Civil structures made of steel reinforced concrete normally suffer from corrosion of the steel by the salt, which results in the failure of those structures. Constant maintenance and repairing is needed to enhance the life cycle of those civil structures. There are many ways to minimize the failure of the concrete structures made of steel reinforce concrete.
The custom approach is to adhesively bond fibre polymer composites onto the structure. This also helps to increase the toughness and tensile strength and improve the cracking and deformation characteristics of the resultant composite.Basically this method of reinforcing the concrete substantially alters the properties of the non-reinforced cement-based matrix which is brittle in nature, possesses little tensile strength compared to the inherent compressive strength.
The advancement of the building industry is associated with continuous research, development and design of new and improved materials and construction of structures. The construction of mega structures requires materials with increasingly improved properties, particularly strength, stiffness, toughness, ductility, durability and chemical resistance to various aggressive media. Concrete is an inherently brittle material with a relatively low tensile strength compared to compressive strength. Now a day, research on cement matrix materials is focused on the inclusion of additives, polymeric admixtures, and fibres to improve certain physical and mechanical properties, although keeping its strength, low cost and capacity to fill almost any shape.This chapter deals with the basic theory related to Quality Concrete, concept of Steel-Polypropylene Fibre Reinforced Concrete, its behaviour, detailed of fibre used in SPFRC mixes i.e.
description of requirements of Steel and Polypropylene fibres as per the relevant standards, various properties of SPFRC like workability, compressive strength, flexural strength, effect of temperature on SPFRC mixes etc. The phenomenon of fibre balling in SPFRC mixes is also presented in the subsequent section.2.
2 Concrete Generally flexural stresses are induced in rigid pavements; hence the design of rigid pavements is based on the flexural strength of concrete. The concrete slab having flexural strength 4.5 MPa, equivalent M 40 to M 50 grade of concrete, is called as Quality Concrete. It is designed to ensure minimum flexural strength with desired tolerance level in the field.
This minimum flexural strength in known as characteristic flexural strength. The characteristics flexural strength of should not be less than 4.5 MPa .The mix design of mixes