冻融环境下再生混凝土毛细吸水特性研究  

Capillary water absorption characteristics of recycled concrete under freeze-thaw environment

作　　者：肖前慧[1] 师姗姗 邱继生[1] 李蕾蕾[2] 武哲 XIAO Qianhui;SHI Shanshan;QIU Jisheng;LI Leiei;WU Zhe(School of Architecture and Civil Engineering,Xi’an University of Science and Technology,Xi’an 710054,China;POWERCHINA Northwest Engineering Corporation Limited,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]中国电建集团西北勘测设计研究院有限公司,陕西西安710065

出　　处：《冰川冻土》2024年第3期909-918,共10页Journal of Glaciology and Geocryology

基　　金：国家自然科学基金项目(42071100);陕西省自然科学基金项目(2018JQ5215)资助。

摘　　要：本文采用ASTM C1585-13水工混凝土毛细吸水标准试验方法,研究了冻融循环和再生混凝土粗骨料取代率(0%、20%、40%和60%)对再生混凝土(RAC)毛细吸水性能的影响,建立了冻融环境下RAC初期毛细吸水率的预测模型,并结合非饱和毛细理论,建立了RAC在不同冻融循环次数下相对含水量分布预测模型。结果表明:冻融环境相同时,RAC的累计吸水量和初期毛细吸水率随再生粗骨料取代率的增加而变大;再生粗骨料取代率相同时,RAC累计吸水量和初期毛细吸水率随冻融循环次数的增加而变大;从经济角度来看,40%掺量的RAC抗冻性能较优。经验证,通过回归分析建立的冻融损伤下RAC初期毛细吸水率预测模型,计算精度较高,可用于预测RAC的毛细吸水性能,为RAC的抗冻耐久性评价提供理论依据。Recycled concrete refers to the new concrete prepared by crushing and screening construction waste,mixing according to a certain gradation,and replacing natural aggregate,which can effectively alleviate the problem of recycling of construction waste and shortage of natural sand and gravel materials in China.As a po-rous building material,the transfer of water is an important reason for the deterioration of concrete performance.The migration of water in concrete mainly includes three forms:capillary water absorption,infiltration and diffu-sion.In unsaturated concrete,capillary water absorption is the main way of water transmission,and it is also an important control factor affecting the frost resistance of concrete.In this paper,effects of the number of freeze-thaw cycles and coarse aggregate replacement rate of recycled concrete(0%,20%,40%,and 60%)on the capil-lary water absorption performance of recycled aggregate concrete(RAC)were studied by ASTM C1585-13 stan-dard test method.The prediction model of initial capillary water absorption of RAC under freeze-thaw cycles was established.Combined with the unsaturated capillary theory,the prediction model of relative water content distribution of RAC under different numbers of freeze-thaw cycles was established.The results show that the cu-mulative water absorption and initial capillary water absorption of RAC increase with increasing replacement rate of recycled coarse aggregate under the same freeze-thaw cycles.When the replacement rate is the same,the cu-mulative water absorption and initial capillary water absorption of RAC increase with increasing number of freeze-thaw cycles.When the content of recycled coarse aggregate is 20%and 40%,the capillary water absorp-tion resistance is very similar.From an economic point of view,concrete containing 40%recycled coarse aggre-gate has better resistance to frost.The capillary water absorption of RAC increases rapidly in the early stage,de-creases gradually in the middle stage,and tends to be stable in the later stage.It ca

关 键 词：再生混凝土 毛细吸水 冻融环境 累计吸水量 预测模型 微观结构 

分 类 号：TU528.01[建筑科学—建筑技术科学]