Measurement and correlation of ductility and compressive strength for engineered cementitious composites (ECC) produced by binary and ternary systems of binder materials: Fly ash, slag, silica fume and cement

The purpose of this paper is to investigate the mechanical properties of engineered cementitious composites (ECC) produced by high volume mineral admixtures which are fly ash, slag and silica fume. Emphasis of this study is placed on building the correlation between compressive strength and the parameters obtained in load-deflection curves of 12 different ECC mixtures. The results indicate that the compressive strength has an inverse relationship with deflection, toughness index and fracture energy, respectively; but the compressive strength have an direct proportional relation with flexural strength, first cracking load, and peaking load, respectively. Additionally, in the binary system of binder materials, the ductility of ECC can be obviously improved by introducing high volume fly ash and slag replacing the cement, respectively. However, the compressive strength of ECC with fly ash and slag can reduce 40% and 14%, respectively. For the ternary system of binder materials with replacement 70% of cement, the combination of fly ash and slag can keep not only the excellent ductility of ECC, but also enough stronger matrix strength. Meanwhile, the combination of fly ash and silica fume only increase the compressive strength, but weaken the toughness of ECC. Therefore, based on comprehensively considering both compressive strength and fracture energy, the optimal range of ECC mixture proportion can be properly selected to satisfy the demands in practical engineering applications.