Temperature Aging, Compression Recovery, Creep, and Weathering of a Foam Silicone Sealant for Bridge Expansion Joints

Abstract

Silicone foam was investigated as a sealant for small movement expansion joints in bridge decks. This paper presents results from the laboratory assessment of a model foam sealant subjected to thermal aging (exposure to high and low temperatures and temperature cycling), fatigue conditions, and outdoor weathering. Parallel tests were performed on a commercial solid-silicone bridge-joint sealant. Test results showed that the solid sealant recovered faster than the foam sealant after being subjected to prolonged compression at elevated temperature. When subjected to a constant tensile force, both the foam and solid sealants exhibited high initial creep rates (rate of elongation), but appeared to reach an equilibrium level of elongation at longer times. The foam sealant creeps at a slower rate and takes more time to get to the equilibrium elongation, whereas the solid sealant creeps much faster initially and reaches equilibrium faster. Thermal aging was found to have significant effects on the sealant modulus (increases with temperature); however, the effects on ultimate stress and strain were not apparent for both types of sealants. Temperature cycling between 24 and