Expansion and mechanical properties of high-performance concrete with ASR inhibition measures exposed to alkaline solution at 38℃ for 10 years

Abstract

Continuous follow-up tests on the expansion and mechanical properties of High-Performance Concrete (HPC) with strength classes C40 to C60 using aggregates with potential alkali activity and bulk mineral admixtures in the range of 0.5 % to 1.9 % equivalent alkali content are carried out for 10 years under the action of a standard alkali solution (1 mol/L) at 38 °C. The mechanical properties and expansion of HPC at long ages with potential Alkali-Silica Reaction (ASR) hazards are investigated. The results show: The expansion of HPC soaked in standard alkali solution at 38℃ for 10 years increases with the increase of the equivalent alkali content and decreases with the increase of the HPC strength grade. The KAMJ mathematical model is used to fit and analyze the 10-year expansion of HPC under ASR suppression, and the linear relationship between the expansion constant and Avrami index of the KAMJ model and the equivalent alkali content has been established. The mechanical properties of HPC immersed in standard alkali solution at 38℃ for 10 years decreased with the increase of the equivalent alkali content; During the 10-year immersion period, the compressive strength and flexural strength of HPC experienced a process of first increasing and then decreasing with the increase of soaking time; The use of air entrainment measures has a significant effect on HPC inhibiting ASR expansion and damage and reducing strength loss; A first-order linear equation between the mechanical properties(compressive strength, flexural strength, split tensile strength, axial compressive strength, elastic modulus) of HPC and the internal ASR damage variables within 10 years of exposure to standard alkaline at 38 °C has been established.