Investigation about the optimum alternative of polypropylene fibers in conventional concrete

This study was performing to find out the optimal alternative to expensive polypropylene fibers. This alternative was chicken's keratin-fibers, which were treated with chromium trioxide to eliminate the living materials. Several mixtures were ready using a mixing ratio of 1:1.5:3 (cement: sand: gravel) with keratin or polypropylene fibers, water, and a superplasticizer. Compressive strength, electrical resistance, and ultrasonic pulse velocity were tested by using cubic samples. The load-deflection relation was also tested by testing the reinforced concrete beam sample. The specimens that contain 1% of keratin-fibers showed enhancement in compressive strength, the percentage of increase of about (18.47, and 12.50)% compared with the reference sample and 1% polypropylene sample, respectively at the age of twenty-eight days. The electrical resistance of samples containing 1% and 2% of keratin-fibers was slightly less than the samples containing 1% and 2% polypropylene-fibers. The ultimate-flexural-load for beams that strengthened with 1% of keratin-fibers gave higher values (19.20 kN) than samples of (1 and 2)% polypropylene (17.30 and 17.10) kN and 2%keratin-fibers (18.98 kN) also, while the percentage of 2% keratin- fibers gave ultimate at deflection higher (0.337 mm) than the samples of (1 and 2) % polypropylene and 1 % keratin-fibers samples.