Flexural ductility performance of hybrid-recycled aggregate reinforced concrete T-beam

Abstract

The major target of the current study is to evaluate the flexural ductility indices of the normal aggregate concrete (NAC) and recycled aggregate concrete (RAC) T-beams. Comparing different techniques (Azizinamini, Spadea and Grace) in measuring the ductility indices is another objective of this study. Four extensive T-beams were used, reference beam (T1) and semi-cast T-beams (T2, T3 and T4). Normal aggregate with high strength concrete grade (NAC-50) and recycled aggregate with normal and high strength concrete grade (RAC-25 and RAC-50) were used. Normal and semi-cast methods were adopted as the casting procedure. The results show that using the ductility indices as indictor to the deformability is a very significant technique for the evaluation of the tested beams. The results present also that the flexural performance has a small reduction when replacing the NAC by the RAC. The stiffness of the tested T-beams was associated with the concrete grade of the beam web-core in increasing and decreasing. The maximum and minimum total energy was dissipated by T2 and T3-beams respectively. The ductility indices of RAC-50 were declined by −14.49%, −10.04% and −14.89% in the μΔ, μE1 and μE2 respectively relative to the reference T1-beam. The usage of RAC-25 is led to a reduction by −52.68%, −45.62% and −54.21% in the μΔ, μE1 and μE2 respectively of the semi-cast T-beam. The statistical analysis shows that almost close values were presented between the displacement ductility index (μΔ) adopted by Azizinamini and the energy ductility index (μE2) by Grace.