Development of an Apparatus for Measuring the Load Acting on Joint Sealant when Movement Occurs

Abstract

The sealant that fills the joints of an exterior walls of building is subjected to weather loads, such as sunlight, ambient temperature, and rain, as well as a movement of the joints. As a result, the sealant gradually deteriorates under the combined deterioration factors of weathering and movement. Meanwhile, the results of a 15-year outdoor dynamic exposure test conducted in Japan using the methodology of ISO 11617 showed that the progress of damage varies greatly depending on the type of sealant and the stress relaxation rate. However, the mechanism of damage progression is unclear. In the present study, we focused on the load when the sealant moves and developed a load-measuring apparatus as the first step in clarifying the relationship between the progress of damage and the load. The load was measured at −20, 23, and 40 °C for test specimens with different stress relaxation rates, and it was confirmed that the developed load-measuring apparatus was able to measure the load correctly. Furthermore, it was shown that it is difficult for the stress of the sealant with a high stress relaxation rate to relax over time at low temperature but easy at high temperature, and the load increases when switching from the compressed state to the extended state.

Full document