Assessment on the sustainable use of alternative construction materials as a substitute to natural aggregates

Abstract

South Africa is facing a potential shortage of virgin aggregates used to produce asphalt mixes for road construction. Although these aggregates have demonstrated the desired quality in asphalt mixes and have adhered to project specifications and performance criteria, there are, however, growing concerns regarding their future availability and sustainability. This paper discusses the potential risk of depletion of virgin aggregates that are utilised in typical asphalt mixes in South Africa, and identifies potential construction materials such as glass, slags and recycled asphalt pavement (RAP) that are locally available as alternative aggregate materials to virgin aggregates. An economic cost analysis conducted indicated that it is more cost-effective when using crushed glass for instance, as a substitute to virgin aggregate. Moreover, it was found that the use of crushed glass in asphalt mixes is both sustainable and feasible in South Africa. The findings presented in the paper are informative, emphasizing the need for the utilisation of alternative materials in order to address the depletion of traditional materials utilised in asphalt mix production in South Africa.