Ground waste ceramic brick effect at different times on mortar

Abstract

The work aims to observe the effect of waste ceramic brick (WCB), ground in two times, 60 and 120 min for use in mortar. The crystalline phases presented in clays of the north of Rio de Janeiro have already been identified, indicating that after firing at an adequate temperature, it is possible to apply it as a pozzolanic material. In this direction, in Brazil there is a single metakaolin industry in São Paulo operating in the domestic market supplying pozzolanic material for all regions of the country. The researched material was burned in the industry at approximately 700 °C, and its pozzolanic activity was tested by the Luxán test presenting 2.01 mS/cm (good pozzolanicity). The mortars proportions were 1:6 (cement: sand), with the addition of 0% (reference), 10%, 20% and 30% of WCB, and their crystalline phases were analyzed by XRD and it was not identified a kaolinite peak, a good indication of the transformation to metakaolinite. The tests in both fresh and hardened state were performed. For both grindings, the residue reacted with the paste, a fact confirmed by the nucleation calorimetry of particles <2 μm (20%–25% clay fraction), reducing the pore size from 0.90 to 50 μm to 0.008 at 5 μm, forming C–S–H in the XRD and the portlandite peaks disappearing when compared to the reference. The results showed that the best result was 10% incorporation, both for WCB ground for 60 and 120 min, and this is the proportion indicated.