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工程科学与技术:2022,54(4):155-163
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新型活性混合材料青稞秸秆灰的制备及性能
(1.兰州理工大学 土木工程学院,甘肃 兰州 730050;2.青海民族大学 土木与交通工程学院,青海 西宁 810000)
Preparation and Properties of Highland Barley Straw Ash as New Active Mixed Materials
(1.School of Civil Eng., Lanzhou Univ. of Technol., Lanzhou 730050, China;2.School of Civil and Transportation Eng., Qinghai Minzu Univ., Xining 810000, China)
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投稿时间:2021-05-24    修订日期:2021-06-23
中文摘要: 一定条件下制备的青稞秸秆灰中活性SiO2含量较高,可作为新型的水泥基辅助胶凝材料。为了研究青稞秸秆灰作为新型活性混合材料的制备条件,以及对氯氧镁水泥砂浆(MOCM)力学和耐水性能的影响,利用扫描电子显微镜、X射线衍射仪、傅里叶红外光谱仪以及激光粒度仪等微观测试技术,研究不同煅烧及研磨条件下,青稞秸秆灰的活性;通过力学测试,分析不同掺入方式及青稞秸秆灰掺量的MOCM耐水性能;利用核磁共振技术测试MOCM的孔结构;通过红外光谱及微观形貌表征MOCM的微观结构;最后,揭示青稞秸秆灰对MOCM力学及耐水性能的影响机理。结果表明,青稞秸秆自然焚烧后,在600 ℃二次煅烧2 h,再研磨2 h,所得灰分活性最高。MOCM中掺入适量青稞秸秆灰,外掺方式比内掺方式可以获得更优的力学及耐水性能。随着青稞秸秆灰掺量的增加,外掺时,干燥、饱水状态下抗压强度先增大后减小;内掺时,干燥及饱水状态抗压强度不断减小。青稞秸秆灰外掺量为5%时力学性能最好,外掺量为10%时耐水性能最好。外掺量为10%时,MOCM中可以生成大量的水化硅酸镁(M-S-H)凝胶。有害、多害孔隙比例显著减少,从而优化孔隙结构,显著提高耐水性能。
Abstract:The content of active SiO2 in the highland barley straw ash (HBSA) prepared under certain conditions is high, which could be used as a new type of cement cementitious materials. In order to study the preparation conditions of HBSA as a new active mixing material and its effect on the mechanical properties and water resistance of magnesium oxychloride cement mortar (MOCM), the activity of HBSA under different conditions of calcination and grinding was studied by scanning electron microscopy (SEM), X-Ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), and laser particle size analyzer (LPSA). The water resistance of MOCM with different mixing methods and HBSA contents was analyzed by mechanical property test. The pore structure of MOCM was measured by Nuclear Magnetic Resonance (NMR), and the microstructure of MOCM was characterized by FTIR and SEM. Finally, the influence mechanism of HBSA on mechanical properties and water resistance of MOCM was revealed. The results showed that the HBSA obtained by calcination at 600 ℃ for 2 h and grinding for 2 h has the highest activity. The way of external mixing of appropriate amount of HBSA into MOCM could obtain better water resistance compared with the way of internal mixing. With the increase of the contents of HBSA, the compressive strength under dry and saturated conditions increases first and then decreases in the way of external mixing. The compressive strength in dry state increases first and then decreases, and the compressive strength in saturated state decreases continuously in the way of internal mixing. Mechanical property is the best when the addition of HBSA was 5% in the way of external mixing, and the water resistance is the best when the addition of HBSA was 10% in the way of external mixing. When the HBSA content is up to 10% in the way of external mixing, MOCM could generate a lot of hydrated magnesium silicate (M-S-H) gels. The proportion of harmful pores and more harmful pores are significantly reduced, so as to optimize the pore structure and improve the water resistance.
文章编号:202100480     中图分类号:TU526    文献标志码:
基金项目:国家自然科学基金项目(51868044);青海省基础研究计划项目(2022–ZJ–921)
作者简介:第一作者:曹锋(1989-),男,博士生,讲师.研究方向:水泥混凝土材料力学及耐久性.E-mail:286840511@qq.com;通信作者:乔宏霞,E-mail:qhxlut7706@163.com
引用文本:
曹锋,乔宏霞,王鹏辉,舒修远.新型活性混合材料青稞秸秆灰的制备及性能[J].工程科学与技术,2022,54(4):155-163.
CAO Feng,QIAO Hongxia,WANG Penghui,SHU Xiuyuan.Preparation and Properties of Highland Barley Straw Ash as New Active Mixed Materials[J].Advanced Engineering Sciences,2022,54(4):155-163.