Field Evaluation of Three Joint Sealants

About the report:

The purpose of the study reported here was to evaluate the performance of three joint sealants compartmented (A) and closed cellular (B) preformed neoprene, and a two-component cold-mixed polysulfide (C)-- that were used in the interchanges for Interstate 64 near Charlottesville. The condition of the sealants and joints was observed, and the extent of the failures was estimated during a preliminary survey. The specific types of failure were then either measured or documented photographically during the warm- and cold-weather surveys. It was concluded that: 1. The neoprene sealants far out-performed the polysulfide sealant. 2. The polysulfide sealant probably failed because of compression set. The particles in the joints caused more distress by contributing to the loss of load transfer than by causing any damage such as spelling. The lack of confinement near the expansion joints and the open ends of the ramps permits one-way movement of the slabs; this contributes to the loss of load transfer and the discrete functioning of the slabs so that they break up under heavy loads. It was recommended that: 1. The Department discontinue the use of cold-mixed material to seal contraction joints in PCC pavements. polysulfide The Department use preformed neoprene sealants or comparable sealants to seal joints in PCC. These first two recommendations have already been put into effect by the Materials Division on the basis of field tests made by the Materials Division and the conclusions of this report. Expansion joints be eliminated, and the anchoring of slabs near the open ends of ramps be investigated.

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