Cracking Of Concrete Cover Research Articles

Mechanics of durability of structural concrete: new approach to the phenomenon of degradation. Part 2. Corrosion of reinforcement

There are several models in which the corrosion rate, rust expansion, and resulting crack propagation around reinforcement can be assessed. The effect of crack-induced corrosion on the behavior of the structure can also be assessed. Several methods have been proposed to evaluate the mechanical performance of reinforced concrete structures with corroded reinforcing bars. Changes in the mechanical properties of reinforcing bars, concrete and their interactions need to be modeled based on the concept of analytical methods. The load-bearing capacity of reinforced concrete beams with reinforcement corrosion was calculated using the finite element method. The influence of reinforcement corrosion is considered from the point of view of changes in the mechanical properties of reinforcement and adhesion of reinforcement to concrete. Instead of reducing the cross-sectional area of the reinforcement, the Young’s modulus and yield strength of the corroded reinforcement are reduced. Numerical modeling of the structural performance of reinforced concrete structures with reinforcement corrosion using a finite element program has shown that modeling of structural deterioration, such as reinforcement corrosion and concrete cover cracking, sometimes has a large impact on the analytical results. The structural characteristics of reinforced concrete elements with reinforcement corrosion are calculated. Using this modeling method, an analysis of the degree of influence of corrosion on structural characteristics was carried out.

Meso-crack propagation of RC induced by non-uniform rebar corrosion and the predictive model of time to concrete cover cracking

Non-uniform corrosion expansion in reinforced concrete (RC) structures will lead to concrete cracking, bond degradation, and an overall reduction in load-bearing capacity, severely threatening structural safety and durability. Accordingly, meso-crack propagation of RC induced by non-uniform rebar corrosion and the predictive model of time to concrete cover cracking are investigated in this paper, and the theoretical solutions for the critical corrosion rate and the corresponding time are proposed for structural durability evaluation and design. Firstly, based on the mesh-mapping technique of multi-shape random aggregates, a finite-element generation method for three-dimensional concrete three-phase meso-scale model is proposed, with modeling corrosion-expanded cracking of RC, reproducing the crack morphology and propagation process of concrete cracking due to non-uniform rebar corrosion. Subsequently, single factor influence analysis and multi-factor orthogonal test were employed to reveal the degrees of influence of various factors on the critical corrosion rate as follows: concrete strength > cover thickness > interface layer strength > aggregate content > aggregate grading > aggregate shape. A theoretical predictive model for the corrosion expansion cracking time of the RC cover was proposed, considering the influence of key factors including concrete strength and cover thickness. Finally, the validity of theoretical prediction method and the numerical model’s damage mode are verified through accelerated corrosion tests of RC.

Local scour effects on seismic behavior of pile-group foundations in cohesionless soils: Insights from quasi-static tests

Local scour has been reported as a common phenomenon for pile-group foundations in marine, coastal, and riverine sites, while its effects on the seismic behavior of pile-group foundations are yet to be well documented. This paper reported a pair of quasi-static cyclic loading tests on 2 × 3 scoured pile-group foundation specimens, one in global scour and the other in local scour, to understand the influence of local scour on the seismic behavior, particularly in terms of soil-pile interaction features and failure mechanisms. Test results indicate a flexural failure mode for both specimens. Local scour does not change the order of limit states but postpones the occurrence of concrete cover cracking and rebar yielding due to the reduced lateral stiffness of the locally scoured piles. Moreover, local scour rarely changes the aboveground damage regions at the top of outer piles (one time the side length of squared pile section, D), but significantly aggravates and deepens the underground damage regions at outer piles (from 4 ∼ 5D for global scour to 3.7 ∼ 6D for local scour). Besides, local scour reduces the displacement ductility factor from 2.50 to 1.25 for the Easy-to-Repair limit state, resulting in adverse impacts on pile-group foundations in general.

Creep Effect on Time to Corrosion-Induced Cracking of Concrete Cover

This paper presents an innovative method to include creep deformations in the prediction of time to corrosion-induced cover cracking. Using experimental results, creep and cracking criteria used in this method are verified. It is argued in the paper that the cover cracking problem under corrosion is close to a relaxation problem and the conventional creep formulations based on the effective elastic modulus cannot be adopted. It is found in the paper that accurate consideration of creep deformation would lead to about 30–40% longer time to cover cracking when compared to no consideration of creep deformations whilst for the currently practiced methods, the time can be up to 200% longer, which is unconservative in predicting time to cover cracking. Results in this paper open the debate on modelling of creep in the analysis of corrosion-affected structures and serve as an important step towards the accurate prediction of corrosion-induced concrete cracking.

