高龄混凝土表面碳化与应力腐蚀关系的调查与试验研究

Experimental study and survey on relation of eld concrete's carbonized layer and stress corrosion

基于混凝土表面碳化破坏了钢筋周围的钝化膜以及碳化层(CaCO3)随时间推移逐渐由脆性转为塑性,塑性裂纹扩展导致钢筋锈蚀,从而使得混凝土结构承载能力降低。通过对多栋在役80年的混凝土建筑的调查检测与室内试验,分析高龄混凝土结构表面碳化发展机理,结果表明:普通混凝土的表面碳化速度与结构应力状态密切关联,只有处于低应力状态的混凝土才有可能达到理想的在役年限。该结论对于正确评估混凝土结构的寿命提供了试验依据。

Based on that surface carbonization destroys passivation menbrane and the concrete＇s carbonizated layer（CaCO3） transfers from brittleness to plasticity gradually, the spreading of plastic crack causes corrosion of the steel bar,thus reduces bearing capacity of the concrete structure.The study analyse cause of the spreading of the eld concrete＇s crack by surveying and experimenting many eld concrete building.The result indicate：the spreading rate of concrete crack is linked to stress corrosion.Only in low stress condition the concret have the possibility to achieve in the ideal service age.The result supply the experimental basis to evaluate the life-span of concrete accurately.