THE EFFECT OF BUILDING JOINT MOVEMENTS ON OUTDOOR PERFORMANCE OF SEALANTS DURING THEIR CURE : Part 1. Studies in the prevention of failures of sealant in building joints

Due to changes in environmental conditions, such as temperature, building joints move continually. Accordingly, sealants in joints are subjected to such movements from the time they are applied. Failures of sealant in joints, such as crack, breakage and deformation particularly those which occur in the short period of time after a sealant has been applied may be caused by the movements of joints during the sealant curing. To study the relation between failures of sealant and the movement of joints, the following were pursued : (1) Development of a strain-cycling exposure rack. (2) Exposure of various types of sealant using the exposure rack. (3) Observation of sealant failures caused by the exposure. (4) Consideration to the relation between the types of failures and the types of sealant. (5) Study of the factors which affect failures of sealant. (6) As a result, a new testing method for outdoor sealant performance which takes into consideration the curing period is proposed.