Warm mix asphalt for better sustainability under tropical climate

Abstract

This research has been conceived with the aim of lowering the production temperature of the traditional HMA to produce warm mix asphalt (WMA) through the use of an additive as well as incorporating RAP in the mixtures. The suitability of a wax-based additive, under tropical climatic conditions, has been assessed through standard laboratory tests with varied dosages of the additive at various production temperatures and with varied RAP contents. Experimental results reveal that the wax can be used at an economical and optimum dosage of 2%, by mass of the asphalt binder, to reduce the production temperature of HMA from 160 to 140 °C, with a net cost increase of 1.6% per tonne of WMA manufactured while incorporation of RAP in WMA at 25% has been successfully achieved with comparable properties to locally used asphalt. The 20 °C reduction in temperature and the incorporation of RAP will highly reduce the exposure of workers to fumes and provide a better working environment in tropical weather.

Keywords:

• Reclaimed asphalt pavement
• Tropical climate
• sustainability
• hot mix asphalt
• warm mix asphalt

Acknowledgements

The authors acknowledge Sasol Ltd (South Africa) for provision of Sasobit^® and Transinvest (Mauritius) Ltd and Colas (Mauritius) Ltd for their help throughout the paper.