Silicone sealants have a long history of successful use in high performance windows and curtainwalls, such as structural glazing systems. With the recent threat of terrorist attacks, there has been an increased use of windows designed to mitigate the impact of bomb blasts. Due to the high strength and durability characteristics of silicone sealants, structural silicone sealants have been utilized in new bomb blast mitigating window designs. Effective bomb blast mitigating window designs allow the window system to withstand a moderate bomb blast without causing significant injury to building occupants from the blast itself or flying glass shards. The occupants are protected because laminated or filmed glass, which can withstand the blast, is attached in the framing with a silicone sealant. Silicone sealants provide unique benefits to these window designs due to their strength properties and their ability to anchor the laminated glass in the framing during a blast situation. In this paper, three commercially available high strength structural silicone sealants are evaluated at applied load velocities (movement rates) up to 5.0 m/s. These elevated load velocities are intended to simulate loads encountered during a bomb blast. Sealant joints are fabricated to evaluate the sealant in tension, shear, and combined tension and shear loads. Sealants joints are also exposed to accelerated weathering (heat, water, and artificial light through glass). Results show that the sealant strength values increase substantially at elevated rates of applied load. The paper discusses the effect of joint configuration, load velocities, and accelerating weathering on the performance and durability of the silicone sealants tested.

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The successful performance of exterior insulation and finish systems (EIFS) is related directly to the sealants used to weatherseal the EIFS and adjacent materials to EIFS. With millions of square feet of EIFS installed, proper restoration of EIFS joints can help ensure long-term watertight performance of the EIFS wall. A new test method that closely parallels ASTM C 1135—Test Method for Determining Tensile Adhesion Properties of Structural Sealants, is currently under consideration by ASTM Task Group C 24.20.12. This new test method allows sealant joints to be evaluated in many conditions to more closely simulate actual field conditions. This paper will focus on types of EIFS joint failure and possible causes for failure. Different restoration methods will be discussed with particular attention to the use of sealants to overlay failed sealant joints. A modification to the test method under review by ASTM Task Group C 24.20.12 will be used to evaluate various joint conditions with EIFS, including standard square joints, hourglassshaped joints, overlay joints with wet sealants, and overlay joints with performed sealants.