Tensile Behaviors of Textile Grid–Reinforced Engineered Geopolymer Composites

Lam, Chi Chiu; Gu, Jiaming; Wang, Xiaoyi; Cai, Jingming

doi:10.1061/jmcee7.mteng-14886

Cited by 6 publications

(2 citation statements)

References 43 publications

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“…Such ECCs exhibit superior self-consolidating, mechanical, and durability characteristics. In recent studies, the behavior of geopolymer composites has also been investigated and a micro-mechanics-based approach, as used for the development of conventional ECCs, has been used to characterize the strain/deflection-hardening properties [ 13 , 14 , 15 , 16 , 17 , 18 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, the alkalinity of the geopolymer matrix did not adversely affect the PVA and steel fibers [ 8 ]. In a recent study [ 13 ], the tensile capacity of novel textile grid–reinforced engineered geopolymer composites was 5.72 times greater than that of conventional textile-reinforced mortar and an increase in alkali concentration increased the tensile strength but decreased the tensile ductility capacity.…”

Section: Introductionmentioning

confidence: 99%

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The Strength and Fracture Characteristics of One-Part Strain-Hardening Green Alkali-Activated Engineered Composites

Hossain

Sood

2023

Materials

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Alkali-activated engineered composites (AAECs) are cement-free composites developed using alkali activation technology, which exhibit strain hardening and multiple micro-cracking like conventional engineered cementitious composites (ECCs). Such AAECs are developed in this study by incorporating 2% v/v polyvinyl alcohol (PVA) fibers into alkali-activated mortars (AAMs) produced using binary/ternary combinations of fly ash class C (FA-C), fly ash class F (FA-F), and ground-granulated blast furnace slag (GGBFS) with powder-form alkaline reagents and silica sand through a one-part mixing method under ambient curing conditions. The mechanical and microstructural characteristics of eight AAECs are investigated to characterize their strain-hardening performance based on existing (stress and energy indices) and newly developed tensile/flexural ductility indices. The binary (FA-C + GGBFS) AAECs obtained higher compressive strengths (between 48 MPa and 52 MPa) and ultrasonic pulse velocities (between 3358 m/s and 3947 m/s) than their ternary (FA-C + FA-F + GGBFS) counterparts. The ternary AAECs obtained a higher fracture energy than their binary counterparts. The AAECs incorporating reagent 2 (Ca(OH)2: Na2SO4 = 2.5:1) obtained a greater fracture energy and compressive strengths than their counterparts with reagent 1 (Ca(OH)2: Na2SiO3.5H2O = 1:2.5), due to additional C-S-H gel formation, which increased their energy absorption for crack propagation through superior multiple-cracking behavior. A lower fracture and crack-tip toughness facilitated the development of enhanced flexural strength characteristics with higher flexural strengths (ranging from 5.3 MPa to 11.3 MPa) and a higher energy ductility of the binary AAMs compared to their ternary counterparts. The tensile stress relaxation process was relatively gradual in the binary AAECs, owing to the formation of a more uniform combination of reaction products (C-S-H/C-A-S-H) rather than a blend of amorphous (N-C-A-S-H/N-A-S-H) and crystalline (C-A-S-H/C-S-H) binding phases in the case of the ternary AAECs. All the AAECs demonstrated tensile strain-hardening characteristics at 28 days, with significant improvements from 28% to 100% in the maximum bridging stresses for mixes incorporating 40% to 45% GGBFS at 365 days. This study confirmed the viability of producing green cement-free strain-hardening alkali-activated composites with powder-form reagents, with satisfactory mechanical characteristics under ambient conditions.

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