盐冻作用后风积沙混凝土孔结构对抗压强度影响的灰熵分析  

Grey Entropy Analysis on Effect of Pore Structure on Compressive Strength of Aeolian Sand Concrete After Salt-freezing

作　　者：董伟 付前旺 申向东[2] 薛慧君[2] 王尧鸿[3] 李志强[4] DONG Wei;FU Qianwang;SHEN Xiangdong;XUE Huijun;WANG Yaohong;LI Zhiqiang(College of Civil Engineering,Inner Mongolia University of Science and Technology,Baotou 014010,Inner Mongolia,China;College of Water Conservancy and Civil Engineering,Inner Mongolia Agricultural University,Hohhot 010018,China;College of Civil Engineering,Inner Mongolia University of Technology,Hohhot 010051,China;College of Water and Architectural Engineering,Shihezi University,Shihezi 832003,Xinjiang,China)

机构地区：[1]内蒙古科技大学土木工程学院,内蒙古包头014010 [2]内蒙古农业大学水利与土木建筑工程学院,呼和浩特010018 [3]内蒙古工业大学土木工程学院,呼和浩特010051 [4]石河子大学水利建筑工程学院,新疆石河子832003

出　　处：《材料导报》2023年第2期65-70,共6页Materials Reports

基　　金：国家自然科学基金(52268044);内蒙古自治区自然科学基金(2020BS05008,2021LHMS05019);内蒙古科技大学创新基金(2019QDL-B48)。

摘　　要：为了研究盐冻环境下孔结构对风积沙混凝土抗压强度的影响,对不同风积沙掺量下的混凝土进行抗压强度和核磁共振孔结构试验。采用灰熵法分析孔结构特征参数对冻融循环后混凝土抗压强度的影响规律,在此基础上建立了不同冻融循环次数下孔结构参数和风积沙贡献率的复合型抗压强度模型。结果表明:混凝土的抗压强度和束缚流体饱和度随着冻融循环次数的增加逐渐降低,孔隙率和自由流体饱和度随着冻融循环次数的增加逐渐增大。30%以内风积沙掺入对混凝土的抗冻性能具有一定增强作用,20%的风积沙对混凝土抗盐冻后的抗压强度、孔隙率和束缚流体饱和度的抗损伤劣化提升效果最为明显。由灰熵分析可知,束缚流体饱和度和孔径小于10μm的孔体积占比与抗压强度的关联度较高。本研究建立了混凝土抗压强度与束缚流体饱和度、孔径小于10μm的孔体积占比和风积沙有效贡献率的抗压强度复合模型,模型拟合度较高。本研究可为风积沙混凝土在西北地区的推广提供理论基础。To investigate the influence of pore structure on the compressive strength of aeolian sand concrete in salt-freezing environment,concrete samples with different aeolian sand content were tested for their the compressive strength and nuclear magnetic resonance pore structure.At the same time,the grey entropy method was used to analyze how freeze-thaw induced characteristic parameters of pore structure impact the compressive strength of concrete after freezing.Further,a composite compressive strength model under different freeze-thaw cycles was established with pore parameters and aeolian sand contribution rate as predictors.The results show that the increase of freeze-thaw cycles results in the decrease of the compressive strength and bound fluid saturation of concrete specimens and the increase of the porosity and free fluid saturation.When the content of aeolian sand is less than 30%,the frost resistance of concrete is enhanced,and when the aeolian sand content is 20%,the compressive strength,porosity and bound fluid saturation of concrete show the best damage resistance.The grey entropy analysis reveals that the saturation of the bound fluid and the proportion of pore volume with a pore diameter of less than 10μm have a high correlation with the compressive strength.This research has established a well-fitted composite compressive strength model with predictors of bound fluid saturation,the proportion of pore volume with a diameter of less than 10μm,and the effective contribution rate of aeolian sand.It will provide a theoretical basis for the promotion of aeolian sand concrete in the northwest region.

关 键 词：混凝土 抗压强度 孔隙 束缚流体饱和度 灰熵 

分 类 号：TU528[建筑科学—建筑技术科学]