LAUSR

Abstract Highway pavements are very expensive infrastructures that consume very high amounts of natural resources. Utilisation of recycled concrete aggregates (RCA) for highway pavement construction can bring a number of benefits towards environmental, economic and societal sustainability. This would reduce the carbon footprint of the construction industry, result in natural resource conservation, reduction in harmful emissions, and minimisation of cost of pavement construction. This paper reviews available literatures on the use of RCA for highway pavements. Both flexible and rigid pavements were covered. The studies revealed that RCA can be applied in all pavement layers; subgrade, capping, subbase, roadbase, and surfacing. The physical and mechanical properties of the RCA and how they affect its performance were studied and compared with those of natural aggregates (NA). Available techniques for improving the performance of RCA in concrete and asphalt mixes were also discussed. The benefits and sustainability gains of RCA utilisation were summarised from available life cycle assessments conducted in the literatures. RCA has been considered as a feasible sustainable alternative to NA in highway pavement applications, but there still exists a large disparity in the recommendations of the replacement levels for asphalt mixes. To ensure that the pavements are sustainable without compromising their quality and functionality, the utilisation of RCA should be encouraged after further indebt studies that would lead to a more consensus standard specifications and guidelines.