Impact of Fatigue Exposure on Extensibility Performance of Standard Joint Reservoir and Sealant Designs for Jointed Plain Concrete Pavements

The transverse joint sealant for a jointed plain concrete pavement (JPCP) minimizes the entry of moisture, deicing salts, and incompressibles. This reduces the potential for the development of durability issues, erosion, pumping, faulting, spalling, and blow-ups. Sealant performance is influenced by sealant material, joint reservoir design, and the timing and quality of the installation. A laboratory study was performed to evaluate three joint design/material combinations subjected to simulated joint opening/closing and vehicle load fatigue that would occur in a 15 ft JPCP throughout a 42-year service life and freeze-thaw cycles. Data collected from an instrumented pavement was used to establish the loading conditions throughout the 42 years. Extensibility testing was performed on newly sealed joints as well as sealed joints with the simulated service life loadings to assess the performance. The adhesive strength for the asphalt sealed joints (26 pounds per square inch [psi]) was found to be statistically significantly higher than the silicone sealed joints (22 psi). Additionally, it was observed that asphalt filled joints exhibited substantial cohesive failures because of the narrow joint width and the difficulty in adequately filling the joint. From these results, it was concluded that silicone and asphalt sealant material and reservoir designs are sufficient to achieve long-term performance for 15 ft JPCPs for the JPCP design and environmental conditions considered, while asphalt filled joints are recommended for shorter slabs. These results assume that all joints are activated before sealing to prevent over- and under-filling of the joints, which can lead to premature sealant failure.