Influence of Mineral Admixtures on the Autogenous Shrinkage and Porosity of High-Strength Concrete

Abstract

This paper illustrates the effect of silica fume, ultra fine ash, and ground granulated blast furnace slag on compressive strength, shrinkage, and development of pore structure of high performance concrete (HPC). Shrinkage measurements were conducted using a modified version of ASTM C-341, as proposed by Tazawa. The experimental data obtained demonstrates how the material composition, the water to binder ratio, and the distribution of pore volume influence strength, autogenous, drying, and total shrinkage. HPC mixtures containing ultra fine fly ash, silica fume, and ordinary Portland cement exhibited an increased drying shrinkage rate, as compared with the slag mixture. By using a 10% replacement of UFFA, a large improvement with respect to autogenous shrinkage, relative to a 10% silica fume replacement in HPC occurs, without any noticeable effect on compressive strength. Pore structure of the matrix paste at early stages of hydration seems to have a strong effect on autogenous shrinkage.