冻融与硫酸盐侵蚀共同作用对再生混凝土的复合损伤研究  

Research on composite damage of recycled concrete by the combined action of freeze-thaw and sulfate attack

作　　者：肖前慧[1] 齐晓 李蕾蕾 邱继生[1] 刘书林 XIAO Qianhui;QI Xiao;LI Leilei;QIU Jisheng;LIU Shulin(School of Architecture and Civil Engineering,Xi′an University of Science and Technology,Xi′an 710054,China;China Electric Power Northwest Survey,Design and Research Institute Co.,Ltd.,Xi′an 710065,China)

机构地区：[1]西安科技大学建筑与土木工程学院,陕西西安710054 [2]中国电建西北勘测设计研究院有限公司,陕西西安710065

出　　处：《混凝土》2024年第8期32-37,共6页Concrete

基　　金：国家自然科学基金面上项目(42071100);陕西省自然科学基础项目研究(2018JQ5215)。

摘　　要：对于不同取代率再生混凝土在冻融循环与硫酸盐侵蚀耦合作用下的损伤,采用快冻法,对再生粗骨料取代率为0、30%、50%和100%的再生混凝土进行试验。试验测试了混凝土的质量损失、相对动弹性模量、立方体抗压强度,并利用电子显微镜和X射线衍射等方法分析混凝土的微观结构及侵蚀产物。试验结果表明:再生粗骨料对混凝土耐久性影响巨大,随着取代率的提高,再生混凝土的性能随冻融循环次数的增加逐渐下降,硫酸盐在一定程度上减缓了混凝土的劣化,冻融循环是混凝土劣化的主要原因,并提出了盐胀与冻胀、静水压及化学腐蚀复合作用下的损伤机理。For the damage of recycled concrete with different substitution rates under the coupled action of freeze-thaw cycles and sulfate attack,the rapid freezing method was used to test recycled concrete with 0,30%,50%and 100%of recycled coarse aggregate replacement rates.The mass loss,relative dynamic elastic modulus and cubic compressive strength of concrete were tested in the experiment and the microstructure and erosion products of concrete were analyzed by means of electron microscope and X-ray diffraction.The test results show that the recycled coarse aggregate has a great influence on the durability of concrete.With the increase of the replacement rate,the performance of recycled concrete gradually decreases with the increase of the number of freeze-thaw cycles.Sulfate slows down the deterioration of concrete to a certain extent,and freeze-thaw cycle is the main reason for concrete deterioration.Therefore,the damage mechanism under the combined action of salt heave and frost heave,hydrostatic pressure and chemical corrosion is proposed.

关 键 词：再生混凝土 硫酸盐侵蚀 冻融循环 复合损伤 微观结构 

分 类 号：TU528.01[建筑科学—建筑技术科学]