Durability of Reinforced Concrete Structure Repaired by Desalination

海水淡化修复钢筋混凝土结构的耐久性

基本信息

批准号：
12450178
负责人：
MIYAGAWA Toyoaki
金额：
$ 6.85万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

Desalination is an electrochemical method aimed at removing chlorides from reinforced concrete structures. In this study, influences of applying desalination on durability and load-carrying capacity of RC structures were investigated.The results obtained in this study can be summarized as follows.(1) As results of the pull-out test, maximum bond stress of treated specimens was found to be smaller than that of non-treated specimens. The decrease due to desalination became larger with an increase in the amount of premixed chlorides or an increase in the total current density, because soft layers were formed around the steel bars due to passing of electric current.(2) According to the results of flexural test of beams containing 8.0 kg/m3 of C1, the change in the ultimate load was slight and the capacity of deflection increased at 8 weeks treatment.(3) In the case of flexural failure type beams, maximum crack width at the reinforcing steel level of specimens receiving 4 weeks treatment was less than that of non-treated ones. However, in some specimens treated for 8 weeks, maximum crack width at the reinforcing steel level was greater than the permissible crack width. Moreover, by applying desalination, the number of cracks was decreased and crack distribution became deteriorated.(4) Slow strain rate tensile tests on prestressing steel removed from treated PC prism specimens indicated no change in elastic behavior nor strength-related properties but the fracture behavior was altered by the absorbed hydrogen. For example, the falling branch in stress-strain curves was shortened and the contraction rate of fractured steel section decreased as compared with non-treated specimens.(5) As results of flexural loading tests on treated PC beams, the rupture of prestressing steel due to hydrogen embrittlement were not observed, and both load-displacement performance was not reduced by desalination, compared with the non-treated specimens.

脱盐是一种电化学方法，旨在从钢筋混凝土结构中去除氯化物。在这项研究中，研究了对RC结构的耐久性和负载能力的影响。该研究中获得的结果可以汇总如下。（1）作为拔出测试的结果，发现经过处理的标本的最大键应力小于未经处理的标本的结果。随着预混合氯化物的量增加或总电流密度的增加，由于脱盐而引起的下降变得更大，因为由于电流的传递，在钢筋周围形成了柔软的层。（2）根据包含8.0 kg/m3的光束测试的结果，C1的弯曲结果是C1的8.0 kg/m3，最终范围的变化是限制的限制和限制的最大范围。接受4周治疗的标本的钢筋钢水平的宽度小于未经处理的标本。但是，在某些经过处理8周的标本中，在钢筋钢水平上的最大裂纹宽度大于允许的裂纹宽度。此外，通过施加淡化，裂纹的数量减少并裂纹分布变化。（4）在从处理过的PC Prism样品中取出的预应力钢的缓慢应变速率拉伸试验表明弹性行为和强度相关性能没有变化，但与吸收的氢可以改变分裂行为。例如，与未处理的样品相比，应力应变曲线中的下降分支缩短，钢截面的骨折截面的收缩率降低。（5）作为处理过的PC梁的弯曲负荷测试的结果，由于氢交易置的普雷斯特钢破裂，并未观察到与载荷降低的性能相比，由于氢交易置均未降低。