Small-Scale Test of Transparent Adhesives in Glass Structures under Shear Stress and Their Ageing Resistance

Glass load-bearing structures, which have been popular in recent years, require careful attention to detail, because with improper design there is a concentration of stress leading to failure and subsequent collapse of the structure. Mechanical connections are mainly used but there are disadvantages such as stress peaks, weakening of the cross-section, or aesthetic reasons. Adhesive connections eliminate these disadvantages. The lack of information and standards about adhesives (except for silicones) obstruct their wide-ranging use. Especially problematic is an ageing of adhesive and its influence on the mechanical properties. This study is focused on experimental testing of two transparent epoxy adhesives that were used for small-scale specimens with float glass. Two sets of specimens were prepared for each adhesive. The first set was an unaged reference set, the second set was exposed to an artificial ageing method based on EN ISO 9142. The specimens were subjected to shear stress in a displacement controlled test. One adhesive showed good mechanical properties in the reference set, but resistance to artificial ageing was poor. The second adhesive does not achieve good mechanical properties in the reference set in comparison to the first adhesive. The artificial ageing method was devastating for the second adhesive. Poor mechanical properties of the second adhesive could be caused by the age of the uncured adhesive. The first adhesive can only be recommended for the interior where the adhesive is not exposed to aggressive environmental effects.