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硅酸盐通报 ›› 2023, Vol. 42 ›› Issue (6): 2015-2026.

所属专题: 水泥混凝土

• 水泥混凝土 • 上一篇    下一篇

基于核磁共振法的纳米TiO2混凝土抗冻性能研究

赵燕茹1, 张建新1, 李娜2,3, 关鹤1   

  1. 1.内蒙古工业大学土木工程学院,呼和浩特 010051;
    2.内蒙古工业大学理学院,呼和浩特 010051;
    3.内蒙古建筑职业技术学院艺术设计学院,呼和浩特 010070
  • 收稿日期:2023-03-13 修订日期:2023-03-13 出版日期:2023-06-15 发布日期:2023-06-25
  • 作者简介:赵燕茹(1971—),女,博士,教授。主要从事混凝土力学及耐久性能方面的研究。E-mail:zhaoyanru710523@126.com
  • 基金资助:
    国家自然科学基金(12162025,11762015)

Frost Resistance of Nano-TiO2 Concrete Based on Nuclear Magnetic Resonance Method

ZHAO Yanru1, ZHANG Jianxin1, LI Na2,3, GUAN He1   

  1. 1. School of Civil Engineering, Inner Mongolia University of Technology, Hohhot 010051, China;
    2. College of Science, Inner Mongolia University of Technology, Hohhot 010051, China;
    3. Art Design College, Inner Mongolia Technical College of Construction, Hohhot 010070, China
  • Received:2023-03-13 Revised:2023-03-13 Online:2023-06-15 Published:2023-06-25

摘要: 孔结构演化对混凝土抗冻性能至关重要,为研究纳米TiO2对混凝土孔结构及抗冻性能的影响,本文选取替代率分别为0%、1%、3%、5%(质量分数,下同)的纳米TiO2混凝土为研究对象,进行了快冻法试验、抗压强度试验、核磁共振试验及扫描电子显微镜试验。通过纳米TiO2混凝土冻融循环前后质量、动弹模量、抗压强度、孔结构及微观形貌的变化,评估-18~5 ℃条件下的冻融损伤并分析纳米TiO2对混凝土性能的改善机理;同时建立抗压强度、相对动弹模量、自由水饱和度及裂缝占比响应模型以确定纳米TiO2的最佳掺量。结果表明:适量的纳米TiO2可有效改善混凝土微观形貌,增加混凝土微孔及中孔的比例,减小大孔及裂缝的比例,过量的纳米TiO2会使混凝土中大孔和裂缝的比例增大,不利于混凝土抗冻性能的提高;纳米TiO2掺量为1%时,混凝土抗冻性能最佳。基于抗冻性能指标与孔隙测试结果建立响应模型,确定纳米TiO2最佳掺量接近1%,这与试验结果相符合。

关键词: 纳米TiO2, 混凝土, 抗冻性能, 核磁共振, 孔结构, 响应面分析

Abstract: The evolution of pore structure is very important to the frost resistance of concrete. In order to study the effect of nano-TiO2 on pore structure and frost resistance of concrete, the nano-TiO2 concrete with substitution rates of 0%, 1%, 3%, 5% (mass fraction, the same below) were selected as research object, and the quick freezing test, compressive strength test, nuclear magnetic resonance test and scanning electron microscope test were carried out. The changes of mass, dynamic elastic modulus, compressive strength, pore structure and micro-morphology of nano-TiO2 concrete before and after freeze-thaw cycle were analyzed to evaluate the freeze-thaw damage at -18~5 ℃ and to analyze the improvement mechanism of nano-TiO2 on concrete properties. At the same time, the response models of compressive strength, relative dynamic modulus, free water saturation and crack ratio were established to determine the optimum content of nano-TiO2. The results show that an appropriate content of nano-TiO2 effectively improves the micro-morphology of concrete, increases the proportion of micropores and medium pores of concrete, and reduces the proportion of macropores and cracks, while excessive nano-TiO2 increases the proportion of macropores and cracks in concrete, which is not conducive to the improvement of frost resistance of concrete. When the content of nano-TiO2 is 1%, the frost resistance of concrete is the best. Based on the frost resistance performance index and pore test results, the response model is established, and the optimal content of nano-TiO2 is close to 1%, which is consistent with the test results.

Key words: nano-TiO2, concrete, frost resistance, nuclear magnetic resonance, pore structure, response surface analysis

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