Temperature Aging, Compression Recovery, Creep, and Weathering of a Foam Silicone Sealant for Bridge Expansion Joints
Temperature Aging, Compression Recovery, Creep, and Weathering of a Foam Silicone Sealant for Bridge Expansion Joints
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DOI：
10.1061/(asce)mt.1943-5533.0000166
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发表时间：
2011-03-01
影响因子：
3.2
通讯作者：
Brijmohan, Smita B.
中科院分区：
文献类型：
--
作者：
Malla, Ramesh B.;Shrestha, Matu R.;Brijmohan, Smita B.
研究了硅橡胶泡沫塑料作为桥面小伸缩缝密封胶的性能。本文介绍了一种模型泡沫密封胶在热老化(高、低温暴露和温度循环)、疲劳条件和室外气候条件下的实验室评估结果。在一种商用实心硅胶桥接密封胶上进行了平行试验。试验结果表明，固体密封胶在高温下长时间压缩后恢复快于泡沫密封胶。当承受恒定的拉力时，泡沫和固体密封胶都表现出较高的初始蠕变速率(伸长率)，但在较长时间内似乎达到平衡伸长水平。泡沫密封胶的蠕变速度较慢，达到平衡伸长率所需的时间较长，而固体密封胶的蠕变速度要快得多，达到平衡的速度也更快。热老化对密封胶的模数(随温度升高)有显著影响，但对两种密封胶的极限应力和应变影响不明显。在24到-29摄氏度之间的温度循环被观察到将两种密封剂的极限应力和应变降低了大约25%；但是，在模数方面没有发现明显的变化。对有限数量的室外风化密封胶试件的测试结果表明，风化似乎会导致密封胶的拉伸和剪切模数(即风化硬化效应)增加，而极限应变降低。风化后的试件表现出与未老化试件相似的拉伸加卸载行为。室外老化的密封胶的拉伸应力松弛速率与实验室固化(未老化)的密封胶没有区别。DOI：10.1061/(ASCE)MT.1943-5533.0000166。(C)2011年美国土木工程师学会。
Silicone foam was investigated as a sealant for small movement expansion joints in bridge decks. This paper presents results from the laboratory assessment of a model foam sealant subjected to thermal aging (exposure to high and low temperatures and temperature cycling), fatigue conditions, and outdoor weathering. Parallel tests were performed on a commercial solid-silicone bridge-joint sealant. Test results showed that the solid sealant recovered faster than the foam sealant after being subjected to prolonged compression at elevated temperature. When subjected to a constant tensile force, both the foam and solid sealants exhibited high initial creep rates (rate of elongation), but appeared to reach an equilibrium level of elongation at longer times. The foam sealant creeps at a slower rate and takes more time to get to the equilibrium elongation, whereas the solid sealant creeps much faster initially and reaches equilibrium faster. Thermal aging was found to have significant effects on the sealant modulus (increases with temperature); however, the effects on ultimate stress and strain were not apparent for both types of sealants. Temperature cycling between 24 and -29 degrees C was observed to diminish the ultimate stress and strain of both the sealants by roughly 25%; however, no significant changes in modulus were found. Results from the tests on a limited number of outdoor-weathered sealant specimens showed that weathering appeared to produce an increase in sealant tensile and shear moduli (i.e., hardening effects because of weathering) and a decrease in ultimate strain. The weathered samples show tension loading-unloading behavior similar to the unaged samples. The tensile stress relaxation rate of the outdoor-weathered sealants could not be distinguished from those laboratory-cured (unweathered) counterparts. DOI: 10.1061/(ASCE)MT.1943-5533.0000166. (C) 2011 American Society of Civil Engineers.