Breakout test for dimension stone cladding with epoxy bond

Dimension stone claddings, widely used as nonstructural exterior finishes on apartment buildings, low-rise public facilities, and high-rise facades, are typically installed using dowel pin connections in accordance with construction specifications. However, the use of epoxy bonding has been increasingly observed in the field, often being applied sorely and in violation of standard guidelines. To assess the structural safety of epoxy bonding, this study conducted unit joint tests by varying key parameters: connection type, epoxy width, bonded length, and chemical treatment conditions. Test results revealed that the primary failure mode of epoxy joints was detachment at the interface between the epoxy and the angle surface. The maximum strength of the joints generally increased with the epoxy adhesion area, and the influence of epoxy width on strength was found to be more significant than that of the bonding length. Additionally, breakout tests under accelerated weathering conditions demonstrated that environmental degradation of epoxy durability had a substantial impact on joint performance. While epoxy-only connections exhibit limited reliability and durability, combining epoxy with dowel pins significantly enhances performance. These findings highlight the importance of proper application methods and durability considerations when epoxy bonding is used in stone cladding installations. • Breakout tests evaluated epoxy-bonded joints in stone cladding without dowel pins. • Peak strength increased with epoxy bonding area, especially on the stone surface. • Epoxy-only connections showed large strength variability and reduced reliability. • Accelerated weathering reduced strength by up to 82%, highlighting durability risks. • Combined epoxy and dowel pins improved strength and reduced variability in failure.