Evaluation of polyurethane dense graded concrete prepared using the vacuum assisted resin transfer molding technology

In recent years, the polyurethane (PU) was widely investigated and applied in pavement engineering as a sustainable binder to develop pavment materials with superior mechanical and functional properties. However, the two-component PU binders exhibit rapid curing and thus it is difficult to control the material workability through paving and compaction. Hence, the precast mehtod concept has been proposed to obtain good workability as well as the optimal engineering performances of the polyurethane mixtures (PUMs) used in pavement. In the current study, a method based on the vacuum assisted resin transfer molding (VARTM) technology was developed for the precast PUMs. The results showed that the optimal VARTM-based preparation method is to perfusion the normally compacted specimens with 2 ~ 4 wt% PU content to obtain the optimal compaction uniformity and mechanical properties. Based on the developed methods, the water and freeze-thaw sensitivity of the VARTM-formed PUM samples were evaluated by performing laboratory tests. According to the immersion Marshall stability and freeze-thaw splitting tests, the VARTM-formed PUM samples showed improved Marshall and water stability comparing the performance of samples developed using a conventional compaction method. Given the above excellent performances, the VARTM-formed PUMs were validated to serve as the rapid repair pavement materials or pavement materials with high waterproof performance requirements, for example, the bridge deck paving materials. This research has made a breakthrough in the construction technology of PUMs to a large extent. It has made significant contributions to the further application and promotion of PU binder in transportation infrastructures.