【作者】 杜应吉；

【导师】 梁正平； 蔡跃波；

【作者基本信息】 河海大学 ， 结构工程， 2005， 博士

【摘要】 混凝土耐久性研究如何从定性化过渡到定量化、耐久性指标如何合理反映原型混凝土工程的实际状况、多因素作用下如何评价混凝土耐久性和预测其耐久寿命、对于地铁工程特有的杂散电流导致的钢筋锈蚀如何从材料角度予以降低,这是目前混凝土研究领域的重要课题。 本文结合“南京地铁工程高性能混凝土试验研究”项目,进行了高性能混凝土的物理力学性能和混凝土碳化、氯离子渗透、杂散电流以及硫酸盐侵蚀等方面试验研究,通过研究得出了以下结论: (1) 建立了混凝土碳化模拟试验的相似关系和试验方法;试验表明,碳化速度随着粉煤灰和磨细矿渣掺量增加而加快;混凝土碳化模型试验能较好反映工程实际。 (2) 建立了以抗折强度为指标,综合考虑硫酸根浓度、水胶比等因素的抗硫酸盐侵蚀耐久寿命预测模型;预测结果说明南京地铁工程所选用的C30高性能混凝土具有很强的抗硫酸盐侵蚀能力。 (3) 降低水胶比,有利于提高混凝土抗氯离子渗透性能;分别单掺或双掺粉煤灰和磨细矿渣,均可以降低混凝土氯离子扩散系数,且双掺优于单掺。 (4) 分别单掺或双掺粉煤灰和磨细矿渣,均可以降低混凝土杂散电流腐蚀;双掺混凝土杂散电流可减少到同水胶比普通混凝土的1/5,显著降低了地铁混凝土的杂散电流腐蚀。 (5) 运用模糊多属性决策理论,进行多因素下混凝土耐久寿命评价,结果表明:最佳配合比为双掺55%粉煤灰和磨细矿渣的配合比;南京地铁工程所选用的C30高性能混凝土的耐久寿命均大于100年。更多还原

【Abstract】 The durability of concrete is an important subject in concrete research field. But how to transit it from qualitative analysis to fix quantitative analysis? How can the durability index reflect the actual state of the concrete construction? How to give a overall evaluation of the durability and service life of the concrete under multi- actions? How to decrease the steel corrosion induced by the stray current through the material design? All these problems need the further study.Combining the project of the experimental study on Nanjing subway HPC, the physical and mechanical properties of HPC (C30) are studied. The concrete carbonation, the chloride ions ingress, the stray current corrosion, the sulfate attack on concrete and so on are also studied. From the test results, several conclusions can be drawn as follow:Firstly, the analogical relation and test method of concrete carbonation are built. The test result shows that the carbonation speed increases with the addition of fly ash and mineral powder. The model of concrete carbonation can reflect the actual state very well.Secondly, considering the thickness of sulfate ions, water- cement ratio and other factors, the prediction model of sulfate resistance is built, which choose the flexural strength as the evaluation index. The prediction result shows that concrete of Nanjing subway construction has the strong ability of sulfate resistance.Thirdly, decreasing the water- cement ration is helpful to improve the ability of concrete to resist the chloride ions ingress. Adding fly ash or adding both fly ash and mineral powder can reduce the chloride diffusivity coefficient, and adding both fly ash and mineral powder is better to reduce the chloride diffusivity.Fourthly, adding fly ash or adding both fly ash and mineral powder can decrease the corrosion caused by stray current. Adding both fly ash and mineral powder can decrease the stray current to only one- fifth of the normal concrete with the same water- cement ratio, so the corrosion caused by stray current can be evidently decreased.Lastly, using the fuzzy various attribute decision-making theory, an overall evaluation of the durability life of the concrete can be made. The result shows that adding both fly ash and mineral powder is the best proportion and the subway C30 HPC’s overall durability life is longer than 100 years.更多还原