Use of hollow glass microspheres and hybrid fibres to improve the mechanical properties of engineered cementitious composite

Engineered cementitious composite (ECC) is a well-known high performance cementitious composites for its superior strain-hardening properties and high impact resistance. ECC has been produced using single type of fibre (mono-fibre). However, producing ECC using hybrid-fibre and as a lightweight construction material is in need for investigation. This paper describes the mechanical properties of ECC containing hollow glass microspheres (HGM) and hybrid-fibre consisted of polyvinyl alcohol (PVA) fibre and steel fibre (SF). The variables in this study were the HGM content (0% and 10%) and the hybrid-fibre volume fraction proportions (PVA : SF of 2.0% : 0.0%, 1.75% : 0.25%, 1.50% : 0.50%, and 1.25% : 0.75%). Compressive strength, flexural behaviour, energy absorption including first crack energy absorption were measured for the proposed cementitious composites. This study aimed at developing a new class of ECC with less unit weight, high-energy dissipation and ductility compared to conventional ECC. The results showed that mono-fibre ECC (PVA : SF is 2.0% : 0.0%) had higher compressive and flexural strengths than those showed by hybrid-fibre ECC mixtures. The ratio (PVA/SF) of 3.0 displayed the highest flexural strength compared to other hybrid-fibre ECC. The compressive and flexural strength of ECC was found to decrease with using HGM, although some lightweight ECC matrixes were deemed viable. Enhancements in compressive and flexural strength with further decrease in unit weight were achieved while w/b ratio decreased from 0.56 to 0.45.