Efficient utilization of waste marine clay for fine aggregate to develop sustainable and cost-effective strain-hardening cement-based composites
Wenhua Chen, Qiang Wang, Zhiyi Huang, Hongjian Du
Abstract
The prevalent overreliance on silica sand within strain-hardening cement-based composites (SHCC) underscores the urgency to address the depletion of natural resource . To address this concern, a novel approach involving the utilization of waste marine clay (WMC), an underutilized construction waste residue, is explored. This study marks the first application of high-volume calcined WMC as a substitute for silica sand within sustainable and cost-effective strain-hardening cement-based composites (SC-SHCC). The investigation encompasses a comprehensive analysis of SC-SHCC, covering mechanical properties, hydration, shrinkage, and cost. The results showed that the integration of calcined WMC instead of silica sand had noticeable improvements in the mechanical properties of SC-SHCC due to the notable pozzolanic activity and filling effect of calcined WMC. The developed SC-SHCC replacing two-thirds of the silica sand with calcined WMC exhibited a compressive strength of 76.34 MPa, a tensile strength of 14.63 MPa, and a tensile strain capacity of 5.99%, which successfully pushed the performance of conventional SHCC. Key indicators such as compressive strength , flexural strength , and tensile strength exhibited promising enhancements as calcined WMC dosage increased. The incorporation of calcined WMC contributed to heightened ettringite formation , thereby improving the tensile strength , and tensile strain energy of SC-SHCC. Besides, SC-SHCC exhibited pronounced drying shrinkage , primarily attributable to the free water evaporation and capillary pore development associated with calcined WMC. Furthermore, substituting calcined WMC for silica sand led to reducing the costs within SC-SHCC production. Therefore, the findings of this study hold promise for advancing the field of SHCC while promoting the environmentally friendly utilization of waste materials.