| 摘要: |
| 以酵母菌为原材料制备微生物发泡剂,揭示微生物发泡剂的发泡机制,并针对不同发泡机制,分别采用混合搅拌法和预制泡混合法制备泡沫混凝土,研究了混泡工艺对泡沫混凝土物理力学性能和微观结构的影响.结果表明：微生物发泡剂既可以利用酵母菌的发酵作用产生CO2形成泡沫,还可以利用酵母菌的自身生化反应降低发泡剂溶液的表面张力,在外力作用下引入空气进行发泡;采用混合搅拌法制备的泡沫混凝土干密度为1560kg/m3,抗压强度为33MPa,试样孔径分布均匀且等效孔径相对较小,为880μm,但酵母菌产生的CO2与水泥水化生成的氢氧化钙（CH）反应形成大量CaCO3,导致成型试件的抗压强度远低于行业标准要求;采用预制泡混合法制备的泡沫混凝土干密度为420kg/m3,抗压强度为11MPa,试样孔径分布较不均匀且等效孔径相对较大,为1080μm,但成型试件中含有大量水化硅酸钙（C S H）,使得其抗压强度远高于行业标准要求. |
| 关键词: 酵母菌 发泡机制 混泡工艺 泡沫混凝土 |
| DOI：103969/j.issn.1007 9629202102027 |
| 分类号: |
| 基金项目:国家自然科学基金资助项目（51978439，51708390）；天津市交通运输科技发展计划项目（2018 38）；中国博士后科学基金资助项目（2019M651000）；天津市企业科技特派员项目（19JCTPJC47400）；天津市自然科学基金资助项目（18JCQNJC77900）；国家重点研发计划项目（2017YFC0703704） |
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| Foaming Mechanism of Microbial Foaming Agent and Its Application in Foam Concrete |
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RONG Hui1, ZHANG Jing2, ZHANG Ying1, YANG Yong1, SHANG Wei3
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1.School of Materials Science and Engineering, Tianjin Chengjian University, Tianjin 300384, China;2.Yantong Precast Concrete Co., Ltd., Beijing 102202, China;3.School of Civil Enigneering, Tianjin Chengjian University, Tianjin 300384, China
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| Abstract: |
| Microbial foaming agent was prepared by using yeast, and its foaming mechanism was revealed. Then foam concrete was prepared by mixed mixing method and prefabricated bubble mixing method based on different foaming mechanisms. Effects of different mixing process on the physical and mechanical properties and microstructure of foam concrete were investigated. The results show that microbial foaming agent can not only produce CO2 by yeast fermentation to form foam, but also can reduce the surface tension of foaming agent solution and introduce air foaming under external force by biochemical reaction of yeast. The dry density of foam concrete prepared by mixed mixing method is 1560kg/m3, and the compressive strength is 33MPa, the pore size distribution of the sample is uniform and the equivalent pore size is relatively small to be 880μm, and the calcium hydroxide(CH) from hydration of cement reacts with the CO2 produced by yeast forms a large amount of CaCO3, which leads to the compressive strength of the formed sample being far lower than the requirements of the industry standard. The dry density of foam concrete prepared by premixed foam mixing method is 420kg/m3, and the compressive strength is 11MPa, the pore size distribution of the sample is not uniform and the equivalent pore size is relatively large, which is 1080μm, at the same time, a large amount of calcium silicate hydrate（C S H）is contained in the sample, with the result that the compressive strength is much higher than the industry standard. |
| Key words: yeast foaming mechanism mixing process foam concrete |
