粗集料类型对寒区混凝土冻融损伤的影响研究  

Effect of coarse aggregate type on freeze-thaw damage of concrete in cold area

作　　者：齐煜 张熙胤[1] 王冲 孙斌洁 张飞凡 QI Yu;ZHANG Xiyin;WANG Chong;SUN Binjie;ZHANG Feifan(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;Northwest Institute of Eco-Environment and Resources,Lanzhou 730000,China)

机构地区：[1]兰州交通大学土木工程学院,甘肃兰州730070 [2]中国科学院西北生态环境资源研究院,甘肃兰州730000

出　　处：《混凝土》2025年第2期80-83,89,共5页Concrete

基　　金：国家自然科学基金联合基金重点支持项目(U21A2012);甘肃省教育厅:优秀研究生“创新之星”项目(2023CXZX-597);甘肃省科技计划资助(23JRRA613)。

摘　　要：在寒冷及严寒地区,冻融循环是混凝土结构耐久性损伤的主要原因,目前对混凝土冻融损伤的研究主要集中于矿物掺合料、水灰比和混凝土外加剂方面,较少考虑粗集料类型的影响,相关规范也未提出具体要求。基于此,通过混凝土快速冻融试验,以表观损伤、相对动弹性模量损失率、质损率、超声波波速损失率、抗压强度和劈裂抗拉强度损失率为指标,综合评价了卵石、碎石混凝土的冻融损伤情况。试验得出:以相对动弹性模量为指标,卵石混凝土的抗冻性比碎石混凝土低16%,冻坏时卵石混凝土的超声波波速、抗压强度、劈裂抗拉强度损失率是碎石混凝土的2.0~2.5倍。抗冻混凝土设计时应将卵石和碎石分开考虑,对卵石混凝土应提出更高的抗冻要求。同时建立了卵石和碎石混凝土抗压强度、劈裂抗拉强度随冻融次数的退化模型,可以为寒区混凝土结构设计提供参考,并指出用相对动弹性模量和质损率作为冻融破坏的评价指标并不全面,应将强度因素纳入考虑。In cold and severe regions,freeze-thaw cycle is the main cause of durability damage of concrete structures.At present,researches on freeze-thaw damage of concrete mainly focus on mineral admixtures,water-cement ratio and concrete admixtures,and rarely consider the influence of coarse aggregate types,and relevant codes have not put forward specific requirements.Based on this,the freeze-thaw damage of pebble and crushed stone concrete was comprehensively evaluated through concrete rapid freeze-thaw test with apparent damage,relative dynamic elastic modulus loss rate,mass loss rate,ultrasonic wave velocity loss rate,compressive strength and splitting tensile strength loss rate as indexes.The results show that the frost resistance of pebble concrete is 16%lower than that of crushed concrete,and the loss rate of ultrasonic wave velocity,compressive strength and splitting tensile strength of pebble concrete is from 2.0 to2.5times that of crushed concrete.Pebble and gravel should be considered separately in the design of freeze-resistant concrete,and higher freeze-resistant requirements should be put forward for pebble concrete.At the same time,degradation models of compressive strength and splitting tensile strength of pebble and crushed stone concrete with freezing and thawing times are established,which can provide reference for the design of concrete structures in cold areas.It is pointed out that the relative dynamic elastic modulus and mass loss rate are not comprehensive evaluation indexes of freezing and thawing failure,and the strength factor should be taken into account.

关 键 词：混凝土 快速冻融试验 卵石 碎石 损伤 

分 类 号：TU528.041[建筑科学—建筑技术科学]