Investigation of durability defect and microstructure evolution laws of concrete of gravity dams
The long-term service as well as safety and stability of concrete dams are closely related to the performance evolution and durability of concrete materials.In this paper,the surface defects and in-ternal defects of long-term service concrete dams are investigated,and the microstructure and perfor-mance of concrete are studied using comprehensive thermogravimetric analysis,scanning electron micro-scope and mercury intrusion method.The results show that the leakage and dissolution are main factors cause internal defects,changes in hydration products composition,degradation of microstructure and performance for concrete dams.Dissolution leads to a decrease in the content of Ca(OH)2 in hydration products,and causes damage to growth forms accompanied by appearance of a large number of CaCO3 particles.At the same time,dissolution will cause further deterioration of the pore structure of concrete and the increase of internal defects such as holes and looseness,which is not conducive to the overall stability of the concrete dam.Special attention should be paid to the effects of cracks,leakage and disso-lution during the operation and maintenance of concrete dams.
万方数据
维普
