Study on the Performance Control and Preparation of Micro-expansion and Self-compacting Concrete Coated with Steel Pipe
With the continuous improvement of construction quality standard in China,the shortcom-ings of ordinary concrete,which is not suitable for vibration in the environment of dense steel rein-forcement,have gradually appeared.The main tower of Sichuan Kahalo Jinsha River Bridge has a thin wall of steel pipe wrapping and dense reinforcement,and ordinary concrete cannot meet the construc-tion quality requirements,so it is necessary to realize full filling of the formwork through self-compac-ting concrete to ensure the appearance quality.Based on the background of Sichuan Kahalo Jinsha Riv-er Bridge project,the design of self-compacting concrete proportion was explored,and the early crack-ing susceptibility of self-compacting concrete was determined by using the flat-plate method.The re-sults show that adding 10％CEA expansion agent,the field application effect is better,and the 28 day compressive strength is 39.2 MPa with an increase of 10.7％.The average cracking area is less than 10 mm2,the number of cracks per unit area is less than 10,which meets the Class Ⅰ crack resistance standard and the engineering quality requirements.
micro-expansion self-compacting concretemixing ratio designCEA expansion agentearly cracking
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