混凝土表面碳化与应力腐蚀关系的实验研究

Experiment Study on Relation of Concrete's Carbonized Layer and Stress Eroding

因高龄混凝土表面碳化,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 a的混凝土建筑的调查检测与室内实验,分析高龄混凝土结构表面碳化发展机理。介绍了高龄混凝土回弹值与表面碳化深度的调查分析、碳化深度与强度的实验对比、表面碳化对混凝土梁承载能力的影响实验。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实验依据。

Based on that carbonization destroys passivation membrane and the transition from brittleness to plastic for concrete's carbonized layer,crack spread brings the rusting of reinforcing bar,and carrying capacity fall.The paper analyses the cause of the old concrete's crack spreading by survey and experiment to many old buildings.Key elements have been presented including the investigation and analysis of resilience number of the old concrete and surface carbonization depth,the experimental contrast between the depth and the strength of carbonization and the test of concrete bearing force influenced by surface carbonization.The result indicates that the surface carbonization speed of normal concrete is linked close to the condition of structure stress.Only the concrete in the low stress condition that can gain the excellent service time.The result supplys the gist for evaluation to life-span of concrete.