Abstract:
Thermal power plants or similar plants in India which use pulverised coal as a fuel, generates million tonnes of fly ash every year as a waste. Conventional disposal of this material which gets easily air-borne and constitutes a serious health hazards to the community, is an expensive operation. On the other hand compacted fly ash can be used in embankments, road sub-bases and also for structural fills. The main limitations of such materials are their limited load carrying capacity and poor settlement characteristics. The performance of such materials can substantially be improved by introducing reinforcing element in the direction of tensile strain. Use of natural materials such as Jute, coir and bamboo, as reinforcing materials to fly ash are very cheap and they are locally available in large quantity. They are biodegradable and hence do not create disposal problem in environment. If these materials are used effectively, the rural economy can get uplift and also the cost of construction can be reduced. Of all the natural fibers, coir has the greatest tearing strength and it retains this property even in wet conditions. Keeping this in view the present study was taken up. In this study the influence of coir fibers on shear strength parameters (c and ?) and stiffness modulus (?d /?) of fly ash have been investigated. In the present investigation, samples of fly ash compacted to its maximum dry density at the optimum moisture content were prepared without and with randomly distributed coir fiber for triaxial compression tests. The coir fiber were taken as 0.25 %, 0.5 %, 0.75 % and 1 % by dry weight of fly ash and the shear strength parameters (c and ?) and stiffness modulus (?d /?) of reinforced fly ash for each fiber content was determined in the laboratory. Finally these strength parameters (c, ? and ?d /?) of reinforced fly ash were compared with that of unreinforced fly ash. Tests results indicate that on inclusion of coir fiber, the shear strength parameters and stiffness modulus of fly ash increases. It was also observed that on increasing the fiber content, the values of these strength parameters further increases and the improvement is substantial at fiber content of 1 %.
Thus there is a significant improvement in the strength parameters of fly ash due to inclusion of coir fiber.
Keywords:Fly ash, Coir Fiber, Shear Strength Parameters, Stiffness Modulus, Fiber content