Technological characterization and utilization of recycled aggregate in the fine fraction in substitution to the fine natural aggregate for concrete production

Abstract

Civil Construction and Demolition Waste (CDW), after screening process, can go through benefication process which enables physical alterations obtaining samples with different granulometry. X-ray diffraction tests were performed in order to identify the mineral components present in the samples. The Scanning Electron Microscopy (SEM) analyzes showed that the samples had rough surface texture with grains present in different formats. The chemical properties are the conditioning factor of the affinity between the aggregate and the binder, and can contribute to the early degradation of the structures. The analysis of physical and mechanical properties is important because, in addition to assessing mechanical strength performance, it also analyzes the performance of CDW concrete. The compression tests and modulus of elasticity of an aggregate are not easy to measure because the particles cannot be tested alone. Test bodies were produced with fractions of 10%, 20%, 30%, 50%, and 100% RCD. As a result of the mechanical tests performed in these test bodies it was observed that the fractions with up to 30 % recycled aggregate obtained good compressive strength ranging from 33 MPa to 46 MPa, with modulus of elasticity varying from 24.96 GPA to 31.54 GPA. However, the same result was not obtained for the fractions that had above 50 % recycled aggregate in the concrete trait that had compressive strength ranging from 10.8 MPa to 15 MPa, with modulus of elasticity varying from 11.82 GPA to 14.45 GPA.