Surface Crack Width Research Articles

Bond-slip model of corroded plain round bars in low-strength concrete under cyclic and monotonic loading

The effect of corrosion on the overall behavior of beam-type bond-slip samples constructed from low-strength concrete and plain round bars was examined in this study. First, a set of nominally identical specimens underwent testing under both monotonic and cyclic loading, and subsequently, the bond-slip interaction was assessed for each individual sample. The observed failure mode for plain round bars was direct pullout without concrete splitting apart, characterized by the loss of cohesion between the rebar and the adjacent concrete surface. Then, an analytical relationship was established by fitting a curve to the average experimental data using the method of least squares. Corrosion-degradation in the bond stress was considered by incorporating an exponential component into the equation of the reference bond-slip curve (i.e., null corrosion). Besides, the degradation in bond strength was predicted as a function of corrosion level, which is in the form of an exponential curve. The maximum surface crack width, an easily quantified variable on-site, was correlated with the bond strength of corroded bars. The regression analysis successfully established the optimal relationship between the maximum surface crack width and the corrosion level in an exponential form as well. Notably, the majority of the data in all cases fell within the 95% confidence interval.

CURRENT LITERATURE REVIEW ON IMAGE PROCESSING ANALYSIS FOR CONCRETE DAMAGE ASSESMENT

Numerous studies have employed computer vision algorithms to analyze images of concrete damage. Therefore, conducting an image processing survey to detect concrete damage is very crucial. Thus, an image processing algorithm analysis survey to detect concrete damage was conducted using various algorithms and types of data from the last decade. The data observed were the first is damage to concrete, which included surface cracks, hairlines, crack width, patterns, holes, diagonal cracks, longitudinal cracks, and transverse cracks. The second part is figuring out where roads, bridges, and buildings are. The third is data sources like digital cameras, cameras built into phones, camera sensor systems, and unmanned aerial vehicles (UAVs). The study's findings indicate that image processing algorithms will play an essential role in future assessment research on the automation of concrete damage detection. This is particularly the case in high-risk regions for security reasons, and UAV technology is required to reach these locations.

A Study on Historical Big Data Analysis of Surface Ecological Damage in the Coal Mining Area of Lvliang City Based on Two Mining Modes

Coal mining inevitably causes damage to the surface ecological environment. In response to the characteristics of multiple factors, wide scope, and long time series of surface ecological environment damage in coal mining subsidence areas, how to integrate multiple data sources and monitoring methods to achieve monitoring and trend analysis of ecological damage throughout the entire mining cycle still needs to be studied. In addition, the 110 mining method provides an innovative method for underground coal mining to reduce its surface ecological damage, but the differences in surface damage between the two mining modes and the effectiveness of the 110 method in realizing surface ecological damage-reducing mining still need to be studied in depth. Therefore, this study takes the surface ecological damage in the mining area of Lvliang City, a typical resource city in Shanxi Province, China, as the object. It establishes a four-in-one “Satellite–UAV–Ground–Underground” information monitoring method, proposes a historical big data evolution analysis method, constructs three spatial scales of historical big databases, clarifies the current situation and development trend of damage in coal mining areas in Lvliang City and explores the differences in surface ecological environment damage characteristics in coal mining areas based on the 121 and 110 mining methods. The results show that: (1) The existing coal mining subsidence area in Lvliang City is as high as 92,191.47 hectares, and it is expected to continue to increase to 130,739.55 hectares in the future 2035, with a growth rate of 41.812%, which realizes the goals of mapping the current situation, retracing the history and predicting the future of the ecological damage of the surface in Lvliang City. (2) The surface NDVI of the 110 working face is restored to the average level of the mining area faster than that of the 121 working face. The surface crack width, step displacement, length, distribution density, and surface settlement height of the 110 working face are all smaller than those of the 121 working face. It has been verified that the unique top-cutting and swelling filling effect of the 110 methods can effectively reduce the ecological damage caused by coal mining subsidence. And its widespread application can effectively realize the ecological environmental protection of the coal mine area and contribute to the high-quality development of the coal industry in Lvliang City.

