Effect of mineral additions on the chemical resistance of high-performance concrete

Abstract

The aim of this paper is to assess the effect of the natural pozzolan (NP) and limestone filler (LF) on the Chimical resistance of high-performance concrete (HPC) in an aggressive environment. (NP) and (LF) were used to replace different proportions of cement (PC). HPCC(100%PC), HPC18(10%LF + 90%PC), HPC7(20%NP + 80%PC), and HPC14(5%LF + 10%NP + 85%PC) were mixed, cast, and cured in pure water for 28 days. The sorptivity coefficients S (cm*s-0.5) of these HPCs were then estimated, and the mass change measuring specimens were immersed in three different mediums: pure water, (5%HCl) acid, and (5%H2SO4) acid. Their masses' changes were measured after 30, 90, and 180 days of conservation. The substitution of (PC) by (LF) and (NP) decreased the sorptivity of (HPC) depending on the type and proportion of the mineral addition. In a medium (5%H2SO4), HPC18 and HPC14 exhibited good chemical resistance compared to that of HPC7. In a medium (5%HCl), the mass loss in HPC7 and HPC14 are less than those in HPC18. The mass losses were in the range 3.32-9.63% and 11.22-13.31% in (5%HCl) acid and (5%H2SO4) acid respectively. Which proves that the chimical attac by sulfuric acid is more agressif than that by hydrochloric acide. When a mass of (PC) was replaced by (10%LF), (20%NP) or (5%LF + 10%NP) the sorptivity decreased. The substitution of 10% of the (PC) mass by (LF) increased the HPC resistance against H2SO4 acid chemical attack. However, The substitution of (PC) by (NP) and (LF) reduced the HPC's resistance to hydrochloric acid's chemical attack.