Experimental Study of the Effects of Moisture on the Performance of Concrete Pavement Joint Sealants

Abstract

Joint sealants play an important role in maintaining concrete pavement. They reduce or prevent numerous distresses, including spalling, faulting, and subbase erosion damage. The successful maintenance of such joint sealants is closely linked to a satisfactory lifespan for rigid pavement. However, it has been found that many sealants often fail in the early stages, as a result of inadequate or insufficient joint preparation. This study examined the effects of moisture content on bond strength, the main cause of joint sealant failure. Sealant use in various climatic regions throughout the United States was examined and Departments of Transportation were surveyed with regard to how they handled moisture. The survey showed that in cold-freeze areas, hot-pour sealants were preferred over silicone, and most states visually inspected the moisture condition of joint reservoirs. This research evaluated the effects of surface moisture on the tensile bond strength between a joint sealant and reservoir. In addition, an indirect measurement method was applied to estimate the reduction in bond strength in response to excessive moisture on the reservoir wall at the allowable strain. The causes of degradation in adhesion strength were evaluated by measuring the sealant wetting angle. Finally, it was determined that, while the choice of sealant may depend on the climate, those not currently preferred in wet-freeze regions could be used if accompanied by proper pretreatment and moisture control, contributing to the stable lifespan of joint sealants and concrete pavement alike.