Evaluation of cold asphalt patching mixes
Thesis (MEng (Civil Engineering))--University of Stellenbosch, 2007.
Cold mixed asphalt concretes consist of bituminous binder, either cutback or emulsion, and aggregates that have not been heated. Cold mix asphalt is often used due to unavailability of hot mix asphalt in the vicinity of the project and also used for temporary patches. The poorer performance of the materials associated with expensive cold mixes will results in greater overall cost for patching due to increased cost of labour, equipment and traffic control. The main objective of this study was to evaluate performance of proprietary cold mix asphalts available in South Africa. Five products were used in this study, which are Roadfix, Tarfix, Much- Asphalt mix, Asphalt King and Glenpatch. Engineering properties of products were investigated, including volumetric properties, permeability and Indirect Tensile Strength. In addition, for performance properties, accelerated pavement testing using Model Mobil Load Simulator (MMLS3) was carried out. The testing was done dry at 50o C up 20,000 load repetitions. It was found out that all five products have high void contents which range between 15.1% and 23.5%. This makes these cold mix asphalts to be highly permeable. Indirect Tensile Strength values were found to be very low compared to minimum value of 800 kPa specified for Hot Mix Asphalt. Products with emulsion as binder (Asphalt King and Glenpatch) were found to be more susceptible to water damage compared to other mixes with cutback binder. MMLS3 test results showed that Asphalt King was less susceptible to rutting compared to the other four products. In general all products are very highly susceptible to rutting compared to Hot Mix Asphalt.