High-performance concrete based on alkaline earth metal ions-activated slag at ambient temperature: Mechanical and microstructure properties

Abstract

The current study introduces novel mixing ingredients and techniques for high-performance concrete based on alkaline earth metal ions-activated slag (HPC-AAS) and looks into the use of alkaline earth activators for the first time. Moreover, the use of limestone powder as the fine ingredient in HPC-AAS has been also evaluated. The specimens of HPC-AAS thus prepared were tested to determine their mechanical characteristics (flexural, compressive, and tensile strength), microstructure, water absorption, and the static and dynamic modulus of elasticity. The results showed that the use of 10% calcium oxide as an activator of HPC-AAS was able to provide the desired characteristics for compressive strength (114 MPa) and flexural strength (9.2 MPa) as well as the dynamic and static moduli of elasticity (43.1 and 34.9 GPa, respectively). Microstructure analyses indicated that the highest peaks for calcium silicate hydrate gel (C–S–H) and Si–O-T (T = Si or Al) and the strongest bond between the geopolymer matrix and aggregates were created for HPC-AAS activated with 10% calcium oxide, which produced the highest ratio of silicon to aluminum.