Comparing Global Warming Impact of Asphalt Pavement Preservation at Maintenance and Use Stages Using Dynamic Life-Cycle Assessment

There are a large quantity of greenhouse gas emissions at maintenance and use stages of pavement. Related research said that the carbon emissions generated by road traffic account for about 16.6% of the entire planet. Meanwhile, in recent years, preventive maintenance treatments were proposed and widely used to extend service life, reduce the frequency of maintenance and improve the quality of pavements. However, instead of environmental protection, the original intention of this technology is to cut down the construction and operation costs. And it needs further discussion on whether pavement preservation has played a significant role in improving the environment benefits. The study aims to explore the global warming impact (GWI) of asphalt different preservation in use and maintenance phases considering temporal aspect of greenhouse gas (GHG) emissions. And the life cycle assessment method is used to build an assessment framework. Thus, the maintenance stage is divided into four modules: raw material, production, transportation and in-site construction. The results show that preventive maintenance treatments bring significant environmental benefit in reduction of CO₂ emission compared with traditional corrective maintenance treatments, although there are some differences in effect. In use stage, GHG emissions vary significantly depending on the roughness of pavement surface. And it is found NovaChip has advantages over hot in-pace recycling in terms of roughness improvement, resulting in that NovaChip is more conductive to reduce the environmental impact. On the other hand, the results indicate that the environmental impact of asphalt pavement preservation is overestimated if temporal aspect is not considered. What’s more, the framework proposed in this study can also provide certain reference ideas for determining the optimum application timing of pavements from the perspective of environmental protection. And it can also make contributions to the pavement preservation mechanism based on life-cycle cost analysis.