泡沫混凝土墙体材料性能及其微观结构研究

发布时间：2019-02-13 16:41

【摘要】：粉煤灰泡沫混凝土具有良好的热工性能和隔音轻质等特性，成为轻质隔墙材料的选择。它与普通混凝土在原材料上最大的区别在于其不使用粗集料，同时引入大量均匀分布的气泡，使得新拌浆体流动度大、易泵送，硬化后质轻、保温隔热、隔音吸声、不燃和抗震等，因此研究泡沫混凝土墙体材料的性能及其微观结构具有深远的意义。文中采用最新的物理发泡工艺，在常温常压下制备泡沫混凝土。并围绕其配合比设计及微观结构展开了如下研究工作：（1）对泡沫混凝土的性能进行了分析，在理论研究的基础上，进行了外加剂和原材料的单因素试验，得出外加剂的最佳掺量，并且绘制出原材料单因素改变对泡沫混凝土干表观密度、28天抗压强度、以及吸水率的影响曲线，通过对图像的分析得出原材料单因素的最佳取值范围。（2）综合考虑各因素对粉煤灰泡沫混凝土性能的影响，通过正交设计试验，对不同材料组成的干表观密度、28天抗压强度和吸水率进行分析，得出影响泡沫混凝土强度的主要因素，并最终得出泡沫混凝土的最佳配合比。（3）通过测定导热系数得出了干表观密度与泡沫混凝土保温隔热性能的关系。结果表明：随着干表观密度的减小，导热系数随之减小，保温隔热能力提高；粉煤灰的掺量增加，导热系数降低。（4）采用扫描电镜观察泡沫混凝土的微观结构，计算得出由于粉煤灰掺量变化，及发泡剂变化而引起的分形维数的变化。分析分形维数与表观密度、28天抗压强度的关系。试验结果表明：随着粉煤灰和发泡剂掺量的增加，分形维数增大，，表观密度减小，28天抗压强度降低。经过上述研究，获得了制备方便的、容重较低、强度较高且保温隔热性能优良的泡沫混凝凝土墙体材料，并对新的发泡工艺下制备的泡沫混凝土的微观结构进行了分析。
[Abstract]:Fly ash foam concrete has good thermal performance and sound insulation and light properties, so it becomes the choice of lightweight wall materials. The biggest difference between it and ordinary concrete in raw materials is that it does not use coarse aggregates, and at the same time it introduces a large number of evenly distributed bubbles, which makes the fresh mortar flow large, easy to pump, light after hardening, heat preservation and insulation, sound absorption. Therefore, it is of great significance to study the properties and microstructure of foamed concrete wall materials. In this paper, the latest physical foaming technology is used to prepare foamed concrete at room temperature and atmospheric pressure. The following research work is carried out around its mix ratio design and microstructure: (1) the performance of foamed concrete is analyzed. On the basis of theoretical research, the single factor tests of admixture and raw material are carried out. The optimum amount of admixture is obtained, and the influence curve of single factor change of raw material on dry apparent density, 28 days compressive strength and water absorption of foamed concrete is drawn. The best value range of raw material single factor is obtained by image analysis. (2) considering the influence of various factors on the performance of fly ash foam concrete, the dry apparent density, 28 days compressive strength and water absorption of different materials are analyzed by orthogonal design test. The main factors affecting the strength of foam concrete are obtained, and the optimum mix ratio of foam concrete is finally obtained. (3) the relationship between dry apparent density and thermal insulation property of foamed concrete is obtained by measuring thermal conductivity. The results show that the thermal conductivity decreases with the decrease of dry apparent density, and the thermal conductivity decreases with the increase of fly ash content. (4) the microstructure of foamed concrete is observed by scanning electron microscope, and the fractal dimension caused by the change of fly ash content and foaming agent is calculated. The relationship between fractal dimension and apparent density and 28 days compressive strength was analyzed. The experimental results show that with the increase of the content of fly ash and foaming agent, the fractal dimension increases, the apparent density decreases, and the compressive strength decreases in 28 days. Through the above research, the foamed coagulant wall materials with convenient preparation, low bulk density, high strength and excellent thermal insulation performance were obtained, and the microstructure of the foamed concrete prepared under the new foaming technology was analyzed.
【学位授予单位】：河北工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528.2

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