Laboratory Evaluation of Reclaimed Asphalt Pavement-Quarry Waste Blends as Unbound Highway Pavement Material

Large quantities of quarry waste (QW) are generated in the blasting of rocks and are stockpiled on production sites. Also, pavement rehabilitation and reconstruction generate a large volume of reclaimed asphalt pavement (RAP) waste that is disposed of along road alignments. All of these wastes are environmental hazards. This paper presents the results of a laboratory evaluation of the characteristics of RAP-QW blends with a view to determine their suitability for use as flexible pavement material. The mixtures were subjected to British Standard light (standard Proctor) compactive efforts to determine their compaction characteristics and California bearing ratios. The test results show that the properties of RAP waste improved with QW treatment. The maximum dry density increased as the optimum moisture content decreased with higher QW contents in the blends. Optimum California bearing ratio values of 52 % (unsoaked) and 66 % (soaked for 24 h) were recorded for 80 % RAP + 20 % QW and 60 % RAP + 40 % QW blends, respectively. With the potential for time-dependent increases in strength in view, the optimum blends satisfied durability requirements with insignificant water absorption and can be used as sub-base material in flexible pavement construction. This research provides results of the evaluation of RAP-QW blends as highway construction material, as based on the determination of the California bearing ratio. Further work may be encouraged to assess the resilient modulus of this material under cyclic load.