摘要
地铁停车场地下侧墙属超长大体积混凝土结构,混凝土施工时具有水化温升高、温降速率大等特点,且受底板和已浇筑侧墙的复杂约束作用,混凝土在降温过程中极易出现早期开裂现象。通过掺入抗裂剂配制具有低水化放热和补偿收缩的侧墙高性能抗裂C35混凝土,以绝热温升和自身体积形变表征混凝土抗裂性能,结果显示:掺入抗裂剂后胶凝材料水化集中放热大幅度缓解,混凝土绝热温升及其早期温升速率明显降低,且混凝土膨胀率增加,自收缩得到有效补偿;应用于地铁超长侧墙结构的混凝土中心温峰为55.8℃,最大温升为23.3℃,侧墙中心厚度方向最大膨胀变形为256×10-6,且拆模后无明显裂缝,为同类超长混凝土结构工程裂缝控制提供参考。
The underground side wall of the subway parking lot is a ultra-long mass concrete structure,which has the characteristics of high hydration temperature rise and large temperature drop rate. Due to the complex constraints of the floor and the poured side wall,the concrete is prone to early cracking during the cooling process. The high-performance anti-cracking C35 concrete of side wall with low hydration heat and shrinkage compensation was prepared by adding anti-cracking agent. The anti-cracking performance of concrete was characterized by adiabatic temperature rise and its own volume deformation,the results indicate that the hydration heat release of cementitious materials was greatly alleviated after adding anti-cracking agent,the adiabatic temperature rise and its development rate of anti-cracking concrete decreased obviously,meanwhile the expansion rate of concrete was increased and the concrete autogenous shrinkage was compensated effectively. The central temperature peak of the concrete applied to the ultra-long side wall structure of the subway was 55. 8 ℃,the maximum temperature rise was 23. 3 ℃,the maximum expansion deformation in the thickness direction of the side wall center was 256×10-6,no cracks were found on the surface of the sidewalls after formwork removal,which provides a reference for the control of cracks in similar ultra-long concrete structure projects.
作者
张武宗
唐吉尧
兰聪
张远
蒋选民
ZHANG Wuzong;TANG Jiyao;LAN Cong;ZHANG Yuan;JIANG Xuanmin(China West Construction Southwest Group Co.,Ltd.,Chengdu 610052,China)
出处
《粉煤灰综合利用》
CAS
2022年第6期60-65,共6页
Fly Ash Comprehensive Utilization
基金
四川省科技计划资助(2021YFG0270)
中建西部建设股份公司2021年度项目(ZJXJ-2021-05)。
关键词
地铁侧墙
超长结构
裂缝控制
温度-应变监测
subway side wall
ultra-long structure
crack control
temperature-strain monitoring
