A Study on Use of Natural Fiber for Improvement in Engineering Properties of Dense Graded Bituminous Mixes with Coal Ash

Abstract

Coal-based thermal power plants have been a major source of power generation in India. The prime waste products of a coal based thermal power plant are fly ash and bottom ash. Heavy dumping of these waste products causes fatal environment pollution to air, water, and land, besides impairing human health. This research work is done to explore the optimum use of ash, namely bottom ash (as part of fine aggregate) and fly ash (as mineral filler) along with natural fiber (such as sisal fiber) used to improvise the engineering properties of bituminous paving mixes. In the present laboratory study, dense graded bituminous mix specimens were prepared using natural aggregates as coarse aggregates, bottom ash as fine aggregates, fly ash as filler and sisal fiber as additive. To strengthen the mix, slow setting emulsion (SS1) coated sisal fiber was added in varying percentages such as 0, 0.25, 0.5, 0.75, and 1 % by weight of the mix, with variations of sisal fiber length such as 0, 5, 10, 15 and 20 mm. The most suitable composition (such as optimum bitumen content and optimum fiber content including the optimum length of fiber in the bituminous mix) was selected based on the results of Marshall tests. Further, for justifying the performances of the bituminous paving mix thus developed, tests for indirect tensile strength and moisture susceptibility in the form of tensile strength ratio and retained stability of bituminous mixes were conducted.