Uso de resíduo cerâmico em cimentos ternários tipo LC³ : estudo dos produtos da hidratação

Abstract

The partial replacement of Portland cement by supplementary cementitious materials (SCM) has been shown to be efficient to produce environmentally friendly cements. This study aims to use red ceramic waste (RCW) as calcined clay, instead of metakaolin, in the production of ternary cement as LC³. The objective of this work is to study the hydration products of LC³ cement containing Portland cement, calcined clay and limestone. At first, the physical, chemical and mineral characterization of the materials that make up the LC³ cement were carried out. Pozzolanic activity analyzes of the calcined clays were analyzed by Frattini, thermal analysis, SAI and modified Chapelle methods. Ternary cements were produced and analyzed for compressive strength and hydrated product formation by thermal analysis and X-ray diffraction. The results of chemical and mineralogical characterization of calcined clays showed that they have amorphous phase in their composition. The physical characterization shown in all SCM shows particle size suitable for use as mineral addition in cement. The ceramic waste presented pozzolanic activity in all types of analyzes. Although the its performance was inferior than metakaolin, the results of pozzolanic activity show that RCV has potential to be used as pozzolanic material in cements. In relation to LC³ cement pastes production, thermal analysis and X-ray diffraction results showed that LC³ cement hydration products with RCV are like MK paste. It was possible to identify the presence of ettringite, hemi and monocarboaluminate, calcium hydroxide and hydrogens. Cements produced with metakaolin resulted in the highest consumption of portlandite among the cements studied. The limestone proved to be more reactive with metakaolin than with RCW. Regarding to the mechanical performance, once again LC³ pastes with metakaolin and limestone resulted in the greatest mechanical strength, even surpassing CP V cement. It is noteworthy that cement produced with ceramic waste and limestone equal the compressive strength of the cement CP V. After all, it is possible to state that RCW can be used as MCS in the production of commercial ternary cements, thus contributing to an environmental impact.