Avaliação das propriedades pozolânicas de um resíduo de cerâmica vermelha para emprego como material cimentício suplementar

Abstract

The final destination environmentally suitable for industrial solid waste is a problem that came gaining more importance over the years. The construction industry consumes large amounts of supplies, generating parallel large quantities of waste. When it comes to recycling of industrial waste, the construction sector plays an important role, recycling waste from various sectors of the economy. Considering the existence of the ceramic polo at the Rio Grande do Sul, and all red ceramic waste (RCV) resulting from this pole, we sought through this study, find what is the percentage of RCV generation in a specific company due the great variability of the data presented in the literature. And in parallel we sought to evaluate the potential of pozzolan RCV and compare their performance with metakaolin, material already recognized as pozzolan. The binder (cement CP II-F-32, Ca(OH)2 – P.A., CH-I) and pozzolanic materials (RCV and metakaolin) employed in the study were chemically characterized by X-ray fluorescence assays (XRF) and Loss Fire (PF), mineralogically by testing X-ray diffraction (XRD) and physically by tests of laser granulometry, specific gravity and specific surface area (BET). Furthermore, the RCV and metakaolin were subjected to tests for determination of humidity content and fineness. To evaluate the pozzolanic activity of the RCV and compare its performance to metakaolin were performed electrical conductivity tests, thermogravimetry and compressive strength tests, guided by the NBR 5752:2014, NBR 5751:2015 and NBR 15894:2010. From the results obtained, found to the percentage of RCV generation in study subject company with the characterization tests it was verified that the RCV meets chemical requirements of the NBR 12653:2014. The grinding procedure gave the RCV adequate particle size for use as pozolona. As the pozzolanic activity, it was found that the RCV met requirement the NBR 12653:2014 with regard to resistance to Ca(OH)2 P.A. agglomerating, since when tested with CH-I agglomerating, the RCV showed compression resistance the considerably higher than metakaolin. Already in the cast with cement mortar, the RCV has not reached the pozzolanic activity index (IAP) required in NBR 12653:2014 preventing classification as pozzolanic material. In mortars tested under the requirements of NBR 15894:2010, containing 15% replacement of cement by RCV, the compressive strength results showed no significant differences from the reference mortar, indicating better performance indications in lower replacement levels. The thermal analysis showed the consumption of Ca(OH)2 pastes. The pastes formulated with 25% of the cement replaced by metakaolin showed increased consumption of Ca(OH)2 relative pastes formulated with 25% RCV, showing the pozzolanic activity of the materials.