Progressive deterioration and staining of concrete bridge substructures and erosion of abutments may, in many instances, be attributed to the leakage of bridge deck joints. The primary difficulty in maintaining a properly sealed joint is the continual expansion and contraction of the bridge spans. Joint seals, of course, must remain in contact with both faces of the disjointed sections and remain flexible at all temperatures encountered.

A study was initiated by the Division of Research for the specific purpose of evaluating the performance of preformed, compressed neoprene seals and to compare the performance of these seals with the performance of conventional joint sealers. This report is based on a field inspection of sealed joints in numerous Kentucky bridges, and the conclusions are derived from the observed performance of formed, sawed, or armored-edge joints sealed with conventional or neoprene seals. Between 1963 and 1965, neoprene seals were installed in one Lexington bridge, two Louisville bridges, and most of the Central Kentucky (Bluegrass) Parkway bridges. These seals, therefore, had been in service from two to three years at the time of field inspections.

It was observed that formed and sawed joints inevitably spall thereby making it difficult for any sealant to adequately seal the joints. Armored-edge joints, when sealed with neoprene seals, were observed to provide the best combination to perform the intended function of joint and seal. The added expense of such an installation may be justified from the standpoint of reduced maintenance costs.

Report Date


Report Number

No. 258a

Digital Object Identifier



The opinions, findings, and conclusions in this report are not necessarily those of the Department of Highways or the Bureau of Public Roads.