Cover Cracking 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.

Corrosion-Induced Cracking Model of Concrete Considering a Transverse Constraint.

The performance of corrosion-induced cracking of reinforced concrete members under transverse constraints was studied. Based on the theory of elastic-plastic mechanics and the hypothesis of uniform corrosion of a steel bar, a three-layer hollow cylinder model was established to predict the critical corrosion of the steel bar at the time of the cracking of the concrete cover. Taking the constraint of stirrups on surrounding concrete into consideration, it can be used to predict the corrosion rate of members with stirrups at the time of the cracking of the concrete cover, which further expands the application range of the corrosion-induced cracking models of concrete. On this basis, the critical corrosion rate of concrete under different stirrup ratios at the time of cracking was measured. The calculated results of the model are in accordance with experimental data. For corner steel bars, when the stirrup spacing is less than 100 mm, the existence of stirrups can effectively delay the occurrence of rust expansion cracks and enhance the durability of the structure. On the basis of this study, the problem of corrosion expansion and cracking of the concrete cover caused by non-uniform corrosion of steel bars along longitudinal and radial directions needs to be further studied in the future.

Mitigation of Steel Corrosion Threshold Utilizing Plant-Based Green Corrosion Inhibitors through Electrochemical Techniques

Corrosion of steel reinforcement is a major cause of deterioration in reinforced concrete structures. The corrosion process is influenced by the concrete-steel interface, with the alkaline concrete pore solution initially providing passivation. However, ingress of aggressive substances like chlorides can disrupt the passive layer, initiating active pitting corrosion above a threshold level often taken as 0.4% chloride by cement weight. Once the chloride threshold is exceeded, corrosion propagation depends on oxygen and moisture availability. The resulting rust formation causes expansive cracking and spalling of the concrete cover. Corrosion damage can be mitigated through use of inhibitors like calcium nitrite though high dosages impair concrete strength. Recently, plant-based organic compounds have shown promise as green corrosion inhibitors. The corrosion behavior of steel in concrete can be evaluated through impressed accelerated corrosion testing along with electrochemical techniques like half-cell potential mapping and resistivity measurements. These allow assessment of the probability of corrosion and corrosion rate. Techniques like linear polarization resistance and electrochemical impedance spectroscopy can also quantify instantaneous corrosion rate. Proper structural condition assessment and repair using both conventional and green inhibitors is crucial to control steel corrosion, maintain service life and ensure safety. Further research is needed on green corrosion mitigation methods and advanced non-destructive testing techniques.

Axial compression behavior of a prefabricated F4T-section thin concrete encased steel short columns with different stirrup types

A prefabricated F4T-section thin concrete encased steel (F4T-TCES) column with a low reinforcement ratio is proposed to address instability, corrosion resistance issues in pure steel columns, and column protrusion out of the wall. The F4T-section is a T-shaped column with internal steel featuring four flanges. Ten F4T-TCES short columns were tested under axial compression loads, examining five new stirrup types to facilitate construction and study their impact on load-carrying capacity. The effects of steel flange and web thicknesses, stirrup and longitudinal bar diameters, stirrup spacing and form, and concrete encasement thickness on axial compressive behavior were investigated through tests and finite element (FE) analysis. Results indicate that less reinforcement and thin concrete cover can restrain steel elastic buckling and fully utilize material properties. Using 8 mm diameter longitudinal bars and a 1.32 % stirrup ratio provides sufficient strength and adequate confinement. Reliable performance is achieved with a flange thickness of 12 mm, while increasing web thickness beyond 8 mm shows no significant improvement. Increasing concrete encasement thickness from 45 to 70 mm effectively reduces the cracking of the concrete cover. Specimen with stirrup type C exhibits the highest load-carrying capacity, delayed crack initiation, and narrower crack widths, with type D also performing well in crack control. All five stirrup types meet load-carrying requirements, with types C and D being easier to construct and thus preferable. Formulas for the axial compressive strength and a simplified load-axial deformation model for F4T-TCES columns are proposed and validated.

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.

Variation of Corrosion Rate, Vcorr, during the Carbonation-Induced Corrosion Propagation Period in Reinforced Concrete Elements.

