AbstractPorous asphalt concrete (PAC) is an open-graded friction course that is specifically designed to have high air void contents for removing water from the pavement surface. PAC surfaces, which include open-graded friction courses, permeable friction courses, and drainage asphalt pavements, have increasingly gained acceptance among agencies and industry in the world. PAC might be susceptible to freeze-thaw damage in cold climates and require winter maintenance practices. The life span of PAC pavements shows a large variation depending on climates, traffic volumes and loadings, design and construction practices. The objective of this paper was to review design, construction, and performance that could maximize the advantages and minimize the disadvantages associated with the use of PAC mixtures. A consolidated review of the worldwide literature on PAC applications was conducted, with attention to the use of PAC in agency practices, and specifications for PAC from the world were evaluated. Based on an analysis of the results of this review, two key features were emphasized: (1) a recommended practice for material selection and design of PAC, and (2) a recommended practice for PAC construction and maintenance. Key points include a careful assessment of the PAC drainage and an adequate asphalt content to improve the performance of the pavement surface. A proper binder content stabilized by additives such as fibers and polymers is essential to ensure sufficient film thickness that is critical to the durability of the PAC mix in the long run.
Internal structure change of porous asphalt concrete under coupled conditions of load, moisture and temperature
