约束状态下混凝土抗氯离子渗透性试验研究

Experimental study on concrete resistance to chloride ion permeability in restrained condition

氯离子渗透性是评价高性能混凝土耐久性的重要指标,混凝土在长期服役过程中会受到很多外在的约束,约束状态会影响混凝土的内部结构。应用板式混凝土早期收缩开裂试验架制成约束状态下C50高性能混凝土,采用ASTM C1202直流电通量法,研究C50高性能混凝土在约束和自由状态下抗氯离子渗透性能。结果表明:与自由状态相比,约束状态降低了混凝土抗氯离子渗透性;在约束状态下,同一配合比混凝土,不同位置的抗氯离子渗透性有所差异;粉煤灰及聚丙烯纤维的加入降低了混凝土抗氯离子渗透性,而掺入硅灰会增强混凝土的抗氯离子渗透性。

Chloride ion penetration is an important indicator to evaluate the durability of high performance concrete.Concrete will suffer a lot of external restraints during the service process,and the restrained condition can affect the internal structure of concrete structure.The C50 high performance concrete under restrained condition was prepared using special models.The resistance to chloride ion penetration of C50 high performance concrete under restrained condition and free condition were studied in electric flux method by ASTM C1202.The results show that the resistance to chloride ion penetration of concrete cut down under constraint condition compared with the free condition.When the concrete has the same mixing proportion,the resistance to chloride ion penetration of concrete in different position is different.The fly ash or polypropylene fiber can deduce the resistance to chloride ion penetration of concrete,but the resistance to chloride ion penetration of concrete mixed with silica powder can be enhanced.