Investigating non-uniform corrosion induced concrete cover cracking with a fracture-contact coupled computational method

Corrosion of steel rebar causes cracks in concrete, significantly impacting the durability of reinforced buildings. While various computational methods aim to simulate this process, only a few successfully handle both internal corrosion pressure and surface crack width evolution. To address this limitation, the study introduces an innovative mesoscale fracture-contact coupled computational method that seamlessly integrates with ABAQUS. Unlike current methods, it creatively utilizes interface elements to model stress transfer and crack propagation under tension in concrete. Additionally, it includes an additional contact model to represent the material's response to compression and shear forces. These innovations allow for accurate simulation of plain concrete mechanical properties under both tension and compression, effectively illustrating the development and failure patterns of cracks in the reinforced concrete cover. After calibrating and validating the method, the study thoroughly analyzed the process of concrete cover cracking, considering factors such as water to cement ratio, spatial location, geometry and size of coarse aggregate, rebar diameter and cover thickness. The modeling results reveal the following findings: (i) Changes in the shape and size of coarse aggregates have minimal effects on internal pressure and crack width. (ii) Higher concrete strength correlates with increased pressure on the outer surface of the rebar in an almost linear fashion, but it has little impact on surface crack width. (iii) Increasing the bar diameter decreases rust pressure but results in more cracks and wider surface cracks. (iv) Augmenting the cover thickness intensifies rust-induced pressure while simultaneously widening surface cracks.

Cracking time and prediction model of low-alloy steel reinforced seawater sea-sand concrete based on DIC technology

The cracking of seawater sea-sand concrete (SSC) cover due to the corrosion of low-alloy steel (LS) is a critical factor affecting its serviceability and durability. To analyze the cracking behavior of the SSC cover, a thick-walled cylinder model was developed in this study. The cylinder was divided into multiple coaxial rings of equal thickness, and damage variables were introduced to determine the extent of damage for each cracked ring based on the position of the rust expansion crack front. A predictive model for the cracking time of SSC cover was established by using the displacement compatibility equation at the interface of reinforcing steel and cover concrete, in combination with Faraday's law. To verify the accuracy of the model, the Digital Image Correlation (DIC) technique was utilized to determine the timings of two pivotal stages: the initial cracking and complete cracking of the cover. The comparison between the predictive outcomes and experimental results showed an error range of 4 %–10 %, indicating that the predictive model is relatively accurate.

Three-Dimensional Finite Element Modelling for Prediction Corrosion Induced Cracking Damaged in Reinforced Concrete Beam

The quality and condition of the reinforced concrete structure is critical, particularly in high-rise buildings where the danger of service life failure is extremely high. Usually, certain structures collapse as a result of cracks and spreading caused by corrosion. Due to this reason, there is a requirement for software program that can promptly measure and evaluate the strength, growth, and longevity of the structure. Researchers use Finite Element Modelling (FEM), a reliable approach to foresee the deterioration and fracturing of structures. The application of finite element modelling in determining the remaining strength of damaged components can provide crucial data, which is particularly relevant for engineers in real-world scenarios. Moreover, it has the ability to replicate the cracking caused by corrosion in reinforced concrete elements. A corrosion-induced cracking model is suggested to be included into a three-dimensional plane-stress finite element model. The cracking model provides an indication of the extent of corrosion-induced damage in the concrete, allowing for the study of strength and behavioural changes. The effect of corrosion-induced cracking in a thick wall cylinder model will be simulated by the finite element model in order to identify and analyse the cracks caused by corrosion in the concrete cover. A corrosion-induced cracking experiment will be conducted with two different cover thicknesses and reinforcement using the Midas FEA commercial software to create a three-dimensional model. There is a slight discrepancy between the numerical analysis modelling and the analytical approach in terms of the crack's initiation and propagation, mostly resulting from variations in modelling assumptions, methods, and parameters. This disagreement arises when comparing the numerical analysis model with the previously published work. Nevertheless, the numerical model may be used to simulate both crack propagation and the critical pressure needed to produce corrosion-induced concrete cover cracking.

