Effect of fine and coarse recycled concrete aggregate on the mechanical behavior of precast reinforced beams: Comparison of FE simulations, theoretical, and experimental results on real scale beams

Abstract

[Abstract:] In this work, we present the effect of using coarse and fine recycled aggregate jointly as a partial replacement of natural aggregate in self-compacting concrete in the mechanical performance of precast beams. The replacement levels of recycled aggregate were set to 0%, 20%, 35%, and 50% of the total amount of aggregate. The effect of the partial replacement of coarse and fine recycled aggregate jointly in the mechanical and physical properties of concrete was analyzed at 28 days. Then, a total of 8 reinforced beams were cast (two beams per each concrete studied) to determinate the effect of the partial replacement of recycled aggregate. One of the beams of each concrete was designed and tested to determine the flexural strength, and the other beam was used to determine the shear strength. The flexural and shear strengths obtained from the tests of real-scale beams were compared with theoretical analyses based on standards EC-2 and EHE-08, and by computational analyses based on the finite element method (FEM). These comparison, allowed us to assess the use of theoretical and computational models as tools to predict the mechanical behavior of real scale beams under different loading conditions (flexural and shear tests) when different proportions of recycled aggregate are used. According to the results, for the shear test, the theoretical models based on standards can be applied for concrete structures regardless of the percentage of recycled aggregate, without losing accuracy in comparison with beams made of plain concrete. In contrast, under flexural conditions, the theoretical models based on the standards are only applicable when considering 20% or less recycled aggregate. In general, computational models based on FEM show good agreement with experimental results in all the studied cases.