Non-uniform distribution model of rust layer around steel bar circumference and its effect on corrosion-induced concrete cracking

This paper presents a critical review of non-uniform distribution models of rust layer around a reinforcing bar’s circumference and a numerical investigation into the effect of non-uniform distribution of rust on (a) crack patterns and (b) development of concrete surface crack width. Different shapes of rust layer simulated by mathematical models were established based on statistical distribution functions which were compared with the transport-electrochemical model and published testing results. In addition, an advanced 2D finite element model was implemented to simulate crack propagation in concrete caused by rebar corrosion. It is found that non-uniform rust distribution shape around the rebar not only affected concrete surface crack width evolution, but also crack length and crack pattern. Transport-electrochemical model and Gaussian distribution-based model could reasonably simulate rust distribution and associated corrosion-induced cracks. In addition, the authors proposed a simplified semi-empirical model that incorporated an analytical chloride transport model and a Gaussian model to simulate time-dependent advancement of non-uniform rust layer. Furthermore, a parametric study of the effect of elastic stiffness of the rust layer on crack patterns and surface crack width development was also performed.

Estimating the Depths of Normal Surface Notches Using Mode-Conversion Waves at the Bottom Tip.

In this work, a two-parameter inversion problem is analyzed, related to surface crack widths for measuring depths of normal surface notches, based on a laser-based ultrasonic measurement method in the time domain. In determining the depth measurement formulas, the main technique is the time delay between reflected and scattered waves. Scattered waves are generated by two reflections along the bottom and three mode transformations at the surface of the crack tips. Moreover, the scattering angle of the mode-conversion waves is 30°. These two key factors lead to corrected item "2wβ" in the depth measurement formula. A laser-based ultrasonic experimental platform is built to generate and receive surface waves in a non-contact manner on aluminum and steel specimens with surface cracks. The depth measurement method proposed in this paper has been validated through theoretical, simulation, and experimental methods. Finally, in this paper, an effective approach for quantitatively measuring crack depths, based on laser ultrasound, using the time-domain properties of surface wave propagation is provided.

Disintegration characteristics of sodic–saline loessial soil after freeze–thaw and wet–dry cycles

AbstractGeological hazards such as gully erosion, collapse and slope failure occur frequently in loess areas, which are closely related to the soil disintegration characteristics. Understanding the impact of freeze–thaw and wet–dry action on soil disintegration in the context of climate change is essential to establish effective soil and water conservation strategies and prevent engineering geological hazards in loess areas. In this study, sodic–saline loessial soils with different clay content were subjected to freeze–thaw and wet–dry cycles, followed by aggregate durability tests, direct shear tests and disintegration tests to investigate the effects of the two natural processes on soil disintegration characteristics. The results showed that the samples subjected to freeze–thaw cycles primarily exhibited rapid and stable disintegration, followed by slow disintegration, whereas the samples subjected to wet–dry cycles revealed weight gain, continuous slow disintegration and eventual sudden disintegration. Freeze–thaw action continuously deteriorated the disintegration resistance of soil, while wet–dry action improved the disintegration resistance of soil after the first cycle, and gradually weakened it in subsequent cycles. Statistical analysis showed that, for samples undergoing freeze–thaw cycles, the number of cycles and clay content were positively correlated with the disintegration rate, while the aggregate durability was negatively correlated with the disintegration rate. For samples undergoing wet–dry cycles, the number of cycles had a positive effect on the disintegration rate, while the clay content, shear strength and cohesion had a negative correlation with the disintegration rate. At a certain clay content, there was a positive correlation observed between the surface crack ratio, crack length and width with the disintegration rate of the wet–dry samples, while shear strength and cohesion had a negative correlation with the disintegration rate of both freeze–thaw and wet–dry samples. Furthermore, the study outlined the disintegration mechanism of loessial soils based on internal factors, driving factors, resistance factors and evolutionary factors. This study contributes to the in‐depth understanding of the catastrophic mechanism of geological hazards in cold and arid areas and provides experimental evidence for its control and management.

