Uso e Aplicação do Poliestireno Expandido (EPS) Reciclado para Impermeabilização por Impregnação de Superfícies de Concreto Pré-fabricado

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The performance and the surface appearance of concrete are both related to its porosity. A reduction in porosity, with a consequent reduction in permeability, could be an option for increasing the durability of the concrete and preserving its surface characteristics. Esthetically, deterioration of the concrete surface causes an imbalance in the utility x appearance equation, and reduces the aggregated value the building by causing a negative visual impact on the environment. A serious problem that currently confronts our major urban centers is graffiti and the unauthorized posting of bills on both public and private buildings. A prophylactic, and economically feasible, treatment of the concrete surface could significantly reduce the impact of these practices, by making the cleaning operation both easier and more efficient, and thereby contributing to an improvement in the quality of life for the population as a whole. This research project was developed in order to identify a new material to be economically, efficiently and easily applied, as part of the PIC (Polymer Impregnated Concrete) system, so as to reduce the permeability of pre-cast concrete surfaces, thereby, reducing the rate of degradation and increasing overall durability. Addition aims are: a) using materials which do not affect the visual aspect of the concrete, so that the system can be used on monuments and other elements that are exposed to inclement weather; b) developing a new technology that makes use of recycled polymers, thereby contributing both socially and environmentally. Expanded Polystyrene (EPS) is widely used in industry, principally in the packaging sector. This material presents a number of significant features, including: a low water absorption coefficient; a slow aging process; pathogenic innocuousness (i.e. it does not possess substrata for the proliferation of animals and/or microorganisms; among others. On the other hand, in most cases, final disposal of the material is extremely detrimental to the environment: recycling is limited, and there is a real need for alternative applications of waste EPS. A further benefit lies in the fact that by increasing the durability of concrete (one of architectures most common structural elements, both historically and at the current time), maintenance and repair costs may be significantly reduced. During the study, concrete test cylinders with a single water/cement ratio were used, so as to maintain the same porosity index for all test samples. In order to reduce the permeability coefficient, the test cylinders were immersed, in the laboratory, in two distinct solutions of EPS dissolved in commercial solvents. Three different time periods were used for immersion in the EPS solutions. Using the concentration of EPS in the solution and total immersion time as references, the efficiency of the treatment in reducing the permeability of the concrete was evaluated. The treated test cylinders were subjected to the following tests: water absorption; liberation of chloride ions in water (Milli-Q); verification of the treatment depth by ultraviolet; electronic microscope sweeps (MEV); biological surface growth on treated and untreated test cylinders; and mercury porosity tests. The results were promising and showed a significant reduction in water permeability, reduction in porosity and, consequently, a reduction in the proliferation of fungus on the surface of the concrete treated with EPS.

ASSUNTO(S)

reciclagem profissional impermeabilização engenharia de materiais e metalurgica poliestirenos superfícies (tecnologia) cocreto pré-moldado

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