WAM-FOAM, ASPHALT PRODUCTION AT LOWER OPERATING TEMPERATURES

Reducing asphalt production temperatures has significant benefits from both cost and environmental perspective. The hot mix asphalt industry has been aware of this for many years. The biggest challenge has always been to achieve adequate asphalt mix quality at lower or ambient operating temperatures. Recently, new production processes at temperatures between 80=120 deg C have attracted much interest because of the possibility to approach or even obtain hot mix quality. In the warm asphalt mixture (WAM) process using foamed bitumen this region is explored using conventional production and laying equipment. The WAM-foam process has been tested in the laboratory and in road trials. The results show that for dense asphalt wearing courses the properties and the performance can be comparable with hot mixture. Additionally the benefits to the environment were confirmed by measured reductions in energy consumption, emissions and fume exposure.