This article recommends some procedures that greatly extend the lives of joint seals. The recommendations pertain specifically to polyvinyl chloride sealants conforming to ASTM D 3406, "Joint Sealants, Hot-Poured, Elastomeric-Type, for Portland Cement Concrete Pavements."
The vertical faces of the joint must be cleaned by sandblasting. Then the joints must be inspected by an inspector capable of discerning whether the surfaces are actually sandblast-clean to the full proposed depth of the sealant. This requires a complete examination of both walls of every joint for its full length.
The cross-sectional shape of the sealant has a very important effect on its performance. For hot-applied sealants conforming to ASTM D 3406 the shape factor (ratio of depth to width) should be 1.0 or less. The sealant must be heated sufficiently and kept sufficiently hot so that it will penetrate the vertical surfaces of the joint and develop good bond.