Sulfate Corrosion Resistance of Reclaimed Coal Gangue Sand Concrete Reinforced with Silica Fume

In order to investigate the strengthening influence of silica fume on the sulfate corrosion resistance of reclaimed coal gangue sand concrete (RCGSC), the compressive strength, failure morphology, micromorphology, phase composition, compressive strength efficiency and corrosion resistance coefficient were analyzed, combining with scanning electron microscopy and X-ray diffraction testing methods. The results show that the damage and failure of concrete are mainly caused by salt crystal expansion corrosion, and the incorporation of silica fume reduces the formation of salt crystals and slows down the deterioration caused by chemical corrosion. The combination of silica fume and coal gangue sand can play a synergistic role in improving sulfate corrosion resistance. For the RCGSC with different strength grades and optimal amount of coal gangue sand, the strengthening effect of sulfate resistance increases first and then decreases with the increase of silica fume dosage, and the improvement effect is the best at the dosage of 10%.