A trial to study the performance of 18 different concrete joint sealants on the A12, Chelmsford by-pass has been monitored for 5 years since construction. Other sites where the contractor chose and applied the joint sealants under normal contract conditions have also been monitored during the same period. Movements occurring at both contraction and expansion joints have been measured and the results are discussed in relation to the capabilities of the sealants applied to these joints. Although the different generic types of sealant performed well in at least one section, there was a wide variation in performance which seemed, in part, to be dependent on source. Laboratory tests to measure the resistance to extension and resistance to penetration were carried out to see if they correlated with the performance of the sealants on site. Unfortunately, predictions of site performance could not be made from laboratory tests, in part because the curing and weathering of the laboratory specimens prior to testing may have been insufficient to simulate conditions in the road. (A)
Abstract