Development and Laboratory Analysis of Silicone Foam Sealant for Bridge Expansion Joints

Sealing of bridge expansion joint systems is important to protect the structural components below the joint. An elastomeric foam-type joint sealant has been developed for sealing small-movement bridge expansion joints. Laboratory tests including tension, compression, shear, bonding, stress relaxation, cure rate, tack-free time, and water tightness were performed on this sealant. In addition, loading-unloading behavior in tension and compression and effects of immersion in saturated saltwater solution on its engineering properties were investigated. The silicone foam sealant showed an increase in volume of ~70% on curing and attained approximately 80% of the 21-day curing strength in the first 7 days. Tack-free time for the foam sealant was below 1.5 h and comparable to that for the solid sealant. The mechanical test results indicated lower stiffness, greater extensibility, and better bonding associated with the foam sealant compared to the solid (unfoamed) sealant. The foam sealant exhibited smaller loss in extensibility at failure due to saltwater immersion compared to the solid sealant. While in tension both sealants exhibited similar rates of stress decay, in compression the foam sealant was found to relax faster than the solid. Neither sealants exhibited any water leakage during a 96-h test period.

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  • English

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  • Accession Number: 01055755
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Aug 4 2007 9:42PM