Residue of manufacture of porcelain stoneware tiles as supplementary material for cement mortars

Abstract

This paper presents the results of the chemical and morphological characterization of a residue produced during the manufacture of the porcelain stoneware tiles, and an alternative for its recycling as cement mortar addition material. The residue studied was provided by a factory in Argentine that produces more than 30 ton/month of dry material, which is currently discarded without a recovery destination. The material was dried in an electric oven at 60°C during 180 min in order to remove surface moisture and break off the agglomerations. The characterization of the residue includes X-Ray fluorescence to determine chemical composition, X-Ray diffraction to determine crystallographic phases, determination of particle size by sieve analysis, specific gravity analysis, and determination of pozzolanic activity by conductivimetric test. Finally, the waste was used as supplementary material for mortar in partial replacement of Portland cement, in a rate of 15 % and 30 % of substitution. The compression strength of mortars was evaluated at 7, 28, 60 and 120 days for probes manufactured using a proportion of cement: sand of 1:3 on weight with water/cement ratio of 0.5 v/v and in probes with cement without sand. The substitution of 15 % of cement for the waste showed acceptable results of mechanical resistance, but at 30 % the influence was significant with a detrimental effect, however the strengths keeps inside the limits of the norms. We conclude that the waste can be added to mortars up to 15 % without influence on the properties of mortars, adding value to this residue and avoiding the cost of sanitary burial.