Using fly ash as a partial substitute for cement in concrete construction has become popular mainly because of its easy availability and economy in large volume construction. But the resulting deficiency in performance of the concrete has been a cause for concern. This study proposes the introduction of polypropylene fibers adaptively to compensate for strength. A series of experimental programs were carried out with fly ash, fiber content, and layers as parameters. The fly ash content varied from 0-30% and fiber content from 0-0.60%. From the studies, it was found that the loss due to the introduction of fly ash could be easily compensated through fibers. This study was carried out to investigate the feasibility of polypropylene fiber usage and the effect of fiber length and content on the structural properties of this composite.

The infrastructure needs of our country are increasing day by day, and with concrete being used as the material of construction in a significant portion of this infrastructural system, it has become necessary to look into the ways and means of improving its characteristics in terms of strength and durability. Another dimension is added in the form of using waste materials to reasonably compensate concrete and contribute in volume and cost-saving. The use of fly ash as partial replacement of cement is an example. One of the many ways in which this enhancement could be achieved is by developing new concrete composites with fibers locally available so that even non-engineered construction can perform well under extreme loads like earthquakes or man-made attacks.

Existing literature on concrete composites (ACI Committee-544, 1973) is quite varied, ranging from experimental to analytical studies, mostly from generic strength and behavior points of view, with tests on cubes and cylinders. Similarly, literature on the use of fly ash in concrete abounds (Swamy, 1974; Ghosh et al., 1989; and Thomas and Prakash, 1999) with data from mechanical and chemical strengths to assess the material parameters. There are very limited publications available in the area of ordinary concrete with different fibers, mostly from strength and cracking points of view.

Siddique (2003) found that with high volume of class `F' fly ash, the workability of concrete increased and the cube compressive strength, split tensile strength, and flexural strength decreased, which had no significant effect on the impact strength of plain (control) concrete. Sekar (2004) conducted tests on fiber reinforced concrete from industrial waste. The test results indicate that addition of waste fibers from lathe and wire winding industries to plain concrete enhances the strength markedly, whereas inclusion of waste fibers from wire drawing industry decreases the strength of concrete. Also, the percentage increases in strength and the strength-to-weight ratio achieved by incorporating lathe industry waste fibers in plain concrete is higher than those obtained by adding wire winding industry waste fibers.

Structural Engineering Journal, Structural Properties, Polypropylene Fiber, Fly ash, Infrastructure, Chemical Strength, Split Tensile Strength, Flexural strength, Lathe Industry Waste Fibers, Strength-to-Weight Ratio, Artificial Fibers, Infrastructural Systems, Wire Winding Industries, Experimental Programs.