Simultaneous enhancement of ductility and sustainability of high-strength Strain-Hardening Cementitious Composites (SHCC) using recycled fine aggregates

• Published in: Journal of cleaner production Vol. 470; p. 143357
• Main Authors: Li, Qing-Hua, Zhao, Shu-Yue, Huang, Bo-Tao, Xu, Ling-Yu, Xu, Shi-Lang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 10.09.2024
• Subjects: compression strength; Engineered Cementitious Composites (ECC); Microstructures; Multiple cracking; Recycled aggregate; silica; Strain-Hardening Cementitious Composites (SHCC); Sustainability; tensile strength; Ultra-High-Performance Concrete (UHPC); Ultra-High-Toughness Cementitious Composites (UHTCC); Strain-Hardening Cementitious Composites (SHCC); Recycled aggregate; Engineered Cementitious Composites (ECC); Ultra-High-Toughness Cementitious Composites (UHTCC); Sustainability; Ultra-High-Performance Concrete (UHPC); Multiple cracking; Microstructures
• ISSN: 0959-6526
• DOI: 10.1016/j.jclepro.2024.143357

In this study, recycled fine aggregates (RA) were successfully adopted to produce strain-hardening cementitious composites with a compressive strength of over 120 MPa. A multiple-scale investigation was conducted to study the tensile performance and cracking mechanism of the developed cement-based composites. Compared to the fine silica sand-based counterpart, significantly higher tensile strain capacity (>5%), more distinguished multiple cracking, and smaller average crack width (<100 μm) were achieved in RA-based strain-hardening cementitious composites. Supported by microscopic and mesoscopic results, the old mortar of RA with loose microstructures and weak RA/matrix interfaces were found to work as “additional flaws” in the matrix, which effectively tailored the distribution of active flaws and promoted multiple cracking behavior. In addition, the developed RA-based composites presented higher sustainability and lower material costs compared to fine silica sand-based ones. This study provides a new avenue for the upcycling of construction wastes in developing greener high-performance fiber-reinforced cementitious composites. [Display omitted] •Recycled fine aggregates (RA) were successfully adopted in SHCC with a compressive strength of over 120 MPa.•Higher RA content resulted in a higher tensile strain capacity (>5%) and a smaller average crack width (<100 μm).•RA tailored the distribution of matrix active flaws and hence promoted the multiple cracking behavior.•Higher RA content reduced the embodied carbon, embodied energy and cost of SHCC matrices.•Use of RA simultaneously enhanced the tensile ductility and sustainability of high-strength SHCC.