New polyurethane modified coating for maintenance of asphalt pavement potholes in winter-rainy condition

Potholes are common distresses on poor quality or heavily trafficked asphalt pavements. Timely and durable maintenance is required to reduce the impacts on traffic, especially in winter and rainy conditions. Conventional coating materials for repair either require complex preparation or are of poor durability. This paper introduces a new polyurethane modified coating material to be used in pothole repairs, and compares it with the other two coating materials which are widely used in pothole maintenance, i.e., emulsified asphalt and cutback asphalt. Laboratory tests concerning workability, bonding performance and durability, and field surveys of three pothole patches installed in different environments were conducted. The results showed that the curing time and workability performance of the polyurethane modified coating were stronger than that of the control materials in low temperatures. Shear strength and pullout strength were greater at different test temperatures and moisture levels. The use of the polyurethane modified coating enhanced the ability of pothole patches to resist freezing-thawing cycles, dishing and shoving, when compared with the emulsified asphalt and cutback asphalt. The polyurethane modified coating had good pavement performance in field as well. Therefore, it is concluded that the polyurethane modified coating is a suitable choice for timely asphalt pavement potholes maintenance in cold and wet conditions.