Caracterização de concretos de reduzido impacto ambiental produzidos com a substituição parcial dos agregados naturais por agregados reciclados de artefatos de concreto

Abstract

The construction sector is known as the the largest residue generator of civil construction and industrial origin, besides being the largest consumer of natural resources existing, especially aggregates of mineral origin, one of the most used materials in its processes. Inside this panorama, studies about civil construction residue recycling as aggregates arise as an alternative to minimize the impacts caused by the sector . In this context, the present work aims to characterize aconcrete with a low environmental impact by replacing natural aggregates for recycled concrete blocks aggregates of factory origin. First, the constituent materials were characterized for the standardized specimens production with dimensions of 20x10 cm in the trace: 1:1,6:2,51:0,44. In order to correct greater water absorption of recycled aggregates and avoid problems with consistency and hydration, reference concretes were produced and a cone trunk slump test was realized. The obtained result became a reference for the following samples. The confection of recycled aggregate concrete was made replacing natural aggregates with recycled aggregates in the proportions of 5%, 10%, 15% and 20 %, and following the pre-established slump trunk. After the initial curing period (24 hours), the specimens were removed from the molds and proceeded to wet cure (28 days). Subsequently, capillarity absorption tests and resistance to axial compression test were performed. In view of the results, was possible to observe that the recycled aggregates concrete registers the values of average compressive strength between 88.7% and 97.95% of the value applied by the reference concrete. A greater water absorption by capillarity was observed and water rise by capillarrity in the concrete with larger amounts of aggregates, indicating that material is more porous than conventional concrete. The sample with substitutuion content of 5% presented better results, getting a very close values of mechanical resists and capillarity by absorption, comparing with reference concrete. Thus, it is concluded that, according to the initial results, is possible to produce concrete from recycled aggregates, being needed further studies to define its best application.