Properties of Self-Consolidating Engineered Cementitious Composite Modified with Rubber

Abstract

This study aims to investigate the feasibility of utilizing waste rubber as a partial replacement for silica sand in the development of self-consolidating engineered cementitious composite (SCECC). The effects of the percentage of rubber (–5%), rubber size [crumb rubber (CR) and powder rubber (PR)], and supplementary cementing materials (SCMs) (fly ash, ground-granulated blast-furnace slag, silica fume, and metakaolin) on the fresh and hardened properties of SCECC were studied. The results indicated that both CR and PR had promising potentials to be more economical and environmentally friendly alternative aggregates to develop sustainable SCECC with higher ductility. Although the inclusion of CR negatively affected the fresh and mechanical properties of SCECC, a number of successful mixtures with up to 3% CR could be developed with strengths greater than 4 MPa. The addition of PR showed a better performance in terms of fresh and mechanical properties compared with CR, allowing up to 4% replacement of rubber to be safely used. The inclusion of CR appeared to continuously increase the deformation capacity of SCECC up to 2% replacement level, while PR continued to improve the deformation capacity up to 5% replacement. Combining PR and different SCMs, especially metakaolin, allowed higher percentages of rubber to be used, achieving semi-lightweight concrete with adequate mechanical properties for multiple structural applications.