Effect of sub-elevated temperature on mechanical properties of ECC with different fly ash contents. (30th November 2020)

• Record Type: Journal Article
• Authors: Zhang, Zhigang; Liu, Jin-Cheng; Xu, Xiaoqing; Yuan, Liqun
• Is Part Of: Construction & building materials. Volume 262(2021)
• Publication Date: 2020-11-30
• Subjects: ECC -- Fly ash content -- Mechanical properties -- Sub-elevated temperature -- PVA fiber; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2020.120096
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: The micro-pore structure of ECC is refined after exposed to sub-elevated temperature. The high fly ash content in ECC favors its tensile performance under sub-elevated temperature. The underlying mechanism was discussed at micro-scale level. Abstract: In this paper, the mechanical properties of Engineered Cementitious Composites (ECC) with two different fly ash contents after sub-elevated temperature exposure were investigated systematically at multiple scales. At composite level, uniaxial compressive and tensile tests were performed on specimens underwent 20 °C, 50 °C, 100 °C, and 200 °C exposure. The results indicate that, as temperature rise from 20 °C to 200 °C, the compressive strength of both ECC mixtures increased due to the refinement of the matrix pore structure. In term of tensile properties, after exposed to 100 °C and 200 °C, ECC M1 with relatively lower fly ash content shows a substantial reduction in strain capacity, but still retaining strain-hardening behavior, whereas ECC M2 with higher fly ash content exhibits a comparable or even enhanced tensile strength and strain capacity. At micro-scale, ECC matrix toughness was increased and PVA fiber strength was degraded under 200 °C exposure, which deteriorates the tensile properties of ECCs. However, the above negative effects are diminished due to the reduced fiber/matrix interfacial bond. Furthermore, the rather low matrix toughness and fiber/matrix interfacial bond associated with high fly ash content are the main reasons for the highly remained ductility in ECC M2 after sub-elevated temperature exposure.