Avaliação de blocos intertravados com agregados reciclados provenientes de resíduos de construção e demolição de obras do município de Natal/RN

Abstract

This work aims to analyze the use of construction and demolition waste in Natal / RN as recycled aggregates for precast concrete paving blocks. In the first stage, the detailed characterization of the aggregates (fine and coarse) was carried out. The tests used for this purpose were grading curves, bulk density, dry specific density, powdery material, organic material, water absorption, X-ray fluorescence (FRX), X-ray diffraction (XRD) and electron microscopy of Scanning (SEM). From the characterization tests of natural and recycled aggregates is possible to analyze physical, chemical and microscopic properties. Ten different mixes were analyzed with an effective water/cement ratio of 0.4 for recycled rates of coarse and fine aggregates of 100%. This research analyzed the conditions of the recycled aggregates in the mixture (dry, washed and saturated), evaluation of the performance of aggregates in a concrete mix. The tests to analyze the technical viability of the concrete blocks, according to the specific norm NBR 9781 (2013), were compressive strength (at ages of 7, 14, 28 and 270 days) and water absorption (at ages of 28 and 270 days). To evaluate the durability, a prototype was constructed, which was analyzed after one year of construction. The blocks made with only recycled sand showed an increase in the results of compressive strength when compared to the reference blocks. The blocks made with recycled coarse obtained the smallest resistance. It was also observed that when the recycled aggregates are washed present a better performance in the final product. The results obtained were satisfactory for the application of the blocks in streets of low movement and low load. With the intense growth of waste from civil construction, the relevance of this research is proposes the manufacture of a sustainable product that aims to minimize the use of natural resources and promote a proper destination for the waste generated.