Near-in-situ investigation of surface crack healing and strengthening mechanism of Ti-43.5Al-4Nb-1Mo-0.1B alloy by novel electroshock treatment

The Ti-43.5Al-4Nb-1Mo-0.1B (TNM) alloy is prone to emerge surface cracks and other defects during processing and service, which will deteriorate the mechanical properties and fatigue life of the materials. In this work, a novel electroshock treatment (EST) for the surface crack repair and strengthening process has been proposed. Combined with near-in-situ experiments and theoretical analysis, the influence law and healing mechanism of different current densities and EST modes on the healing of surface cracks in the alloy were investigated. The scanning electron microscopy (SEM) near-in-situ observation reveals that the main factors influencing the healing of surface cracks relate to the time of energization, the current density, and the cracking angle. Meanwhile, the crack tip and locally bulging deflected positions are more likely to be healed in a short time under continuous EST mode and medium current density (75 A/mm2). The surface crack width at the calibration position decreases from 0.47 μm and 2.23 μm to 0 μm and 0.03 μm, respectively. The electron back scattered diffraction (EBSD) results show that the dislocation density increases around the surface crack healing area, and the dislocation density at the crack tip and away from the healing region is decreased and uniformly distributed after EST, which can further suppress the generation and propagation of the crack, resulting in a 20.1 % increase in tensile strength and a 40.3 % increase in fracture strain. Considering the coupling influence of the thermal and non-thermal effects of EST, a two-stage progressive atomic diffusion of thermal compressive stresses and crack bonding interfaces has been proposed to describe the evolution process of surface crack healing during EST.

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.

Evaluation of Parameters Service Standard Minimum (SPM) Based on Perceptions of Road Users National Segment Kayee Lon - Meulaboh

In an effort to address community needs and assist the acceleration of regional economic development, road construction has become a government priority. The problem in road services is that the Minimum Service Standards (SPM) have not been met based on the functional indicators of road sections, road structure and road safety. Road SPM refers to the provision of roads to meet the needs of the community in terms of the physical size of the road in accordance with certain technical criteria. The government, as the operator of the road, is required to carry out the legal mandate as a form of service to the community using the road. The purpose of this study was to determine the service quality of the Kayee Lon - Meulaboh National Road Segment based on the level of importance and performance and to find out which variables are the top priority for improving performance. To perform this study, 135 randomly chosen respondents were given questionnaires on a Likert scale, and the data was processed using the IPA (Importance Performance Analysis) method. The service quality of the Kayee Lon–Meulaboh National Road Segment with Functional Indicators of Road Sections is at the “Important” level with a mean of 3.924 and at the “Moderate” level with a mean of 3.400 based on performance level. Structural indicators of road sections are at the “Important” level in terms of importance, with a mean of 4.189, and at the “Moderate” level in terms of performance, with a mean of 2.995. The Road Safety Indicator is at the “Important” level based on importance, with a mean of 3.924, and at the “Not Good” level based on performance, with a mean of 2.171. Lane width is the factor whose performance has to be enhanced as a top priority for Road Section Functional Indicators. Pavement surface drainage and crack width are two variables that need to perform better in relation to the Road Section Structural Indicators’ top priority. Variables that need to be improved in terms of performance as a top priority for Road Safety Indicators are street lighting, zebra crossing and crossing facilities.

Experimental and numerical simulation research on the flexural performance of beams reinforced with GFRP bars and three-sides UHPC layer

This paper presents the results of the experimental investigation and numerical investigation conducted to study the flexural response of reinforced concrete beams reinforced with glass fiber reinforced polymer (GFRP) bars using three-sides ultrahigh performance concrete (UHPC) layer. The interface treatment of bubble wrap was applied in the internal surface of UHPC layer to ensure the enough interfacial bond behavior between UHPC layer and original concrete. Three tested beams, including two beams reinforced with three-sides UHPC and a reference beam, were studied through four-point bending tests and the effectiveness of flexural strengthening scheme associated with three-sides UHPC layer was evaluated. The results showed that the cracking load and ultimate load of beams reinforced with UHPC increased by 36.7%, 55.3%, and 30.0%, 42.7%, respectively, relative to the reference beam. The employment of UHPC layer could effectively control the development of surface crack width in beams. In addition, parametric studies were conducted to investigate the effects of the height of the UHPC, the thickness of the UHPC on both sides, and the longitudinal length of the three-sided UHPC layer using finite-element (FE) analysis. The results of numerical simulation were good agreement with the experimental results, indicating that the proposed finite element model could accurately predict the flexural responses of beams.

