Innovative Design of Paving Cold Mix and Cohesive Overlays for Sustainable Pavement Maintenance

A cold mix overlay is a typical preventive maintenance treatment that is applied to an existing pavement surface. However, the service life of cold mix overlay is limited because of its poor skid resistance and high tendency to crack, especially in cold regions. This study presents a new technology of high-performance cold mix overlay materials that slows skid resistance reduction, increases the resistance to thermal cracking, and shows long-lasting anti−icing performance. The sustainable performance of paving cold mix overlays can be assured by adding high-performance anti−icing agents, fiber, and emulsified asphalt to the cold mix. A series of laboratory tests were conducted to evaluate the performance and anti−icing effect of the cold mix. The results showed that the freezing temperature of the cold mix dropped to more than −10 °C. The open-to-traffic time can be shortened to 3.5 h after construction. The anti-wearing ability and cracking resistance were evidently increased in comparison with traditional micro-surfacing techniques by conducting indoor wet-wheel wearing tests and low-temperature bending beam tests. Based on the study, the new-tech cold mix overlay has shown promising applications in North America.