Highly ductile fiber reinforced geopolymers under tensile impact. (February 2022)

• Record Type: Journal Article
• Authors: Farooq, Mohammed; Krishna, Anurag; Banthia, Nemkumar
• Is Part Of: Cement & concrete composites. Volume 126(2022)
• Publication Date: 2022-02
• Subjects: PVA -- Alkali-activated materials -- Geopolymer -- Impact -- Dynamic -- Strain-hardening -- Strain-rate effects -- DIF; Composite-reinforced concrete -- Periodicals; Concrete -- Periodicals; Composite materials -- Periodicals; Composites de ciment -- Périodiques; Béton -- Périodiques; Composites -- Périodiques; Béton léger -- Périodiques; Cement composites; Composite materials; Composite-reinforced concrete; Concrete; Lightweight concrete; Periodicals; Electronic journals; 620.135
• DOI: 10.1016/j.cemconcomp.2021.104374
• Languages: English
• ISSNs: 0958-9465

Abstract

Abstract: Eco-friendly Ductile Geopolymer Composites (EDGCs) are a class of fiber reinforced geopolymers with strain capacity exceeding 3% in pure tension. In this study, EDGCs were produced using a hybridized binder carrying Class F fly ash, Class C fly ash and slag activated by an alkaline solution. The alkaline activator comprised of sodium silicate and 12 M sodium hydroxide solution in the ratio 2.5:1. Workability, setting time, compressive strength, and tensile stress-strain response under quasi-static (strain rate of 10 −4 s −1 ) and dynamic loading (strain rate of 0.51 ± 0.2 s −1 ) were investigated. Heat curing weakened the EDGCs due to early age drying shrinkage, reducing their compressive and tensile strength. All EDGCs irrespective of curing type or source material depicted a ductile strain-hardening behavior under quasi-static loading. Under dynamic loading, some ambient-cured EDGCs depicted a brittle failure, and some ductile. All heat-cured EDGCs showed a ductile behavior under dynamic loading. The peak tensile stress under dynamic loading was significantly higher than that under quasia-static loading irrespective of matrix type or curing regime. The dynamic increase factors (DIF) ranged between 1.18 and 1.86 for ambient-cured specimens and between 1.68 and 2.2 for heat-cured specimens. These DIFs were higher than the models predicted. Under dynamic loading, the strain capacity of the EDGCs was also smaller than under quasi-static loading, and the dynamic strain factors observed were 0.08–0.34 for ambient-cured, and 0.12 to 0.57 for heat-cured EDGCs. Overall, the hybrid EDGCs demonstrated better tensile properties under both quasi-static and dynamic loading curing.