A Comprehensive Experimental Investigation on Flexural Behavior of Alccofine-based Engineered Concrete Infused with Steel Fibers

Alccofine is an ultrafine supplementary cementitious material with an inherent tendency for pore refinement. This has substantially enhanced the strength and durability properties of concrete. The studies so far have exhibited limited investigations on the flexural properties of Alccofine-based concrete. This study addresses the feasibility of Alccofine-based concrete as a structural material with enhanced flexural properties by infusing 0.5% steel fibers. The steel fibers impart tensile strength to the concrete at the micro level and improve the flexural strength of the RC beams. The combinations framed in this study were for M30 grade concrete with the replacement of Alccofine by 5 to 15% and fly ash by 30% by weight of cement. The steel fibers with 0.5% of the weight of cement were added to the mix. The % of steel fibers and fly ash was kept constant in all the design mix combinations to examine the contribution of Alccofine individually on the performance of concrete. By considering four sets of combinations with under-reinforced and over-reinforced conditions each for the RC beams, the optimum combination among the defined mixes was explored through experimentation. The results on Young’s modulus, relative stiffness, and ductility index of these mixes, emphasize the role of steel fibers in upgrading the deficiency of concrete to resist flexural loads. This engineered concrete matrix with reinforcement exhibits remarkable performance for the combination of 15% Alccofine with 0.5% steel fibers, among the defined combinations. The addition of 0.5% steel fibers in combination with 10% Alccofine replacement to cement has facilitated the effective transfer of tensile stresses generated at the cracked surfaces by bridging the cracks, thereby the flexural strength of the RC beams has an improvement. The mechanism has appreciable outputs in enhancing the tensile behavior of concrete at the micro level.