Civil Researchers

Principal Investigator : Prof. Mrs. A. Rajan

Title: Experimental study of fiber reinforced blended concrete
Date of Commencement and Period of funding: 23.04.2008 April 2010
Amount (Rs.) : 1,50,000
Funding Agency : University Of Pune

The acceptance of fiber reinforced concrete by construction industry has lead to a number of developments. Among these developments, metallic fibers, polymer fibers, mineral fibers and naturally occurring fibers are used to modify properties of concrete and mortar. A large number of researchers around the world are trying to investigate the various aspects of fiber-reinforced composites. The use of metallic fibers enhances compressive, tensile & flexural strength of concrete. Polymeric fibers improve the resistance to wear & tear in flooring tiles. The metallic fibers have typically high modulus and high strength. The reasons for using strong fibers such as steel fibers in a relatively weak (in tension) brittle matrix are to improve the ductility of the matrix.  These fibers contribute to the increase in strength as well. Fly ash conforming to I.S. with high fineness, low carbon content, results in reducing the heat of hydration of cement with reduction in drying shrinkage. Fly ash contributes the strength of concrete due to its pozzolanic reactivity and is used as a secondary blend to replace Ordinary Portland Cement in concrete.

One of the very promising applications of fiber reinforced concrete is in improving the shear resistance of concrete. The randomly distribution of fibers in the concrete beams bridges the cracks in all directions, which helps in increasing the shear capacity. The test variables investigated include shear span to depth ratio (a/d), where ‘a’ is shear span defined as the distance between load & the nearest support and ‘d’ is the depth of beam measured from extreme compression fibers to the center of gravity of flexural tension steel. The aim in present work is to investigate the influence of shear span depth ratio on the shear strength of concrete as well as shear characteristics of concrete, prepared using fly ash and the steel fibers.

Experimental programme was planned to find out the feasibility of use of steel fibers in fly ash blended concrete. The results of an experimental investigation on a model of Fiber Reinforced Concrete Beams strengthened in shear with steel fibers are presented. The tests such as tensile strength test, compressive strength test will be conducted according to IS & ASTM norms. The tests were conducted on different fiber & fly ash fractions to find the behavior of shear capacity.