth construction for any value and a particular maximum wheel load. • The standard procedure to conduct `the C.B.a test requires the sample to be tested after soaking it for four days to simulate the worst possible subgrade conditions. iherefore, when tuffs method is to be used on large projects considerable tine is required to fulfil the requirement for soaking. Aence, it may be worthwhile to devise an indirect method of determining the C.B.A. value from other simple and rapid tests like the un-confined compression test alone or in combination with the routine tests for liquid limit, plastic limit and optimum moisture con6ent. In the present study, an attempt has been made to correlate the C.B.A. value with unconfined compressive strength and plasticity characteristics. Fifty soil sanples collected from different parts of Uttar Pradesh and Madhya Pradesh were tested for their C.b.R. value, liquid limit, plastic limit, • (ii) unconfined compressive strength and optimum moisture. content. three correlations have been obtained on the basis of statistical analysis viz; C.B.R. with unconfined. compressive strength, C.B.R with unconfined compressive strength and plasticity index, C.B.d, with unconfined compressive strength and liquid limit