In-Depth Steel Crack Analysis Using Photoacoustic Imaging (PAI) with Machine Learning-Based Image Processing Techniques and Evaluating PAI-Based Internal Steel Crack Feasibility

Steel plays an indispensable role in our daily lives, permeating various products ranging from essential commodities and recreational gears to information technology devices and general household items. The meticulous evaluation of steel defects holds paramount importance to ensure the secure and dependable operation of the end products. Photoacoustic imaging (PAI) emerges as a promising modality for structural inspection in the realm of health monitoring applications. This study incorporates PAI experimentation to generate an image dataset and employs machine learning techniques to estimate the length and width of surface cracks. Furthermore, the research delves into the feasibility assessment of employing PAI to investigate internal cracks within a steel sample through a numerical simulation-based study. The study’s findings underscore the efficacy of the PAI in achieving precise surface crack detection, with an acceptable root mean square error (RMSE) of 0.63 ± 0.03. The simulation results undergo statistical analysis techniques, including the analysis of variance (ANOVA) test, to discern disparities between pristine samples and those featuring internal cracks at different locations. The results discern statistically significant distinctions in the simulated acoustic responses for samples with internal cracks of varying sizes at identical/different locations (p < 0.001). These results validate the capability of the proposed technique to differentiate between internal crack sizes and positions, establishing it as a viable method for internal crack detection in steel.

Investigating the self-healing performance of cracked undersea constructions

The undersea construction has undergone long-term exposure to erosive high-pressure seawater. Hence, it has become urgent to meet long-term requirements for seepage resistance and corrosion resistance. The objective of this study was to delve into the feasibility of remedying capillary cracks narrower than 0.3 mm in concrete constructions by using self-healing properties of concrete within a marine environment. Through the test of pressurized water seepage, micro-examinations, and numerical simulations of low water-to-binder ratio concrete subjected to simulated marine conditions, this study investigated the impacts of initial crack width, hydrostatic pressure, and curing age on water permeability, crack width, splitting tensile strength, and free chloride content in cracked concrete. The findings revealed that the concrete exhibiting capillary cracks with a width of under 0.3 mm indicated excellent self-healing performance. Notably, the results indicated the decrease in the water permeability, the gradual decline in surface crack width, and a slight recovery of the splitting tensile strength. However, the chloride ion transport was less evident compared to seepage as fracture closure decreased. The healing indexes of cracked concrete were enhanced with the decrease in the initial crack width, the shortening of curing period, and the decline in hydrostatic pressure. Moreover, the results demonstrated that the seepage velocity negatively impacted concrete healing, while continuous hydration during the early stages of concrete formation positively affected the healing process. These results provided valuable insights for devising maintenance strategies for concrete structures exposed to seawater environments.

Investigating cracking behavior of saline clayey soil under cyclic freezing-thawing effects

