Sand particle erosion of cement mortar under sulfate and chloride attack and exposure to freeze–thaw cycles

The erosion behaviour of cement mortar subjected to sand particle blasting was investigated using the gas-blast method with different impact angles and sand particle fluxes. The corrosion regime under the action of freeze–thaw cycles was also investigated. The erosion rate of the cement mortar was measured and analysed under freeze–thaw cycles using two concentrations of corrosive solutions (8% and 10% mass fractions of salt solutions of sodium chloride and sodium sulfate). Moreover, with the support of scanning electron microscopy images, X-ray diffraction patterns and laser scanning confocal microscopy, the erosion mechanism at different impact angles and freeze–thaw cycles was investigated. The results showed that the erosion rate increased with increasing impact angle and decreased with an increase in sand particle flux. The erosion rate of the cement mortar was also found to first decrease and then increase with an increasing number of freeze–thaw cycles. The erosion damage of the cement mortar surface with significant mass loss was found to be due to two mechanisms – horizontal cutting and vertical pressing.