Experimental study and modeling of fiber volume effects on frost resistance of fiber reinforced concrete

In the present study, the effectiveness of fiber inclusion on enhancing frost durability was experimentally examined. Polypropylene fiber of 0.2, 0.3, 0.4, and 0.5% and steel fiber of 0.2, 0.4, 0.6, 0.8, and 1.0% by volume fraction were used. Additionally, reference and air-entrained specimens (with 5% air content) were prepared to compare the results. The water/cement ratio for all concrete mixtures was 0.465. The compressive and tensile strengths, and longitudinal strains of frost-exposed specimens were measured. The results showed that both fibers improved the frost resistance of concrete, and 1% steel fiber inclusion caused the samples to be safe against freeze–thaw cycles as well as air entraining. Minimum fiber volumes of 0.4 and 0.5% were required for frost resistance in the steel and polypropylene fiber specimens, respectively. The results were also numerically examined using an artificial neural network (ANN). Data analysis showed that the ANN was capable of generalizing between input and output variables with reasonably fine predictions.