Study on sulphate erosion resistance of damaged concrete specimens reinforced with sprayed glass fibre-epoxy mortar

Sulfate erosion has been identified as a primary factor contributing to the reduction in durability of concrete, particularly in the salt lakes of western China and the saline-alkali regions of North China. Consequently, enhancing the sulfate erosion resistance of damaged concrete structures is of paramount importance for prolonging the service life of building structures. The paper goes on to address the drawbacks of existing reinforcement methods, such as complex construction processes and the tendency of coatings to age and peel off, requiring frequent replacement. The study proposes the use of sprayed glass fibre-epoxy mortar reinforcement layers. The present study aims to elucidate the reinforcement mechanism through performance evolution studies of three groups of specimens (unreinforced undamaged concrete specimens, reinforced undamaged concrete specimens, and reinforced damaged concrete specimens) under 5% Na 2 SO 4 solution corrosion and coupled dry-wet cycling environments. The findings indicate that following 120 cycles in a sulfate erosion-dry-wet alternating multi-cycle coupled environment, there was a 66% decrease in the mass loss rate of the reinforced damaged concrete specimen, from 0.62% to 0.21%, while the compressive strength increased from 19.87 MPa to 25.93 MPa, an increase of 23.37%, in comparison to the unreinforced undamaged concrete specimen. The application of a glass fibre-epoxy mortar reinforcement layer around damaged concrete has been shown to enhance the performance of the concrete in terms of its resistance to sulphate, thus demonstrating a positive effect on the concrete's capacity to resist sulphate.