气凝胶膨胀珍珠岩的一种制备方法及其在混凝土中的应用

发布时间：2018-04-19 02:32

本文选题：气凝胶膨胀珍珠岩 + 气凝胶　；参考：《太原理工大学》2015年硕士论文

【摘要】：气凝胶是一种质轻且导热系数极低的纳米级保温材料，以其优异的保温性能被广泛关注，，大量应用于航空等高精尖领域。但由于其制备工艺复杂、制品强度较低、制备成本昂贵，使其在建筑领域的应用受到严重限制。如何在提高气凝胶制品强度的同时，降低制备成本是其能够广泛应用于建筑领域亟需解决的关键问题。膨胀珍珠岩是一种广泛应用于建筑领域的价格低廉、耐火良好、强度较高、导热系数较低的保温材料。目前建筑节能与防火要求给建筑墙体保温提出了更高的要求，而膨胀珍珠岩作为无机保温材料中的主要保温骨料，闭孔率是影响其导热系数的关键指标，但由于膨胀的过程存在很大随机性，要想通过改进生产工艺控制闭孔率、降低导热系数是极其困难的。如何在保证膨胀珍珠岩强度与成本控制的同时，降低其导热系数是其在建筑节能领域中能否可持续发展的关键问题。本文拟以廉价的膨胀珍珠岩作为载体，将气凝胶吸入到膨胀珍珠岩内腔结构中，形成新型复合保温材料—气凝胶膨胀珍珠岩。气凝胶膨胀珍珠岩在提高材料性价比的同时，实现两种材料的优势互补，一方面采用膨胀珍珠岩作为气凝胶外壳，可提高气凝胶强度；另一方面将气凝胶充满膨胀珍珠岩空腔，可降低膨胀珍珠岩导热系数，并避开膨胀珍珠岩工艺改进瓶颈。本文基于以上目标，进行了如下研究：（1）气凝胶制备工艺研究。本文选择溶胶-凝胶法制备气凝胶，研究了各原材料用量以及三种疏水处理方法对气凝胶成品性能的影响规律，采用多种微观手段对表征成品性能的各项指标进行测定，综合考虑气凝胶成品的微观结构特征、疏水性能以及热稳定性，得到了制备气凝胶的最佳配合比，并分析得到最优疏水工艺。（2）气凝胶膨胀珍珠岩制备工艺研究。本文采用半细胞法技术将气凝胶吸入到膨胀珍珠岩内部复合形成气凝胶膨胀珍珠岩，研究了不同粒径范围膨胀珍珠岩载体对气凝胶膨胀珍珠岩制品性能的影响，采用微观手段对表征气凝胶膨胀珍珠岩制品的各项指标（比表面积、热稳定性、导热系数）进行测定，结合气凝胶膨胀珍珠岩的微观结构以及化学成分组成，得到了最佳载体粒径范围。（3）气凝胶膨胀珍珠岩在混凝土的应用研究。本文基于玻化微珠保温承重混凝土C30基础配方，将研制的气凝胶膨胀珍珠岩作为保温骨料应用于混凝土中，对其立方体抗压强度和导热系数的进行测定，对比分析得到气凝胶膨胀珍珠岩保温混凝土导热系数低于玻化微珠保温混凝土和膨胀珍珠岩保温混凝土，且远低于普通C30混凝土，同时证明通过合理的保温骨料纳米改性可有效降低混凝土导热系数。
[Abstract]:Aerogel is a kind of nano-scale thermal insulation material with light weight and extremely low thermal conductivity. It has been widely paid attention to for its excellent thermal insulation properties and has been widely used in aviation and other high-precision fields.However, because of its complex preparation process, low strength and expensive preparation cost, its application in the field of construction is severely restricted.How to improve the strength of aerogel products and reduce the cost of preparation are the key problems that need to be solved in the field of architecture.Expanded perlite is a kind of thermal insulation material with low price, good fire resistance, high strength and low thermal conductivity, which is widely used in the field of architecture.At present, the requirements of building energy saving and fire prevention put forward higher requirements for building wall insulation. As the main thermal insulation aggregate of inorganic insulation materials, expanded perlite is the key index affecting its thermal conductivity.However, due to the randomness of the expansion process, it is very difficult to reduce the thermal conductivity by improving the production process to control the closed porosity.How to ensure the strength and cost control of expanded perlite and reduce its thermal conductivity is the key to sustainable development in the field of building energy conservation.In this paper, a new composite thermal insulation material, aerogel expanded perlite, is formed by taking cheap expanded perlite as carrier and inhaling aerogel into the inner cavity structure of expanded perlite.The aerogel expanded perlite enhances the material performance and price ratio, and realizes the complementary advantages of the two materials. On the one hand, the aerogel is used as the aerogel shell to increase the aerogel strength; on the other hand, the aerogel is filled with the expanded perlite cavity.The thermal conductivity of expanded perlite can be reduced and the bottleneck of technological improvement of expanded perlite can be avoided.Based on the above objectives, this paper has carried out the following research:Preparation of aerogel.In this paper, we choose the sol-gel method to prepare aerogels, study the influence of the amount of raw materials and three kinds of hydrophobic treatment methods on the properties of aerogel products, and use a variety of microscopic methods to measure the properties of the aerogels.Considering the microstructure, hydrophobicity and thermal stability of aerogel products, the optimum mixture ratio of aerogels was obtained and the optimum hydrophobic process was obtained.Preparation of aerogel expanded perlite.In this paper, aerogel was inhaled into expanded perlite to form aerogel expanded perlite by semi-cell technique. The effect of dilated perlite carrier with different particle size on the properties of aerogel expanded perlite product was studied.The indexes (specific surface area, thermal stability, thermal conductivity) of aerogel expanded perlite products were determined by microcosmic method, and the microstructure and chemical composition of aerogel expanded perlite were combined.The optimum particle size range of the carrier was obtained.Application of aerogel expanded perlite in concrete.Based on the C30 formula of vitrified microbead thermal insulation bearing concrete, the aerogel expanded perlite is applied to concrete as insulation aggregate, and its cube compressive strength and thermal conductivity are measured.The thermal conductivity of aerogel expanded perlite insulation concrete is lower than that of vitrified microbead insulation concrete and expanded perlite insulation concrete, and is far lower than that of ordinary C30 concrete.At the same time, it is proved that the thermal conductivity of concrete can be effectively reduced by proper nano-modification of thermal insulation aggregate.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528

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