Avaliação do uso do resíduo cerâmico e do metacaulim para o desenvolvimento de cimentos sustentáveis

Abstract

The red ceramic industry is considered one of the sectors that contributes most to the global production of solid waste. In Brazil, in 2014, the manufacture of red ceramics, such as bricks and tiles, generated a significant amount of waste, estimated at between 3.9 and 6.5 million tons. These discarded materials can be reused in the construction industry as aggregates and cementitious materials. The main advantages are the saving of natural resources and the reduction of Portland cement, an industry responsible for large emissions of carbon dioxide into the atmosphere. However, exploring new types of cement using red ceramic waste is still an unfinished topic. Therefore, this study aims to evaluate the binary mixture of red ceramic waste (RCV) and metakaolin (MK) to obtain alkali-activated cements. For this purpose, damaged ceramic blocks were collected and processed to powder form, subsequently, 04 alkaliactivated pastes were produced with varying proportions of red ceramic waste and metakaolin. In the fresh state, the samples were subjected to the Kantro mini-slump test, setting time and specific gravity. In the hardened state, compressive strength tests were performed at ages of 7, 28 and 91 days, and the water absorption test. Finally, the microstructure of the compositions was analyzed by Scanning Electron Microscopy (SEM). According to the results obtained, the paste produced with 100% RCV precursor presented the largest spreading diameter of 94.5 mm and the composition with 75% MK and 25% RCV presented the highest compressive strength, with 42.79 MPa at 7 days. The formation of binder gels was observed in the microstructural analysis. Thus, the feasibility of using alkali-activated cement based on red ceramic waste and metakaolin in the production of cement pastes is confirmed.