Warm-Mix Asphalt and Pavement Sustainability: A Review

Abstract

Within the past two decades or so, the asphalt paving industry has responded positively to increasing global concerns over shrinking natural resource reserves and worsening environmental conditions through the development and deployment of warm-mix asphalt technologies. Such technologies make it possible to produce and place asphalt concrete at reduced temperatures compared to conventional hot-mix methods. Several studies have reported on the potential of warm-mix asphalt with regard to improved pavement performance, efficiency and environmental stewardship. This paper reviews several of those studies in the context of pavement sustainability. Overall, warm-mix asphalt provides substantial sustainability benefits similar to or, in some cases, better than conventional hot-mix asphalt. Sustainability benefits include lower energy use, reduced emissions, and potential for increased reclaimed asphalt pavement usage. Growth in utilization of warm-mix asphalt worldwide may, in the not-too-distant future, make the material the standard for asphalt paving. Regardless, there are concerns over some aspects of warm-mix asphalt such as lower resistance to fatigue cracking, rutting and potential water-susceptibility problems, particularly with mixes prepared with water-based technologies, which require further research to address.

A Review of the Application of Zeolite Materials in Warm Mix Asphalt Technologies

“…The idea behind WMA technology assumes that, with decreased production temperature, the physical and chemical properties of mix asphalt will be better or the same as in case of HMA [44,45].…”

Improving the Environmental Sustainability of Low Noise Pavements: Comparative Life Cycle Assessment of Reclaimed Asphalt and Crumb Rubber Based Warm Mix Technologies

“…The use of WMA leads to a reduction in mixing and compaction temperatures of about 20-40 • C, if compared to the traditional HMA [18] and the addition of zeolites has been shown to further decrease the temperature [20]. As the required heat is reduced, plant and site emissions are lowered [21]. Life cycle assessment (LCA) studies have shown that a reduction of processing temperature is associated with a reduction of air pollution, smog production, and fossil fuel depletion [22]; on the other hand, the production of required additives may counteract the reduced environmental impact [7,23,24].…”

Investigation of Rutting Performance of Different Warm Mix Asphalt (Wma) Mixtures

“…This places elevated responsibility on industry professionals, to indulge in sustainable construction practices, in order to ensure that the activities of today's generation would not compromise and be detrimental to the ability of tomorrow's generation to prosper unhinged. It is reported that in the United States (U.S) alone, over 320 million tons or raw materials are used in the construction, rehabilitation and maintenance operations of the nation's road infrastructure network; project annual costs of over $150 billion [1].…”