Aggregate Correction Factors for Concrete Elastic Modulus Prediction

The structural design of concrete is typically based on service limit states and uses the modulus of elasticity as a design parameter. However, the modulus of elasticity of concrete used for the design of structures is typically determined indirectly using specified compressive strength. This research investigated the differences between the physical and empirically based relationships of the modulus of elasticity and compressive strength of concrete. Concrete incorporating various types of coarse aggregate was evaluated with particular emphasis on limestone from Florida formations, better known as limerock. The goal of this research was to establish the accuracy of coarse aggregate correction factors used for predicting the modulus of elasticity of concrete. It was found that a value of 1.0, rather than 0.9, was appropriate for the correction factor for Florida limerock; the current structural design guidelines used by the Florida Department of Transportation have revised the specifications to reflect this finding.