Gel Permeation Chromatography Analysis of Asphalt-Based Joint Sealants

The premature failure of field molded pavement joint sealants has led to increased maintenance cost and can reduce the life cycle of a pavement structure. Two possible causes of premature failure of pavement joint sealants are prolonged heating prior to installation and excessive aging after it has been installed into the joint. This laboratory study was conducted to evaluate the use of gel permeation chromatography GPC as a method for identifying sealants that have been exposed to prolonged heating or that have aged because of natural weathering. This research consisted of a literature review and a three-phase laboratory study. Material specification testing and GPC analysis were conducted to determine if physical andor molecular size distribution changes could be detected in the sealants. The conclusions of the laboratory study indicated that GPC analysis could be used to detect changes in sealant materials caused by exposure to extended heating and aging, but that the detected changes were inconsistent and could not be correlated with physical test properties.