Optimization of Concrete by Minimizing Void Volume in Aggregate Mixture System

Abstract

The behavior of concrete is affected by the size, distribution of the voids, the porosity and of the granulometry of the aggregate mixture. As a consequence it necessary for engineers to consider in detail particle packing concepts and their influence on the physical performance of concrete. The present study included determination of the fineness modulus, cement paste volume based on slump test and the properties of fresh and hardened concrete. It also comprised a study of the applicability of two theoretical models Toufar’s and 4C-packing program for selecting suitable relative amounts of the concrete constituents, for obtaining a minimum void ratio. Comparison of the results was made from using these theoretical models literature-derived experimental data. The models gave similar results and suggest similar combinations of materials to give minimum void ratio. Optimization of the composition of the aggregate material in concrete is beneficial with respect to economy (low cement content), strength and durability. It was noted that minimizing the void ratio (V) tends to raise the stiffness and that the compressive strength (〖f_c〗^') is closely related also to the remolding (R) and fineness modules (FM). It was found that the compressive strength can be predicted by applying the formula; 〖f_c〗^'=-2.1-63.8 V+0.150 R+10.4 FM; R2=0.94, and two other relationships related to slump data and cement content.