INFLUÊNCIA DO TEMPO DE CURA SOBRE AS PROPRIEDADES DE UM NOVO CIMENTO GEOPOLIMÉRICO A BASE DE VIDRO RECICLADO

Abstract

Geopolymers, or “inorganic polymers”, are materials formed from the dissolution of natural raw materials based on aluminosilicates in an alkaline solutions. The result of this reaction is the formation of a synthetic compound, produced at low temperatures or even at room temperature. In this work, inorganic polymers were developed form recycled glass an agalmatolite. The Si/Al ratio esttablished in the formulation was 1.5. Cylindrical and prismatic specimens were obtained conventionally and cured at room temperature/23 days at 65 ^oC for different times. Denser microstructures were characterized with increased cure times, resulting better mechanical properties. Significant microstructures changes occur from 7 days of cure 65 ^oC, with the precipitation of prysmatic nephelene-like feldspathoid structures in the material pores. These structures seem to anchor the glass particles, been able to act as reinforcement of the polymeric matrix. The increase in these zeolitic precipitates produces microstructures with large total pore area,  however, with smaller diameters. At 28 days of curing, a real density of 2.29 g/cm³ was obtained, apparent density of 1.17 g/cm³, apparent prorosity of 24.8 % and values of mechanical resistance to compression and bendin above 10 MPa. However, in view of a trend towards the increase of these properties, it is considered that the geopolymer structure is not fully consolidated. The formation of acicular crystals of sodium carbonate heptahydrate in the microstructure of the material is a result of the carbonation of NaOH not reacted with atmospheric CO₂.