Effect of partially replacing crushed oyster shell as fine aggregate on the shear behavior of short RC beams using GFRP rebar strengthened with TRC: Experimental and numerical studies

Abstract An experimental campaign was carried out in order to evaluate the shear behavior of beams. The crushed oyster shell (COS) was replaced partially with natural sand in different mixtures. All specimens maintained the same GFRP rebar arrangement and geometric properties, with several beams strengthened by U-shaped textile-reinforced concrete (TRC) configurations using either two or three layers of carbon textile. Through the three-point bending test on short-span beams, many characteristics reflecting shear performance were evaluated. Beams with TRC strengthening demonstrated enhanced shear resistance, up by 39–44% and by 49–58% in shear capacity observed in specimens, respectively, with two and three textile layers. However, the results also showed a significant reduction in shear performance by an increase to 40% as the replacement ratio of COSs. Additionally, a constitutive finite element model was developed and validated against experimental results, including load–strain relationship and failure mechanism. The simulation accurately predicted the load–deflection behavior with less than 10% deviation from the experimental data and effectively captured failure patterns. The work reported in this study indicates a luminous trend application of oyster shell concrete and gives a reference for improving the mechanical properties of beams strengthened by TRC.