Electrodeposition has been proposed as a method to promote mineral precipitation in cracked reinforced concrete, potentially limiting ingress of aggressive agents and delaying corrosion initiation. However, the extent to which electrodeposition-induced crack filling improves corrosion resistance under marine exposure, and the influence of electrolyte composition on the effectiveness and mechanism of electrodeposition, remains overlooked.This study investigated deposition behaviour of electrodeposition in either artificial seawater or Ca-Mg nitrate solution and evaluated corrosion performance of electrodeposition-treated (2x3) and non-electrodeposition-treated (references, 2x2) specimens during artificial seawater exposure.Reinforced concrete cylinders containing tensile-induced transverse cracks underwent three-month electrodeposition treatment, followed by a three-month artificial seawater exposure. Crack filling and deposition patterns were examined using X-ray computed tomography (XCT), optical microscopy, and μXRF elemental mapping, while corrosion behaviour was assessed through half-cell potential monitoring and post-exposure CT. Analytical interpretation was further used to interpret observed electrodeposition behaviour.A difference in Ca2+ and Mg2+ ion concentrations between the Ca-Mg nitrate solution and artificial seawater results in different crack-filling behaviour. Electrodeposition in Ca-Mg nitrate solution resulted in extensive internal crack filling reaching the steel-concrete interface, independent of crack geometry and width (maximum surface crack width 0.75 mm), and no corrosion was observed. In contrast, electrodeposition treatment in artificial seawater resulted in deposits primarily near the crack mouth and an influence of crack geometry. In these specimens, corrosion was prevented in two specimens and reduced in the third. The findings demonstrate that electrodeposition can delay corrosion initiation in cracked concrete when sufficient internal crack filling is achieved.

Corrosion of steel reinforcement is a major cause of deterioration in concrete structures, yet the mechanical response at the steel-mortar interface remains insufficiently understood. This study introduces an image-informed mechanics framework that quantifies the stress–strain behaviour of the corrosion layer and its role in cover cracking. X-ray and neutron computed tomography of a reinforced mortar specimen were used to determine corrosion-induced displacements at the steel-mortar interface. These image-derived displacements were applied as boundary conditions in non-linear finite element analyses that closely reproduced the geometry and loading conditions of the tested specimen, enabling evaluation of the stress–strain response of the corrosion layer. Two cases were analysed: one in which all corroded regions contributed to stress build-up, and one where expansion in regions containing interfacial voids was reduced to account for (near) stress-free expansion into these voids. The analyses revealed that radial stresses at the steel-mortar interface are strongly non-uniform, with only a few corroded regions dominating stress build-up. The quantified stress–strain response of the corrosion layer exhibited a non-linear mechanical behaviour, characterised by an apparent non-linear stiffness that increased with increasing strain, consistent with earlier mechanical characterisations. Overall, this image-informed mechanics framework offers new insights into the stress–strain behaviour of the corrosion layer. The results clarify parameters that govern crack propagation and provide quantitative measures to support future modelling and durability assessment of reinforced concrete.

Accurate modeling of structures exhibiting nonlinear response due to progressive damage, such as cracking, re mains a major challenge, as resolving the subscale leads to computationally intensive simulations. To address this, we propose an effective constitutive damage model formulated directly at the sectional level. By expressing the response in terms of generalized sectional quantities, the model eliminates the need for through-thickness integration and evaluation of local material behavior, improving computational efficiency. The formulation is thermodynamically consistent, employs global damage variables in the cross-section, and accounts for the cou pling between normal force and bending moment. Calibration and validation are performed against representative volume element-based simulations of textile-reinforced concrete that resolve yarn-matrix slip and matrix soft ening. Despite its simplicity, the model accurately reproduces axial force and bending moment responses under non-proportional strain and curvature histories. Compared with a fully resolved simulation of a one-way textile-reinforced concrete slab, the model achieves a two-order-of-magnitude reduction in computational cost, with an error below 5 %. The framework captures nonlinear behavior arising from stiffness degradation, making it suit able for textile-reinforced concrete structures in which the structural response is governed by concrete cracking and crushing, as well as bond-degradation. It is, however, also applicable to other beam-like structures exhibiting damage-dominated behavior.

