Computational and experimental research of the contact debonding process when rigid reinforcement is pressed into concrete

Flexible fittings with corrugated surfaces are traditionally used to improve the bond and minimize its debonding with concrete. But rigid I-beam reinforcements, the type required for heavy load bearing, are not corrugated. The onset of the debonding process that occurs when rigid I-beam reinforcement was pressed into concrete was established through comprehensive calculations and experimentation. The aim of the paper was to define the parameters and types of fractures in the “steel-concrete” contact zone. The Cohesive Zone Material Model (CZM), provided by ANSYS Workbench software, was used with the bilinear behavior law on the contact layer and described the separation of “steel-concrete" surfaces. A mathematical model of the contact boundary problem was solved by the finite element method. A comparison of calculations and experimentation confirmed that the bond for smooth rigid reinforcement for B35 class concrete is provided by adhesion; and it is best described by the CZM model. Distribution patterns of contact pressure in the contact zone and of shear stresses on the concrete faces and surfaces adjacent to the I-beam were revealed. The relative displacement of concrete when impacted by an external force was measured. Results of this investigation indicate that the mathematical model is consistent and reflects the experimental data.