冻融循环过程中混凝土内部微观结构的演变

Development of microscopic structure of concrete exposed to freeze-thaw cycles

试验研究了冻融破坏过程中混凝土强度、内部结构的演变规律。试验结果表明：与抗压强度相比，抗折强度、劈拉强度的劣化趋势更明显；冻融破坏使水泥水化产物的结构从堆积状密实体逐步变成疏松状态，气泡壁逐步出现了开裂。从孔径分布情况来看，孔径25～75nm之间的孔隙所占的比例呈增大趋势。

Strength and internal structure of concrete subjected to freeze-thaw cycles were experimentally studied.Results show that flexural strength and splitting tensile strength of concrete presented more evident damage than compressive strength.After freeze-thaw cycles,density of hydration products of cement was decreased,leading to the cracking of bubble wall and the increase of 25~75 nm porosity.