Combined Effect of Silica Fume and Steel Fiber on Modulus of Elasticity of High Performance Concrete


Concrete elastic modulus is a basic property required for the appropriatepredicting of its basic behavior and for its correct implementation in a variety ofconstructional and engineering applications. This study presents an experimental and analytical evaluation of elastic modulus of high performance concretes (HPC) produced bysteel fiber and silica fume. The aim of this study is to develop the elastic modulus propertyof HPC and to show the applicability of ACI models to predict the elastic modulus of HPC from compressive strength. Four volume fractions of steel fiber with an aspect ratio (fiber length/ fiber diameter) of 60 were used (0, 0.5, 1.0, and 2.0 %). Incorporations of silica fume into the concrete were 0% and 15% by weight as a cement replacement. Water/cement ratio was ranged (0.28-0.4) with different amount of superplasticizer, and the reference slump was 170 mm. Both compressive and elastic modulus tests were made on hardened concretes reinforced with steel fibers and then compared with control specimens at 14 and 28 days. The results showed that the presence of silica fume enhanced the compressive strength and modulus of elasticity of evaluated concretes. In addition, adding steel fiber slightly increased both strength and modulus of elasticity values. Also, results showed that the elastic modulus of HPC is relative to the compressive strength, the ACI 318 expression is predicting elastic modulus of HPC and HPC-SF superior than ACI 363, but ACI 363 equation seems to be better in prediction modulus of elasticity of HPC-SF0.5S, HPC-F1.0S, and HPC-SF2.0S in comparison with ACI 318.