Aggregate-Based Modulus of Elasticity for Florida Concrete (05-0713)**
Nur Yazdani, University of Texas, Arlington
Bryant McKinnie, No Organization
Saif Abdullah Haroon, SAIFUL/BOUQUET STRUCTURAL ENGINEERS, INC.

The current Florida Department of Transportation (FDOT) concrete modulus of elasticity ('E') empirical model is a function of concrete compressive strength and unit weight. Recent testing shows that this model consistently underestimates the 'E' for FDOT concrete. This underestimation may lead to construction problems caused by over-prediction of camber and deflection of concrete structural members. 'E' values were experimentally determined at various concrete ages for the typical concrete mix used in FDOT projects. Regression analyses were used to find the best fit 'E' models to the generated data, and such models were compared with existing 'E' models from the literature. It was found that the aggregate type and specific gravity plays a significant role in influencing concrete 'E'. Best fit 'E' models for FDOT concrete together with suggested modification factors for various aggregate types were recommended.