Shear property of structural epoxy adhesive exposed to tropical weathering condition

Abstract

As a consequence of tropical climate featuring abundant rain and sunshine throughout the year, adhesive bonded joints undergo substantial exposure to moisture and elevated temperatures. It is known that the degradation of adhesive materials such as structural epoxy due to weathering could affect the overall bond performance of structural integrity of reinforced concrete such as carbon fibre reinforced polymer composites (CFRP) plate system. The objective of the study is to investigate the in-plane shear properties of structural epoxy material exposed to tropical environmental conditions using Arcan Test Method. The epoxy adhesive was casted in a closed metal mould to produce butterfly shaped specimens. The specimens were exposed to four conditions; laboratory, outdoor, plain water, and salt water. The specimens were tested for shear properties and failed in brittle form. Microstructure analysis was performed to study the fracture surface of the test specimens. The study showed that the tropical exposure conditions influenced the shear strength of the epoxy material, especially for those exposed to plain and salt water conditions, which were 32% lower than the control specimen for specimens exposed to plain water followed by salt water (26.6%), laboratory (25.4%) and finally outdoor (18.4%).