Engineered cementitious composites (ECC) exhibit superior durability performance even after cracking, primarily due to their very low permeability and diffusivity to chlorides. However, accurately quantifying these transport properties is challenging, as they are strongly dependent on factors such as crack tortuosity, fibers bridging the crack, and other microstructural heterogeneities. This paper assesses permeability and diffusion in individual cracks of ECC using X-ray computed tomography (XRCT) imaging and numerical modeling, explicitly incorporating the complex crack morphology and its evolution over time due to self-healing.High-resolution XRCT scans are performed on two different cracked ECC specimens at predefined healing stages. The crack is then segmented and converted into a Finite Element mesh for numerical simulations that are performed directly on the experimentally acquired data. At each healing stage, Stokes flow and chloride diffusion are solved within the crack domain, yielding effective permeability and diffusion coefficients as a function of the healing state.The obtained simulation results were compared against permeability predictions based on experiments using analytical formulas showing that they can differ significantly from numerically derived values. In addition, a parametric study on the impact of the fiber volume fraction showed that permeability decreases by about 8.4% per 1% increase in fiber volume, whereas the diffusion coefficient declines more modestly, by about 2.3% per 1%.By explicitly accounting for self-healing, the exact crack morphology, and bridging fibers, the investigation links microscopic changes in cracks to macroscopic transport parameters relevant for service-life design.

Limestone calcined clay cement ( LC^3 ) is a promising low- CO_2 alternative to ordinary Portland cement (OPC), but its long-term performance with respect to corrosion-induced cracking in reinforced concrete remains poorly understood. This study investigates the interplay between binder type, material properties, and corrosion-induced cracking in steel-reinforced mortars made with OPC and LC3. Accelerated corrosion experiments were conducted using the impressed current technique, and the time-to-cracking was determined from electrical potential measurements to assess the corrosion level leading to matrix cracking. LC3 mortars exhibited cracking at lower corrosion levels compared with OPC mortars, indicating a lower resistance to corrosion-induced mechanical stresses. This behavior could be correlated to fracture energy, which was lower in the LC3 systems. Although LC3 mortars showed superior resistance to chloride ingress, their reduced fracture performance suggests a potential trade-off. These findings highlight that durability assessments may benefit from considering both transport and fracture-related properties.

Concrete structures and infrastructures in cold regions can undergo internal frost damage. However, it is still not clear how external conditions, such as moisture boundary conditions and drying shrinkage influence the internal frost damage in concrete. To investigate this aspect, plain concrete cubes without air-entrainment were prepared for Freeze-Thaw Cycles (FTCs) in different ways. In addition to a reference group, four distinct groups exposed to FTCs were examined. Three groups experienced drying shrinkage and then FTCs under different conditions: a) in air, b) withwater maintained on the top surface, and c) submerged in water. The fourth group was submerged in water both before and during FTCs. Ultrasonic and compression tests were conducted to assess internal frost damage. Results showed no internal frost damage in concrete cubes exposed to air during FTCs, while all specimens in contact with water exhibited internal frost damage of different magnitude. Furthermore, prior drying shrinkage intensified internal frost damage in concrete compared to conditions without previous shrinkage.

Textile-reinforced concrete (TRC) exhibits a complex mechanical response, necessitating accurate and advanced models for analysis. This work shows the possibilities to model TRC using a two-scale approach. On the sub-scale, the response is predicted using Representative Volume Elements (RVEs), where the textile yarns are resolved. This approach makes it possible to capture the effects of bond-slip, interfilament slip, as well as concrete cracking and crushing. The large-scale plate response, in terms of membrane forces and bending moments, is obtained by homogenizing the results from the RVE using Kirchhoff plate kinematics. The outcome shows the possibilities of obtaining effective large-scale responses for varying sub-scale configurations. In this way, we omit the need for re-calibrating the large-scale model for every new reinforcement configuration. The scale-bridging framework developed in this work can be employed in large-scale plate and shell models to predict the effective constitutive response of TRC.

