Flexural Response of Reinforced Concrete One-Way Slabs Embedded with Pet Bottles

Abstract

The feasibility of a cost-effective and eco-friendly slab system to be used in developing regions is investigated. The system consists of a thin reinforced concrete slab that is embedded with polyethylene terephthalate (PET) bottles as void creators. The voids will reduce the amount of concrete that could have been used in an equivalent solid slab without compromising the capacity. The main objective of this proposal is to investigate the flexural behavior of one-way reinforced concrete slabs embedded with PET bottles using laboratory experiments and numerical studies. To do so, 11 reinforced concrete slabs of 2200 mm length and 600 mm width were constructed and instrumented with strain gauges and LVDT’s and tested by a 4-point loading scheme under a displacement-controlled loading rate. The study considered the effect of the slab thickness (180 mm and 230 mm) concrete compressive strength (30 MPa and 50 MPa), steel reinforcement ratio (0.291% and 0.418%), percentage of the void (29% 22% and 17%) as well as top reinforcement ratio (0% and 0.192%). The results addressed stiffness, elastic behavior, yielding, post yield performance, ductility and ultimate strength. The behavior of tested voided slabs were compared with that of corresponding solid slabs. ACI-318 code equations were used to predict the moment capacities of the tested specimens. In addition, nonlinear finite element models were created using ANSYS and load-deflection curves from those models were compared with the experimental curves of the corresponding specimens. In general, findings of the study demonstrated that voided slabs exhibit on average a 5.1% decrease in moment capacity, 6.5% decrease in ductility, 12% increase in residual capacity factor and 4.29% decrease in stiffness. The ACI-318 code equations were found too conservative when used to predict the moment capacities of voided and solid specimens as on average, the experimental results yielded a 22.5% increase in moment capacity. However, in general finite element models created by ANSYS accurately predicted the flexural behavior of the specimens.