Utilisation of steel fibres to reinforce waste glass concrete: Alkali–silica reaction, engineering properties, and 3D mesoscale modelling

Abstract

Waste glass concrete (WGC) suffers from the limitations of alkali–silica reaction (ASR) and poor mechanical properties. The incorporation of steel fibres (SFs) is promising to reinforce WGC. However, the influences of the length, volume fraction, and hybrid mixing of SFs on the performance of SF-reinforced waste glass concrete (SFRWGC) are still unclear. Moreover, the similarities and differences in ASR between WGA and natural reactive aggregate (NRA) have not yet been reported. In this study, the ASR mechanism and characteristics of waste glass aggregate (WGA) were investigated. The influences of the volume fraction, length, and hybrid mixing of SFs on the mechanical properties of SFRWGC were also investigated. Three-dimensional mesoscale models were developed to help understand these effects. As compared to NRA, the different ASR characteristics of WGA were attributed to the pre-existing cracks, high-calcium pozzolanic C–S–H at the periphery, higher Ca/Si ratio, and lower Na/Si ratios of ASR gel. The volume fraction of SFs was the principal factor that improved the mechanical properties of SFRWGC, followed by the length of SFs. The increase in mechanical properties was reduced for the hybrid incorporation of SFs because the short SFs could not bridge the large cracks, unlike the long SFs. This study provides guidance regarding the engineering applications of SFRWGC.