长沙夏季地铁车站抗裂混凝土配合比优化及工艺控制

Mix Ratio Optimization and Technology Control of Crack Resistant Concrete for Changsha Subway Station in Summer

在混凝土施工中,开裂是一种普遍出现并长期困扰技术人员的难题。以长沙地铁汉王陵公园车站主体结构为例,从配合比和工艺控制角度探索了改善混凝土防裂抗渗性能的措施。经过配合比优化,坍落度降为10 mm以下,混凝土28 d龄期抗压强度、抗水渗透性、电通量等耐久性均满足标准要求。另外,对混凝土原材料先降温再使用,用运输罐的隔热棉喷水浸湿,浇筑后延长外侧模板拆模时间,并及时做好养护控温等措施,可有效防止温差降低速度过大,降低混凝土施工中的开裂问题。

Cracking is a common problem in concrete construction,which has puzzled technicians for a long time.Taking the main structure of Hanwangling Park Station of Changsha Metro as an example,this paper explores the measures to improve the crack prevention and impermeability of concrete from the angle of mix proportion and process control.Through mix proportion optimization,the collapse degree is less than 10 mm,and the compressive strength,water permeability and electric fiux of concrete at 28 days of age all meet the standard requirements.In addition,measures such as cooling the raw materials of concrete before using,soaking them with heat-insulating cotton spraying water of transport tank,prolonging the demolition time of outer formwork after pouring,and timely maintenance and temperature control can effectively prevent the excessive reduction of temperature difference and reduce the cracking problem in concrete construction.