Crumb Rubber Modified Asphalt Concrete: A New Material for Pavements

摘要

The experimental investigations carried out using crumb rubber modifier obtained from the scrap tyres enhances the rheological properties and increases the moisture sensitivity of asphalt concrete. The ideal temperature for blending the asphalt with crumb rubber modifier is 170 deg C. Maximum stability is obtained when the gradation of the crumb rubber modifier is passing through 1mm and retained on 150 microns. The bituminous concrete with bitumen requires optimum bitumen content of 5.2 percent whereas the optimum binder content for bitumen with 15 percent crumb rubber modifier requires 4.9 percent of the binder content which contains only 4.17 percent of pure bitumen and 15 percent of crumb rubber modifier by weight of the bitumen. The modified binder requires lesser percentage of bitumen approximately equal to the percent of crumb rubber added leading to an overall economy. Fifteen percent crumb rubber modifier by weight is considered to be optimum value to be added with bitumen in bituminous mixes. Addition of crumb rubber modifier increases the hardness of the bitumen. The penetration value and ductility values are found to be decreasing with increase in the crumb rubber modifier percentage and the softening point value is found to be increasing with same indicating improvement in the rheological properties of the bitumen.