早期受冻对混凝土力学性能的影响研究  

Study on the effect of early freezing on the mechanical properties of concrete

作　　者：徐存东 李欣达 高懿伟 连海东 王文丰 刘子金 李智睿 XU Cundong;LI Xinda;GAO Yiwei;LIAN Haidong;WANG Wenfeng;LIU Zijin;LI Zhirui(School of Water Conservancy,North China University of Water Resources and Electric Power,Zhengzhou 450046,Henan,China;Key Laboratory for Technology in Rural Water Management of Zhejiang Province,Hangzhou 310018,Zhejiang,China;Henan Provincial Hydraulic Structure Safety Engineering Research Center,Zhengzhou 450046,Henan,China;College of Water Conservancy&Hydropower Engineering,Hohai University,Nanjing 210098,Jiangsu,China;South-to-North Water Transfer Planning and Design Administration of the Ministry of Water Resources,Beijing 100038,China)

机构地区：[1]华北水利水电大学水利学院,河南郑州450046 [2]浙江省农村水利水电资源配置与调控关键技术重点实验室,浙江杭州310018 [3]河南省水工结构安全工程技术研究中心,河南郑州450046 [4]河海大学水利水电学院,江苏南京210098 [5]水利部南水北调规划设计管理局,北京100038

出　　处：《水利水电技术（中英文）》2022年第7期154-161,共8页Water Resources and Hydropower Engineering

基　　金：国家自然科学基金资助项目(51579102);“十三五”国家重点研发计划(2018YFC0406901);河南省高校科技创新团队支持计划(19IRTSTHN030);“中原千人计划”—中原科技创新领军人才支持计划(204200510048);河南省高等学校重点科研项目计划(20A570006)。

摘　　要：秋冬季节,西北盐渍地区气温突降的情况时有发生,为探明早期受冻混凝土在冻融循环和盐离子侵蚀共同作用下的力学性能损伤规律及其机理,采用室内加速试验方法,观察了混凝土在经历4种养护龄期(1 h、3.5 h、8 h、24 h)和2种冻结温度(-5℃、-10℃)的早期受冻影响后,盐冻循环作用对混凝土试件的立方体抗压强度、相对动弹性模量、质量损失率以及损伤层厚度等指标值的影响规律,探讨了早期受冻混凝土力学性能损伤机理。结果表明:不同养护龄期的混凝土在冻融循环和盐离子侵蚀的共同作用下力学性能出现不同程度的损伤,其中,养护龄期处于初凝与终凝间的混凝土试件受早期受冻的影响最大;混凝土损伤层厚度与盐冻循环次数呈正相关关系,且损伤层厚度受冻结温度影响较小;与冻结温度相比,养护龄期对混凝土力学性能损伤的影响更大。相关研究可为相似环境下的混凝土结构优化设计与维护提供有益参考。Autumns and winters see occasional sudden temperature drop in the saline areas in Northwest China. In order to explore the damage patterns and mechanisms of mechanical properties of early frozen concrete under the combined action of the freezing and thawing cycle and saline ions erosion, this paper conducted an indoor accelerated testing. Based on the observed effects of early freezing on the concrete samples subject to four curing ages(1 h, 3.5 h, 8 h and 24 h) and two freezing temperatures(-5 ℃,-10 ℃), this paper explores the influence of salt freezing cycle on the cubic compressive strength, relative dynamic elasticity modulus, mass loss rate and damage layer thickness of concrete samples, etc., as well as the damage mechanism of mechanical properties of early frozen concrete. The results are as follows: the mechanical properties of concrete with different curing ages are damaged to varying degrees under the combined action of the freezing and thawing cycle and saline ion erosion;concrete samples cured between the initial and final settings are the most affected by early freezing;the thickness of concrete damage layer is positively correlated with the number of salt freezing cycles and less affected by freezing temperature;compared with freezing temperature, curing age has a greater impact on the damage of concrete′s mechanical properties. These findings offer useful references for structure optimization designs and maintenance of concrete under similar environment.

关 键 词：混凝土 盐冻循环 养护龄期 劣化规律 损伤层 

分 类 号：TU528.01[建筑科学—建筑技术科学]