Investigations on laboratory performance of bituminous mixes with reclaimed asphalt pavement materials - a step towards sustainable road infrastructure in India

The present work addresses the issue of building sustainable road infrastructure in India with recycling of bituminous pavement materials as an effective alternative to conventional rehabilitation techniques. In the present investigation, a project of upgrading an existing two lane to four lane of a national highway is considered. The properties of existing bituminous layer materials were collected from the project site and evaluated in the laboratory. The percentage of virgin aggregate is estimated. The possibility of substituting the virgin material demand with the reclaimed material is explored. Bituminous mixes with recycled materials are assessed for their mechanical behaviour, tensile strength, durability and rutting resistance. Laboratory results and analysis showed that the use of recycled materials go up to 85% in substitution to virgin materials and can bring in substantial savings in the cost of raw materials like aggregates and bitumen. The use of recycled material in bituminous layers did not affect the tensile strength and moisture susceptibility of mixes as well as their mechanical response. The rutting resistance of bituminous mixes with recycled materials was found to be comparable to that of virgin mix. Overall, the benefit accrued using recycled materials is found to be as high as 54% in terms of savings in the initial construction cost. Recycling of bituminous layer material is the key for sustainable road infrastructure in India, in the years to come. The findings of the study will help in the development of sustainable guidelines for recycling in India.