Accelerated Laboratory Evaluation of Joint Sealants Under Cyclic Loads

The sealing of joints and cracks in pavement structures has been in practice since the early 1900s. The optimized selection of joint sealant products can extend pavement service life and reduce annual maintenance and rehabilitation needs particularly in regions which experience extreme climatic conditions. Early sealant materials were not subjected to standardized testing procedures and many failed as a result. Since then, several test procedures have been investigated and a few have been accepted into approved standards, such as the American Society for Testing and Materials (ASTM), for many of the materials on today’s market. Variability within the sealants and the empirical nature of the tests have been ineffective in predicting sealant behaviour in the field. In addition, ASTM laboratory test procedures require long and sophisticated tests that many highway or transportation agencies are unable to perform, relying on past performance or previous field trials. This potentially leaves many newer and better performing sealants off the approved list of many agencies because of the lengthy and expensive process of field acceptance. The purpose of this research was to investigate and rank the performance of eight hot pour joint and crack sealant materials for applicability of use in Manitoba through a performance-based lab testing approach. The project involves laboratory testing of sealant materials to verify fundamental properties and performance simulation under cyclic loading. Sealants were tested using a repeated compressive and tensile fatigue test at +30ºC, 0ºC and -30ºC. The results of the laboratory tests indicated that Type I sealants exhibited higher initial load values and also experienced adhesion failure at both the 0°C and -30°C test temperatures. The Type IV sealants generally exhibited lower resistance to load and three of the eight sealants did not show signs of failure at any of the three test temperatures.