Quantification of Effect of Dynamic Movement for Weatherability of Construction Sealants
Quantification of Effect of Dynamic Movement for Weatherability of Construction Sealants
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动态运动对建筑密封胶耐候性影响的量化
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
Kyoji Tanaka
中科院分区：
文献类型：
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作者：
榎本 教良;田中 享二;Kyoji Tanaka
建筑密封胶是保证建筑物外接缝防水功能的材料，密封胶的耐候性是维持接缝功能性能的一项非常重要的性能。密封胶劣化是一种受节理运动、环境因素等因素影响的复杂现象，其强度取决于区域气候。虽然许多与密封胶耐候性相关的研究已经完成，但密封胶表面退化的评估需要定量的性能标准。在这项研究之前，开发了一种新型的试验样品来评估密封胶的耐候性。试件的构造是这样的，即可以在单个试件上连续地施加接头的延伸和连接。对于密封胶表面退化的定量评估，使用了基于ISO 4628评估标准的公式。本研究采用的方法包括新的试件结构和ISO评估方法，用于定量评估因风化而导致的密封胶退化。密封胶的耐候性被认为由三个因素组成：在静态条件下的降解程度：由于关节运动而导致的降解速率增加，以及来自密封胶所暴露的地区气候的环境制剂的影响。在这项研究中，8种密封胶在日本山梨县进行了为期4年的耐候性测试。密封剂暴露在该位置的目的是为了排除区域环境因素对密封剂降解的影响。提出了一个函数方程，给出了在给定曝光时间后，密封胶在静态和动态条件下的表面退化指数。关于密封胶在该耐候性试验方案下的劣化情况，得到了以下结果：硅酮密封胶没有劣化，但改性后的硅酮密封胶在静态条件下略有劣化。增加关节运动大大加速了材料的降解。与本研究中评估的其他类型密封胶的降解相比，关节运动对聚氨酯密封胶的降解影响较小。
Construction sealants are materials that ensure the waterproofing function of external joints of building, and the weatherabilty of sealant is a very important performance to sustain the functional performance of the joint. Sealant deterioration is a complex phenomenon influenced by factors such as joint movement and environmental agents whose intensity depends on the regional climate. Though many studies related to the weatherability of sealants have previously been completed, the evaluation of the surface degradation of sealants requires quantitative performance criteria. Prior to this study, a new type of test specimen was developed to assess the weatherabilty of sealants. The configuration of the test specimen is such that extension and of the joint can be applied continuously on a single specimen. For the quantitative evaluation of the surface degradation of sealants an equation based on the ISO 4628 assessment criterion was used. The approach adopted in this study for the quantitative evaluation of sealant degradations due to weathering thus included the new test specimen configuration and the ISO assessment method. The weatherability of sealants was considered to be composed of three factors: degree of degradation in the static conditions: increased rate of degradation due to joint movement, and: effects of environmental agents derived from the regional climate to which the sealant is exposed. In this study, eight sealants, commercially available in Japan, were subjected to a 4-year weathering test program carried out in the Yamanashi Prefecture, Japan. The exposure of sealants in this location was intended to exclude the effects of regional environmental factors on the degradation of the sealants. A functional equation is proposed that gives a surface degradation index of sealants subjected to static and dynamic conditions after a given exposure time. The following results were obtained in regard to the deterioration of sealants subjected to this weathering test program: silicone sealants did not deteriorate, though modified silicone sealants deteriorated slightly in static conditions. The degradation was greatly accelerated by adding joint movement. The degradation of polyurethane sealants was less influenced by joint movements as compared to the degradation of other types of sealant evaluated in this study.