Effects of Hygrothermal Environment on Tensile Capacity of Adhesive-injected Anchor Bolt of ALC Panel and ETICS

Abstract

The connection between the autoclaved lightweight concrete (ALC) and an external thermal insulation composite system (ETICS) is accomplished by anchors. The anchor is consisted of a connector and an anchor bolt, where the anchor bolt is an important force transmission element. Adhesive is used to install an anchor bolt, and significantly improves the anchoring force of the anchor bolt. However, the hygrothermal environment influences the adhesion of the anchor adhesive, which adversely affects the reliability and security of the ALC panel and ETICS connection. To investigate the effect of high temperature and a humid environment on the anchor bonding performance, 5 sets of durability tests were conducted. Each group of 15 specimens was tested for 0, 15, 30, 45, and 60 thermal rain cycles. The test results reveal that, as the number of cycles increased, the tensile capacity of the adhesive-injected anchor bolts decreased, and the capacity's discount factor decreased. The discount factors of the anchor bolt tensile load capacity values after 15, 30, 45 and 60 cycles were 85.5%, 72.1%, 56.2%, and 50.4%, respectively. A prediction model was established based on the relationship between the number of thermal rain cycles and the tensile capacity. Based on the anchor bolt tensile capacity requirements, the model can calculate the number of cycles over which the adhesive-injected anchor bolts need in a hygrothermal environment must be tested, reinforced, and replaced to ensure a good connection between the ALC panel and an ETICS.