掺矿物掺合料水泥水化模型及其应用研究

发布时间：2018-01-19 03:05

本文关键词： 水化模型水泥浆体水化过程水化度微观结构粉煤灰矿粉 CH 化学结合水电阻率抗压强度湿度扩散　出处：《浙江大学》2014年硕士论文　论文类型：学位论文

【摘要】：建筑工程的耐久性问题需要人们对水泥基材料的水化过程有较好的认识。本文研究水泥净浆和掺矿物掺合料水泥浆体的水化过程,提出相应的水化模型,利用水化模型深入研究水泥浆体电阻率发展规律、混凝土抗压强度和湿度扩散发展规律。主要研究工作如下： (1)为了精确预测水泥水化过程,分析水泥水化过程中微观结构的时变发展规律,提出了水化单元的概念,基于水泥水化的微观信息,采用Krstulovic-Dabic水化反应动力学方程式,构建了水泥水化度与微观结构之间的联系,考虑了水灰比、水泥化学组分、孔隙水分、温度、水泥颗粒和水接触面积、水泥颗粒粒径分布等因素对水泥水化过程的影响,建立了改进的水泥水化动力学模型。在本研究中通过热重分析法、压汞试验、环境扫描电镜扫描(ESEM)等一系列试验方法分析水泥净浆的水化度、孔隙率、微观结构等的时变发展规律。试验结果与模型预测结果吻合良好,表明该模型可以较准确地模拟水泥水化过程的时变发展规律。 (2)基于水泥水化模型,类比水泥水化,得出了粉煤灰／矿粉的水化方程,通过考虑粉煤灰的稀释、物理效应、化学效应和矿粉的稀释、化学效应,提出了掺粉煤灰／矿粉水泥水化模型,能够模拟掺粉煤灰／矿粉水泥水化过程并预测粉煤灰／矿粉水化度、化学结合水、CH含量等水化特征参数。通过盐酸选择性溶解法、EDTA选择性溶解法、热重分析法、压汞试验和ESEM扫描等一系列试验方法研究掺粉煤灰／矿粉水泥浆体中的粉煤灰／矿粉水化度、化学结合水、CH含量、微观形貌等参数的时变规律,试验结果和模型预测结果吻合较好,说明模型能够较好预测掺粉煤灰／矿粉水泥水化过程。 (3)通过水化模型中提取特征接触面积、连通固态体积率和外层水化产物体积等微观结构参数,研究水泥浆体电阻率和混凝土的抗压强度、湿度扩散发展规律。用无接触电阻率仪监测水泥浆体的电阻率发展规律,研究了电阻率和微观结构参数的关系。在Maekawa抗压强度公式基础上,结合本文水化模型,考虑到不同水灰比、不同矿物掺量和浆骨比等因素的影响,预测了混凝土抗压强度的发展规律,并通过试验对模型的准确性进行了验证。初步提出混凝土湿度扩散系数修正公式,通过已有试验验证了湿度扩散系数公式的正确性。论文得到了国家高科技发展计划(863计划,2012AA050903),国家自然科学基金项目(51320105013,51178413,51378012),国家重点基础研究发展计划(973计划,2009CB623200)以及浙江省重点科技创新团队(2010R50034)的资助。
[Abstract]:The durability of building engineering requires people to have a better understanding of the hydration process of cement-based materials. In this paper, the hydration process of cement paste and mineral admixture cement paste is studied, and the corresponding hydration model is proposed. The development law of resistivity of cement paste, compressive strength and moisture diffusion of concrete are studied by hydration model. The main research work is as follows: In order to predict the cement hydration process accurately and analyze the time-varying development law of the microstructure in the cement hydration process, the concept of hydration unit is put forward, which is based on the micro-information of cement hydration. The relationship between hydration degree and microstructure of cement was established by using the kinetic equation of Krstulovic-Dabic hydration reaction. The water-cement ratio, cement chemical composition, pore moisture and temperature were considered. The effect of cement particle and water contact area and particle size distribution on the hydration process of cement was studied. An improved dynamic model of cement hydration was established. In this study, the mercury injection test was carried out by thermogravimetric analysis (TGA). A series of test methods, such as environmental scanning electron microscope (SEM) and ESEM, are used to analyze the time-varying development of cement paste, such as hydration degree, porosity and microstructure. The experimental results are in good agreement with the predicted results of the model. It shows that the model can accurately simulate the time-varying development of cement hydration process. Based on cement hydration model, the hydration equation of fly ash / mineral powder is obtained by analogy with cement hydration. The dilution, physical effect, chemical effect and dilution and chemical effect of fly ash are considered. The hydration model of fly ash / mineral powder cement is proposed, which can simulate the hydration process of fly ash / mineral powder cement, predict the hydration degree of fly ash / mineral powder, and chemically combine water. The hydration characteristic parameters such as Ch content were determined by selective dissolution of hydrochloric acid, EDTA selective dissolution and thermogravimetric analysis. A series of test methods, such as mercury injection test and ESEM scanning, were used to study the time-varying laws of the hydration degree of fly ash / mineral powder in fly ash / mineral powder cement paste, the content of chemically bound water and Ch, and the microstructure of cement paste. The experimental results are in good agreement with the prediction results of the model, which indicates that the model can predict the hydration process of cement with fly ash / mineral powder. The specific contact area was extracted from the hydration model, and the microstructure parameters such as solid volume ratio and outer hydration product volume were connected to study the resistivity of cement paste and the compressive strength of concrete. The relationship between resistivity and microstructure parameters of cement paste was studied by using contactless resistivity meter. Based on the formula of Maekawa compressive strength. Combined with the hydration model in this paper, considering the influence of different water-cement ratio, mineral content and slurry / bone ratio, the development law of compressive strength of concrete is predicted. The accuracy of the model is verified by experiments, and the modified formula of moisture diffusion coefficient of concrete is put forward preliminarily, and the correctness of the formula is verified by existing tests. The paper has been obtained from the National High Technology Development Program No. 863 (2012AA050903) and the National Natural Science Foundation (NSFC) project 5132010501351178413. 51378012, the National key basic Research and Development Program of 973. 2009 CB623200) and Zhejiang Province key scientific and technological innovation team 2010 R 50034).
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528

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