USE OF PULSE VELOCITY MEASUREMENTS TO ESTIMATE STRENGTH OF AIR-DRIED CUBES AND HENCE IN SITU STRENGTH OF CONCRETE.

This paper presents extensive test evidence to substantiate the validity of the paste efficiency principle. It is shown that use of air-dried cubes produces consistent results; this has the further advantage that the method can be used to estimate the probable strength distribution in a structure prior to construction. The results show that in reality the k values relating control specimen strength to structure strength depend on concrete mix proportions, cement content, size and type of dense coarse aggregate and the type of concrete i. e. , normal or lightweight. Based on this project, a set of k values is recommended.