高温高湿环境下方块大体积海工混凝土抗裂性能研究

Study on Cracks Resistance of Cuboid Large Volume Marine Concrete under High Temperature and High Humidity Environment

针对南海区域高温高湿环境,采用大粒径粗骨料、小坍落度的配合比设计方法,预埋冷却水管及创新施工养护方式,制备方块大体积海工混凝土。对其收缩性能、热学性能、水化产物、抗裂性能等方面进行分析,并结合工程应用,得出方块大体积海工混凝土抗裂设计及施工的相关措施。研究表明,采用5~31.5mm(占比40%~50%)与31.5~63mm两种连续级配碎石拥有很好的紧密堆积效果,260h收缩率为4.03×10^(-4),低于5~31.5mm连续级配碎石的260h收缩率4.74×10^(-4);方块仿真模型和工程实体温度分析检测得出中心最高温度出现在浇筑后40h,接近70℃,中心温度和表层温度最大差值接近25℃;高温高湿环境下采用预埋冷却水管及养护剂+土工布+薄膜+土工布四层体系的养护方式对方块抗裂效果明显。

According to exploited large particle of coarse aggregate, designed small slump for mix proportion, embed- ded cooling water pipe and innovated construction and maintenance, the large volume marine concrete of cuboid was pre- pared. The shrinkage properties, thermal properties, hydration products, cracks resistance, etc of concrete were analyzed, and the research was combined with engineering applications so that some related cracks resistance design and construc- tion measures of concrete were obtained. Research results show that two continuous gradation gravels with 5 ~31.5mm （40%~50%） and 31.5~63mm accumulated closely. The 260h shrinkage of 4.03×10^-4 which was lower than 5-31.5mm con- tinuous gradation concrete 260h shrinkage of 4.74×10^-4. Simulation results show that the center maximum temperature was close to 70℃ which appeared at 40h after pouring, and the maximum temperature difference between the center and the surface approached 25℃. Cooling water pipe and four systems of curing agent-geotextile-membrane-geotextile had good effect on cracks resistance under the condition of high temperature and high humidity.