Investigations on the influence of manufacturing and curing effects on the properties of structural-glazing adhesives subjected to tensile stresses

Demand for structural glazing joints has increased considerably in recent years due to the ever-increasing loads resulting from growing dimensions, especially in spectacular glass structures. Within the scope of planning and production monitoring, existing influences are analyzed based on the standard H-sample from the current structural glazing guidelines. These guidelines do not define any specific methodology or guidance for manufacturing test specimens. For determining load-bearing properties, various parameters, such as specimen age and curing condition, have a relevant influence during and after manufacturing. This study aims to investigate the manufacturing process for H-specimens systematically to identify and minimize the interfering influences. On this basis, the influence of the curing of modified H-specimens was investigated in detail for specimens under tensile load. Next to curing at room temperature, tempering at 40 °C was investigated for two different H-joint geometries. Thereby, a relevant influence of specimen age and different curing conditions on the strength as well as stiffness properties could be determined. As one result of the study, the curing time can be shortened by tempering the specimens in relation to the specified 28 days by ETAG 002-1. For calculation methods used in practice, like the structural spring method, suggestions for statistically validated strength and stiffness parameters representing the load-bearing behavior are proposed, considering the adhesive’s curing state and the joint’s nominal stress.