Effect of bottom ash as a cement replacement and internal curing on mechanical and durability properties of high performance concrete

Abstract

This article presents the effects of bottom ash as pozzolanic material to replace Portland cement at high level and as an internal curing material on mechanical and durability properties of high performance concrete. Bottom ash was sieved through a sieve No. 50 and ground to have high fineness (GBA). Then, it was used to replace OPC at a rate of 70% by weight of binder (70GBA). In addition, bottom ash passing a sieve No. 4 and retaining on a sieve No. 50 (SBA) was used as a fine aggregate replacement at rates of 25, 50 and 75% by volume of the fine aggregate in order to use as internal curing material in concrete under the different curing conditions i.e, curing in water and air. Slump flow, slump flow time at 50 cm (T50), compressive strength,
modulus of elasticity, heat evolution, and chloride diffusion of high performance concrete were investigated. The results showed that the slump flow of concrete was decreased and T50 was increased with the increased of SBA. High performance concrete containing 70% of GBA and 50% of SBA had the compressive strength similar to that of the control concrete at all testing ages. The elastic modulus was decreased with the increased of SBA, while the chloride diffusion coefficient and chloride penetration ofconcrete were increased with the increased of SBA. The use of SBA at 50% and 75 % of the SBA could reduced the heat evolutionof high performance concrete by 5% and 15%, respectively that compared to the control concrete.