摘要
在原材料优选和配合比优化的基础上,通过协同调控水化速率与膨胀历程,设计制备了低温升高抗裂混凝土(M0不掺抗裂剂、M1和M2掺抗裂剂),对比研究了其力学性能、绝热温升和自生体积变形。在此基础上,依托江阴靖江长江隧道现浇大体积C40混凝土工程,采用基于水化-温度-湿度-约束多场耦合机制的收缩模型对该工程不同结构部位的开裂风险进行了定量评估。试验结果表明:掺入适量抗裂剂能有效改善混凝土的绝热温升和自生体积变形,且对抗压强度影响不大。开裂风险评估计算结果表明:底板、侧墙可选择M1配合比,并控制入模温度不大于28℃,同时在侧墙中心布置冷却水管;顶板可选择M2配合比,并控制倒角处和其他部位的入模温度分别不大于28℃和32℃。工程现场持续跟踪监测6个月,未发现混凝土出现开裂、渗漏,达到预期目标。
On the basis of optimizing raw materials and mix proportions,low-temperature rise and crack-resistant concrete(M0 without anti-cracking agents,M1 and M2 with anti-cracking agents)was designed and prepared by synergistically regulating the hydration rate and expansion process,and the mechanical properties,adiabatic temperature rise,and autogenous volume deformation were compared and studied.On this basis,relying on the cast-in-situ C40 mass concrete engineering in the Jiangyin Jingjiang Yangtze River Tunnel,a shrinkage model based on the coupling mechanism of hydration-temperature-humidity-constraints was used to quantitatively evaluate the cracking risk of different structure parts of the engineering.The experimental results show that adding an appropriate content of anti-cracking agents can effectively improve the adiabatic temperature rise and autogenous volume deformation of concrete,and has little effect on compressive strength.The calculation results of cracking risk assessment indicate that M1 mix proportion can be selected for the bottom plate and the side wall,and the molding temperature should not exceed 28℃,and at the same time,a cooling water pipe should be arranged in the center of the side wall.The top plate can choose the M2 mix proportion and control the molding temperature at the chamfer and other parts to not exceed 28℃and 32℃,respectively.Continuously tracking for 6 months,it is found that the concrete do not crack or leak,achieving the expected goal.
作者
徐思睿
王晓琼
吴烁
李明
杨睿
王文彬
XU Sirui;WANG Xiaoqiong;WU Shuo;LI Ming;YANG Rui;WANG Wenbin(State Key Laboratory of High Performance Civil Engineering Materials,Jiangsu Research Institute of Building Science Co.,Ltd.,Nanjing 210008,China;China Railway 14th Bureau Group Co.,Ltd.,Jinan 250101,China;China Railway 14th Bureau Group Big Shield Engineering Co.,Ltd.,Nanjing 211800,China)
出处
《混凝土与水泥制品》
2024年第3期74-78,共5页
China Concrete and Cement Products
基金
国家自然科学基金青年基金项目(52008192)。
关键词
现浇
大体积混凝土
隧道
收缩模型
开裂风险
Cast-in-situ
Mass concrete
Tunnel
Shrinkage model
Cracking risk