Characterising steel corrosion at the steel-concrete interface and linking it to concrete damage is challenging due to limitations of current non-destructive techniques. This study combines electrical resistance measurements, full-field image-based analyses and analytical techniques to comprehensively characterise steel corrosion and damage in small-scale specimens. X-ray and Neutron Computed Tomography of two reinforced mortar samples, before and after accelerated corrosion, were used to examine corrosion morphology, interfacial voids, and estimate volumetric strain in the corrosion layer. Inductively Coupled Plasma Mass Spectrometry was employed to measure iron isotope concentrations in water surrounding the specimens. The results revealed delayed transport of corrosion products relative to mortar cracking. The volumetric expansion coefficients of corrosion products (3.84 and 3.90) align with previous research, and the risk of pitting corrosion correlated with the void size. Overall, the measurements obtained through the various techniques closely aligned with visual observations, providing a robust dataset for calibrating corrosion models.

This study investigated the interactive effects of pre-damage, water boundary conditions, and internal frost damage on concrete at dual-scale. The pre-damage included pre-cracking, which has not been studied experimentally before, and pre-compressive damage. Concrete specimens underwent pre-damage and had varied water boundary conditions during Freeze-Thaw Cycles (FTC). At the macro-scale, wedge-splitting tests combined with Digital Image Correlation (DIC) were conducted to assess post-FTC strength and fracture behaviour. At the meso-scale, X-ray CT scanning was employed to identify internal crack patterns. Results reveal that at the macro-scale, significant interaction between pre-damage and frost damage reduced splitting tensile strength compared to the internal frost damage alone. Besides, increased water exposure during FTCs reduced both splitting tensile strength and compressive strength, with a less pronounced reduction in splitting tensile strength. It also led to a diffuse crack pattern and increased tensile ductility. At the meso-scale, specimens subjected to the interactive effects of pre-damage and internal frost damage exhibited cracks along aggregate-cement interfaces and within the cement paste. Reference specimens displayed no internal cracks, while specimens exposed to only FTCs showed only cracks along aggregate-cement interfaces. Full submersion of specimens during FTCs induced more internal cracks than solely water on top. These findings on the interactions between pre-damage, water boundary conditions, and internal frost damage offer insight into the causes of frost damage, vital for the design and assessment of concrete structures in frost-prone environments. Furthermore, the results of these dual-scale tests can be used as a test case for the development of upscaling numerical models describing heat transfer and frost degradation in concrete.

Bending and corrosion-induced cracks interact and impact the durability of Reinforced Concrete (RC) beams in a complex manner. Still, research on the mechanisms behind this interaction is limited. In this study, a 3D nonlinear finite element modelling method of RC beams was developed to explore this interactive mechanism. The models were assessed against experimental benchmarks, showing good agreement in terms of crack pattern and growth. Moreover, the modelling method offered the advantage of visualising the internal condition of beams, including the propagation of internal cracks and the expansion of corrosion products represented by interface elements. A parametric study was conducted to examine the influence of three crucial factors: the transport of the corrosion products, the distance between bending cracks, and bending crack width. The modelling results revealed that the transport of corrosion products appeared to play a decisive role in the location of initiation and evolution of corrosion-induced cracks. Additionally, as the distance between the bending cracks decreased, the onset of corrosion-induced cracks transitioned from the midpoint between the bending cracks to the vicinity of them. Furthermore, an increase in bending crack width had no impact on the initiation and evolution of corrosion-induced cracks, while their widths, and variation of width along the bar, decreased.

