Greener strain-hardening cementitious composites (SHCC) with a novel alkali-activated cement

Abstract

This paper focuses on developing strain-hardening cementitious composites (SHCCs) with a new alkali-activated cement (AAC). The AAC was synthesized with a calcined solid waste, i.e., cutter soil mixing residue (CSMR), as a primary precursor. The test variables included the water-to-binder (w/b) ratio and silica modulus (Ms) of alkali activators. The binder chemistry, mechanical performances, and micromechanical parameters of the new SHCCs were investigated. Results demonstrated that a moderate w/b ratio with a high Ms value favored the trade-off between the quantity of alkali-activated hydrates, matrix properties, and fiber bridging behaviors, leading to optimal overall macroscopic performances of the composites. The SHCCs with proper mix design exhibited high tensile strain capacities of 4.43–5.13% and sufficient compressive strengths at 3 days (23.6–28.9 MPa) and 28 days (32.7–56.3 MPa). Compared to Portland cement-based SHCCs, the new SHCCs achieved comparable mechanical properties, while possessing around 20% less embodied energy and 40% less CO2 emissions.