Study of method to characterize the physical properties of construction and demolition waste coarse aggregates. / Estudo de métodos para caracterização de propriedades físicas de agregados graúdos de resíduos de construção e demolição reciclados.




The low consumption of Construction and Demolition Waste (CDW) recycled aggregates happens, nowadays, because its natural variability and quality control absence that limit its use in applications with larger demands, such as concretes. One way of concrete aggregates control is done by determining its porosity, express by physical properties absorption and relative density. The method that measures its properties is the NM 53, standard derived from ASTM C127. But this standard was conceived to characterize natural aggregates, and is not appropriate on CDW recycled aggregates. In this way, the purpose of this work is to establish a quick and accurate method for quality control and selection of recycled aggregates in recycling plants, which could increase the possibilities of fields for its use. Thus, this work comparatively studied three distinct methods - NM 53, submerged mass in time and drying - for determining physical properties absorption and relative density of recycled aggregates. The experimental plannings were based on statistical models type Design of Experiments (DOE) that allow improvement on a selected process, in accordance with established needs, through analysis of possible significant variables for results. The adaption of NM 53 to recycled aggregates characterization depends on: 1) increase of sample pores saturation; 2) decrease of mass loss during the tests; and 3) increase of determination speed. After execution of experimental plannings, a new method for determining CDW coarse recycled aggregates physical properties could be proposed. This method statistically increased the measured absorption values (pores saturation increase), decreased mass loss during tests executions and reduced the characterization time from 48 hours (minimum used by NM 53) to approximately 4 hours. The method uses simple and low costs equipment, having real potential to be implemented for quality control of CDW recycled aggregates on recycling plants.


quality control agregados (reciclagem) controle da qualidade aggregates (recycling) concreto absorption resíduos de construção usinas de reciclagem de resíduos urbanos construction waste relative density absorção concrete

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