摘要
水下明挖现浇隧道混凝土因结构尺寸大、分段浇筑长度长、强度等级高、分步浇筑等因素的影响,容易在施工期内出现贯穿性收缩裂缝.从降低混凝土温升、补偿收缩出发,在原材料调研优选、配合比优化的基础上,进一步掺加具有温升抑制及微膨胀功能的抗裂剂制备了低温升高抗裂混凝土,混凝土7 d绝热温升不超过45℃,且早期发展速率较低,混凝土69 d自生体积膨胀变形超过100με且后期收缩趋势较小.工程应用结果表明,实体结构混凝土温升处于较低水平且抗裂剂在温升及温降阶段发挥了全过程补偿变形作用,监测及持续跟踪未发现混凝土出现贯穿性收缩裂缝及渗漏的现象。
With the characteristics of large size,long casting length,high concrete grade and casted by step,open-cut cast in situ tunnel concrete under water is susceptible to suffer penetrating shrinkage crack at the early age during construction stage.From the perspective of reducing temperature rise and compensating shrinkage deformation,concrete with low temperature rise and high crack resistance was prepared by optimizing raw materials,concrete mix proportion and adopting a temperature rise inhibited and slight expansion anti-crack agent.Experimental results showed that the adiabatic temperature rise was no more than 45℃at 7 days with low development rate at early age,the autogenous deformation was not less than 100μεat 69 days with less shrink trend at later age.Engineering application indicated that the temperature rise of entity structure concrete was at the low level,the anti-crack agent generated expansion at the entire process from temperature rise stage to temperature drop stage,no penetrating shrinkage crack and leakage were found by continuous monitoring and observing of entity structure concrete.
作者
周欣
李明
谢彪
徐文
王育江
ZHOU Xin;LI Ming;XIE Biao;XU Wen;WANG Yujiang(Jiangsu Transportation Engineering Construction Bureau,Nanjing 210004,China;State Key Laboratory of High Performance Civil Engineering Materials,Jiangsu Research Institute of Building Science Co.,Ltd.,Nanjing 210008,China;Jiangsu Sobute New Materials Co.,Ltd.,Nanjing 211103,China;College of Materials Science and Engineering,Southeast University,Nanjing 211189,China)
出处
《混凝土》
CAS
北大核心
2021年第6期145-148,154,共5页
Concrete
基金
国家重点研发计划项目(2017YFB0310100)
江苏省交通工程建设局科技项目“太湖隧道混凝土结构抗裂及防水成套技术研究”
中铁隧道集团科技创新计划项目(隧研合2017-03)。
关键词
现浇隧道
低温升
补偿收缩
全过程
cast in situ tunnel
low temperature rise
compensating shrinkage
entire process
