Performance of Warm Mix Asphalt containing Sasobit®: State-of-the-art

Reducing the environmental impact of concrete and asphalt: a scenario approach

A comprehensive life cycle assessment of asphalt pavements was conducted including hot mix asphalt (HMA), warm mix asphalt (WMA) with the addition of synthetic zeolites, and asphalt mixes with reclaimed asphalt pavement (RAP). The environmental impacts associated with energy consumption and air emissions were assessed, as well as other environmental impacts resulting from the extraction and processing of minerals, binders and chemical additives; asphalt production; transportation of materials; asphalt paving; road traffic on the pavement; land use; dismantling of the pavement at the end-of-life and its landfill disposal or recycling. Monte Carlo simulations were also conducted to take into account the variability of critical input parameters. Taking into account the entire life cycle, the impacts of zeolite-based WMA pavements were almost equal to the impacts of HMA pavements with the same RAP content. The reduction in the impacts of WMA resulting from the lowering of the manufacturing temperature was offset by the greater impacts of the materials used, especially the impacts of the synthetic zeolites. Moreover, by comparing asphalt mixes with different RAP contents, it was shown that the impacts of asphalt mixes were significantly reduced when RAP was added. All endpoint impacts as well as climate change, fossil depletion and total cumulative energy demand were decreased by 13–14% by adding 15% RAP. A key advantage of WMA is the potentially greater use of RAP. Thus, the decrease in the impacts achieved by adding large amounts of RAP to WMA could turn these asphalt mixes into a good alternative to HMA in environmental terms.

Life cycle assessment of hot mix asphalt and zeolite-based warm mix asphalt with reclaimed asphalt pavement

In this work the environmental sustainability of asphalt pavement is analyzed, from material production and maintenance strategy point of view. The work consists of an analysis of the life cycle of 1 km of road pavement and includes all stages of the life cycle: from extraction of virgin materials to end of life. Three types of pavements are compared, among which one produced with virgin materials and traditional technologies in plant, which is used as a reference, and two in which the use of Reclaimed Asphalt Pavement (RAP) and Warm Mix Asphalt (WMA) technology are combined. Also the implementation of the practice of Cold In-Place Recycling (CIR) at the end of life is considered from an environmental point of view: after the first 15 years of life the comparison is made between traditional recycling in plant and CIR. The impacts are evaluated using different methods. Decrease in environmental impacts are found for the options that combine the use of RAP and WMA reaching up to a percentage of reduction of 12% for CO2eq, 15% for energy consumptions, 15% for water used during the lifecycle, and 10–15% for the three macro-categories of damage evaluated in the ReCiPe endpoint method. Additional reductions could be achieved by applying also CIR technology especially for greenhouse gas emissions (−9%).

Luis Baena

Papers

Warm mix asphalt: an overview