Researchers at Shandong Jianzhu University studied the benefits of high-dosage polyurethane (PU)-modified asphalt to improve its resistance to deformation, cracking, and rutting under extreme temperatures and heavy loads. PU enhances asphalt performance by forming carbamates through reactions between isocyanate groups and hydroxyl and carboxyl groups in the asphalt, with additional hydrogen bonding. The study tested asphalt mixes with 40%, 50%, and 60% PU content, finding that 50% PU provided the best curing reaction and improved bonding with aggregates, enhancing water stability. Performance tests, including rutting, low-temperature bending, and freeze-thaw splitting, showed significant improvements in flexural tensile strength, strain, and splitting strength after freezing and thawing.

Source: Urethanes Technology International