Fundamental Research On Durability Assessment And Quality Control Of Concrete Structure

The fundamental research on concrete durability is becoming one of the heated problems that are being discussed by scientists in engineering area and scholars at home and abroad. Especially with the increased amount of the aging concrete structures, the problem has been more and more serious. So how to ensure the concrete durability of newly-built structures and how to assess the status of present structures to make a decision become the practical problems which have to be urgently solved as soon as possible. Combining with the character of structures, this thesis gives a systematic and thorough study on some technical research of concrete durability .which includes:(1) Integrating with the research results in engineering, a fuzzy synthetical system has been established to assess the durability of concrete structures, which was on the basis of analyzing the major factors influenced concrete durability. Regarding the influencing factors as durability assessment factors, the model realized assessing the durability grade of structures by the way of fuzzy synthetical assessment theory(2) Considering design factors of concrete durability and incomplete massage during the process of design, an optimal proposal chosen model has been built which based on the grey relation theory. It supplies a theoretic basis for choosing an excellent design proposal.(3) Discussing the relationship between construction quality and structural reliability theories, this paper indicated that it was necessary to accomplish dynamic quality control during the construction process and then brought forward the dynamic quality control equation, which can fit for the material quality formula of the current standard and improve the quality control theories. A quality control method of concrete production process has been explored meanwhile.(4) Considering the time-variation of the resisting force and the load, reducing the random process to random variable, a structural reliability model has been built of aging structures by dispersion, which provides a more suitable pattern for analyzing reliability of aging concrete structures.(5) A damage assessment model has been created based on BP neutral network, this model exactly demonstrate the un-linear mapping relationship between influencing factors and assessment results, it can reflect the current status of damaged concrete structures also.