The Constitutive Relationship for Corroded Steel Bars: Model and Analysis

Abstract

Combining the theoretical derivation and numerical calculations, the characteristic changes of the tensile constitutive relation of corroded steel bars and their underlying mechanisms are studied. Corroded steel bars are regarded as a combination of three parts, which include uncorroded part, corroded part with variable cross section, and uniform corroded part. It is assumed that in all three parts the steel material follows a simplified trilinear constitutive relation of a mild steel material (elasticity, yielding, and hardening), from which an analytical model describing the overall tensile constitutive relation of the corroded steel bar is developed. Based on the experimental data of slotted steel bars, the validation of the present analytical model is provided. The results show that the trilinear model can give relatively accurate prediction of the characteristic parameters of corroded steel bars. The influences of corrosion rate on the mechanical properties of corroded steel bars are examined using the proposed model.

Prediction of RC Bridge Member Resistance Decreasing in Time under Various Conditions in Slovakia

“…This corrosion model assumes the creating of the corrosion products on the surface of the material that protects the original metal and slows down the corrosion losses. This protective layer, during the first twenty years represented by a power function of the corrosion loss D corr (t as ≤ 20) (14), then follows the linear function of the corrosion loss D corr (t as > 20) (15). The exponent b can be calculated either by a chemical composition of a metal or the recommended value for carbon steel is b = 0.523.…”

“…The corrosion of reinforcement does not influence only the resistance (bending, shear) of member-Ultimate Limit States (ULS) [8][9][10], but it also influences the durability of members [11,12] and crack development-Serviceability Limit States (SLS) [13]. The research activities are also focused on the influence of corrosion on mechanical properties of steel reinforcement [14,15].…”

Chloride Distribution and Steel Corrosion in a Concrete Bridge after Long-Term Exposure to Natural Marine Environment

“…Expansion of corrosion products may cause cracking and spalling of the cover concrete, which will then no longer protect the reinforcing steel effectively. Furthermore, the mechanical properties of steel bars were greatly impacted by the increase in corrosion degree [ 7 , 8 ].…”