A Comparative Review of Hot and Warm Mix Asphalt Technologies from Environmental and Economic Perspectives: Towards a Sustainable Asphalt Pavement

Abstract

The environmental concerns of global warming and energy consumption are among the most severe issues and challenges facing human beings worldwide. Due to the relatively higher predicted temperatures (150–180 °C), the latest research on pavement energy consumption and carbon dioxide (CO2) emission assessment mentioned contributing to higher environmental burdens such as air pollution and global warming. However, warm-mix asphalt (WMA) was introduced by pavement researchers and the road construction industry instead of hot-mix asphalt (HMA) to reduce these environmental problems. This study aims to provide a comparative overview of WMA and HMA from environmental and economic perspectives in order to highlight the challenges, motivations, and research gaps in using WMA technology compared to HMA. It was discovered that the lower production temperature of WMA could significantly reduce the emissions of gases and fumes and thus reduce global warming. The lower production temperature also provides a healthy work environment and reduces exposure to fumes. Replacing HMA with WMA can reduce production costs because of the 20–75% lower energy consumption in WMA production. It was also released that the reduction in energy consumption is dependent on the fuel type, energy source, material heat capacity, moisture content, and production temperature. Other benefits of using WMA are enhanced asphalt mixture workability and compaction because the additives in WMA reduce asphalt binder viscosity. It also allows for the incorporation of more waste materials, such as reclaimed asphalt pavement (RAP). However, future studies are recommended on the possibility of using renewable, environmentally friendly, and cost-effective materials such as biomaterials as an alternative to conventional WMA-additives for more sustainable and green asphalt pavements.

Sustainable Pavement Construction in Sensitive Environments: Low-Energy Asphalt with Local Waste Materials and Geomaterials

“…Ten samples of each of the aggregate fraction were obtained by quartering procedures using riffle sample splitters and the laboratory analysis according to the test methods of the European Standards (EN). (3) of Cecabase RT ® Proportion (%) 20.93 (1) 36.27 (1) 38.88 (1) 3.92 (1) 6 ( 2 (1) Percentage by weight of total aggregate; (2) Percentage by weight of mixture; (3) Percentage by weight of bitumen.…”

“…The production of hot mix asphalt (HMA) for paving is among the most energy-and emission-intensive construction activities [2], with an annual global production of nearly 1.2 billion metric tons. The mixing temperatures are typically between 160 and 170 • C. This implies a yearly fuel consumption of over 9 billion liters (2.4 billion gallons) and CO 2 emissions of approximately 26 million metric tons per year worldwide (based on an average of 7.5 L of fuel consumption and 21.5 kg of CO 2 per metric ton of HMA [3]).…”

The Microscopic Mechanism and Rheological Properties of SBS-Modified Asphalt with Warm Mixing Fast-Melting

“…When compared to HMA (150–170 °C), WMA may be generated and built at lower temperatures (100–140 °C) without degrading the mix’s performance [ 17 ]. The use of WMT is effective in reducing harmful emissions and hazardous fumes [ 18 , 19 ]. In addition to the benefits of lower temperatures, the use of WMA improves workability and increases transportation distances.…”

Evaluation of Resilient Modulus and Rutting for Warm Asphalt Mixtures: A Local Study in Iraq

“…One of the most significant issues and obstacles that people globally must overcome is the environment, including global warming and energy use [1,2]. Significant fuel and energy use, which results in pollutant emissions, is a factor with flexible pavement, which largely uses HMA [2].…”

“…Significant fuel and energy use, which results in pollutant emissions, is a factor with flexible pavement, which largely uses HMA [2]. Warm-mix asphalt (WMA) was created by road builders and pavement scientists to replace hot-mix asphalt (HMA) to lessen these environmental issues [1]. There are numerous challenges in asphalt pavements [3], and it is necessary to create bitumen with improved properties in comparison to traditional asphalt binder [4].…”