ABSTRACT
The issues of sealant durability, long-term performance and similar issues related to the service life of joint seal products have been the focus of research for the past 35 to 40 years. This research has been one of the primary concerns of technical committees such as RILEM TC 139 “Durability of Sealants”, ASTM C24 “Building seals and sealants”, as well as related ISO working groups. The approach in these technical committees has been one in which product performance, as opposed to system performance, has been the overriding consideration. Previous work in the area of product degradation conducted by Karpati [ 1-3] has provided considerable insight into the long-term performance of sealants subjected to outdoor climatic conditions and in laboratory conditions to develop accelerated test methods. The work established that cyclic movement is the most significant factor causing degradation in these products. It also provided a means of correlating evidence of failure obtained from simulated field conditions (in devices simulating building joint movement) with that derived from laboratory accelerated tests using hand-operated vises [4-6]. The use of cyclic techniques to assess the long-term performance of sealants products has been the focus of considerable research; Beech [7], Lacasse [8] and Wolf [9,10] have prepared useful reviews on the topic. Work in this area by Lacasse [11] using hand operated vises follows significant efforts by Karpati as mentioned earlier.