The structural systems of residential buildings in many developed countries have widely utilized reinforced concrete as the most common solution in construction systems since the early 20th century. The durability of reinforced concrete columns and beams is compromised, in most cases, by pathologies caused by the corrosion of their reinforcements. This study analyses the corrosion processes induced by carbonation in 25 buildings with reinforced concrete structures. The models estimate the service life of reinforced concrete elements by differentiating between the initiation period and the propagation period of damage, considering two possible stages: the time of corrosion propagation until the cracking of the concrete cover, and the time of propagation until a loss of section is considered unacceptable for structural safety. However, the mathematical expressions that model the propagation periods consider the same corrosion rate in both cases. This research has found that the average corrosion rate in elements with an unacceptable loss of reinforcement section was in the order of 8 times higher than the corrosion rate in cracked columns and beams without a loss of reinforcement. This opens up a path to improve the definition of the different stages experienced by a reinforced concrete element suffering corrosion of its reinforcements due to carbonation, because once the concrete has cracked, the corrosion rate increases significantly.

ПОВЕРХНОСТНЫЕ ГРАВИТАЦИОННЫЕ ВОЛНЫ В СЕВЕРНОЙ АТЛАНТИКЕ И В ДРЕЙФУЮЩЕМ ЛЬДУ АРКТИКИ

Sea ice in the Arctic is one of the main dynamic elements in the interacting atmosphere–ice–ocean system. Currently, theoretical and experimental studies of drifting and soldered ice are used to develop predictive models of the mechanical state of sea ice. This paper presents the results of an experimental study of physical and mechanical processes on the surface of the Arctic Ocean. Field work was carried out using the spatial placement of autonomous seismic stations directly on the drifting ice. Data on surface gravitational waves of the ocean, accompanied by periodic deformations of bending and shear in the ice, have been obtained. On the basis of amplitude spectra, the features of the process of propagation of storm waves of swell in the ice cover are considered and a comparative analysis with map of maximum heights of sea waves is performed. A significant factor is the use of microseismic oscillations recorded at coastal stations of the Greenland Sea to determine the time and place of a powerful storm. The spectrum of the wave field in the ice sheet indicates an increase in the frequency of oscillations due to the dispersion of the wave field. New data have been obtained on the large-scale mechanics of the occurrence of cracks in the ice cover and discrete flexural-gravity waves as one of the main indicators of ice destruction. The results of the study are important for improving weather and climate forecasting models, as well as for solving engineering problems on the Arctic shelf.

Monitoring corrosion-induced concrete cracking adjacent to the steel-concrete interface

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.

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.

Quantitative characterization of reinforcement cross-sectional roughness and prediction of cover cracking based on machine learning under the influence of pitting corrosion

The roughness characteristics caused by pitting corrosion on the reinforcement surface have an important influence on cover cracking. This study proposes two new indicators, RMPC and CMPC, for quantitatively evaluating reinforcement roughness and concavity. Then a novel approach to predicting crack volume was introduced based on ML. Results show that, RMPC is more applicable than commonly used morphological indicators for reinforcement roughness evaluation. The dry-wet cycle corrosion produces more severe section roughness and concavity than the applied current corrosion, up to about 2.4 times. When the corrosion level exceeds 3%, average RMPC of the dry-wet cycle samples are consistently higher. When the corrosion level is less than 1%, the cross-section is typically concave. The introduction of roughness indicators significantly improves the accuracy of crack volume prediction, increasing R2 value from 0.646 to 0.956. Machine learning prediction models using ensemble learning algorithms demonstrate superior accuracy and stability compared to non-ensemble models.

Determination of the Predominant Orientation of Cracks in Ice Cover of the Laptev Sea from the Ice Drift Data