This study investigates the cyclic freeze-thaw (F-T) effect on crack patterns in saline clayey soil. Samples with different NaCl concentrations (0 M, 1 M, 2 M, and 3 M) are prepared and subjected to cyclic F-T processes. Each cycle involves freezing the samples at a constant temperature of −20 °C for 24 h and thawing at room temperature (21 °C) for 24 h. Additionally, a parallel experiment is conducted to observe the effects of desiccation at room temperature. The weight and surface crack patterns of the samples are continuously monitored. The image processing technique quantifies crack morphology and determines crack area, surface crack ratio, crack width, crack length, and fractal dimension. The results reveal that as the salt concentration increases, the F-T and desiccation samples exhibit decreased crack area and width. This decrease is attributed to the reduced saturation vapor pressure caused by higher salt concentrations, which slows down water evaporation and delays crack formation. The final crack pattern in the F-T samples is closely linked to the initial pattern of ice crystal formation. Lower salt concentrations result in the formation of larger ice crystals, leading to larger cracks during thawing. In the experiment, where the temperature was above the NaCl eutectic point, only ice crystals were formed, and the salt remained isolated as the salt concentration increased in the unfrozen solution. Conversely, during the freezing process, samples with higher salt concentrations with higher unfrozen solution content experience upward movement of the solution due to temperature gradients and water evaporation. This study provides new insights into understanding the soil water and salt movement and the phenomenon of surface clay soil cracking during the freezing-thawing process.

Reproducible estimations of internal corrosion distribution from surface cracks using MPC-RBSM

Rebar corrosion estimation is essential for maintenance of reinforced concrete structures against deterioration. Currently available non-destructive methods of evaluating corrosion do not clearly indicate the internal corrosion condition along the rebar and its effect within the concrete. In prior research, an inverse analysis scheme has been proposed in which the model predictive control (MPC) optimization method is utilized within a rigid body spring model (RBSM) to estimate the corrosion-induced expansion distribution along the rebar from corresponding surface crack width data. In this study, an innovative approach is introduced to verify the precision of MPC-RBSM outcomes and systematically examine the major contributing factors. To facilitate this verification, target cracking is generated by precisely controlling the corrosion expansion within the RBSM framework. In total, three sets of simulations are considered: two cases with varied expansive strain distribution profile along a straight rebar, and third in which a bent rebar arrangement is subject to corrosion. The simulated expansion distribution is compared against the original expansion used to generate the crack width data to validate the reproducibility of the MPC-RBSM results. The inverse analysis results show that the automated expansion scheme in MPC-RBSM successfully reproduces the target surface cracking. In the inverse analysis process, the necessity to account for corrosion distribution is identified. When appropriate corrosion distribution criterion is used to estimate corrosion-induced expansive strain levels along the reinforcement, the results are in good agreement with the assumed corrosion-induced expansive strain profiles (including both uniform and non-uniform profiles). Additionally, simulations of bent rebar corrosion are performed. The results indicate that surface cracking local to the bent region is mainly influenced by corrosion-induced stresses along the straight lengths of the rebar, which complicates the corrosion analysis of bent rebars via this form of inverse analysis.

Corrosion-induced cracking behavior of lightweight aggregate concrete: Experimental and numerical study

The corrosion-induced cracking potentially undermines the durability of concrete structures, while the fracture mechanism of lightweight aggregate concrete (LWAC) differs from that of the normal concrete subjected to expansive corrosion products due to the low-strength coarse aggregate. Eleven beams considering different diameters of LWA, the volume fraction of LWA, and surface crack widths were subjected to the accelerated corrosion setup, and the corrosion-induced cracks and steel mass loss were observed. The mesoscopic finite element model was established for the analysis of LWAC, and the model was verified according to the test results. The results of numerical study showed that decrease in the strength of LWA led to the inner damage of LWAC, while the increase in cover thickness made the cracking process of LWAC more rapid. On the basis of mesoscopic simulations, the critical cracking mass loss of steel bar and the empirical cracking parameter were derived, and then the linear equations were adopted for the establishment of relations between mass loss of corroded rebar and the corrosion-induced surface crack width by considering the effect of concrete cover and the rebar spacing.

Modeling Electrochemical Performance of Reinforced Concrete in Natural Marine Airborne-Exposure Environments: DURACON Project,10-Year Evaluation

This research evaluation consisted of a detailed statistical analysis of the recorded data in 72 reinforced concrete specimens, from 12 natural test sites (in nine countries) located in chloride-laden environments (marine airborne-exposure test sites located between 50 m and 250 m from seashore), during a natural exposure period of 10 y. The parameters evaluated included the concrete physical-mechanical characteristics; meteorochemical information; natural reinforcing steel’s instantaneous corrosion current density (icorr) and cumulative icorr; and concrete chloride concentration; surface crack width and rebar cross-section loss correlations. This statistical analysis resulted in empirical instantaneous icorr predictions as a function of the exposure microclimates, through linear multiple regressions. These models showed a high linear dependence of the cumulative icorr with the concrete capillary absorption as well as with the meteorochemical parameters. Results obtained in this investigation showed higher corrosion aggressiveness in tropical environments when compared to nontropical ones. The cumulative icorr proved to be an effective tool to indicate the corrosive likelihood and differentiate the stages of Tuutti’s service life model.

