Recent applications and developments of Polyurethane materials in pavement engineering.

[Display omitted] • The PU prepolymers can chemically react with the base asphalt. • The PU has superior high-temperature stability, adhesion strength, and durability to asphalt. • The anti-aging performance of PU sealants is always a great concern. • High-density PU foam injection has been implemented as an alternative to the conventional cement. • PU-bonded mixture can improve the performance and extend the service life of pavements. In the past decades, Polyurethane (PU) as an emerging polymer material has been widely used to construct, repair, reinforce, and protect civil engineering infrastructures. Meanwhile, various PU-based materials are increasingly employed in pavement engineering for new construction and maintenance, due to their excellent physical and chemical properties. In this review paper, the synthesis method, chemical structure, and engineering properties of PU materials were first introduced briefly. Secondly, the practical applications of PU materials in pavement engineering at present were summarized, mainly including PU-modified asphalt, PU-bonded mixture, PU sealant, and PU foam injection. Finally, the potential economic benefits and environmental impacts of utilizing PU materials in pavement engineering were further discussed towards sustainability. [ABSTRACT FROM AUTHOR]