Study of the compressive and tensile strengths of mortar with addition of red-ceramic waste

The increasing generation of wastes results in great concerns about the final disposition of certain materials. The waste from the red-ceramic industry has aroused interest for its potential use in concretes and mortars because of its composition, as well as its capability to generate a pozzolanic reaction. In this work, tests were done with the wastes collected in 3 industries (A, B and C) from the southern Santa Catarina State (Brazil). The wastes were characterized, and subsequently, mortars were produced with 10% substitution and addition in relation to the cement mass. With the use of an experimental design of mixtures, the influence of each waste on the compressive and tensile strengths of the mortars was verified. Although the chemical compositions and the X-ray diffractograms demonstrated similar characteristics for both wastes, the samples containing only C waste obtained better values of compressive and tensile strengths. Despite the differences observed in the mechanical properties between the mixtures, the statistical analysis of the experimental design proved that with 10% addition/substitution, the mechanical strengths were not significantly changed by the composition. Except for the composition with the addition of 10% waste, there was no statistical evidence that the mechanical properties of the mixtures combining the worst results of compressive and tensile strengths were different than the reference sample. The results showed that a part of the cement can be substituted by red-ceramic waste without affecting the mechanical performance of the mortar, and that with the additions, there is an increase in the compressive strength, enabling its incorporation and creating a way for the recycling of the material.