Abstract:
Upgrading, maintenance and rehabilitation of road infrastructure is expensive, especially in view of the growing scarcity and cost of suitable road building materials. In areas with high mica content and secondary minerals such as smectite in the natural materials, stabilisation with cement is not viable. The Council for Scientific and Industrial Research of South Africa has embarked on a research programme to evaluate the performance of substandard materials improved with anionic nano-silane modified bitumen emulsions for use in base and subbase layers. This work comprises laboratory testing as well as Accelerated Pavement Testing using the Heavy Vehicle Simulator (HVS). The results of a full-scale HVS test on a light pavement as well as initial analysis on a medium traffic road are discussed. It has been shown that stabilisation of available substandard materials using an anionic nano-silane modified bitumen emulsion compared with the standard approach of importing high quality crushed aggregate can lead to savings as high as 40%–50% for equivalent performance. In addition, there was also a significant reduction in construction effort and time.