Received April 10, 2023; revised May 25, 2023; accepted June 27, 2023The paper shows that in order to solve the problem of predicting the predominant orientation of cracks in ice covering the Laptev Sea, when the satellite information is absent, the orientation of cracks in ice cover can be calculated using data on the ice drift in the Sea. We have selected 200 satellite images made in both visible and infrared spectral bands allowing to obtain actual data on ice cracks in the Laptev Sea for seasons 2016–2021, and then calculated the predominant orientation of them using data on the OSI SAF ice drift for the date of each image as well as for several previous days. Results obtained were compared with actual modal orientations of the cracks and with characteristics of the atmospheric pressure fields in these days. It was found that selecting of initial ice drift data should be done with regard for the intensity of air flows, the invariability or constancy of the direction of air flows over the sea aquatory during several days, and the presence of a cyclone centered over the sea area. An algorithm has been developed for automatic selection of a date when the ice drift can be most likely accompanied by formation of cracks on the day under consideration, and calculation of predominant orientation of cracks should be made exactly on that day. The selected data on ice drift serve as a basis for calculating. It was revealed also that with the difference in the types of intensity of air flows in the northern and southern parts of the Laptev Sea, the developed algorithm for determining the date of ice drift should be applied to each part of the sea separately. The number of squares of the Laptev Sea grid in which the calculated orientation of cracks corresponded to its actual meaning with an established permissible error of 30° has been determined. The ratio of this number to the total quantity of grid squares (skill score) was equal to 69% on the average. The skill score exceeded 70% in 46 percent of the cases. The skill score falls below 60% in only 16 percent of the cases, with minimum value of 50%.

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.

Influence of stochastic chlorine environment on the spatiotemporal deterioration of marine RC structures

The stochastic nature of the chloride environment plays an instrumental role in the variability of the deterioration processes afflicting marine reinforced concrete structures. The objective of this study is to investigate the influence of the stochastic chloride environment on the spatiotemporal variability of deterioration processes based on spatiotemporal reliability analysis. Based on long-term detection data from the Zhapu Port of Hangzhou Bay, the scale of fluctuation of chloride concentration and chloride diffusion coefficient in the depth dimension was obtained. The effect of the spatiotemporal variability of chloride environmental impacts and structural resistance on structural deterioration was evaluated in terms of both extent and probability based on three random field models. The results demonstrate that appropriate access to information on the scale of fluctuation in terms of both environmental impacts and structural resistance can construct more robust random fields. Moreover, the effect of the previous limit state on cover spalling is greater than the effect on cover cracking and structural collapse. In addition, the relationship between corrosion failure and structural failure was obtained, and the extent and duration of cover spalling constitute an important indicator of structural reliability.

Overview of phase-field models for fatigue fracture in a unified framework

The phase-field method has gained much attention as a novel method to simulate fracture due to its straightforward way allowing to cover crack initiation and propagation without additional conditions. More recently, it has also been applied to fatigue fracture due to cyclic loading. This publication gives an overview of the main phase-field fatigue models published to date. For the first time, we present all models in a unified variational framework for best comparability. Subsequently, the models are compared regarding their most important features. It becomes apparent that they can be classified in mainly two categories according to the way fatigue is implemented in the model — that is as a gradual degradation of the fracture toughness or as an additional term in the crack driving force. We aim to provide a helpful guide for choosing the appropriate model for different applications and for developing existing models further.

Corrosion products of low-alloy steel bars and their induction of cracking in seawater sea-sand concrete cover

The integration of low-alloy steel reinforcement (LS) with seawater sea-sand concrete (SSC) offers an opportunity for marine infrastructure construction that utilizes local resources, such as seawater and sea-sand, while ensuring exceptional durability of structures in challenging environments. However, the cracking of the concrete cover resulting from rebar corrosion remains the primary factor contributing to the deterioration of reinforced-concrete structures exposed to marine environments. In this study, an external current was applied to accelerate the corrosion process of both LS and ordinary steel bars (OS), which were embedded in SSC that was shallowly buried in a wet-salt sand environment. To accurately determine the timing and location of SSC cover cracking, Digital Image Correlation (DIC) technology was utilized. Microscopic analysis was conducted to examine the morphology, phase composition, and content of each component of the corrosion products. Then, the expansion coefficients of the corrosion products of the rebars embedded in SSC with different water–binder ratios were determined. The results indicated that the primary corrosion products formed on OS are α-FeOOH, β-FeOOH, γ-FeOOH, Fe2O3, and Fe3O4, which form a porous structure. In comparison, corrosion products of LS are fundamentally similar to those of OS but include Cr2O3, producing a compact rust layer for better steel protection. Furthermore, the corrosion products of LS exhibit a lower expansion coefficient compared to those of OS in SSC with an identical water–binder ratio. Finally, the cracking time of the SSC cover, as determined through DIC, was validated through the use of a conventional prediction model.