Development of bendable concrete with locally available ingredients

Abstract

Engineered Cementitious Composites (ECCs) are a type of high ductility concrete enhanced with fibers, which allows for strain-hardening behaviour and higher strain capacities than traditional concrete. Supplementary cementitious materials (SCMs) used in ECC include fly ash and ground granulated blast-furnace slag (GGBS). While fly ash have been shown to improve the mechanical properties of ECC, its substitution ratio of cement is limited. Comparatively, slag is able to substitute more of cement, allowing for higher cost savings. However, research into how incorporating slag will affect the mechanical properties of high strength ECC is limited. Hence, this study was carried out to develop high strength ECC with consistent mechanical performance using slag. Compressive and direct tensile tests were conducted on both fly ash and slag ECCs reinforced with polyethylene (PE) fibers. Two different water-to-binder (W/B) ratios of 0.16 and 0.20 were used. It was found that for a substitution ratio of 30% and a curing temperature of 60ºC, at both W/B ratios, slag-river sand ECC had higher ultimate tensile strength and tensile strain capacity than fly ash-river sand ECC. Also, increasing the slag substitution amounts from 30% to 40% resulted in an increase in ultimate tensile strength, but a decrease in ductility of slag ECC. High strength slag-laboratory sand ECC with compressive strengths greater than 120MPa were also achieved.