Inhibitory Effect of Porcelain Tile Polishing Residue on Alkali-Silicate Reaction under Different Alkali Environment

Previous studies showed that porcelain tile polishing residue was able to effectively inhibit alkali-silica reaction(ASR) expansion. However, due to its high alkali content, it is necessary to further study the inhibition of ASR expansion in different alkali environments. Then the inhibitory mechanism of porcelain tile polishing residue on ASR was investigate. The mortar samples were prepared by using porcelain tile polishing residue as mineral admixture to replace part of cement, and their expansion ratios in KOH solution were measureed. SEM analysis of the near aggregate area of the mortar samples were carried out, and the experimental data in NaOH solution were compared. Experimental results show that porcelain tile polishing residue is able to effectively inhibit the ASR expansion of cementitious materials in NaOH or KOH solution. When the content of porcelain tile polishing residue is lower, the expansion ratio of samples is smaller in NaOH solution. When the content of porcelain tile polishing residue is larger, the expansion ratio of samples is smaller in KOH solution. In the two alkali solutions, potassium and aluminum are enriched in the near aggregate area simultaneously, and non-expansive scaffold aluminosilicate KAlSiO4 is formed. The high content of SiO2 and Al2O3 and low content of CaO in porcelain tile polishing residue play an important role in inhibiting the expansion of ASR. © 2021, Editorial Department of Journal of Building Materials. All right reserved.