ABSTRACT The need for treated water is essential for life. With the constant increase in population, the most common way to purify surface water is through conventional water treatment plants (WTPs). The high volume of residue (sludge) generated in this process is most often returned to the catchment site, negatively affecting the ecosystem. The sludge of WTPs is similar to soil because it is composed of inorganic solids. Adobe is a construction material made from water and soil without the burning process, so it is considered sustainable, recyclable, and energy-efficient and can be stabilized with various materials. Therefore, the objective of this work is to develop adobes using the sludge of WTPs and to analyse their physical, mechanical and thermal properties. Adobes were produced with five concentrations of sludge by mass: 0, 1, 3, 5 and 7%. It was observed that with the increase in the sludge concentration, there was an increase in the capillarity and a decrease in mass, the water absorption was limited to 3% of sludge, and there was an increase in the bulk density. The linear shrinkage, thermal conductivity and compressive strength were not influenced. The addition of WTP sludge altered some properties of adobe. The use of WTP sludge in adobe is limited to 3%; above that, the adobe becomes unstable in relation to water. Therefore, the use of WTP sludge in the manufacture of adobe is feasible in controlled concentrations and is a sustainable use of the residue.

Este trabalho teve por objetivo avaliar a viabilidade técnica de produção de painéis cimento-madeira compostos por diferentes proporções de resíduos das madeiras de cedro-australiano (Toona ciliata M. Roem.), Pinus taeda e clone de híbrido de Eucalyptusgrandis x Eucalyptus urophylla,utilizando-se dois processos distintos de cura: vaporização e climatização. Foi utilizado o cimento Portland CP V - ARI/Plus como aglomerante e o cloreto de cálcio como aditivo químico. As partículas de madeira foram previamente tratadas em água fria durante 24 h. Foram considerados os seguintes parâmetros: relação madeira/cimento - 1/2,75; relação água/cimento - 1/2,5 (base peso do cimento); taxa de água de hidratação/cimento - 25% (base peso do cimento); aditivo químico - 4% (base peso do cimento); densidade nominal - 1,10 g/cm³; e dimensões dos painéis - 480 x 480 x 150 mm. Os parâmetros de prensagem foram: temperatura ambiente, pressão específica de 40 kgf/cm² e tempo de 10 min. O tempo de grampeamento foi de 24 h. As propriedades avaliadas foram absorção de água e inchamento em espessura após 24 h, flexão estática, compressão e ligação interna. O experimento foi instalado segundo um delineamento inteiramente casualizado com três repetições e seis tratamentos, arranjados num esquema fatorial de três composições x dois processos de cura. Os painéis compostos pela mistura de T. ciliata com o clone de Eucalyptus apresentaram valores médios superiores para inchamento em espessura e resultados inferiores para a maioria das propriedades mecânicas. A cura a vapor melhorou as propriedades físicas, mas afetou negativamente a maioria das propriedades mecânicas.

The objective of this work was to evaluate the technical feasibility of producing cement-wood panels made up from different proportions of Australian cedar (Toona ciliata M. Roem.), Eucalyptus grandis x Eucalyptus urophylla and Pinus taeda wood wastes using two different curing procedures: acclimation and vaporization. Portland CP V - ARI/Plus cement was used as binder and calcium chloride as additive. The wood particles were previously treated in water for 24 hours. The following parameters were considered for the estimation: wood/cement ratio- ½.75; water/cement ratio - ½.5 (based upon cement weight); hydration water/cement ratio - 25% (based upon cement weight); chemical additive - 4% (based upon cement weight); target density - 1.10 g/cm³; panel dimensions - 480 x 480 x 150 mm. The pressing parameters were the following: room temperature, specific pressure of 40 kgf/cm² and a time period of 10 minutes. Clasping time was 24 hours. The properties evaluated were water absorption and thickness swelling after 24 hours, static bending, compression and internal bonding. Experimental statistical design was entirely randomized with three replications and six treatments, arranged in a factorial design of 3 compositions and 2 curing procedures. Panels made from T. ciliata and Eucalyptus grandis x Eucalyptus urophylla presented higher average values for thickness swelling and inferior values for most mechanical properties. Vaporization cure improved physical properties, but negatively influenced most of mechanical properties.