An assessment of factors affecting the elastic modulus of concrete

Abstract

Abstract The elastic modulus of concrete is required for the design of reinforced concrete structures, including in predicting creep deformation. Current models that estimate the elastic modulus (E), primarily on the basis of concrete compressive strength, vary in their accuracy and have hence proved to be inadequate to apply to the wide range of concretes. In this investigation, the E values of 108 concrete specimens which differed in aggregate type, cementitious material (binder) type, strength and curing age were measured. Seven factors were assessed for their degree of influence on concrete's elasticity, namely, aggregate type, aggregate percentage content, cementitious binder type, curing age, strength, water/cement ratio and density. The aggregate type, in particular, correlated significantly with the E value. In addition, the influence of density on E was highly significant (P = 2.39 × 10 −5 %). Concrete compressive strength, by contrast, was less influential than the aggregate type and density, and did not generally significantly correlate with the E value. This study provided additional confirmation that concrete strength is an unreliable primary factor on which to base concrete E estimations, as is the current common practice. It is therefore recommended that models to estimate E values of concrete should be based primarily on the type of aggregate used and the density of concrete.