泡沫混凝土孔结构表征与调控方法及其性能研究

发布时间：2018-06-02 09:51

本文选题：泡沫混凝土 + 泡沫稳定性　；参考：《武汉理工大学》2014年硕士论文

【摘要】：轻质泡沫混凝土是一种施工工艺简便、工作性能良好、具有优异的保温隔热性能和缓冲吸能特性的新型建筑材料，适用于外墙保温系统、机场阻滞隔离带等重要的工程建设，其特点符合节能减排、绿色环保的要求，具有广阔的应用前景，但应用过程中也存在诸如强度低、耐久性差、浆体不够稳定等问题。本文通过大量系统实验对轻质泡沫混凝土泡沫稳定性、浆体特性、微观孔结构表征方法、物理力学性能、水分吸收和迁移性质等方面进行了深入研究，探讨了材料组成、微孔结构和宏观性能三者间的相互作用和影响规律，对推动该材料的理论发展与应用具有重要意义。本文的主要工作和取得的结论如下：运用光学显微镜和尺寸测量软件分析了泡沫水膜和泡沫直径，通过调节泡沫含水量来控制泡沫水膜排液速度和直径在其形成、稳定和破裂过程中的变化规律，提出了通过调节泡沫含水量来控制泡沫水膜排液速度和泡沫直径扩张速度的方法，建立了泡沫含水量和稳定性之间的关系，确定了获得最佳稳定性所需的发泡倍数。采用图像处理和软件统计等方法对泡沫混凝土孔结构进行分析，定量表征了孔隙率、孔径、气孔变形、气孔密度等参数，提出了空间因子概念及其计算方法。分析得到不同配比样品的孔结构参数，系统研究了泡沫混凝土组成对孔结构的影响规律，拟合得到了孔结构各参数间的定量关系，为控制形成孔径细小、形状规则、分布均匀的气孔提供了理论依据。从流动性和稳定性两方面分析了泡沫混凝土新拌浆体性能的影响因素，为设计、制备出工作性能优异的泡沫混凝土材料提供了理论指导。采用体积吸水率和基于不饱和流动理论的吸水性分析方法，研究了泡沫混凝土水分吸收、迁移性质，提出了泡沫混凝土在工作环境中的耐久性评价方法。通过探讨吸水率和孔结构的关系，，结合浆体结构缺陷、气孔数量、气孔尺寸等因素对水分迁移的影响规律和作用机制的研究，明确了水分在泡沫混凝土内部的迁移动力和途径。通过真空饱水法和浸水法的吸水率对比、孔壁结构的SEM分析，构建了非饱和条件下气孔的吸水模型，指导泡沫混凝土耐久性设计。系统分析了泡沫混凝土物理力学性能的影响因素，确立了最佳强度-孔隙率结构模型，为泡沫混凝土的配比设计提供了理论依据。对研制的容重等级为400Kg～600Kg/m3的轻质泡沫混凝土进行了工程验证实验，结果表明其工作性能优异、浆体具有较高稳定性、与石膏板粘结性良好，可以满足工程应用的要求。
[Abstract]:Lightweight foam concrete is a new type of building material with simple construction technology, good working performance, excellent thermal insulation and cushioning and energy absorption characteristics. It is suitable for exterior wall insulation system, airport block isolation zone and other important engineering construction. Its characteristics meet the requirements of energy saving and emission reduction, green environmental protection, and have broad application prospects. However, there are still some problems in the application process, such as low strength, poor durability, unstable slurry and so on. In this paper, the stability of light foamed concrete foams, the characteristics of slurry, the characterization of micropore structure, the physical and mechanical properties, the water absorption and migration properties, etc., are studied through a large number of systematic experiments, and the composition of the materials is discussed. The interaction and influence of micropore structure and macroscopic properties are of great significance to the theoretical development and application of this material. The main work and conclusions of this paper are as follows: The foam water film and foam diameter were analyzed by means of optical microscope and size measurement software. By adjusting the foam water content, the velocity and diameter of the foam water film were controlled during its formation, stabilization and rupture. The method of controlling the velocity of foam water film efflux and the velocity of foam diameter expansion by adjusting foam water content is put forward. The relationship between foam water content and foam stability is established, and the foaming times needed to obtain the best stability are determined. The pore structure of foamed concrete was analyzed by image processing and software statistics. The parameters such as porosity, pore diameter, pore deformation and porosity density were quantitatively characterized. The concept of spatial factor and its calculation method were put forward. The pore structure parameters of the samples with different proportions were analyzed, and the influence of foam concrete composition on the pore structure was systematically studied. The quantitative relationship between the pore structure parameters was obtained by fitting the quantitative relationship between the pore structure parameters, in order to control the formation of fine pore diameter and regular shape. The evenly distributed pores provide the theoretical basis. In this paper, the influencing factors of the performance of fresh foam concrete paste are analyzed from the aspects of fluidity and stability, which provides theoretical guidance for the design and preparation of foam concrete materials with excellent working performance. The water absorption and migration properties of foam concrete are studied by using volume water absorption and water absorption analysis based on unsaturated flow theory. The durability evaluation method of foam concrete in working environment is put forward. By discussing the relationship between water absorption and pore structure, combining with the influence law and mechanism of slurry structure defect, pore quantity and pore size on water migration, this paper clarifies the migration power and path of water in foam concrete. Based on the comparison of the water absorption rate between the vacuum saturated method and the immersion method and the SEM analysis of the pore wall structure, the water absorption model of the pore under unsaturated conditions was constructed to guide the durability design of the foam concrete. The factors influencing the physical and mechanical properties of foamed concrete are systematically analyzed, and the optimum strength-porosity structure model is established, which provides a theoretical basis for the design of foamed concrete proportioning. The experimental results show that the lightweight foamed concrete with bulk density grade of 400Kg~600Kg/m3 has excellent performance, high stability and good adhesion to gypsum board, which can meet the requirements of engineering application.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528

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