Flexural behavior of FA-GGBS geopolymer concrete beams reinforced with carbon textile rods

Abstract

Geopolymer concrete reinforced with carbon textile rods is a comparatively new technology that needs more research for a better understanding and application in the construction industry. Since, corrosion in steel is a serious issue that demands the repair and maintenance of structural concrete elements, use of non-corrosive carbon fibers as carbon textile rods is an alternative to replace steel reinforcement in concrete. High tensile strength, excellent durability, and light weight of carbon fibers make it more prevalent. Geopolymer concrete was used in this study since it has lower carbon dioxide emissions and adds sustainability by using waste materials. Industrial waste materials, such as fly ash (FA) and ground granulated blast-furnace slag (GGBS), were used to make geopolymer concrete (GC).The present work attempts to provide a deep understanding of ambient temperature-cured GC and the behavior of carbon textile rods as flexural reinforcement in GC. In addition, the effect of grid spacing of textile rods on improving the load-bearing behavior of GC beams was evaluated by a four-point bending test. From the experimental observations, it was observed that adding GGBS into FA helps to develop a GC having setting time and compressive strength comparable to that of cement concrete. The optimum proportion of GC has a binder content of 400 kg/m3 (70% FA and 30% GGBS), AL of 200 kg/m3, 10 M SH solution and SS/SH ratio 2, coarse aggregate of 985.58 kg/m3, fine aggregate of 779.86 kg/m3, EW/B ratio of 14% and SP of 2%. With ambient temperature curing, the aforementioned optimum mix attained a compressive strength of 50 MPa. Carbon textile rods improved the flexural strength of the beams and confirmed the reinforcing benefits as seen from ultimate load-carrying capacity, post-peak behavior, and failure mode. Beams reinforced with carbon textile rods with grid spacing-15 mm carried more load and showed ductile behavior due to the higher number of warp rods to take the flexural loading.