Punching shear capacity of rubberized high strength concrete slabs containing waste glass powder as cement substitute

This paper investigates the combined effect of crumb rubber (CR) and waste glass powder (WGP), which are partially substituted for fine aggregates (FA) and cement in concrete, respectively, on the punching shear behavior of high-strength concrete (HSC) slabs. Twelve separate concrete mixes were produced, each of which had a different ratio of CR and WGP. With 10 % incremental steps for each, four WGP levels varied from 0 % to 30 % as cement substitution and three CR levels varied from 0 % to 20 % as FA substitutes were considered. A total of twelve 1000 × 1000 × 100 mm simply supported reinforced HSC slabs were prepared and tested. The experimental findings revealed that the inclusion of 10 % WGP as a cement substitution resulted in a remarkable improvement in the punching shear capacity (V_u). On the contrary, the inclusion of CR caused a negative impact on the V_u of HSC slabs. From an engineering and environmental perspective, the mix containing a combination of 10 % WGP and 10 % CR proved to be the most suitable, as it has a slight impact on the V_u of HSC slabs. Five different approaches (ACI 318–2019, CSA A23.3, BS8110, Euro Code 2, and ECP 203) were used to predict the Vu, and the predictions were compared with the experimental findings. Moreover, the Applied Element Method was used to perform a numerical simulation of the slabs to validate the experimental findings and gain additional insights into the punching shear behaviour. The numerical model was calibrated against experimental data, achieving a mean error of approximately 1 % in ultimate shear force and ultimate deflection. The satisfactory agreement between the numerical and experimental results confirms the reliability and validity of the slabs' numerical modeling.