低水化热高抗裂机制砂海工混凝土试验研究与应用  

Experimental research and application of mechanized sand marineconcrete with low hydration heat and high crack resistance

作　　者：刘汝华 孙淼 施一春 LIU Ru-hua;SUN Miao;SHI Yi-chun(Ningbo Fubang Highway Engineering Construction Co.,Ltd.,Ningbo,Zhejiang 315613,China;Ningbo Fubang Infrastructure Investment Co Ltd.,Ningbo,Zhejiang 315613,China)

机构地区：[1]宁波富邦公路工程建设有限公司,浙江宁波315613 [2]宁波富邦基础设施投资有限公司,浙江宁波315613

出　　处：《中国港湾建设》2023年第11期50-55,共6页China Harbour Engineering

基　　金：宁波市交通运输科技项目(202112)。

摘　　要：为解决滨海滩涂围垦区暗埋隧道箱体结构狭长、体积大、底板侧墙和顶板厚度薄、难以布置冷却水管降温而导致温度应力大、结构易开裂及天然砂石资源短缺的问题,试验通过原材料特性分析、配合比设计与优化、耐久性研究、混凝土结构开裂风险评估以及工程应用效果评价,提出了一种低水化热高抗裂机制砂海工混凝土配制及应用关键技术。结果表明:所配制混凝土不仅工作性、力学性能、体积稳定性和抗氯离子渗透性均满足施工及设计要求,而且经验算评估,隧道箱体按20 m分段浇筑施工时,3 d、7 d和28 d龄期的结构最小安全系数均大于1.4,控裂保障率高;5个节段侧墙的结构内部温度、内表温差和降温速率的峰值基本符合温控标准要求,且裂缝分布密度低至0.32条/m,平均裂缝宽度也均低于设计规范要求,抗裂效果好。In order to solve the problems of long and narrow box structure,large volume,thin thickness of bottom side wall and top plate,difficulty in arrange cooling water pipe for cooling in the buried tunnel in coastal mudflat reclamation area,which lead to large temperature stress and easy cracking of the structure and shortage of natural sand and stone resources,a key technology for the formulation and application of low hydration and high crack resistance mechanism sand marine concrete has been proposed through the analysis of raw material characteristics,ratio design and optimization,durability research,risk assessment of concrete structure cracking,and evaluation of engineering application effects.The results show that the formulated concrete meets the construction and design requirements in terms of workability,mechanical properties,volumetric stability and resistance to chloride ion penetration.After checking calculation and evaluation,the minimum safety factor of the structure at the age of 3 d,7 d and 28 d is greater than 1.4 when the tunnel box is constructed in 20 m sections,with a high guarantee rate of crack control;the peak values of the internal temperature,internal surface temperature difference,and cooling rate of the five section side walls basically meet the requirements of temperature control standards,and the distribution density of cracks is as low as 0.32 per meter.The average crack width is also lower than the design specification requirements,and the crack resistance effect is good.

关 键 词：低水化热 高抗裂 机制砂 海工混凝土 

分 类 号：U654[交通运输工程—港口、海岸及近海工程]