Development of sustainable self-healing engineered cementitious composites incorporating maximum amounts of natural pozzolan

In light of the scarcity of the most commonly used supplementary cementitious materials in Engineered Cementitious Composites (ECC), there is a pressing need to explore alternative materials to replace them. This paper considers the influence of integrating high amounts of natural Pozzolan (NP) on the sound and self-healing characteristics of ECC, including compressive and flexural strengths, deflections, cracking behavior, ultrasonic pulse velocity, rapid chloride permeability, and microstructure both before and after pre-cracking and recovery periods. NP contents at Portland cement (PC) ratios of 1.2, 1.5, 1.8, and 2.2 were explored, along with a combination of (50 % NP + 50 % slag)-to-PC ratio of 2.2. The results obtained indicate that superior self-healing properties can be achieved with the use of NP instead of slag, particularly at higher NP/PC ratios. Furthermore, the ductility of ECC significantly increased with the inclusion of NP, reaching more than twice the deflection capacity of the control specimens at various ages. The results of this research confirm the formation of additional C-A-S-H-type healing products as the outcome of the NP incorporation on the self-healing ability of ECC. In addition, the life cycle assessment analysis (LCA) highlights the significant reductions in energy consumption, CO2 emissions, and cost of ECC mixtures prepared with increased inclusion of NP, up to a 2.2 NP/PC ratio.