Comparative numerical and experimental studies of the tensile strengths of concrete incorporating recycled and natural aggregates

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The aim of this study is to carry out a comparative numerical and experimental analysis of the tensile strengths of concrete. To do this, a physical and mechanical characterization of the aggregates was carried out, followed by the formulation of current concretes. Tensile strength characterization tests and a theoretical numerical study according to BAEL 91 revised 99 and Eurocode 2 of the concrete samples were carried out. The analysis of tensile strengths shows that at 7 days of age the average tensile strengths calculated according to Eurocode 2 are higher than those experimental and BAEL 91 revised 99. At 28 days of age, the experimental results are higher than the theoretical results obtained, except for the average tensile strengths of BR2 (2.25 MPa) and BC1 (2.23 MPa) of Eurocode 2, which are slightly higher than those obtained experimentally (BR2=2.08 MPa ; BC1=2.09 MPa). Furthermore, the relationship established between the theoretical and experimental results shows at 7 days of age that the average tensile strengths according to BAEL 91 revised 99 are closer to those experimental with respectively a correlation coefficient and the standard error equal to 0.502 and 0.1687. At 28 days of age those of Eurocode 2 are closer to the experimental values with respectively a correlation coefficient and the standard error equal to 0.9206 and 0.0813. From these analyses, it can be seen that Eurocode 2 provides a better prediction of the mechanical tensile behaviour of concrete based on recycled and/or natural aggregates.