Review of warm mix rubberized asphalt concrete: Towards a sustainable paving technology

Abstract

In recent years, transportation agencies and the general public alike are demanding increased considerations of sustainability in transport infrastructure. Warm mix asphalt (WMA) is developed for reducing energy consumptions and emissions in asphalt paving industry. In addition, the use of rubberized asphalt concrete (RAC) has proven to be economically and environmentally sound and effective in improving the performance of pavements around the world. The combination of WMA and RAC, namely WarmRAC, is a novel and promising paving technology that can realize pavement sustainability from principles to practices. This study summarizes the best practices and recent research findings on warm mix rubberized asphalt concrete, including mix design, construction techniques, performance evaluation, feasibility of recycling, and environmental and economic benefits. Although most research findings to date about WarmRAC are positive, it still has a long way for WarmRAC to be fully adopted worldwide. Therefore, life cycle assessment including environmental and economic impacts, and long-term performance of WarmRAC need further research with involvement of transportation agencies, industry and academia.

Incorporating Sustainable Practices in Asphalt Industry

“…An impactful approach in increasing the sustainability of warm mix asphalts is the use of rubberized asphalt concrete (RAC). This novel technology, which is addressed as WarmRAC, is both economically and environmentally sound [26]. Although these mixes have been used since the 1960s in the US [27], their technology is still evolving.…”

“…Although these mixes have been used since the 1960s in the US [27], their technology is still evolving. Research has shown a satisfactory functionality of these pavements for improving aging, oxidation, fatigue, skid, reflection cracking, and rutting resistance as well as mitigating noise generation [26], improved durability and lower maintenance costs [28,29]. To enhance various aspects of warm mix pavements, the research findings can be categorized into design, construction, performance, and recycling [26] as shown in Table 6 (data from [26]).…”

Evaluation of Warm Rubberized Stone Mastic Asphalt Mixtures through the Marshall and Gyratory Compactors

“…This technology has been frequently used in mixtures without CRM in Europe [10] and worldwide [11,12]. In the case of modified CRM asphalt mixtures, the leading technologies involved in temperature reduction are organic and chemical additives [13], but the application of foamed bitumen technologies has not been frequent. Organic additives are usually waxes, with melting points around 110 • C, which a decrease in the viscosity of the CRM modified binder at the manufacturing and compaction temperatures.…”

“…In the review by Wang et al [13], depending on the technology used, temperature reductions of between 20 and 30 • C were achieved in various test sections. Oliveira et al [14] obtained temperature reductions of 30 • C in an SMA mixture with a surfactant additive.…”

Effect of Recycled Rubber on the Properties of Road Bitumen

“…e results published by Wang [16] indicate that the swollen rubber powder is mutually adhered to form a network structure and the matrix bitumen changes from a homogeneous body into a two-phase continuous blending structure system constituted by rubber powder and bitumen. In the review paper, it was found that regardless of temperature modification, the introduction of crumb rubber into the paving technology can not only solve the disposal issue of waste tires but also improve the performance of asphalt pavements, including reducing traffic noise [17]. is paper presents the results of bitumen modification.…”