Mechanical Properties and Bond Behaviour of Polypropylene Fibers and Nano Silica in Concrete

Abstract

Concrete has a substantial impact on the environment. As cement is the main ingredient, whose production generates a significant amount of CO₂. A small amount of nanoparticles added to concrete can change the nano-structure of cementitious materials, resulting in high durability. This present work explains the effects of using nano-silica material and polypropylene fibres in the traditional concrete mix. The Nano silica contents of 2%, 3%, and 4 % by replacing cement and polypropylene fibre with 0.1%, 0.15%, and 0.2% of the volume of concrete were considered. Various properties of concrete, such as flexural tensile strength, compressive strength, and split tensile strength were determined. Pullout tests (IS 2770 part 1: 1967) were also conducted to study the effect of nano silica and polypropylene fibre on the bond strength of the reinforcement bars and compared them with normal concrete. The tests are carried out at the casting age of 28 days. It is concluded that the use of nano-material and polypropylene fibres has a minute change in their compressive strength. The Split tensile strength and flexural tensile strength get enhanced by a considerable amount. The results of the study showed that the presence of both nano silica and polypropylene fibre in optimal percentages can improve the mechanical properties as well as bond strength of reinforcement bars embedded in concrete.