再生混凝土碳化模型与结构耐久性设计

Carbonation Model and Structural Durability Design for Recycled Concrete

通过分析现有模型并结合各国试验结果,建立了再生混凝土碳化深度的计算模型。在此基础上提出了极限状态法和分项系数法2种再生混凝土结构耐久性的设计方法,并对再生混凝土梁使用寿命进行了可靠度分析。结果表明:增大再生混凝土强度等级和再生混凝土保护层厚度可以明显提高再生混凝土构件的耐久性;受力状态、钢筋位置对再生混凝土构件的耐久性有重要影响。综合考虑再生混凝土中钢筋开始锈蚀对结构使用功能的影响程度和再生混凝土的不同受力状态,提出了上海地区再生混凝土构件中钢筋的最小保护层厚度。

Based on the investigation of available achievements on carbonation of recycled concrete and concrete carbonation test data at home and abroad, the calculation model of recycled concrete carbonation depth was established and the limit state method and the partial safety factor method for recycled concrete structures were put forward. The reliability analysis of service life for recycled concrete beams was undertaken. Results show that the increase of compressive strength grades of recycled concrete and thickness of recycled concrete cover can improve the durability life of recycled concrete structures remarkably; while stress state of recycled concrete and the placement of reinforcing bars will have significant effects on the durability life of recycled concrete structures. Comprehensively considering the effect extent of carbonation-initiated corrosion of reinforcement on the functionality of recycled concrete structures and the different stress states of recycled concrete elements, the minimal thickness of recycled concrete cover of reinforcement in recycled concrete elements was proposed in Shanghai area.