Experimental investigation on flexural and direct shear behaviors of specimens made of lightweight carbon textile-reinforced cementitious composites

摘要

Textile-reinforced cementitious composites (TRCCs) have recently receivedsignificant attention in structural engineering as promising retrofitting materialsas well as reinforcements for thin and slender structural components. Forapplicability in the precast industry, the weight of the structural componentsmade of TRCCs is a major concern. In this study, lightweight (LW) TRCCmaterials were developed and their flexural and direct shear performanceswere investigated. Carbon fabric is used as the textile reinforcement of the LWTRCCs, and expanded glass aggregates made from industrial refractory materialswith fine particle sizes of 0.25–0.5 mm incorporating the mineral admixture(silica fume) are used to develop the LW cement-based matrix. The maintest series in this study include the expanded glass-to-binder (EG/B) ratio, surfacecoating methods used for textile fabrics, and volume dosages of short polyvinylalcohol (PVA) fibers used to modify the cement-based matrix. Threemain series, including a total of 30 flexural test specimens and 30 shear testspecimens, are fabricated and tested. The flexural behavior of LW TRCCs isinvestigated via four-point bending tests and the direct shear behavior of LWTRCCs is investigated based on the FIP standard using one shear failure plane.The experimental results indicate that the EG/B ratio significantly affects theoverall flexural and shear performances of LW TRCCs, wherein the use ofhigher EG/B ratios might lead to greater reduction in flexural properties aswell as shear properties in the pre-peak stage. The coating methods employedfor fabric surface treatment via epoxy impregnation combined with roughlayers are effective in enhancing flexural properties in terms of load and deformationcapacity and shear properties in terms of peak stress compared withthe counterpart using only the epoxy coating method. Additionally, incorporatingshort discrete PVA fibers within the LW cement-based matrix results inoutstanding performance due to improvement in bonding quality at the textile/matrix interface, which can be applied as a potential solution for fabricatingLW, high-performance TRCCs.