作者：陈延飞^1,2, 艾杰², 车俊², 袁文金², 于本田¹, 李双洋³

作者单位：1. 兰州交通大学土木工程学院，甘肃 兰州 730000;
2. 甘肃省交通规划勘察设计院股份有限公司，甘肃 兰州 730000;
3. 中国科学院 西北生态环境资源生态研究院冻土工程国家重点实验室，甘肃 兰州 730000

关键词：混凝土;冻融循环;力学性能;孔隙结构;灰熵关联度

摘要：

为研究混凝土在冻融循环过程中孔隙结构对力学性能的影响，对不同冻融循环次数的混凝土进行力学性能、扫描电子显微镜（SEM）、低场核磁共振（NMR）等试验，并利用灰色关联熵方法建立冻融循环过程中抗压强度与孔隙结构之间的数学模型。结果表明：随着冻融循环次数的增加，混凝土力学性能下降明显，孔隙度增加且$ {T_2} $谱总面积逐渐增加；冻融循环过程中对力学性能影响最大的两个因素分别为少害孔孔隙占比以及自由流体饱和度（FFS），对应的灰熵关联度分别为0.9893和0.9952。以抗压强度为参考，以自由流体饱和度和少害孔孔隙占比为比较序列建立GM（1，3）模型，模型预测值与试验平均值相对误差仅为0.29 %，表明预测模型可以为混凝土冻融循环过程中力学性能提供公式依据。研究成果有助于加深对冻融循环过程中混凝土结构损伤演化规律的认识。

Study on mechanical properties and pore structure model of concrete under freeze-thaw action based on grey correlation entropy
CHEN Yanfei^1,2, AI Jie², CHE Jun², YUAN Wenjin², YU Bentian¹, LI Shuangyang³
1. School of Civil Engineering, Lanzhou Jiaotong University, Lanzhou 730000, China;
2. Gansu Province Transportation Planning Survey & Design Institute Co., Ltd., Lanzhou 730000, China;
3. State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
Abstract: In order to study the influence of pore structure on the mechanical properties of concrete during freeze-thaw cycles, the compressive strength, dynamic elastic modulus, scanning electron microscope (SEM), low-field nuclear magnetic resonance (NMR) and other tests of concrete with different freeze-thaw cycles were carried out, and the mathematical model between compressive strength and pore structure during freeze-thaw cycles was established by using the grey correlation entropy method. The results show that with the increase of freeze-thaw cycles, the mechanical properties of concrete decrease obviously, the porosity increases and the total spectral area increases gradually. The two factors that have the greatest influence on the compressive strength during freeze-thaw cycle are the proportion of less harmful pores and free fluid saturation (FFS), and the grey entropy correlation degree is 0.9893 and 0.9952 respectively. The GM (1,3) model is established based on the compressive strength, free fluid saturation and the proportion of less harmful pores. The relative error between the predicted value of the model and the average value of the test is 0.29%, which indicates that the predicted model can provide a formula basis for the mechanical properties of concrete during freeze-thaw cycles. The research results are helpful to deepen the understanding of the damage evolution law of concrete structures during freeze-thaw cycles.
Keywords: concrete;freeze-thaw cycle;mechanical properties;pore structure;grey entropy correlation degree
2024, 50(5):29-35  收稿日期: 2022-02-09;收到修改稿日期: 2022-04-12
基金项目: 中国科学院重点部署项目（ZDRW-ZS-2020-1）；中国铁路总公司科技研究开发计划（P2018G004）
作者简介: 陈延飞(1994-),男,甘肃兰州市人,助理工程师,硕士,研究方向为高性能混凝土结构研究。
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