Combined Effect of Fiber Content and Fly Ash on Low Velocity Impact Resistance of Slurry Infiltrated Fibrous Concrete

Cement is the most expensive and energy-intensive ingredient in concrete. Partially replacing cement with fly ash can help lower the unit cost of concrete. Additionally, fly ash disposal poses a significant environmental challenge, as its accumulation as waste leads to serious ecological concerns. Additionally, it improves concrete properties by lowering water demand for the same workability, minimizing bleeding, and reducing heat generation. The influence of a mineral admixture on concrete strength varies considerably depending on its characteristics and the percentage of replacement. Slurry infiltrated fibrous concrete (SIFCON) is used in constructing structures that require high strength, superior concrete quality, and durability. SIFCON offers excellent ductility and impact resistance. The present study is to investigate the combined effect of fiber content and fly ash on impact strength of slurry infiltrated fibrous concrete (SIFCON). The experimental program was carried out on low velocity impact resistance of slurry infiltrated fibrous concrete containing different fiber volumes (0, 6, 8, 10%) with partial substitution of cement by fly ash (0, 10, 20, 30, 40, 50%). Hooked-end steel fibers of an aspect ratio of 30 and a constant mix proportion 1:1 and water binder ratio of 0.4 were used. Energy absorption capacity at the initiation of first crack and ultimate failure was evaluated by testing specimens of 150mm diameter and 60mm height as per ACI Committee 544.2R-89 guidelines using a selffabricated drop weight impact test apparatus. The first crack and ultimate energy absorption capacity of SIFCON containing different fiber volumes with binary blend of fly ash were determined and the results were compared to SIFCON without fly ash. The test results revealed that the first crack and ultimate energy absorption capacities of SIFCON with addition of 30% of fly ash were superior compared to all other replacement levels. Keywords: SIFCON, Fly ash, Drop weight impact test, Energy absorption, Impact residual ratio, Crack resistance.