[摘要]近年来，我国在海工高性能混凝土及海工混凝土使用寿命预测的理论研究取得了一定进展,但是在这方面的工程应用技术研究成果尚未出现。本文从工程应用的角度，在对杭州湾地区既有海工混凝土工程作实地调研的基础上，研究分析杭州湾地区既有海工混凝土结构的腐蚀特点和破坏原因；以海工高性能混凝土为研究对象，着重研究复合胶凝材料体系对混凝土性能的影响，并应用激光粒度仪、EMPA等分析手段，就复合胶凝材料的作用机理进行初步探讨；试验研究混凝土暴露时间、胶凝材料对氯离子的吸附、环境温度、应力和裂缝状态等因素对混凝土中氯离子迁移运动的影响，并结合国内外相关研究报导，探讨这些因素在混凝土使用寿命预测模型中的表征；在上述研究基础上，提出以氯离子侵蚀为基础的海工混凝土使用寿命预测的工程应用模型。
本文创新性研究工作及主要研究结论有：
1．研究分析了杭州湾地区既有海工混凝土结构的腐蚀特点和破坏原因，认为，海洋环境下，氯离子侵蚀是引起混凝土结构破坏，决定混凝土结构使用寿命的最主要的也是至关重要的原因。而混凝土保护层厚度和氯离子表观扩散系数的波动也在很大程度上决定着混凝土结构的使用寿命。
2．研究了复合胶凝材料体系对混凝土性能的影响。结果表明，矿物掺合料的掺入可以极大地改善混凝土的性能，特别是抗氯离子侵蚀性能，从而提高混凝土结构的使用寿命。应用激光粒度仪、EMPA等分析手段，就复合胶凝材料的作用机理进行初步探讨，发现不同矿物掺合料的复合可以发挥其各自特长。由于其交互叠加效应的作用，复合掺合料对混凝土性能的改善，特别是对抗氯离子侵蚀性能的改善比单一掺合料更为优越。
3．试验研究了混凝土中氯离子迁移的多种影响因素。研究表明，暴露时间、胶凝材料对氯离子的吸附作用、混凝土保护层应力和裂缝状态、环境温度等对混凝土中氯离子的迁移均有较大的影响，这些影响因素可以通过对氯离子表观扩散系数的修正来表征，将其引入使用寿命预测模型。
4．在海工混凝土使用寿命模型的研究中，以Fick第二定律为基础建立了基本数学模型，引入混凝土氯离子扩散系数的时间修正因素、温度修正因素、应力和裂缝状态等修正因素，并结合可靠度理论，从而建立了海工混凝土寿命预测模型及其计算软件SLPMC。
现场调查研究杭州湾地区既有海工工程的使用状态，获得必要的现场检测数据，为高性能混凝土在海工工程中的应用提供了科学依据。
研究复合胶凝材料在海工高性能混凝土中的应用，探讨复合胶凝材料的作用机理，对于促进矿物掺合料的高效利用、海工高性能混凝土应用技术水平的深化、加速混凝土掺合料技术发展有一定的经济、技术和社会意义。
研究分析各种因素对混凝土中氯离子迁移的影响，并在前人研究成果的基础上，建立以氯离子侵蚀为基础的海工混凝土使用寿命预测的工程应用模型及其计算软件，可以用于海洋环境下的混凝土结构或构件的使用寿命预测，为拟建海工建筑物的耐久性设计提供指导性意见，对建设中的海工工程质量控制体系的建立提供必要的依据，就现存海工工程的使用寿命进行预测，并制定相应的维护措施和修补方案，因而具有一定的实用价值。
ABSTRACT
In the past few years, much progress has been made in the theory study of HPC used in Marine and the prediction of its service life, but few has been achieved in engineering application technique of these theories. From the angle of engineering application, this article analysed the corrosion characteristics and damage causes of the current structural used concrete in the region of Hangzhou gulf， on the basis of on-site survey of all the Marine concrete projects in that area. Taking HPC used in Marine as research objective, this article put great emphasis on the influence of the composition cementing material system to concrete performance, and make a preliminary probe into the action mechanism of the composite effects of various mineral materials in improving the performance of concrete by laser measuring size machine and EMPA. Through experiments, the article discussed how chloride ingression in concrete will be effected by such factors as exposure time, chloride binding, environment temperature, stress and cracks conditions; and also analysed the symptoms of these factors in the model of concrete service life prediction by conference to all related research reports both home and aboard. On the foundation of abovementioned research, this paper brought up an engineering model of service life prediction of marine concrete, which is based on chloride-induced corrosion.
The innovative research work and main conclusion are as follows:
1. The corrosion characteristics and damage reason of the current structural used concrete in region of Hangzhou gulf have been studied and analysed. It is suggested that, under marine environment, chloride ingression is a main cause to the concrete construction breakage and therefore mostly determined the service life of concrete construction. The service life of the concrete construction is also in a large extent decided by the flunctuation of the thickness of concrete cover and the apparent diffusion coefficient Da of chloride.
2. The influence of the composition cementing material system to concrete performance has been studied. The research results indicated that the performance of concrete, particularly the performance of resistance to chloride ingression, has been greatly improved by adding various reactive mineral materials, such as ground granulated blast furnace slag, fly ash and silica fume. As a result, the service life of the concrete construction will also be lengthened. The action mechanism of the composite effects of various mineral materials in improving the performance of concrete has been researched by the application of laser measuring size machine and EMPA. It is found out that those mineral materials composite could bring mutual advantages into action. With composition of those mineral materials, the concrete performance, particularly the performance of resistance to chloride ingression, has been improved more than any one of them alone.
3. Experiments show that chloride ingression in concrete is influenced by many factors. The research indicated that chloride ingression is largely determined by exposure time, chloride binding, environment temperature, stress and cracks conditions, the symptoms of which could be found with the modifier of the apparent diffusion coefficient Da of chloride, in the model of concrete service life prediction.
4. In the research of the model of the service life prediction of marine concrete, the Fick’s II laws is taken as the basic mathematics model, considering the effect elements, such as exposure time, chloride binding, environment temperature, stress and cracks conditions, and united reliability analysis method, which established the model of the service life prediction of marine concrete and its calculation software SLPMC.
It provided scientific evidence for HPC applied in marine concrete by acquiring the necessity experiment data by the spot investigation to study the usage appearance of the current structural used concrete in region of Hangzhou gulf.
It has a certain economical, technical and social meaning to promote an efficient use of mineral admixture so as to deepen the technique level of HPC applied in marine concrete, and accelerate the development of concrete admixture technique through the study of the composition cementing material system applied to HPC in marine and the discussion of the action mechanism of the composite effects of various mineral materials in improving the performance of concrete.
The engineering application model of the service life prediction of marine concrete based on chloride-induced corrosion and its calculation software is established in this article by analysing all factors influencing chloride ingression and referring to some other researchers conclusions. All of those conclusions can be used to predict the service life of concrete in marine environment, provide a guiding idea for the endurance design of marine project intending to build, offer necessity basis for establishing of quantity control system of marine project in building, and predict the current structural used concrete in marine so as to establish relevant maintenance and repair scheme. In this way, it is also expected to have a certain practical meaning.
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