The effects of particle sizes of expanded perlite on the mechanical properties and chloride penetration resistance of ECCs

Abstract

This study presents the development of engineered cementitious composites (ECCs) incorporating expanded perlite particles (EPPs) with varying sizes, namely 150 mesh, 50–70 mesh, and 5–15 mesh, as well as an equivalent combination of these three sizes. The primary focus of the investigation was to evaluate the microstructures at different ages, mechanical properties, and chloride penetration resistance of ECCs incorporating EPPs. The results showed the presence of a compact interfacial transition zone (ITZ) between the matrix and EPPs, attributable to the internal curing effect. The incorporation of EPPs effectively mitigated fiber damage during fiber-matrix separation, thereby preventing premature fiber rupture. Specifically, the inclusion of 150 mesh EPP demonstrated improved mechanical properties compared to the control group. Furthermore, the addition of 5–15 mesh or mixed EPP enhanced the chloride penetration resistance of ECC, while contrasting results were observed for 150 mesh and 50–70 mesh EPPs. Additionally, this study explored the use of 150 mesh recycled rubber (RR) as an additional defect. ECCs with simultaneous incorporation of RR and EPPs (at a 2% content) exhibited excellent ductility, with an overall tensile strain ranging from 4.3% to 4.7%. The results for the combined addition of RR and EPPs aligned with those observed for the singular addition of EPPs in terms of chloride penetration resistance.