【作者】 张奕；

【导师】 金伟良； 赵羽习；

【作者基本信息】 浙江大学 ， 结构工程， 2005， 硕士

【摘要】 我国人口众多建筑密集，是火灾多发国家之一。每年火灾都给我们造成巨大的生命财产损失。在提高建筑物防火能力的同时，研究制定完备的灾后建筑物的鉴定标准、提高灾后建筑物的再利用率，成为减少火灾带来财产损失的一个关键问题。因此对于占建筑物中绝大多数的混凝土结构在火灾后的性能研究就显得尤为重要。 长期以来，火灾后混凝土结构的试验研究主要集中在材料的强度和结构的整体刚度和稳定性上，存在着重视结构的“安全性”和“适用性”，而轻视“耐久性”的问题。在这种思维下进行的灾后维修加固工程就存在耐久性隐患，这种隐患在日后的使用中逐渐暴露，进而使结构在维修有效使用年限内提前失效，造成了维修成本的巨大浪费，进一步加重了火灾给国民经济带来的损失。因此，有必要对火灾后混凝土结构耐久性领域进行深入的研究，制定相应的耐久性评估标准来指导灾后的维修工作。本文将混凝土结构耐久性问题扩展到火灾后混凝土结构耐久性领域中，提出了火灾后混凝土结构耐久性评定方法。具体来说，研究工作可以分为以下几个部分： (1) 分析混凝土结构耐久性中常见的氯离子侵蚀、碳化等问题在火灾条件下新的表现形式，结合国内外既有的研究成果，提出控制火灾后混凝土耐久性寿命的关键因素。 (2) 分析氯离子侵蚀原理和经典的氯离子扩散微分方程，推导火灾后混凝土结构在不同使用环境中内部氯离子扩散分布方程，为评定灾后混凝土结构抵抗有害介质侵蚀的耐久性寿命提供理论依据。 (3) 采用目前最为先进可靠的测定氯离子扩散系数的方法—RCM法测定各种标号混凝土在各种高温条件下的氯离子扩散系数以及其随时间的衰减系数，使利用推导的氯离子扩散模型来推算灾后混凝土结构耐久性寿命的方法成为可行。 (4) 分析火灾导致混凝土中性化机理，引入火灾条件下混凝土中温度场分布理论，提出火灾后混凝土结构碳化剩余寿命评估方法。 此外，还分析其它较为普遍的耐久性问题在火灾后混凝土结构中存在的可能性。从而全面地分析了火灾后混凝土结构存在的耐久性问题，提出了相应的耐久性寿命估算方法，填补了国内外在火灾后混凝土结构耐久性评估领域的空白，完善了灾后混凝土结构评估体系。更多还原

【Abstract】 Every year there is a tremendous number of fire hazards in our country for the huge population and crowed buildings, which cause multitude loss to our country. In first place, many should be done to improve the ability of the buildings to resist fire. And secondly criterions should be laid down to assess the post-fire buildings because improving the rate of building reusing is also a key to reduce fire caused loss. To lay down criterions, researches on the performance of the concrete structure after fire hazard are especially important because majority of the structures are made in concrete.Early research work about the concrete structures after fire focus on the strength of the material and the stability of the whole structure, which causes most of the cares being taken around the "strength" and "flexibility". However, the "durability" of the concrete structure is often ignored. The repairing of the post-fire buildings under the direct of this thought always causes the hidden problem of "durability". As time going on, the hidden problem will gradually come out to invalid the structure, which will cause the waste of repairing expense and intensify the loss to the National Economy. So it is necessary to study on this field and lay down criterions of assessment of the durability of the post-fire concrete buildings to direct the repairing engineering. On the base of the achievements of past researches, this paper extends the study on the durability of concrete structure to the field of durability of the post-fire concrete structure. Assessment methods for the durability of the post-fire concrete structure are put forward to complement the assessment system. Main research contents in this paper are posed as follows:(1) Analyze the new mechanic of common durability problems such as chloride erosion and carbonization etc in the field of the durability of post-fire concrete structure. By combining the achievements of home and abroad, put forward the key factors which influence mostly the durability of post-fire concrete structure.(2) Analyze the mechanic of chloride erosion. Based on the classic diffusion equation, derive the equation of chloride ions distribution in the post-fire concrete structure in different using environment, which is the theoretical basis of assessing the durability life span of the post-fire concrete structure.(3) Measure the chloride ion’s diffusion coefficient of the concrete suffered from different high temperature and its corresponding recovery coefficient by the most advanced and reliable method available at present (RCM method), which makes it possible to use the derived equation to assessing the durability life span of the post-fire concrete structure.(4) Analyze the mechanic of the neutralization of concrete suffered from fire. By applying the theory of temperature field here, derive the equation on the assessment of the structure’s remnant life span because of carbonization.In addition analysis is also done about the other durability problems which may happen to the post-fire concrete structure. In doing so, the durability problems about the post-fire concrete structure are detected all-sided, correspondingly, the method of assessment of structure’s life span is also present, which fill the blanks of the field of assessment of the post-fire concrete structure’s durability, and perfect the assessment system of post-fire structure.更多还原