Expansive fracture agent behaviour for concrete cracking
Expansive fracture agent behaviour for concrete cracking
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DOI：
10.1680/macr.2010.62.6.443
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发表时间：
2010-06-01
影响因子：
2.7
通讯作者：
Wortman, J.
中科院分区：
文献类型：
--
作者：
Laefer, D. F.;Ambrozevitch-Cooper, N.;Wortman, J.
对诉讼和恐怖主义的日益关注为减少建筑业使用烈性炸药提供了强大的双重动机。本文提供了参数的考虑和初步准则的应用，膨胀断裂剂，通常用于混凝土和软岩拆除。这种方法在环境和历史敏感地点附近可能特别适用。三十三个未加固块（约四分之三立方米）的不同强度，由砂，水泥，粉煤灰，在不同的温度环境下进行了测试，不同的膨胀剂，限制水平和后开裂处理。分析了裂纹的萌生和扩展等开裂特性。尽管膨胀水泥的性能取决于一组高度复杂的变量相互作用，但较高的环境温度、较高的试剂混合物温度和为较冷温度设计的化学配置减少了首次开裂的时间并加速了开裂的程度。相反，较高强度的材料需要更多的时间来第一次开裂，以及延长的时间来实现25.4 mm宽的裂纹。对正常材料体积膨胀的手动干预减缓了开裂过程，但没有截断它，而制造商建议在开裂后引入水实际上减少并减缓了开裂的程度。
Increasing concerns regarding litigation and terrorism provide a strong dual motivation to decrease high explosives usage in the construction industry. This paper provides parameter considerations and initial guidelines for the application of expansive fracture agents, typically used for concrete and soft rock removal. This approach may be especially appropriate near environmentally and historically sensitive sites. Thirty-three unreinforced blocks (approximately three-quarters of a cubic metre each) of varying strengths, composed of sand, cement, and fly ash, were tested under various temperature environments, with differing expansive agents, confinement levels and post-cracking treatments. Cracking characteristics such as crack initiation and crack expansion were analysed. Although the performance of expansive cement was dependent on a highly complex set of variable interactions, higher ambient temperatures, higher agent mixture temperatures and chemical configuration designed for colder temperatures decreased the time to first crack and hastened the extent of cracking. Conversely, higher strength material required more time to first crack, as well as an extended time to achieve a 25.4 mm wide crack. Manual interference with the normal material volume expansion slowed the cracking process but did not truncate it, while the manufacturer's recommendation to introduce water post-cracking actually reduced and slowed the extent of cracking.