Self-Healing Polysulfide–Epoxy Sealants for Concrete Pavement Joints

Abstract

The development of self-healing polymers has primarily focused on enabling healing functionality, while comparatively little attention has been paid to meeting specific performance criteria. Without performance benchmarks, it is difficult to guide material design toward practical use. This study investigates a self-healing sealant for concrete pavement joints that incorporates dynamic disulfide bonds. The sealant—prepared from commercially available thiol-terminated polysulfides (LP55) and bisphenol-A epoxy resin—was evaluated under environmental and load conditions typical for concrete pavements. Static displacement was applied to assess self-healing and bond durability under freeze–thaw cycling. Two tertiary amines, 2,4,6-tris(dimethylaminomethyl)phenol (DMP) and triethylamine (TEA), were tested as initiators to study their effect on polymer curing. Fourier transform infrared analysis confirmed complete curing under ambient conditions within 3 weeks. The cured polymer exhibited a low glass transition temperature ( − 35 ° C ), favorable for flexibility in cold climates. Tensile tests showed higher strength for the TEA-cured sample (465 kPa) compared to the one cured with DMP (190 kPa). The thiol–epoxy sealant demonstrated stronger adhesion to concrete than a commercial silicone. Self-healing efficiency improved in some formulations when joint displacement increased from 1 mm to 2 mm. Overall, the results demonstrate that thiol–epoxy sealants with dynamic bonding can meet key performance requirements for pavement applications. They also highlight the need for further investigation into the effects of initiator chemistry on polymer performance and strategies to reduce residual deformation under low-rate loading.