Multi-peak nonuniform model of rust distribution and corrosion-induced concrete cracking in reinforced concrete slabs

Corrosion-induced concrete cracking is of importance in evaluating service life of reinforced concrete (RC) slabs. Rust distribution and steel bar configuration are two of the most parameters affecting not only internal and surface crack patterns, but also evolution of surface crack width. In this paper, a mathematical model based on AsymmetricalGeneralisedvonMises distribution (AGvM model) was proposed to simulate multi-peak asymmetrical nonuniform rust layer around the steel bar's circumference. Besides, an advanced 3D finite element (FE) model was developed incorporating rust distribution obtained from the AGvM model to simulate corrosion-induced concrete cracking. An experimental programme of six RC slabs with three different steel bar configurations and two corrosion levels was conducted to validate the AGvM and the FE models. As a result, it showed that the proposed AGvM model was capable of simulating rust distribution around the steel bar better than the other six existing mathematical models, especially when the rust layer had two peaks and its distribution was highly asymmetrical. Moreover, the 3D FE model could reasonably predict internal and surface crack patterns, as well as evolution of surface crack width of RC slabs. Based on the test results and numerical models, effects of steel bar configurations on corrosion-induced concrete cracking were discussed.

鉄筋腐食に伴うコンクリート内部に進展するひび割れが表面ひび割れ性状に与える影響

Concrete structure is usually inspected by appearance at the periodical inspection. However, highly skilled engineers are necessary for this preliminary and qualitative inspection. Considering decrease in expert and increase in deteriorated concrete structures, more quantified inspection method is needed to evaluate the performance more accurately and easily. Previous researches have presented the relationship between corrosion mass loss of reinforcing steel bar in concrete and surface crack width. These studies were often conducted by using reinforced concrete specimen which includes single longitudinal rebar. On the other hand, on-site structures include not only longitudinal rebar also transverse rebar which is located with larger cover thickness. For this reason, the accelerated corrosion test using the specimens and inspection at an on-site corroded structure were conducted to evaluate the effect of the transverse rebar and its corrosion on the behavior of surface crack. As a result, it was revealed that internally propagated crack would have a large influence on the surface crack and the index of the surface crack density could bring more accurate evaluation of the corrosion mass loss of rebar than only the crack width.

Force-electric characteristics of cement-based materials with silica fume and fly ash during uniaxial compression

Force-electric of structural materials made early warning viable before structural failure, e.g., by monitoring resistivity of cement-based materials, which could predict main crack about 10 s ahead. Length of this time window might be elongated or shortened by modifying the cement-based materials with different additives. This paper investigated the effect of fly ash and silica fume on force-electric characteristics of cement-based materials. A real-time monitoring system was constructed by digital scatter diffraction (DIC) and multi-functional resistivity measurement instrument to explore and analysis of force-electric response, resistivity development, and surface crack width of cement-based materials under uniaxial compression. Mechanical and electrical response of prisms subjected to uniaxial compression were found highly correlated. We showed that properly defined indicators derived from the high-frequency resistivity measurement were useful for predicting fracture. Addition of silica fume tended to insulate the mortar and delay the electrical response, whereas addition of fly ash was conducive to reduce resistivity and activate the force-electric response of the cement-based materials, the resistivity fluctuation noise was relatively small and the resistivity fluctuation wass the most stable, with the lowest RSDmax and RSDave values of 4502 and 0.086, respectively.

Concluding destructive investigation of a nine-year-old marine-exposed cracked concrete panel

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.