Comparison of Durability and Mechanism between Sprayed Concrete and Ordinary Concrete at Different Erosion Age

Abstract

The differences in corrosion between the erosion mechanisms of sprayed concrete (SpC) and ordinary concrete (OC) under sulfate attack at different corrosion ages were investigated in this paper. Here, 10% sodium sulfate was used to corrode SpC and OC under the condition of a 24-h drying-wetting cycle. The microdeterioration process and the change-rule of the durability of the two kinds of concrete are analyzed from the perspectives of microstructure and durability by means of scanning electron microscope (SEM) and relevant laboratory tests. The results show that the erosion products of SpC first accumulate in the original defects, such as pores and holes, whereas the erosion products of OC first concentrate on the surface of the specimen. Thereafter, the original defects in SpC are gradually filled and recracked, whereas OC is directly cracked. As a result, the corrosion resistance and durability of SpC is ultimately better than that of OC to some extent. Moreover, reported experiment data indicate that the damage degree and time of SpC and OC are different, and corrosion products can be detected before the deterioration degree of concrete increased significantly.