Substantial research effort has been devoted on linking corrosion-induced cracking of concrete with the internal corrosion damage level. Still, numerical models of the corrosion and cracking process require internal parameters, that cannot be directly evaluated from experimental data. Therefore, this study provides a novel experimental method for monitoring the effects of steel corrosion adjacent to the steel-concrete interface. This non-destructive method is suited for small-scale laboratory-made specimen, and was designed to provide missing information required for subsequent calibration of numerical models. Hollow steel bars were cast into concrete and subjected to accelerated corrosion using the impressed current technique. The deformations of the hollow steel bars were measured using distributed strain sensing in an optical fibre, attached to the inner surface of the hollow steel bars. After the corrosion period, X-ray Computed Tomography scans were performed to evaluate concrete cracking and corrosion level. The results reveal a non-uniform distribution of strain around the perimeter of the steel, indicating a non-uniform radial stress distribution. The non-uniformity correlated very well with the position of the corrosion-induced cracks; with extension hoop strains in the steel at the location of these cracks and contraction hoop strains in between. Further, the corrosion level varied around the perimeter, with higher values near cracks. The combination of non-destructive monitoring techniques used in this study on small-scale laboratory-made specimens show great potential to reveal new insights on how the corrosion pattern, corrosion-induced cracking of the concrete cover and stress (indirectly measured through the strain in the steel) interact throughout the corrosion process.

This paper presents a modeling approach to analyze the flexural response of hybrid reinforced concrete beams with localized corrosion. A new mechanical model based on extensive uniaxial testing is proposed to describe the stress–strain relationship of corroded bars with a single pit. The proposed mechanical model is then incorporated into a sectional analysis to determine the moment curvature relationship of hybrid reinforced concrete sections with pitting corrosion. The actual crack pattern is used to divide a beam into discrete hinge elements which are then combined to compute the load–deflection response of statically determinate beams. The modeling approach is evaluated with available experimental data showing good predictive capabilities. A parametric study revealed the importance of the interaction between the tensile reinforcement ratio and the concrete postcracking residual stress. Furthermore, the deformation capacity of reinforcement bars with pitting corrosion levels beyond 0.25 was shown to have a dominant effect on the ultimate deflection of hybrid reinforced concrete beams.

Textile reinforced concrete has raised increasing research interest during the last years, mainly due to its potential to be used for freeform shell structures involving complex load situations. Yet, most experimental work has focused on test setups with primarily uniaxial loading. In the current work, such setups are complemented with a novel test setup of deep beams, including in-plane bending and shear. Further, nonlinear finite element analyses were carried out, applying an earlier calibrated bond-slip relation and efficiency factors for strength and stiffness of the textile reinforcement. It was found that the structural behaviour in terms of the overall stiffness, ultimate load and deformation, number of cracks, and total (summed) crack width, could be described with reasonably good accuracy. The inclusion of a calibrated efficiency factor for the stiffness of the yarn was shown to be vital. Moreover, it was shown to be important to weaken and randomise the material properties of the concrete at the location of transverse yarns, to trigger localisation (cracking) in the numerical model.

Modeling of corrosion-induced cracking is limited by lacking knowledge on the behavior of corrosion products. In this work, the corrosion and cracking processes were experimentally investigated in 3D at two different stages. The processes were measured at micro-structural scale, applying nondestructive neutron and X-ray computed tomography in two scans at different stages in the corrosion process. A method to evaluate the average volumetric strain of the compressed corrosion layer was proposed and displacements in the concrete matrix were measured. Strain localization revealed cracks not directly visible in the images. Multimodal tomography demonstrated to be an effective method for investigating steel corrosion in reinforced concrete.

Modeling of corrosion-induced cracking is limited by lacking knowledge on the behavior of corrosion products. In this work, the corrosion and cracking processes were experimentally investigated in 4D (three spatial dimensions + time). The processes were monitored at micro-structural scale, applying nondestructive neutron and X-ray computed tomography in multiple scans at different stages in the corrosion process. A method to evaluate the average volumetric strain of the compressed corrosion layer was proposed. Further, displacements in the concrete matrix were captured with subvoxel sensitivity. Strain localization revealed cracks smaller than direct visible in the image data.

This study undertaken on a nine-year-old cracked concrete panel further investigates the impact of cracks on the corrosion performance of conventional steel reinforcement in marine-exposed concrete to explain observed monitoring data. The present data covers seven 1.80 m long (12.6 m) reinforcing bars embedded in good quality concrete (w/b = 0.40 and cover >75 mm). Each bar was crossed by two horizontal cracks (surface crack widths 0.20-0.30 mm). The investigation showed no corrosion on the surface of the reinforcing bars, in either cracked or uncracked areas. Two of the seven reinforcing bars were instrumented in the vicinity of the cracks. Extensive corrosion was found in the interior of all instrumented parts of these bars. This may explain the monitoring data despite the lack of corrosion on the exterior surface of the two instrumented rebars. However, with no other weaknesses, the remaining conventional rebars showed no impact from the cracks.

