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Degradation Process and Life Span Estimation of Marine Concrete Structures

海洋混凝土结构的退化过程和寿命估算

基本信息

批准号：
09305032
负责人：
MIYAGAWA Toyoaki
金额：
$ 16.13万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09305032/
关键词：
Marine Concrete Structure Degradation Process Life Span Estimation Chrolide Corrosion High Performance Concrete Fiber Sheet Confined Concrete Construction Joint 海洋コンクリート繊維補強コンクリート

项目摘要

In this study, in making width volume ratio of confinement, existence of the CFRP sheet reinforcement, placing joint of the concrete including the salinity on the assumption of the macrocell corrosion, use of high workable concrete to be a factor, reinforcement corrosion of the RC flexural member in the salt water sprinkling accelarating environment was monitored. Results got are as follows.(a) The axial crack of width over 0.2mm and over several length has been all generated in specimens under salt water sprinkling at present. Though the difference of the crack by rho_s was not clear, in the CFRP sheet specimen, the crack width tended to be small. Both crack width and length of the high workable concrete specimen tended to be larger than the plain concrete(b) From corrosion loss rate of the bending span of the degraded specimen by AC corrosion monitor, more corrosion loss rate was observed in those specimens with confinement. Corrosion loss rate of the CFRP sheet reinforcement specimen comparatively small, It is due to the shielding of the salinity by the restraint of the crack in addition to the surface coating of the CFRP sheet.(c) Judging from aging of corrosion rate by the rectangular wave corrosion monitor, corrosion rate once increases on the dispersion from the axial cracking (around 97/7) and it tends to decrease afterwards. The increase is due to the crack propergation and the decrease is due to plugging of corrosion product.

本研究在设定约束宽度体积比、CFRP片材配筋的存在、在假定大细胞腐蚀的前提下，考虑盐度、采用高工效混凝土等因素，对钢筋混凝土受弯构件在盐水洒水加速环境下的钢筋腐蚀进行了监测。得到的结果如下：(a)目前在盐水洒水作用下，试件均产生了宽度在0.2mm以上、长度在数个以上的轴向裂缝。虽然rho_s对裂纹的差异不明显，但在CFRP片材试样中，裂纹宽度趋于较小。高工作面混凝土试件的裂缝宽度和裂缝长度都有大于素面混凝土试件的趋势(b)从交流腐蚀监测仪对退化试件弯曲跨的腐蚀损失率来看，有约束的试件的腐蚀损失率更大。CFRP片材增强试件的腐蚀损失率相对较小，除了CFRP片材的表面涂层外，还由于裂纹的约束对盐分的屏蔽作用。(c)从矩形波腐蚀监测仪对腐蚀速率的时效判断，腐蚀速率在轴向裂纹扩散时一度增加（约97/7），之后有减小的趋势。增加的原因是裂纹扩展，减少的原因是腐蚀产物堵塞。