LAUSR

Abstract The use of engineered cementitious composites (ECCs) have been gained wide attention considering their properties such as high values of tensile strength and ductility. However, the required methods to direct measurement of their tensile strength are not developed adequately. This study investigates some mechanical properties (compressive and flexural strengths) with more emphasis on the direct tensile strength as well as changes in the used raw materials. Therefore, the ground-granulated blast-furnace slag (GGBFS) and fly ash (FA) were used as cementitious materials and two types of silica and river aggregates for making cementitious mixtures. Moreover, the direct tensile strength of the specimens with two different configurations was evaluated. The composites' microstructure was analyzed by the images obtained from scanning electron microscopy (SEM) and X-ray energy diffraction spectroscopy (EDS). According to the results, though mixtures containing fly ash had significantly lower mechanical strength, they had significantly higher energy absorption and strain-hardening behavior than the slag. Furthermore, the direct tensile proposed model's results showed the ultimate strength and strain up to 56% and 21% higher than the model proposed by previous researchers. Consequently, parametric analysis and finite element modeling performed for the tensile model revealed acceptable model output compared to the experimental results.