Energy and Environmental Gains of Warm and Half-Warm Asphalt Mix: Quantitative Approach

Abstract

The solutions, currently proposed to improve the energy efficiency of asphalt mixing processes are categorised in warm and half warm, depending on whether their manufacturing temperature is above or below 100°C. Evaluating the energy content of such asphalt mix is essential for its environmental validation. The energy content of six types of manufacture representative of hot, warm and half-warm mixes is presented. The method takes into account the thermal losses related to the processes and the types of manufacturing installations as well as the fuel used. Based on the thermodynamic method used to study the half-warm process LEA, presented at TRB 2006 sessions, the method includes: (1) The numerical simulation, of the kinetics of the transfers accompanying the changes in the physical and chemical properties of the constituents. (2) The energy management model of producing equipment, applicable an industrial installation as well as the laboratory. This approach enables a better understanding and control of the physical phenomenas mobilized by the different warm, and especial half-warm processes. It offers a thermal model of process operation and allows the calculation of related energy parameters. Its application can be extended to all types of mixes, whether hot, warm or half-warm. All the players involved in the production and use of asphalt mixes will find an instrument measuring their effectiveness in terms of environmental compliance. The method gives answer to the question: how many joules can be saved? Gas and fuel oil are not equal in terms of environmental discharges, whether from the qualitative or quantitative viewpoints. Everyone involved in the production and use of bituminous mixes will find an instrument for measuring their effectiveness in environmental protection.