RAP as an improved layer for low volume roads

Abstract

A good road network infrastructure is required due to increased urbanization. There is a shortage for the available of natural resources of virgin aggregates for the construction. So, the engineers are forced to use the available waste materials like recycled asphalt pavement (RAP) through proper processing in pavement construction. As the construction of pavement involves huge quantity of materials, the proper use of RAP in construction can address the issue of waste disposal and help in prevention of natural resources. In this investigation, RAP was collected from a stockpile and characterized for its physical and mechanical properties. As RAP is brittle in nature, mineral fillers such as cement and hydrated lime were used to enhance the properties of RAP. The RAP was processed in laboratory through jaw crusher to obtain the usable size particles. The processed RAP was heated to 160–170 °C so that the binder present in the RAP softens and coats the aggregate particles providing enhanced bonding in comparison with sample considered. The mineral filler dosage was varied from 0 to 2.5% with an interval of 0.5%. The test results indicated that 100% RAP with no mineral filler added is found to be brittle and undergone premature failure. Addition of mineral filler to the RAP improved the stability and flow, making the mixture less brittle. Among cement and lime, cement imparted higher stability. Provision of an improved layer with RAP just below the bituminous layer in the pavement is expected to improve the service life of the pavement by reducing the pressure transferred to the subgrade and thus, it can be successfully implemented for low volume roads.