Study on chloride ion diffusion behavior of waste glass concrete under carbonation and chloride corrosion

The long-term exposure of structures to the dual corrosive medium of chloride and carbonation accelerates the deterioration of concrete durability. Based on the corrosion resistance of waste glass, this study explores the mechanical performance, chloride ion diffusion patterns, and microstructural evolution of waste glass concrete under the combined effects of carbonation and chloride attack, elucidating the mechanisms underlying chloride diffusion and the durability evolution of the material. The results show that the carbon-absorbing properties of fine-grained glass sand significantly enhance the strength development of concrete, with compressive strength increasing by 14.78%. The enrichment effect of chloride ion on the surface of waste glass concrete increases exponentially with corrosion time. The angular characteristics and inert components of glass sand can reduce the chloride ion penetration rate. However, a threshold effect is observed with the glass sand dosage: excessive substitution leads to the formation of permeable channels in the interfacial transition zone between aggregate and paste, increasing the cumulative porosity to 1.56%. In addition, an excessive amount of glass weakens the chemical binding capacity of the cementitious matrix toward chloride ions, shifting the material from corrosion resistance to deterioration.