Correlation of ASTM C1135 to Structural Testing for Curtain-Wall Applications

The purpose of the research presented herein is to correlate structural sealant laboratory test methods with structural test methods for full-scale curtain-wall mockups. Glass panels were adhered around the perimeter of the glass to extruded anodized aluminum frames using multi-component structural silicone sealants. This is considered “four-sided structural silicone glazing.” These panels were tested and deflection was recorded at various typical wind load pressures (in the spirit of ASTM E330: Standard Test Method for Structural Performance of Exterior Windows, Doors, Skylights and Curtain Walls by Uniform Static Air Pressure Difference, ASTM International, West Conshohocken, PA, 2014, www.astm.org) during multiple cure times of the adhesives. The data has been compared to ASTM C1135 (Standard Test Method for Determining Tensile Adhesion Properties of Structural Sealants, ASTM International, West Conshohocken, PA, 2011, www.astm.org) specimen testing performed at the same cure times. The goal of the research was to better understand how well ASTM C1135 characterizes sealant behavior; and use the data as a platform to predict the performance of full-scale construction. By validating structural performance with cure time, assurance of the structural silicones' integrity during transportation to the site can be confirmed. This data set also took into consideration the time needed for removal of temporary fasteners during a replacement of broken glazing on an existing structure. A unique observation concluded that temporary fasteners could in fact be removed within 1 day of application depending upon site conditions. Two sealants were considered in the testing: a conventional two-part, 10:1 ratio structural silicone sealant that has been in use in commercial glazing for 30 years and a new 1:1 ratio two-part, structural silicone sealant that is currently available in hand-held packaging.