Low-Energy Asphalt with Performance of Hot-Mix Asphalt

The paper presents an original process to produce a warm asphalt mixture: low-energy asphalt (LEA) with the performance of hot-mixasphalt(HMA). The Kyoto agreements continue to divide the planet, while protocol signatories are defining their application conditions. People wonder what the resulting repercussions will be on their respective fields of activity and their quality of life. A new aggregate coating technique is being presented in that context. The technique, the LEA process, substantially reduces energy consumption and greenhouse gas emissions. The low-energy coating technique LEA (EBE, from the French “enrobage à basse energie” involves the manufacture and application of asphalt mixes at a temperature lower than 100°C. These mixes offer a performance equivalent to that of HMA. They combine the action of the mixing energy, temperature, and water on the components of the mix, its bitumen, and aggregate skeleton. The originality of the process lies in the best use of changes in the condition of the bitumen: fluid when it is hot and able to transform into foam or to emulsify when in contact with water. Moreover the moderate-temperature heating of only the chippings (coarse aggregates) is involved; the rest of the aggregate skeleton is used cold and wet. This technique yields a significant saving in mixing energy and reduces the resulting gas emissions. The paper looks briefly into the process and sets it within its appropriate context.