Estudo de compósitos geopoliméricos à base de metacaulim reforçados com fibras de rami e sisal

Abstract

The concrete, as it is largely used by civil construction industries, has also resulted in serious environmental impacts due to the emission of pollutants, mainly because of the production of Portland cement. In this way, the search for materials that can reduce the consumption of natural resources and energy, as well as reducing the generation of residues and gases harmful to the environment, has been intensified. One of the solutions is the replacement of Portland cement by new binders systems that use alkali-activated aluminosilicates, known as geopolymers, which have great ecological potential. It is also of interest to develop mixtures that have better ductility and tensile strength, without involving the use of materials that generate environmental impact, in this context, natural fibers appear as a good alternative. Thus, this work consists of the performance analysis of metakaolin-based geopolymers with addition of ramie and sisal fibers, aiming to increase the flexural strength of the geopolymer, as well as other related properties. Therefore, the source of aluminosilicate used was metakaolin, which had as an activating solution an association of sodium silicate and sodium hydroxide. Different fiber contents and lengths were studied to reinforce the geopolymeric matrix, in order to analyze the influence of these parameters on the physical-mechanical characteristics of the material. In addition, the results obtained were compared with ramie and sisal fibers, in order to evaluate the difference in behavior between them when used as reinforcement of geopolymeric composites. As a result, it was found that only the fiber content variable proved to be statistically significant; regarding the difference in behavior between the fibers it was attested that, for sisal fiber, the content was directly proportional to the mechanical properties, while, for ramie fiber, the content was inversely proportional.