The impact of the nonlinear concrete behaviour on the required liner thicknesses of spray-repaired concrete pipes

Buried reinforced concrete pipes (including sewers, stormwater pipes and other gravity flow structures) that experience unsafe levels of deterioration are commonly rehabilitated using trenchless solutions, such as the application of cementitious liners. Cementitious liners are centrifugally cast onto the inner surface of the damaged pipes with a spinning head that travels along the length of the pipe. Once cured, the liner increases the strength of the damaged pipe to resist applied earth and surface loads. A design method previously proposed by the authors provides guidance for selecting the required liner thickness to rehabilitate deteriorated concrete pipes situated at deep burials. However, this design method considers the linear elastic behaviour of the soil and pipe materials. Neglecting the nonlinear effects of crushing concrete within the host pipe may impact the predicted liner thicknesses for repair. Thus, the current study evaluates the impact of incorporating nonlinear compressive material behaviour on the required liner thicknesses to repair damaged concrete pipes. The required liner thicknesses obtained from the nonlinear version of the design method for rehabilitations of several pipes selected from the ASTM C76-11 Standard experiencing varying levels of deterioration are compared to thicknesses obtained using the authors' linear elastic solutions. The comparisons indicated that considering the nonlinear material response of the concrete generates slightly larger estimates of required liner thickness. The discrepancies between the estimated liner thicknesses were observed to be insignificant for pipes experiencing cracking and losses of concrete cover, demonstrating that the linear elastic model is suitable for design purposes. However, for damaged pipes situated at deep burials experiencing losses of tensile reinforcement, the discrepancies between the liner and nonlinear calculations become more significant. It is recommended that the results of the linear elastic model be checked with the nonlinear model for the repair of pipes experiencing loss of tensile reinforcement, or for deeply buried pipes.

Concrete Cover Cracking and Reinforcement Corrosion Behavior in Concrete with New-to-Old Concrete Interfaces.

In reinforced concrete (RC) structures, new-to-old concrete interfaces are widely present due to precast splices, repairs, and construction joints. In this paper, both monolithic and segmental specimens were fabricated with five kinds of water-cement ratios, including ordinary and high-strength concrete. The impressed current-accelerated corrosion test was used, and the degree of reinforcement corrosion was controlled by Faraday's Law. In the accelerated corrosion process, the concrete surface cracking, steel corrosion, and mechanical properties of the corroded steels in the segmental specimens were investigated and compared with monolithic specimens considering the pouring method, concrete strength, and the strength difference between new and old concrete. The prediction of concrete cracking time was also discussed. The results indicated that, for the monolithic specimens, longitudinal cracks could be observed on the ordinary concrete surface, while no cracks were produced on a high-strength concrete surface; only the rust leaked out at the ends. For the segmental specimens, both longitudinal and transverse cracks were produced on an ordinary concrete surface, while only transverse cracks were produced at the high-strength new-to-old concrete interfaces. The steel embedded in the segmental specimens suffered more sectional loss at the new-to-old concrete interfaces. An influence coefficient based on the section loss of the rebar was proposed to evaluate the influence of interfaces on the rust uniformity of rebars. When there were differences in strength between new and old concrete, the influence of the interface on the uniformity of steel bar cross-section loss slightly increased. Based on available theoretical analysis for uniform corrosion, the concrete cracking time of the monolithic specimens was predicted, which was basically consistent with experimental phenomena. However, further research is needed to predict the service life of segmental specimens with new-to-old concrete interfaces.

Investigation of the filling-overflow behavior of corrosion products in reinforced mortar

The investigation of the filling-overflow behavior of corrosion products in concrete is important for accurately predicting corrosion-induced concrete cover cracking. This paper utilizes the ethylene diamine tetra acetic acid (EDTA) titration method to quantitatively study the iron content in each zone of corroded reinforced mortar specimens. Based on this, the proportion and distribution of corrosion products are analyzed. Results show that approximately 50% of the corrosion products are transported to the mortar and corrosion products show a transport pattern to the surrounding low-concentration area in mortar. The direction of ion invasion on the mortar specimen does not exhibit a significant impact on the transport of corrosion products, while both the geometric size and quality of the mortar specimen affect the transport of corrosion products. Furthermore, the proposed method employs EDTA titration to quantify the filling and overflow of corrosion products, providing a valuable approach for further experimental research.

