Prediction of CBR value of fine grained soils at any rational compactive effort

Abstract

At present, no empirical correlation exists for prediction of the California Bearing Ratio (CBR) value of fine-grained soils at any compaction energy other than that corresponding to a standard Proctor test. This paper presents the salient features of an experimental investigation and the subsequent analysis for development of a correlation for the CBR value of fine-grained soils at any rational compactive effort. By defining a fine-grained soil type by its toughness limit, the interrelationship between compaction energy and CBR value is brought within a definite framework. The proposed model is also presented in the form of predictive curves for reduced Proctor, standard Proctor and modified Proctor compaction energies. These curves are very useful in geotechnical engineering for a quick estimation of CBR value without performing either a laboratory compaction test or CBR test. The validity of the reported methods for prediction of the CBR value corresponding to standard Proctor energy are also critically re-examined.