Cover cracking in reinforced concrete elements due to corrosion
Cover cracking in reinforced concrete elements due to corrosion
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DOI：
10.1080/15732479.2010.505376
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发表时间：
2012-06
影响因子：
3.7
通讯作者：
D. Val;L. Chernin
中科院分区：
文献类型：
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作者：
D. Val;L. Chernin
本文考虑钢筋锈蚀引起混凝土保护层裂缝萌生的解析模型。首先，对描述这一现象的现有分析模型进行了批判性的回顾。然后提出了一个新的分析模型，并用已有的实验数据进行了校准。该模型基于厚壁圆筒方法。为了解决混凝土保护层的部分开裂问题，圆柱体被分为两部分--有裂纹的内筒和未开裂的外筒。该模型确保了内筒和外筒内的应力-应变公式是一致的，并且能够实现圆筒之间边界上的应力和应变的完全连续，这有别于以前发表的分析模型。然后，该模型被用来估计在混凝土保护层完全开裂之前，已经扩散到混凝土孔隙和裂缝中的腐蚀产物的数量。结果表明，这一数额可能比之前假设的要大。研究还表明，假设腐蚀产物只扩散到混凝土中，直到它们完全填满钢筋周围的所谓“多孔”区域，这将导致从物理角度难以解释的结果。提出了一种解释腐蚀产物扩散到混凝土中的替代方法。最后，考虑了腐蚀速率随时间降低的可能性及其对裂纹萌生时间预测的影响。
The article considers analytical modelling of crack initiation in the concrete cover caused by corrosion of reinforcing steel. Initially, existing analytical models describing this phenomenon are critically reviewed. A new analytical model proposed by the authors is then presented and calibrated against available experimental data. The model is based on a thick-walled cylinder approach. To account for partial cracking of the concrete cover the cylinder is divided into two parts – a cracked inner cylinder and an uncracked outer one. The model ensures a consistent stress–strain formulation within both the inner and outer cylinders and enables to achieve complete continuity of stresses and strains on the boundary between the cylinders that distinguish it from the previously published analytical models. The model is then used to estimate the amount of corrosion products, which have diffused into concrete pores and cracks before full cracking of the concrete cover. It is shown that this amount may be larger than has been previously assumed. It is also shown that the assumption that corrosion products diffuse into concrete only until they fully fill the so-called ‘porous’ zone around a reinforcing bar leads to results, which are difficult to explain from a physical point of view. An alternative approach to account for the diffusion of corrosion products into concrete is proposed. Finally, a possible decrease in the corrosion rate with time and its influence on the prediction of the time to crack initiation are considered.