冻融循环作用下混凝土毛细孔结构的劣化机制

研究冻融循环作用下混凝土毛细孔结构的演变规律,并与吸水性及宏观性能相结合,探索毛细孔结构的劣化机制及其对混凝土宏观性能的影响规律.结果表明:水饱和状态是造成冻融循环过程中混凝土孔结构改变的重要因素;利用混凝土毛细吸水系数能够较为明确地反映冻融循环作用下混凝土内部结构的改变;毛细吸水系数初值和增长速率是表征毛细孔结构演变规律的关键参数,毛细吸水系数越大,冻融循环后混凝土强度越低.

Degradation Mechanism of Concrete Pore Structure Under the Action of Freeze-Thaw Cycle

The influence of freezing-thawing cycle on capillary pore structure of concrete was investigated. Combining water absorption and macro performance, the capillary pore structure degradation mechanism under freezing-thawing cycle under the effect of capillary pore structure and its influence on macro properties of concrete were discussed. The results show that the water saturation state is an important factor to change concrete pore structure under freezing-thawing cycles; the change of internal structure of concrete under freezing and thawing cycles can be clearly defined by the capillary water absorption coefficient of concrete; the initial value and its growth rate of capillary water absorption coefficient are the key parameter for characterization of pore structure evolution; as capillary water absorption coefficient increases, the concrete strength decreases after freezing-thawing cycle.