Using special coarse aggregate to enhance the tensile strain capacity of engineered cementitious composites

Abstract

This study introduced fly ash cold-bonded coarse aggregate (CA) to produce a special kind of engineered cementitious composites (CA-ECC). Four mixtures of ECC with different particle sizes of coarse aggregate were fabricated at a constant water-to-binder ratio. Experimental and analytical studies including mechanical behaviors, micro-mechanical analysis, microstructure analysis, and chemical characterization of CA-ECC were conducted from macro-, meso-, and micro-scales. The results showed that CA-ECC can achieve the characteristic of strain-hardening with high ductility. Remarkably, ECC with aggregate size ranging from 5 to 8 mm achieved tensile strain capacity up to 11 %. The mechanism of over-saturated cracking and high ductility behaviors were explained by pseudo-strain-hardening index and microstructure analysis. By calculating the materials sustainability index (MSI) of all mixtures, the CA-ECC was proven to possess environmental advantages over conventional ECC. The present study extends the fundamental knowledge for developing ECC materials.