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硅酸盐通报 ›› 2021, Vol. 40 ›› Issue (11): 3608-3616.

• 水泥混凝土 • 上一篇    下一篇

基于孔结构分形的混杂纤维混凝土抗冻性能研究

王春晓1, 董建明1, 李得胜1,2   

  1. 1.中国公路工程咨询集团有限公司,北京 100089;
    2.长安大学,特殊地区公路工程教育部重点实验室,西安 710064
  • 收稿日期:2021-04-28 修回日期:2021-06-12 出版日期:2021-11-15 发布日期:2021-12-08
  • 作者简介:王春晓(1980—),男,高工。主要从事路基路面方面的研究。E-mail: 394706953@qq.com

Research on Frost Resistance of Hybrid Fiber Reinforced Concrete Based on Fractal Theory of Pore Structure

WANG Chunxiao1, DONG Jianming1, LI Desheng1,2   

  1. 1. China Highway Engineering Consultants Group Co., Ltd., Beijing 100089, China;
    2. Key Laboratory for Special Region Highway Engineering of Ministry of Education, Chang'an University, Xi'an 710064, China
  • Received:2021-04-28 Revised:2021-06-12 Online:2021-11-15 Published:2021-12-08

摘要: 为研究粉煤灰掺量对钢-聚丙烯纤维混凝土抗冻性能的影响,设计并制备6种粉煤灰替代率的混杂纤维混凝土,对其进行冻融循环及盐冻循环试验,测试其质量损失、相对动弹模量及弯曲韧性。基于热力学模型计算冻融前后混凝土孔结构分形维数,建立分形维数与混凝土弯曲韧性之间的关系。结果表明:当粉煤灰质量掺量为5%~15%时,随粉煤灰掺量增多,混杂纤维混凝土的抗冻性能明显提升;继续增加粉煤灰掺量至20%,混杂纤维混凝土的弯曲韧性开始降低。混杂纤维混凝土内部孔具有明显的分形特征,分形维数与无害、少害孔总孔隙占比及多害孔孔隙占比均有良好的线性相关性。同时,混杂纤维混凝土孔分形维数与峰值荷载、能量吸收值呈正相关,分形维数越大,混凝土所能承受的峰值荷载越高、能量吸收值越大。

关键词: 混凝土, 混杂纤维, 粉煤灰, 冻融循环, 分形维数, 弯曲韧性

Abstract: In order to study the influence of fly ash content on the frost resistance of steel-polypropylene reinforced concrete, five kinds of hybrid fiber concrete with fly ash replacement rate were designed and prepared. The freeze-thaw cycle and salt-freeze cycle tests of concrete were carried out, the law of mass loss, dynamic modulus and bending toughness of the concrete as freeze-thaw cycles increase had been analyzed. Based on the thermo-dynamic model, the pore structure fractal dimension of concrete before and after freeze-thaw was calculated, and the relationship between fractal dimension and concrete bending toughness was established. The results show that when the fly ash content ranges from 5% to 15%, with the increase of fly ash content, the frost resistance of hybrid fiber concrete is improved obviously. With the increase of fly ash content to 20%, the residual flexural toughness of hybrid fiber concrete begins to decrease. The internal pores of hybrid fiber concrete have obvious fractal characteristics, and the fractal dimension has good linear correlation with the total pore proportion of harmless and less harmful pores and the pore proportion of more harmful pores. At the same time, the fractal dimension of the fiber reinforced concrete is positively correlated with the peak load and energy absorption value. The larger the fractal dimension is, the higher the peak load and energy absorption value the concrete can bear will be.

Key words: concrete, hybrid fiber, fly ash, freeze-thaw cycle, fractal dimension, bending toughness

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