Blast fragility assessment of aging coastal RC columns exposed to non-uniform CIC attacks using LBE function

Along the service period of aging coastal reinforced concrete (RC) structures, chloride-induced corrosion (CIC) is a major cause affecting their life-cycle performance and durability. RC columns are the important vertical members of many long-span highway bridges and high-rise buildings, and they are vulnerable to the deterioration effects caused by non-uniform CIC and the intentional terror activities or accidental explosive attacks. The catastrophic failure of RC columns could trigger the progressive collapse of buildings and bridges, leading to huge economic losses and casualties. Very few studies have investigated the time-dependent blast fragilities of deteriorating coastal RC columns exposed to non-uniform CIC. To this end, we proposed an integrated time-dependent blast fragility assessment framework for aging coastal RC columns, considering the deterioration effects caused by non-uniform CIC in marine conditions. Firstly, a three-phase time-variant deterioration rate model for steel bars that considers the accelerated increase of the steel corrosion rate after the cover concrete cracking was incorporated in the analytical modeling of non-uniform CIC of aging RC structures. Secondly, Load-Blast-Enhanced (LBE) function in LS-DYNA was implemented to numerically simulate blast loads, and the effectiveness of the numerical models was validated by the available field blast test results reported in the literature. Subsequently, the performance damage states (e.g., low, medium, and high) of RC columns under intensive blast loads were defined in terms of the damage degree index (D) by using the LBE method, and the pressure-impulse (P–I) models were constructed accordingly. Finally, by using the scaled distance (Z) as the blast loading intensity measure (IM), Monte Carlo Simulations (MCS) were used to conduct the blast fragility analysis for a typical aging coastal RC column. The proposed time-dependent blast fragility assessment framework for aging RC columns is demonstrated to be appropriate and effective in evaluating their deteriorated blast loading-resistance, and it is also a good candidate to estimate the time-dependent blast fragilities of deteriorating coastal RC columns.

Research on Corrosion Rate Model of Reinforcement in Concrete under Chloride Ion Environments

In a chloride environment, taking reinforced concrete structures as the research object, the corrosion rate of reinforcement determines its corrosion expansion because multiple coupling parameters will affect the corrosion rate of reinforcement, which is extremely difficult to effectively predict. In this paper, 144 sets of experimental data were collected and sorted out by reading the relevant literature, and six empirical models for predicting the corrosion rate of steel bars were compared and analyzed based on these experimental data. Based on the investigations, a new empirical model is proposed for predicting the corrosion rate of reinforcement, and the relevant influencing factors are considered in the new model. By comparing the 144 sets of experimental data and 90 experimental data for this paper, the new prediction model can well predict the corrosion rate of reinforcement. Furthermore, the time variability of the new prediction model is verified. The probability distribution characteristics of seven prediction models are obtained through model error analysis, which provides a theoretical basis for the next step of concrete cover cracking and reliability analysis.

Phase-field method for modeling non-uniform corrosion-induced cracking in concrete

Non-uniform corrosion of rebar leads to the cracking of the concrete cover, which reduces the reliability of structures and increases maintenance costs. In this paper, we present a coupled phase-field model at the mesoscale to investigate the time-dependent process of non-uniform corrosion-induced cover cracking. This model couples chloride and oxygen diffusion, electrochemical reaction, and concrete cover cracking. A time-dependent non-uniform corrosion model is established based on chloride diffusion and electrochemical theory by considering the cracking effect. The cracking behavior of the concrete cover is described using a phase-field regularized cohesive zone model. The model was verified against several experiments available in the literature. Parametric studies were conducted to observe the effects of the crack and chloride diffusion coefficient, the interaction between the corrosion of multiple rebars, and the crack characteristics in three dimensions.

Safety Analysis of Rebar Corrosion Depth at the Moment of Corrosion-Induced Cover Cracking

Concrete cover cracking induced by reinforcement corrosion is an important indication of the durability limit state for reinforced concrete (RC) structures and can be used to determine the structural service life. The process of rebar corrosion from the beginning of rusting to the occurrence of cover cracking due to corrosion expansion can be divided into two phases: the phase of the free expansion of the corrosion product and the phase of cover cracking. Based on the assumption of the uniform corrosion of the reinforcement, one model for predicting the reinforcement corrosion depth from corrosion initiation to cover cracking was established according to the cylindrical cavity expansion theory. The main factors affecting the reinforcement corrosion depth were analyzed. The main factors affecting the corrosion depth of reinforcement were analyzed. The quantitative sensitivity analysis of the factors influencing the calculation formula shows that the depth of reinforcement corrosion and the thickness of the concrete protective layer are approximately linearly increasing, with a growth rate of 0.2366 μm/mm; the diameter of the reinforcement is approximately linearly decreasing, with a decrease rate of 0.2122 μm/mm; the volume expansion rate of rust is approximately power function decreasing; the overall influence range of the yield criterion selection parameter is 0.15 μm; for the concrete strength grade, the overall influence range is 0.1 μm. The coefficient of determination R2 is 0.87, and the overall accuracy of the calculated formula is high, which can be used to predict the service life of reinforced concrete structures and guide the durability design in combination with the research results on the corrosion rate of reinforcement under different environments.

