Ativação alcalina em peças de cerâmica vermelha.

Abstract

Geopolymers or alkaline activator materials are a class of materials that have characteristics and properties that are causing them to be used in various applications. The metakaolin is one of the most widely used materials for the synthesis of geopolymers being found in abundance in red ceramic pieces. Thus, the objective of this research was to activate alkaline red ceramic pieces in order to develop geopolymer material inside and enhance their mechanical properties. The clay was processed and characterized by X-ray diffraction and determination of its chemical composition. The bodies of the test piece was obtained by extrusion and fired at 700 oC. Was performed the physicalmechanical and mineralogical composition of burned bodies. Then the specimens used in evidence were submitted to activation by immersion in alkaline solution NaOH. We evaluated the influence of solution concentration, immersion time and the condition of curing on the mechanical strength of the bodies alkaline activator. We evaluated the evolution of mechanical behavior of bodies alkaline activator, to determine their mechanical strength after 30 and 60 days. Based on the results can be seen that the immersion time does not influence the modulus of rupture of the body cured at room temperature, while varying the concentration of alkaline activation solution increases the bending strength of the bodies cured at room temperature. Moreover, the concentration of alkaline activation solution does not influence the mechanical strength of cured bodies to 60 oC. The evolution of the modulus of rupture of the bodies alkaline activator, in the course of curing time depends on the curing temperature and conditions of alkaline treatment and observed that the highest modulus of rupture are obtained in bodies subjected to alkaline conditions and more severe cured at room temperature.