Analysis of interfacial shear behavior between concrete and wood under water immersion based on experimental and finite element approaches

Exposure of wood-concrete composites to moisture leads to wood swelling, cracking, and distortion, negatively affecting load-bearing capacity and bond strength at the interface. This research experimentally and numerically investigates the bond properties between wood and concrete under water immersion. Eighteen composite wood-concrete specimens subjected to double shear push-out tests were evaluated to assess the impact of the bonding method (epoxy alone, steel anchors alone, or a combination of epoxy and steel anchors) on bond characteristics. Additionally, the influence of environmental conditions (dry state or water immersion for 30 days) was evaluated in terms of failure modes, axial load-slip responses, stiffness, and absorbed energy. The cross-sectional area of the wooden element was also considered (30 × 100 mm², 60 × 100 mm², or 100 × 100 mm²). In addition to the experimental program, ABAQUS software was used to develop a three-dimensional numerical model to analyze variations in shear stress distribution along the interface based on the bonding method and environmental conditions. The combination of steel anchors and epoxy effectively resisted deformations in the wooden section caused by water exposure, outperforming epoxy alone or steel anchors alone. Specimens bonded with epoxy alone failed due to interfacial debonding, while those bonded with steel anchors alone failed due to concrete crushing. In contrast, specimens bonded with both epoxy and steel anchors delayed failure until the wooden element ruptured. Consequently, the dry specimen with a cross-sectional area of 100 × 100 mm², bonded to concrete using both steel anchors and epoxy, recorded the highest ultimate load of 270 kN, whereas the corresponding specimen under water immersion reached 235 kN. • Experimental and numerical evaluation of wood concrete interfacial shear behavior under water immersion • Comparative assessment of epoxy bonding, steel anchors, and combined bonding systems • Water immersion significantly reduced bond strength and stiffness for epoxy bonded interfaces • Combined epoxy and steel anchors effectively mitigated moisture induced deformation and delayed failure • Finite element analysis revealed non uniform shear stress distribution governed by bonding method and exposure condition