Claudio de Souza Kazmierczak

Carbonatação em concretos com agregados reciclados de concreto

Replacement of natural aggregates by recycled aggregates in new concretes can change the properties of this material, due to the porosity of the recycled aggregate and the surface characteristics of the recycled aggregate. This paper evaluates the influence of the strength of recycled concrete aggregate (RCA) in the profile of carbonation of concrete when natural aggregates are replaced by recycled concrete aggregate with different strength. Visual analysis of the carbonation using phenolphthalein indicates changes in the carbonation depth in regions occupied by recycled aggregates. The use of recycled concrete aggregate with higher porosity than the new concrete increase the carbonation depth, while the use of recycled concrete aggregate with lower porosity may result in a small decrease in the carbonation depth.

Estudo da influência dos agregados de concreto reciclado em concretos permeáveis

Resumo The expansion of urban areas under constant changes in the hydrological cycle directly affects the drainage of rainwater. The problems of urban drainage become major engineering problems to be solved in order to avoid negative consequences for local populations. Another urban problem is the excessive production of construction and demolition waste (CDW), in which , even with a increasingly policy of waste management , have been an end up being thrown in inappropriate disposal sites. Alternatively aiming to a minimization of the problems presented, we propose the study of permeable concrete using recycled concrete aggregate. In this study, there were evaluated the performance of concrete by means of permeability, consistency, strength, and interface conditions of the materials . Satisfactory relationships of resistance/permeability of concrete with recycled aggregate in relation to the concrete with natural aggregates was obtained, showing their best potential.

Environmental Evaluation of Stabilized and Solidified Products in Brazil: A Review

The diversity of industrial solid waste has grown exponentially in recent years, requiring waste management strategies focused on the reduction of associated environmental impacts. The solidification/stabilization (S/S) technique is increasingly used in the disposal or recycling of this waste. The Brazilian standard about the leaching of hazardous compounds in waste is being used to evaluate S/S products in their end disposal in landfills, with no description of any protocol to investigate performance during their life cycle, as observed when they are used as admixture to building materials. In this context, this study describes a qualitative review of leaching methods in use to assess S/S products in Brazil, in comparison with the main techniques adopted in other countries.

Contribuição à avaliação ambiental de materiais e componentes construtivos: proposta de método para obtenção de extrato lixiviado

Os materiais de construcao civil estao sujeitos a lixiviacao de seus constituintes, que podem levar a contaminacao do ambiente. No Brasil, a avaliacao ambiental de materiais e componentes com residuos e realizada por lixiviacao, empregando-se os mesmos metodos e parâmetros destinados a residuos, em pequenas amostras solidas, que nao reproduzem a forma de exposicao a que o componente e submetido. O presente trabalho propoe e discute a viabilidade de utilizacao de dois metodos de ensaio para a obtencao do extrato lixiviado para avaliacao ambiental de materiais e componentes construtivos: um por imersao, que simula um cenario de exposicao de intenso e prolongado contato com o lixiviante, como um alagamento; e outro por irrigacao, que busca simular uma exposicao a chuva acida. Como corpo de prova do material a ser testado, e proposto o emprego de placas com dimensoes de 25x200x400 mm, e, como meio lixiviante, uma solucao de acido nitrico ajustada para pH 3,0 ± 0,05. Foram produzidos corpos de prova de cerâmica vermelha, com e sem a incorporacao de oxido de cromo. Os testes foram conduzidos em quatro ciclos de 7 dias; ao final de cada ciclo foram coletas amostras do extrato lixiviado, renovando-se a solucao ao iniciar-se o ciclo seguinte. O extrato lixiviado apresentou comportamento coerente e compativel com os resultados obtidos pelo metodo proposto na NBR 10005 (ABNT, 2005a). Apos quatro ciclos de 7 dias de exposicao, foi possivel observar tendencia a estabilizacao na concentracao de Cr no extrato lixiviado, o que corrobora a viabilidade do experimento em 4 semanas.

Use of waste generated by shoe counter scrap pieces in plaster of Paris composites

The growing increase of industrial waste of difficult degradation is a major concern for industries due to environmental concerns and the strong action of environmental organizations. The ‘Centro Tecnologico do Couro, Calcados e Afins’ (CTCCA), in cooperation with a group of shoe companies, proposed a research project to the University Vale do Rio dos Sinos aiming at recycling counter scrap waste generated by shoe industries. The present paper describes the investigation undertaken by a research team at UNISINOS to develop a competitive alternative for recycling this waste material. In this study a new composite material combining plaster of Paris (gypsum) and waste ground in a knife mill was used. The different types and amount of waste materials available for recycling were studied to select the most suitable. This was followed by a thorough chemical and physical characterization. This work presents the mechanical properties of composites molded with plaster of Paris and counter scrap pieces, determined by compression, impact and flexure strength tests. Results so far indicate that the recycling of these materials in the production of a new construction material is a sound alternative. It was found that some admixtures significantly improve impact resistance properties. Additional characterization studies of these composites are currently under way, alongside with the determination of thermal, acoustic, and durability properties.