Elastic Recovery of Sealants

This paper summarizes some of the important findings from a research project designed to study the causes of sealant failure on building facades. The paper also discusses the development of an on-site diagnostic technique to test the elastic recovery of sealants. The findings from this study indicate the importance of environmental effects on the performance of sealants. The selection of the appropriate types of sealant for outdoor applications, where the sealants will be subjected to the effects of varied weathering, needs careful consideration. Among the three generic types of sealants tested in this study, silicon sealants have shown excellent elastic recovery under the different conditions and hence are suitable for moving joints and harsh weather conditions. The polyurethane sealants have shown relatively high elasticity, although lower than that of silicon sealants. The polysulphide sealants have shown lower recovery values compared to polyurethane and silicon. However, the polysulphide sealants are able to withstand heat beller than some of the polyurethanes. The results reflect the importance of using the right types of sealant for different environmental conditions. The experimental results show that the new on-site testing technique for elastic recovery of sealant is applicable, reliable and sensitive.