C55钢管拱机制砂微膨胀自密实混凝土配制及应用

Preparation and Application of C55 Steel Tube Manufactured Sand Micro-expansion and Self-compacting Concrete-filled

天然河砂日益匮乏,机制砂替代河砂作为混凝土细集料成为发展趋势。为确保机制砂自密实混凝土与钢管协同工作,保证施工质量,提出钢管混凝土性能设计要求,并通过混凝土配合比参数优化、矿物掺和料复配优化、集料粒径及掺量优化及外加剂复配优化等方式,成功制备扩展度大于650mm、坍落度大于270mm、5h几乎无经时损失,达到C55标准,具有微膨胀性能的钢管拱机制砂自密实混凝土。同时,研制的C55钢管拱机制砂自密实混凝土成功应用于乌梅河特大桥,不仅提高工程质量、促进贵黄高速的建设发展,也取得良好的社会、经济效益。

Because of the increasing scarcity of river sand, it has become a development trend to replace river sand with manufactured sand as fine aggregates for concrete. The performance design requirements for concrete-filled steel tube are put forward to ensure that it works together with the steel tube and the construction quality. Through optimization of concrete proportion parameters, mineral admixtures, aggregate and chemical admixtures, etc., the self-compacting concrete with slump flow greater than 650 mm, slump greater than 270 mm, and almost no time loss in 5 hours was prepared. In addition, the compressive strength of the manufactured sand self-compacting concrete filled steel tube concrete meets the requirements of C55 and possesses micro-expansion performance. At the same time, the prepared self-compacting concrete-filled steel tube was also successfully applied to the Wumei river bridge. This not only improved the project quality, promoted the construction and development of the Guihuang Expressway, but also achieved social and economic benefits.