基于钢箱梁栓钉区的聚甲醛纤维混凝土性能研究

Study on the Properties of Polyformaldehyde Fiber Concrete Based on Steel Box Girder Bolting Zone

为提高深中通道浅滩区非通航孔桥60 m栓钉区中钢箱梁调平层的混凝土强度、工作性等性能,对原设计图中拟采用钢锭铣削型钢纤维的C50钢纤维混凝土进行了改进,并分别试拌了上海某品牌钢纤维、天津某品牌钢纤维以及玄武岩纤维和聚甲醛(POM)纤维配置的混凝土,分析了拌合情况的坍落度、扩展度、粘聚性、保水性等,结合28 d抗压、抗折强度及经济性进行了综合对比,以选取最合适的纤维类型。结果表明:POM聚甲醛纤维相较钢纤维具有较好的分散性能,可显著增强拌合物的粘聚性,减少泌浆和泌水,同时能保证混凝土的抗压、抗折性能。

To improve the concrete strength and workability of the leveling layer for the 60 m anchor zone of the steel box girder of non-navigable bridge in the shallow area of the Shenzhen-Zhongshan Channel,modifications were made to the original design,which planned to use C50 steel fiber concrete with steel ingot milled-type fibers.Concrete mixes were tested with steel fibers from Shanghai Harrex,Tianjin Hengfeng,basalt fibers,and polyoxymethylene(POM) fibers.The properties such as slump,spread,cohesion,and water retention were analyzed,along with 28-day compressive strength,flexural strength,and cost-effectiveness for a comprehensive comparison to select the most suitable fiber type.Results indicate that POM fibers offer better dispersion than steel fibers,significantly enhancing cohesion,reducing bleeding and segregation,and ensuring concrete′s compressive and flexural strength.