Experimental Investigation and Finite Element Analysis on Flexural Behavior of PVA Fiber-Reinforced Recycled Concrete Slabs

This paper presents an experimental study on mechanical behavior of Polyvinyl alcohol (PVA) fiber-recycled reinforced concrete (RC) one-way slabs. 21 specimens including 14 PVA fiber-reinforced recycled concrete slabs and 7 recycled RC slabs are fabricated and tested. The specimens are designed with different variables, such as replacement ratio of recycled coarse aggregate (RCA) γ, reinforcement ratio ρs, content of PVA fibers ρf, and span-to-thickness ratio I/h. The findings demonstrate that yielding of longitudinal reinforcement, breaking or pulling out PVA fibers along crack gaps and crushing of recycled concrete eventually dominate the failures of PVA fiber-reinforced recycled RC one-way slabs. The ultimate carrying capacity enhances as ρf or ρs increases, while decreases as I/h increases. The ultimate carrying capacity decreases with the increment of γ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\rlap{--} \gamma $$\end{document}, while the introduction of PVA fibers can alleviate this weakening effect. The ultimate carrying capacity of RCB and PRCB decreases by 11.96% and 2.15%, respectively when the γ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\rlap{--} \gamma $$\end{document} increases from 0% from 100%. The ultimate deflection first increases and then decreases as ρs increases. Increasing γ, I/h or ρf increases the ultimate deflection. Comparatively, the variation of PVA fiber content has a more prominent effect on the ultimate deflection of PRCB-U. The ultimate deflection of PRCB-U and PRCB increases by 73.03% and 15.15% respectively when the content of PVA fibers increases from 1% to 2%. A verified finite element (FE) model for PVA fiber-reinforced recycled RC one-way slabs under static load is established on account of rational constitutive relationship of materials. Then, the parametric studies are carried out to further reveal stress mechanism and the impacts of five main influence parameters on mechanical behaviors are ulteriorly analyzed. Ultimately, several design recommendations are suggested based on the experimental and FE analysis results. The suggested content of PVA fibers is between 0.5% and 2% and the optimal reinforcement rate ranges from 0.49% to 0.59%.