早期受冻混凝土孔隙结构特征及与宏观力学性能相关性分析  

Pore Structure Characteristics of Early Frozen Concrete and Its Correlation with Macroscopic Mechanical Properties

作　　者：屈春来[1,2] 林镕鹏 刘世伟 宿辉 王晓阳[1] QU Chun-lai;LIN Rong-peng;LIU Shi-wei;SU Hui;WANG Xiao-yang(School of Water Conservancy and Hydroelectric Power,Hebei University of Engineering,Handan 056038,China;Hebei Key Laboratory of Intelligent Water Conservancy,Handan 056038,China)

机构地区：[1]河北工程大学水利水电学院,河北邯郸056038 [2]河北省智慧水利重点实验室,河北邯郸056038

出　　处：《水电能源科学》2023年第12期164-167,共4页Water Resources and Power

基　　金：河北省自然科学基金项目(E2021402023);河北省高等学校科学技术研究项目(BJ2019023,QN2021030)。

摘　　要：混凝土早期受冻在我国北方地区水利工程建设中普遍存在,早期受冻致损诱发混凝土结构力学性能劣化,严重影响工程结构的安全稳定性和服役寿命。通过室内单轴压缩试验和CT扫描试验,分析起冻时刻和冻结温度对混凝土力学性能的影响规律,重构不同起冻时刻混凝土三维孔隙结构,探究不同起冻时刻混凝土孔隙分布和孔隙结构特征参数的变化规律,并开展早期受冻混凝土力学性能与孔隙结构相关性分析。结果表明,随起冻时刻的延迟,混凝土试块孔隙率呈先增大后减小的变化规律,平均孔隙表面积呈先减小后增大的变化规律,平均孔径呈二次抛物线增加的变化趋势,平均孔隙形状因子呈先减小后增大又减小的变化趋势;平均孔隙表面积与早期受冻混凝土的抗压强度和弹性模量的相关性最好,建议优先选择平均孔隙表面积构建早期受冻混凝土的细观损伤指标。相关研究成果为揭示早期受冻混凝土的宏细观损伤机制提供了支撑。Early freezing of concrete is common in the construction of water conservancy projects in northern China.Early freezing damage induces the deterioration of mechanical properties of concrete structures,which seriously affects the safety,stability and service life of engineering structures.Through laboratory uniaxial compression test and CT scan test,the influence law of freezing time and freezing temperature on the mechanical properties of concrete was analyzed,the three-dimensional pore structure of concrete at different freezing time was reconstructed,the pore distribution and pore structure characteristic parameters of concrete at different freezing time were studied,and the correlation analysis between mechanical properties and pore structure of early frozen concrete was carried out.The results show that with the delay of freezing time,the porosity of concrete test blocks increases first and then decreases,the average pore surface area decreases first and then increases,the average pore diameter increases with the trend of quadratic parabola,and the average pore shape factor increases first and decreases then increases and decreases.The correlation between the average pore surface area and the compressive strength and elastic modulus of early frozen concrete is the best.It is suggested that the average pore surface area should be preferred to construct the mesoscopic damage index of early frozen concrete.Relevant research results provide support for revealing the macro and micro damage mechanism of early frozen concrete.

关 键 词：早期受冻 混凝土 CT扫描 孔隙结构特征 相关性分析 

分 类 号：TV431[水利工程—水工结构工程]