摘要
再生混凝土抗冻耐久性与混凝土结构内部孔隙分布变化密切相关。为研究再生混凝土结构内部孔隙分布与抗冻耐久性的定量关系,选取再生粗骨料取代率为0%、25%、50%、75%、100%的普通再生混凝土和引气再生混凝土作为研究对象,进行冻融循环试验和核磁共振试验,测试混凝土试件质量、动弹性模量、抗折强度以及结构内部孔隙分布情况。结果表明:在冻融循环试验中,加入引气剂可有效改善试件内部的中孔(0.01~0.05μm)和大孔(0.05~1μm)的占比,从而提高其抗冻性能;在10种不同配比中,引气天然骨料混凝土的抗冻性能最佳,其次是再生粗骨料替代率为50%的引气再生混凝土,其内部孔隙结构相比再生粗骨料替代率为25%、75%和100%的引气再生混凝土更加稳定;再生混凝土冻融循环后的抗折强度变化与结构内部孔隙的分布和占比密切相关。
The frost resistance durability of recycled concrete is closely related to the change of pore distribution in concrete structure.In order to study the quantitative relationship between pore distribution inside the recycled concrete structure and its frost resistance durability,ordinary recycled concrete and air-entrained recycled concrete with 0%,25%,50%,75%and 100%replacement rate of recycled coarse aggregate were selected as the research objects.Freeze-thaw cycle test and nuclear magnetic resonance test were carried out to test the mass,dynamic modulus of elasticity,flexural strength and pore distribution in the structure.The results show that the air-entraining admixture(AEA)can effectively improve the proportion of mesopores(0.01—0.05μm)and macropores(0.05—1μm)in the specimen,so as to improve its frost resistance.In 10 different proportions,the natural aggregate concrete with AEA has the best frost resistance,followed by the recycled concrete with 50%replacement rate of recycled coarse aggregate,which is more stable than that with 25%,75%and 100%replacement rate of recycled aggregate.The change of flexural strength of recycled concrete after freeze-thaw cycle is closely related to the distribution and proportion of pores in the structure.
作者
邓祥辉
高晓悦
王睿
赵崇基
DENG Xianghui;GAO Xiaoyue;WANG Rui;ZHAO Chongji(School of Civil and Architecture Engineering,Xi’an Technological University,Xi’an 710021,China;Shenzhen Research and Design Institute,China Academy of Railway Sciences,Shenzhen 518057,China;Shenzhen Urban Rail Transit Vibration Reduction and Noise Reduction Engineering Laboratory,Shenzhen 518057,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2021年第16期16028-16034,共7页
Materials Reports
基金
陕西省重点研发计划项目(2018SF-391)
陕西省住房和城乡建设厅科技计划项目(2017-K55)
西安市科技局高校人才服务企业项目(2019217214GXRC008CG009-GXYD8.2)。
关键词
再生混凝土
冻融循环
核磁共振
孔隙分布
抗折强度
recycled concrete
freeze-thaw cycle
nuclear magnetic resonance
pore distribution
flexural strength
