Mechanical properties and statistical analysis of Engineered Cementitious Composites (ECC) with ultrahigh-volume limestone powder incorporating several supplementary cementitious materials

Engineered Cementitious Composites (ECC) demonstrate excellent crack resistance and high toughness, displaying multiple-cracking and strain-hardening under tensile conditions. However, traditional ECC is characterized by high cost and high carbon emissions, restricting its extensive use in engineering applications. Compared to conventional concrete, ECC material mix designs usually employ minimal or no coarse aggregate, with raw materials including large quantities of Portland cement and fine sand aggregate. Meanwhile, solid waste like limestone powder can serve as readily available, high-quality, and cost-effective building material products to satisfy the strategic requirements of sustainable development. In this paper, a green PVA-ECC is designed with ultrahigh-volume limestone powder (UVLP) of about 50 % by weight, and the rest consists of Ordinary Portland cement and three supplementary cementitious materials (SCMs) such as metakaolin, fly ash, and blast furnace slag. Compressive tests at 3, 7, 28, and 90 days, along with direct tensile tests at 28 days, were conducted to examine the impacts and trends of various factors on compressive strength, first cracking stress, and ultimate tensile stress. In addition, polynomial regression fitting was performed between the mechanical properties and various cementitious material components. The "positive" or "negative" effects of different SCM on the compression and tensile properties of UVLP-ECC were quantitatively evaluated through single-factor analysis and multi-factor analysis. Further, the "Synergistic" or "Antagonistic" effect of two and three different components on mechanical properties was analyzed. Finally, innovatively assess the significance and influence of these mechanical property regression coefficients by the Spearman correlation coefficients.