Engineering vulnerability evaluation of building structures in coastal areas considering the effects of corrosion

Chloride-induced corrosion is an important factor that affects the durability of building structures in coastal areas; it causes serious deterioration of reinforced concrete (RC) structures and leads to structural failure. However, chloride-induced corrosion is a slow process which spans the whole service life of building structures, and many factors can affect their service life, such as location, structural design, and drug management. This paper aims to predict the service life of building structures in terms of chloride-induced corrosion and through the concept of engineering vulnerability. It first investigates the model of corrosion initiation of reinforcement, along with the consequent concrete cover cracking. Second, according to the characteristics of building structure and corrosion, it determines an evaluation index system of engineering vulnerability and establishes an evaluation method of engineering vulnerability, considering that corrosion is based on the AHP method and fuzzy comprehensive evaluation. Finally, using a case study of a pharmaceutical factory structure in a coastal city, this study verifies the feasibility of the assessment method considering corrosion effects.

Influence Of Marine Environment Exposure On The Engineering Properties Of Steel-concrete Interface

Aims: A detailed and reformed service life prediction model needs to be developed by considering the non-uniform distribution of the porous zone and the non-uniform distribution of the corrosion products layer. Background: The microstructure of the steel-concrete interface (SCI) plays an important role in corrosion initiation and concrete cover cracking. The porous zone around SCI is one of the vital engineering properties that influence the service life of corroding reinforced concrete structures in service life prediction models. Objective: The SCI properties are sensitive to the sample preparation technique of reinforced concrete (RC) samples for studying with the aid of scanning electron microscopy (SEM). A simple step-wise sample preparation technique of RC samples for SEM analysis is proposed where there is minimal damage to the properties of SCI. The development, distribution, and propagation of corrosion products at SCI are investigated for RC samples exposed to the marine environment for different exposure periods. The service life of RC structures was assessed through experimentally determined porous zone thickness (PZT) values. Assuming a uniform and constant value of PZT and uniform distribution of corrosion products around SCI might lead to variation or misinterpretation of the service life of structures. The same is explored in the present study. Methods: In this research investigation, backscattered electron images were obtained for the analysis of porous zone thickness around SCI. The distribution and propagation of corrosion products around SCI were investigated for different mineral admixed reinforced concrete samples exposed to the marine environment. Also, porous zone thickness values were used experimentally measured, and the time from corrosion initiation to corrosion cracking was estimated using a service life prediction model. Results: Results show that porous zone thickness is not uniform around SCI. Once the corrosion is initiated, the corrosion products accumulate in the SCI's porous region. Further, the non-uniform porous zone thickness directly influenced the non-uniform distribution of corrosion products. Assuming a constant or uniform porous zone thickness and uniform distribution of corrosion products around SCI leads to misinterpretation of the service life of corroding reinforced concrete structures. Conclusion: The porous zone thickness values around the steel-concrete interface and corrosion current density play an important role in predicting the service life of reinforced concrete structures exposed to the marine environment.

