Odor-Reducing Additives for Asphalt Applied in Expressway Connection-way

Release time: 2026/05/14 Publisher： original Views：

The NEXCEL 2024 project, titled "Development and demonstration of nonmetallic additives for emission absorption and permanent sequestration of CO2 in asphalt pavement" was conducted by Chang'an University and Shandong University. Its outcomes have been applied in Yangpu Port Expressway connection-way in Danzhou, Hainan, providing a good demonstration for the promotion and application of odor-control and emission-reduction asphalt in sustainable infrastructure.

Asphalt is a complex mixture of hydrocarbons with different molecular weights, which readily releases gaseous pollutants such as VOCs, SO₂, H₂S, NO, and CO under high temperature or normal temperature and pressure conditions, posing significant environmental risks. Effective emission reduction measures are urgently needed. In response to the critical environmental governance demands, the development and demonstration of odor-reducing additives for asphalt pavements represent a concrete implementation of Chinese Developing Comprehensive Transport Network Guidelines.

The Yangpu Port Expressway is a key project in the "14th Five-Year Plan" for comprehensive transportation in Hainan Province's Western Land-Sea New Channel. The demonstration section of the project spans the dual-lane pavement from K33+160 to K35+160. The pavement structure, from top to bottom, consists of: a 4 cm SMA-13-SBS modified asphalt mastic stone concrete surface course, a 6 cm AC-20C-SBS modified asphalt medium-grained asphalt concrete binder course, and an 8 cm AC-25C-70-grade road petroleum asphalt coarse-grained asphalt concrete base course.

Addressing the technical challenge of high emission pollution from asphalt, the project team, after nearly two years of research, developed a composite odor-control and emission-reduction material consisting of "Biomass charcoal + Hydroxy long-chain hydrocarbons odor-control agent + SBS." This material was used to collect asphalt emissions during various stages of construction (Figure 1). The composite material achieved a significant reduction in asphalt gaseous pollutant emissions, with VOCs, H₂S, and SO₂ emission reduction rates of 82%, 61%, and 63%, respectively. The emissions of CO and NO were below detection limits, as shown in Figure 2. This result was applied on-site in the Yangpu Port Expressway connection-way, with a 2 km experimental section paved using 60 tons of the composite material. The on-site construction is shown in Figure 3.

Figure 1. Asphalt VOCs collection and testing at the construction site

Figure 2. Emission reduction effect of the composite additive on asphalt emissions

Figure 3. On-site construction of the Yangpu Port Expressway connected-way

The demonstration application of the odor-control and emission-reduction materials for asphalt pavement effectively meets the needs for controlling gaseous pollutants from asphalt. It also established a complete set of green environmental technology for asphalt pavement hazardous emission reduction applications.