High temperature properties of wax modified binders and asphalt mixtures

The influence of adding two commercial waxes (FT-paraffin and polyethylene wax) to binders of penetration grades 50/70 and 160/220 were investigated for high temperature performance of binders and asphalt concrete mixtures. Binder properties were determined by conventional test methods, dynamic mechanical analysis and bending beam rheometer testing. The high temperature properties of asphalt concrete were investigated using the French rutting tester. The addition of FT-paraffin and polyethylene wax increased the rutting resistance of mixtures for both types of binder. The FT-paraffin modified asphalt mixtures showed the best rutting resistance. Adding polyethylene wax showed the highest stiffening effect in terms of rutting factor by DMA for the binders. However, this could not be verified in asphalt mixture testing. Adding FT-paraffin improved the rutting resistance of asphalt mixtures containing low or high penetration binder, but for the mixture containing high penetration binder the specification limit was exceeded. (C) 2009 Elsevier Ltd. All rights reserved.