Nonlinear Finite Element Analysis of Corroded Reinforced Concrete Beams

Corrosion in reinforcing bars is a major cause of concern for sustainability of Reinforced Concrete (RC) structures exposed to extreme environmental conditions. Various RC structures, such as bridges and buildings are adversely affected due to the rebar corrosion, reducing its global load carrying capacity and ductility. In order to ensure an earthquake resistant design of any structure, the ductility of structural members is of chief concern. However, corrosion of reinforcing steel in RC members reduces its seismic performance. Thus, for safety and economic viability of any RC structure, an effective maintenance and repair work strategy is necessary. Based on the strong column - weak beam design concept of RC frames, the beams are the first structural members to absorb damage due to earthquake. Thus, to carry out maintenance and repair work, structural health assessment of RC beams considering the effect of reinforcement corrosion is of utmost importance. The present study aims at establishing a relation between the amount of corrosion induced and its effect on the ductility of an RC beam. A 3D Finite Element (FE) model of an RC beam including the effects of corrosion for nonlinear performance assessment has been modelled in ABAQUS. The FE model is validated with past experimental study including the effects of corrosion. Modelling of uniform corrosion in reinforcement bars involves defining the loss of bond between rebars and concrete, inducing spalling stresses on concrete and reduction in the cross-section area of the rebars. Bond-slip model between surface of concrete and reinforcement has been incorporated through cohesive surface. Spalling stress for uniform corrosion is applied in form of outward uniform pressure on the reinforcement and concrete interface. The cracking of cover concrete due to corrosion along with the flexural cracking in concrete due to incremental loading are implemented together in the present study. A comprehensive FE model is developed in order to obtain correct assessment of corroded beams. As observed from the FE model, the failure mechanism of the considered corroded RC beam is observed to be mostly shear failure as the corrosion level increases. Concrete crushing at the center of the RC beam is identified at the failure point of the beam due to corrosion induced damage. Evolution of displacement ductility index with respect to corrosion is determined for an RC beam based on the numerical study. It has been observed that the displacement ductility index of the beam is reduced significantly after considering a corrosion level of about 12%. Hence, the present study is an effort to establish a relation between structural performance of RC beams and level of reinforcement corrosion, which will be useful in proactive maintenance and repair work for corroded RC beams.

Phase field modeling of concrete cracking for non-uniform corrosion of rebar

Non-uniform corrosion of rebar in reinforced concrete will lead to concrete cover cracking, thus significantly reducing the durability of structures. A 2D mesoscale phase field model was developed to explore the failure behaviors of corrosion-induced cracking. The expansion of rust was described by a time-dependent non-uniform corrosion model. The phase field regularized cohesive zone model was employed to study the cracking pattern. The proposed model was validated by available experimental results in publications. The effects of several geometric parameters, such as concrete cover thickness, rebar diameter, and clear spacing, on the crack pattern and crack width of single and multiple rebar models were investigated. Finally, the influence of the ratio of cover thickness to rebar diameter on the failure pressure was discussed.

Investigation on the prediction of reinforcement corrosion-induced cover time-vary cracking from multi-scale

Invasion or penetration of chloride ions in concrete will cause reinforcement corrosion, and the corrosion substances accumulated expansion will lead to the cracking of concrete cover, which will affect the durability and service life of reinforced concrete (RC) structures. Combined with the environmental characteristics, the prediction model of corrosion-induced cover time-vary cracking was established by considering the pore distribution characteristics of concrete. Subsequently, the cracking behavior of concrete under corrosion of cover and corner reinforcement was simulated, which the cracking mechanism was discussed. Simultaneously, the equivalent modeling was established for the time-vary evaluation on mechanical properties of RC structures. The calculation results can directly describe the corrosion process of reinforcement at different times, which the cracking behavior of concrete caused by reinforcement corrosion can be obtained. The heterogeneous characteristics of concrete determine the cracking initiation and development in concrete, which controlling and reducing initial damage of concrete is the key to reducing the corrosion-induced cover cracking of concrete. As the corrosion deepens, the corrosion products fill the interfacial transition zones and accumulate as the rust layer simultaneously. Then, as the corrosion deepens and the diffusion process of chloride ions, the corrosion substances accumulated each other to squeeze concrete for cracking.

Modelling Strategies for Reinforced Concrete Elements under Corrosion Degradation.

Aging and corrosion of reinforced concrete structures (RCS) is becoming a global problem, thus proper procedures for simulating the structural performance of corroded RCS should be assessed. Among the main corrosion effects, concrete cover cracking and reinforcement cross-section reduction may influence the materials’ constitutive laws, moreover the confinement contribution and the lateral instability of the longitudinal rebars can be modified. In the present paper, the predictive models available in the scientific literature to assess the materials’ mechanical properties of corroded RCS are recalled and employed into a novel model to derive the theoretical moment–curvature relationships for the cross-section of square and rectangular corroded reinforced concrete elements. The model accounts for cover spalling, buckling of longitudinal reinforcing bars, reduction in confinement pressures, reduction in concrete constitutive law due to the concrete cracking induced by rust formation and decay of mechanical properties for corroded reinforcements. The obtained results are compared with the classical simplified models for corroded RCS, highlighting that buckling and confinement variations cannot be disregarded into a reliable modelling strategy, especially when local ductility plays a key role in the performed investigations.