The edge beams of reinforced concrete bridges with de-icing salts sprayed experience extensive corrosion damage. The average service life of edge beams needing replacement in Sweden has been reported as only 45 years, causing great economic loss to both owners and users. Hence, finding a durable solution for edge beams would benefit society. Hybrid reinforced concrete structures, produced by adding a low-to-moderate fibre content into traditional reinforced concrete, can effectively limit the service crack width and improve resistance to chloride-induced corrosion damage. In this paper, different alternatives of hybrid and traditional reinforced edge beams were designed for a case study. The service life of the alternatives was compared by conducting chloride diffusion calculations and by applying a corrosion-induced cracking model. The economic and environmental (indicated by greenhouse gas emissions) benefits of using hybrid reinforced edge beams were assessed by life-cycle cost analysis and life-cycle assessment. The results showed that the service life of edge beams made of hybrid reinforced concrete can be prolonged by over 58%, thereby enabling a significant reduction in the total life-cycle costs and annual total greenhouse gas emissions.

Surface crack width is regulated in codes to limit corrosion of reinforcement bars in concrete. However, the influence of surface crack width on corrosion damages is not directly inferable from previous research.In this work, data on corroded cracked concrete specimens in chloride environments was compiled. Detailed information was included, such as crack and pit locations, local corrosion pattern, etc. Five hypotheses on the influence of transversal cracks on corrosion damage were formulated, and statistical methods were used to test them on the dataset.Transversal cracks were good indicators of the position of corrosion pits. The corrosion rate of the pit increased in proximity of a crack. With time, pits grew in depth at a slower rate but increased in number. No clear correlation between surface crack width and corrosion damage was found. Results point out discrepancies in the collected data, arguing for the need of well-defined procedures for assessing crack and corrosion damage.Further, the statistical treatment allowed for identification of bias in existing data, which was used as a research planning tool to provide guidance on the design of additional experiments. Thus, recommendations for future experimental work required to reduce the bias are given.

Existing deteriorated reinforced concrete (RC) structures need strengthening to extend service life. Fibre reinforced polymer (FRP) has been widely used to strengthen sound structures, but its application on damaged concrete structures still needs to be investigated. This paper presents non-linear finite element analyses conducted to assess the flexural behaviour of corrosion-damaged RC beams strengthened with externally bonded FRP. Beams in four different categories were analysed: a reference beam, a corroded but non-strengthened beam, and corroded beams strengthened with glass FRP (GFRP) and carbon FRP (CFRP) respectively. Furthermore, the strengthened beams were modelled with different modelling choices to investigate the effectiveness of FRP applied to the beam soffit and as U-jackets. Pre-loading and corrosion-induced cracks were incorporated by reducing the tensile strength of concrete elements at crack locations. Average and pitting corrosion were incorporated by reducing the cross-sectional area of the reinforcement corresponding to the measured corrosion levels. Interface elements were used to simulate the bond between FRP and concrete. The modelling methods were validated against experimental results. It was found that modelling of pitting corrosion, especially the location of pits, lengths and number of pits considered, were influential in predicting the load and deformation capacity of beams. A CFRP plate at the beam soffit, combined with inclined U-jackets at its ends of the CFRP plate provided sufficient flexural strengthening. Thus, intermediate U-jackets did not further increase the load-bearing capacity for the studied beam geometry and corrosion damages. However, with a GFRP sheet at the beam soffit, both inclined and intermediate U-jackets were needed to provide full utilisation of the GFRP sheet for the studied beam geometry. In further studies of the effectiveness of the strengthening methods, it is recommended to investigate beams of varying dimensions, corrosion patterns and levels, and FRP spacing and dimensions.