Study of the combined effect of coffee husk ash and polypropylene fibres on the mechanical properties of concrete

In this research, the effects produced by the combination of coffee husk ash and polypropylene fibers in the production of concrete were studied in order to evaluate the mechanical properties and determine an optimum design combination. Two standard concrete mix designs of f'c= 210 and 280 kg/cm2 were developed, and experimental treatments of standard concrete were designed by adding coffee husk ash at 5%, 10% and 15% combined with polypropylene fibers at 1%, 2.5 % and 5%. The results showed that the resistance differs in 8.94% and 4.11% in compression, 8.55% and 15.03% in traction, 10.89% and 8.96% in bending and increases the modulus of elasticity in 5.66% and 14.15% with respect to the standard designs f'c= 210 and 280 kg/cm2. It is concluded that the mechanical characteristics are relatively lower compared to the standard mix designs.