Experimental and numerical investigation on bond behavior of deformed rebar in concrete with triethanolamine derivatives: A rib-scale study

This study focuses on the bond behavior of deformed rebar in concrete with triethanolamine (TEA) derivatives. Reinforced concrete members with different TEA derivatives were cast and the pull-out tests were conducted using a universal testing machine. A rib-scale 3D finite element analysis (FEA) was performed to explore the mechanical damage mechanism of concrete in the deformed rebar/concrete interface, using a refined deformed rebar model that incorporates realistic crescent ribs. The crack morphology and damage evolution of solid concrete in the members under pull-out load were analyzed. Concrete cracking behavior was simulated using the element deletion method, with criteria based on tensile strain, compressive strain, tensile damage factor, and compressive damage factor defined in the concrete damage plasticity model. Based on agreement with the experimental results, the effects of derivative types on the concrete damage characteristics as well as the micro stress and strain distributions on the main reinforcement surface were analyzed. Results demonstrated that the strain across the deformed rebar surface stabilizes when the applied displacement load exceeds 0.6 times the peak slip. Stress distribution on the main reinforcement surface exhibits significant variation within 20 mm from the loading end, following the order: TP-S1-35 > R-S1-35 > TDS-S1-35.