早期受冻损伤对混凝土耐久性影响的试验研究  

Experimental Study on Influence of Early Freeze Injury to the Durability of Concrete

作　　者：徐存东 高懿伟 田俊姣 张锐 王燕 李振 XU Cundong;GAO Yiwei;TIAN Junjiao;ZHANG Rui;WANG Yan;LI Zhen(School of Water Conservancy,North China University of Water Resources and Electric Power,Zhengzhou 450046,China;Collaborative Innovation Center of Water Resources Efficiency and Protection Engineering,Zhengzhou 450046,China;Henan Provincial Hydraulic Structure Safety Engineering Research Center,Zhengzhou 450046,China)

机构地区：[1]华北水利水电大学水利学院,河南郑州450046 [2]水资源高效利用与保障工程河南省协同创新中心,河南郑州450046 [3]河南省水工结构安全工程技术研究中心,河南郑州450046

出　　处：《人民黄河》2021年第2期131-136,141,共7页Yellow River

基　　金：国家自然科学基金资助项目(51579102,31360204);河南省科技厅科技创新人才支持计划项目(174200510020);河南省高校创新团队支持计划项目(19IRTSTHN030);宁夏省水利厅水利科技项目(TYZB-ZFCG-2017-31)。

摘　　要：北方地区低温季节混凝土结构施工过程中容易受到温度突降的影响而导致耐久性降低,为探究混凝土早期受冻损伤后的耐久性变化及其损伤机理,通过室内模拟不同受冻时刻(养护龄期)、不同冻结温度环境,开展了混凝土早期受冻试验,对比了受冻时刻及冻结温度对混凝土后期抗压强度、相对动弹性模量、损伤层厚度的影响规律,探讨了混凝土早期受冻损伤机理,并构建了以损伤层厚度h_f为损伤变量的评价标准,结合实际损伤特点,对该损伤变量进行修正,并验证了其合理性。研究结果表明:早期受冻混凝土的损伤度为20%~30%;在初凝到终凝期间(3.5 h)受冻,混凝土损伤度最大,冻结温度越低,损伤越严重;在初凝前受冻,混凝土损伤度较小,不同冻结温度越高,损伤越严重;在终凝后受冻,混凝土损伤度最小,冻结温度对混凝土损伤影响基本相同。经修正后的h_f损伤变量能较准确地描述早期受冻环境下混凝土的损伤程度,相关研究可为在低温季节施工的混凝土建筑物的后期耐久性评价和养护提供依据。In the low temperature season,the construction of concrete structures in the northern region is susceptible to temperature drop and the durability is reduced.In order to explore the durability and damage mechanism of concrete after early freeze injury,it simulated different freezing moments(curing age)and different freezing temperatures environments through indoor simulation,carried out early freezing test of concrete and compared the compressive strength,relative dynamic elastic modulus and damage layer thickness of concrete at the late period of freezing and freezing temperature.The mechanism of the early freezing damage of concrete was discussed.The evaluation criteria of damage thickness based on damage thickness hf was established,the damage variable was corrected with the actual damage characteristics and its ra⁃tionality was verified.The research results show that the damage degree of early frozen concrete is about 20%-30%;the frost damage is the most serious during initial coagulation to final set and the damage degree of concrete is the largest.The lower the freezing temperature is,the more serious the damage will be.Before the initial coagulation or after final set,the damage degree of concrete is small,and the higher the freezing temperature,the more serious the damage will be.The relevant research can provide effective basis for the later durability evaluation and maintenance of concrete buildings constructed in low temperature season.

关 键 词：混凝土 早期受冻 超声平测法 损伤层厚度 

分 类 号：TV431[水利工程—水工结构工程]