Title:
Flexure and Shear Behavior of Recycled and Natural Aggregate Concrete Slabs Reinforced with GFRP Bars (Prepublished)
Author(s):
Khaldoun Rahal, Aya Saad, and Ammar Al-Sayegh
Publication:
Structural Journal
Volume:
Issue:
Appears on pages(s):
Keywords:
concrete; deflection; GFRP bars; recycled aggregate; shear; slabs; strength
DOI:
10.14359/51751903
Date:
8/7/2026
Abstract:
The combined use of recycled aggregate concrete (RAC) and glass fiber-reinforced polymer (GFRP) reinforcement raises concerns regarding deflections, cracking, and shear resistance. This study investigates the serviceability and shear behavior of GFRP-reinforced RAC slabs. Eight slabs were tested in a four-point load setup: RAC slabs of two strength levels, reinforced with varying ratios of longitudinal reinforcement, and one control natural aggregate concrete (NAC) slab per concrete grade. All slabs failed in shear following significant flexural deflections. Results indicate that recycled coarse aggregates (RCA) use did not significantly impact service load deflections and maximum crack widths but slightly reduced the shear strength of the higher-strength slab. Furthermore, RCA use did not alter behavioral trends observed in NAC slabs, such as bilinear load-deflection curves, proportionality between crack width and GFRP bar strain, and increased resistance and decreased deflections with higher reinforcement ratios. Observed shear strength was conservatively estimated by ACI CODE-440.11-22 and CSA-S806 equations, and deflections were accurately predicted. ACI crack control provisions effectively limited crack widths to under 0.7 mm.