Effects of Particle Size and Specific Surface Area of Porcelain Tile Polishing Waste on Self-compacting Mortars

Current demands for shorter construction times and concerns about mitigating environmental impact are leading to the development of new technologies and encouraging waste recycling. The aim of this paper was to evaluate the influence of the addition of porcelain tile polishing residue (PPR) from two lots of the same factory in self-compacting mortar production. The water to cement ratio and the additive content were maintained the same. The results show that the PPR grain particle size and specific surface area affected the mortars' flowability and mechanical properties. Mortars with PPR0 (thicker particles than PPR1) presented increased compressive strength and a reduced air entrained, already from a 10% addition. In turn, the addition of PPR1 led to a decrease in the flowability of the mortars, maintaining a high rate of air entrained, which resulted in a lower gain of compressive strength. The results showed that the influence of the air-entrained rate on the compressive strength of the mortars prevailed over any possible improvements in particle packing and nucleation effects. Nonetheless, regardless of the amount and type of PPR used, the study shows the viability of using it to produce satisfactory self-compacting mortars.