Ceramics-Silikáty

The corrosion resistance of rice husk ash concrete and pre-treated rice husk ash concrete under salt environment erosion was examined in this experiment. The deterioration mechanism of concrete under the erosion of a composite salt solution was analysed through dry-wet-cycle tests, with ordinary concrete serving as a control. Durability indices, such as the concrete compressive strength, and microscopic methods, such as scanning electron microscopy, were also used to further the studies. The results indicate that the deterioration process of the three types of concrete is divided into two stages. During the first stage (0∼60d), the concrete′s mass, compressive strength, and relative dynamic elastic modulus increased while the water absorption rate decreased. In the second stage (60∼150d), the mass, compressive strength, and relative dynamic elastic modulus of the concrete experienced a decrease while the water absorption rate increased. The microstructure analysis indicates that the concrete was primarily eroded by gypsum and ettringite in the early stage, reducing the effective porosity and improving the compactness. Consequently, the concrete′s performance was enhanced. In the later stage, the ettringite decomposes with the decreased pH, primarily eroded by gypsum. Consequently, the concrete’s effective porosity, compactness, and internal structure were compromised, resulting in a reduced performance. RHA and P-RHA have the potential to enhance the compactness of concrete and slow down the deterioration process by promoting the generation of C-S-H gels. The performance of P-RHA is superior to that of RHA. The analysis of the concrete degradation depth indicates that the ordinary concrete reaches the destructive limit before the RHA and P-RHA concrete. At the same time, there is minimal difference between the two.