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For the building envelope, the flexible caulking materials are generally applied for the watertight requirement between the interface of concrete and curtain wall. Most of these sealants are low modulus organic materials but not permanent materials. Once they were improperly selected for construction either material itself or application, it occurs the risk of the gradual deterioration for watertightness under the influence of natural factors and human factors. The current water testing specification, AAMA 501.2, is a popular test method for the jobsite. The test concentrates on a specific area in a limited testing period. The testing result is a visual inspection and not a quantifiable measurement. The result might be a misevaluation caused by negligence. As to the deterioration of sealants in a long term harsh environment, it is hard to be inspected by this test.
Testing result discussed here was based on the modification of the water testing method. Formatted concrete specimens were applied with different sealants and kept under a simulated rainfall condition. The watertight performance of each specimen was inspected and recorded separately. According to the various results, it was recognized that even no water leakage was inspected; the relative humidity was increased to a critical level for indoor air quality. When the relative humidity was increasing to 100% for five minutes, no water leakage was inspected either by optic or instrument. Therefore, it is believed that the modification of AAMA 501.2 is more suitable for real watertight performance testing. This research concludes that a successful curtain wall should consider an appropriate treatment for concrete and a suitable selection for the sealant. The conclusion and suggestion in this research is willing to be an applicable reference for both the metal curtain wall construction and the watertight performance testing.
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