陕北地区低湿条件下混凝土碳化深度及影响因素研究

Study of Carbonization Depth of Concrete under Low Humidity Condition in Northern Shaanxi Area and Its influencing Factors

为深入分析导致混凝土碳化的各类因素,降低碳化的破坏作用,通过对陕北地区低湿条件下几座隧道的二次衬砌,桥梁的桥墩、承台、桥台的碳化深度进行测试,分析低湿环境下混凝土强度、龄期、光照、结构物位置与碳化深度的关系,得到适合该地区的碳化深度预测公式xc=0.312 51t和y=0.103t^(0.713)。在降低混凝土碳化的不利影响方面,通过隔绝空气以及调整混凝土配合比,可以保证在密实度得到改善的混凝土中建立一个适度的高碱环境,以减少或避免碳化对混凝土耐久性的破坏。

The analysis of various influencing factors of concrete carbonization is important to reduce the damaging effects of carbonization. The carbonization depth test on secondary lining of tunnels,piers,pile caps and abutment of bridges are carried out under low humidity condition in Northern Shaanxi Area. The relationships between concrete carbonization depth and concrete strength,concrete age,illumination and structural location under low humidity condition are analyzed. The concrete carbonization depth prediction formula in Northern Shaanxi Area is obtained as xc=0.312 51t and y = 0. 103 t^（0.713）. To improve the concrete compactness and provide a moderate high alkali environment,methods such as sealing the concrete surface and adjusting the mixing proportions of concrete materials are adopted,which can further reduce the concrete durability damage induced by concrete carbonization.