混凝土冻融损伤劣化规律与等效冻融循环次数模型  

Deterioration law of frost-damaged concrete and equivalent freeze-thaw cycle number model

作　　者：宋蓉晖[1] 陈昌凯 朱鹏宇 万后林 Song Ronghui;Chen Changkai;Zhu Pengyu;Wan Houlin(Zhejiang Tongji Vocational College of Science and Technology,Hangzhou 311231,China;China Energy Engineering Group Zhejiang Thermal Power Construction Corporation Limited,Hangzhou 311217,China;College of Civil Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]浙江同济科技职业学院,浙江杭州311231 [2]中国能源建设集团浙江火电建设有限公司,浙江杭州311217 [3]同济大学土木工程学院,上海200092

出　　处：《建筑科学》2023年第3期118-127,共10页Building Science

基　　金：浙江省水利厅科技项目(RC2175)。

摘　　要：为探究“人工气候”环境下混凝土材料层面的冻融损伤劣化规律,以冻融循环次数NFTCs、混凝土强度为变化参数,浇筑了21组尺寸为150mm的立方体试块,进而对其展开了冻融循环试验、扫描电镜试验,量测了其抗压强度、相对动弹性模量P、质量变化。研究表明:随NFTCs的增大,C-S-H由颗粒状转变成纤维状;混凝土抗压强度与P均逐渐降低,且降低速率基本相等;混凝土试块的质量在NFTCs≤80时略有增加,而后逐渐下降。随混凝土强度的提高,C-S-H凝胶体由纤维状逐渐转变为网状;抗压强度、P以及混凝土试块的质量均逐渐增大。基于材性试验结果,分别建立了相对抗压强度、相对动弹性模量、质量变化率计算式;进而以P为冻损指标,构建了两种不同冻融制度的NFTCs转换式;从而建立了冻损RC构件荷载与位移时变化剩余评估模型,初步实现了实际冻融损伤环境下各服役龄期RC构件力学与变形性能的时变化定量评估。In order to explore the deterioration law of freeze-thaw damage of concrete material layer in“artificial climate”environment,taking the freeze-thaw cycle numbers(NFTCs)and concrete strength as the change parameters,21 groups of 150mm cubes are poured,and then the freeze-thaw cycle test and scanning electron microscope test are carried out to measure the compressive strength,relative dynamic elastic modulus P and mass change.The results show that with the increase of NFTCs,the C-S-H changes from granular shape to fiber shape.The P and compressive strength of concrete decrease gradually,and the decrease rate is basically the same.The mass of concrete blocks increases slightly when NFTCs≤80,and then decreases gradually.With the increase of concrete strength,the gel gradually changes from fibrous to mesh.Meanwhile,the compressive strength,P and the mass of concrete block are gradually increased.Based on the test results,the calculation formulas of relative compressive strength,relative dynamic modulus of elasticity and mass change rate are established.Furthermore,taking P as the freezing loss index,the NFTCs conversion formulas of two different freezing and thawing schemes are constructed.As a result,the load and displacement evaluation process of the freeze-damaged RC component is established,and the quantitative evaluation of the time-dependent of the mechanical and deformation performance of the RC component in each service age under the actual freeze-thaw damage environment is initially realized.

关 键 词：力学性能 冻融损伤 混凝土 人工气候 等效冻融循环次数模型 时变化评估模型 

分 类 号：TU375.4[建筑科学—结构工程]