Weathering Evaluation of Structural Silicone Sealants Used in Korea

ABSTRACT: Super-tall buildings of over 100 stories are coming to Korea. To prove its economic prosperity, which was developed over the last 50 years af­ter the Korean War, Korea is willing to have super-tall buildings as a symbol of its success. Locally, structural silicone glazing has become very common to achieve aesthetically pleasing and high utilization of small land for both residential and commercial building. Because there has been no industry­wide guideline or specification for structural silicone sealants in Korea, it is worthwhile to look at the performance of locally available structural silicone sealants. In this paper, several weathering techniques were adapted from various global industry standards. Artificial weathering using filtered xenon arc radiation was applied to specimens prepared in accordance with ASTM C1135. Comparative evaluations for temperature variations and salt spraying exposure were conducted as well. Silicones in general are known to have excellent resistance to such exposure. However, since the weathering per­formance of a sealant can be affected by its overall composition (not just the polymer type), some silicone products showed noticeable changes in our testing when compared to their initial properties.

KEYWORDS: structural glazing, silicone, accelerated weathering, adhesive failure, tensile strength, Korea, one part, two part

Introduction

Silicone structural glazing (SSG) is a method utilizing a silicone adhesive to attach glass, metal, or other panel material to the structure of a building. Wind load and other impact loads on the facade are transferred from the glass or

panel through the silicone structural sealant to the systems’ framework. Silicone structural glazing systems are currently a very common method of glazing throughout the world. SSG use has become extremely popular, and its principal advantages include the freedom SSG presents to architects by providing infin­itely more facade design options, as glass and panels no longer must be secured to the facade with mechanical methods. It also offers economical benefits to the contractors and fabricators by increasing productivity in assembly and installa­tion. For these reasons and performance benefits that SSG provides to the over­all glazing system, including waterproofing, acoustic, and thermal benefits, most landmark projects in the world utilize this attractive glazing technology.