Abstract : A laboratory study has been conducted to examine the impact of incorporating polypropylene fibres on the mechanical properties of concrete containing nano alumina and micro silica. Different dosages of nano alumina (1%, 2%, and 3%) and micro silica (5%, 10% and 15%) have been tried and the optimum combination (based on trials) has been found to be 1% nano alumina and 10% micro silica. Polypropylene fibres have been used in volume fractions of 0.1%, 0.2%, 0.3% and 0.4%. The basic mechanical properties investigated include cube compressive strength, cylinder compressive strength, modulus of rupture and modulus of elasticity.