Simulation of corrosion in concrete
Identyfikator grantu: PT01244
Kierownik projektu: Gonzalo Garcia Noxpanco
Politechnika Gdańska
Wydział Inżynierii Lądowej i Środowiska
Gdańsk
Data otwarcia: 2025-03-13
Planowana data zakończenia grantu: 2028-03-18
Streszczenie projektu
The main goal of this research is to simulate corrosion in reinforced concrete structures using coupled thermo-mechanical analysis, enabling a comprehensive understanding of both the transport of chloride ions and their subsequent mechanical impact on steel reinforcement. By capturing how chlorides diffuse through the concrete and interact with structural stresses and strains, we can better predict long-term durability, assess safety margins, and optimize maintenance strategies. In essence, achieving a thorough simulation of corrosion-related damage empowers engineers to design and manage infrastructure that remains resilient under harsh environmental conditions.
The first phase of the process focuses on understanding how chlorides move through the concrete matrix. Traditionally, this has been approached via a straightforward diffusion analysis, where the spatial and temporal evolution of chloride concentration is represented by solutions to the diffusion equation. While a diffusion-only model can provide insights into the rate and depth of chloride ingress, it does not inherently incorporate the mechanical effects that can significantly influence the transport behavior. Indeed, cracks in the concrete due to mechanical loading or temperature-induced expansion might alter diffusion pathways, accelerating chloride penetration in ways that a pure diffusion model fails to capture. Hence, while preliminary diffusion analyses are useful for determining initial chloride concentration profiles, they are inadequate for a complete and realistic representation of corrosion processes.
Recognizing the interplay between mechanical effects and chloride transport, the next logical step is to couple these two phenomena. In particular, a fully coupled temperature-displacement approach, as can be performed in ABAQUS, offers a powerful toolset. By utilizing user subroutines such as UMAT, USDFLD or UEL it becomes possible to integrate custom constitutive models and track specific variables of interest, including stress, strain, damage evolution, and even chemical reaction progress if needed. This allows to capture the way damage or microcracking influences chloride ingress and, conversely, the way chloride-induced damage modifies the mechanical response.
In practical terms, one of the most critical outcomes of chloride ingress is corrosion initiation in the reinforcing steel. Once the chloride concentration at the depth of the rebar surpasses a threshold, corrosion sets in, which then leads to a variety of problems. Rust occupies a greater volume than the parent steel, resulting in internal pressures that can cause cracking in the surrounding concrete. Over time, this expansion may compromise the bond between the steel and the concrete, weakening the composite action that gives reinforced concrete its strength. Moreover, sustained corrosion leads to a gradual reduction in the cross-sectional area of the reinforcing bars, which can severely compromise the load-carrying capacity of the structure.
By coupling diffusion and mechanical effects in a single simulation framework, it becomes possible to model all these phenomena in a more realistic and predictive manner. For example, one can incorporate a damage model that updates the material properties of concrete based on the stress state and crack development, which in turn modifies diffusion coefficients. Conversely, as chloride concentrations rise, the simulation can trigger a deterioration mechanism within the steel reinforcement, accounting for rust expansion and bond degradation. This level of detail is vital for predicting service life and establishing maintenance or repair schedules.
Looking forward, the next steps in this research involve refining these coupled models by calibrating them with experimental data. Laboratory tests and real-world monitoring can provide valuable benchmarks for validating the numerical approach, ensuring that the simulation parameters reflect true material behavior. Additionally, the potential exists to extend the model by incorporating other environmental factors, such as carbonation or sulfate attack, to create a more comprehensive representation of environmental degradation processes. In doing so, we move toward more holistic models that capture the multifaceted nature of concrete deterioration, which is crucial for designing and maintaining sustainable, long-lasting infrastructure.
Overall, pursuing this fully coupled approach is an exciting opportunity to tackle the challenges inherent in corrosion modeling. It helps us understand not only how chlorides penetrate concrete, but also how the mechanical and chemical responses within the structure evolve over time. With the powerful combination of ABAQUS’s numerical capabilities and well-designed user subroutines, researchers and engineers can confidently drive innovation in corrosion prevention and structural resilience, ultimately ensuring that critical infrastructure remains
The first phase of the process focuses on understanding how chlorides move through the concrete matrix. Traditionally, this has been approached via a straightforward diffusion analysis, where the spatial and temporal evolution of chloride concentration is represented by solutions to the diffusion equation. While a diffusion-only model can provide insights into the rate and depth of chloride ingress, it does not inherently incorporate the mechanical effects that can significantly influence the transport behavior. Indeed, cracks in the concrete due to mechanical loading or temperature-induced expansion might alter diffusion pathways, accelerating chloride penetration in ways that a pure diffusion model fails to capture. Hence, while preliminary diffusion analyses are useful for determining initial chloride concentration profiles, they are inadequate for a complete and realistic representation of corrosion processes.
Recognizing the interplay between mechanical effects and chloride transport, the next logical step is to couple these two phenomena. In particular, a fully coupled temperature-displacement approach, as can be performed in ABAQUS, offers a powerful toolset. By utilizing user subroutines such as UMAT, USDFLD or UEL it becomes possible to integrate custom constitutive models and track specific variables of interest, including stress, strain, damage evolution, and even chemical reaction progress if needed. This allows to capture the way damage or microcracking influences chloride ingress and, conversely, the way chloride-induced damage modifies the mechanical response.
In practical terms, one of the most critical outcomes of chloride ingress is corrosion initiation in the reinforcing steel. Once the chloride concentration at the depth of the rebar surpasses a threshold, corrosion sets in, which then leads to a variety of problems. Rust occupies a greater volume than the parent steel, resulting in internal pressures that can cause cracking in the surrounding concrete. Over time, this expansion may compromise the bond between the steel and the concrete, weakening the composite action that gives reinforced concrete its strength. Moreover, sustained corrosion leads to a gradual reduction in the cross-sectional area of the reinforcing bars, which can severely compromise the load-carrying capacity of the structure.
By coupling diffusion and mechanical effects in a single simulation framework, it becomes possible to model all these phenomena in a more realistic and predictive manner. For example, one can incorporate a damage model that updates the material properties of concrete based on the stress state and crack development, which in turn modifies diffusion coefficients. Conversely, as chloride concentrations rise, the simulation can trigger a deterioration mechanism within the steel reinforcement, accounting for rust expansion and bond degradation. This level of detail is vital for predicting service life and establishing maintenance or repair schedules.
Looking forward, the next steps in this research involve refining these coupled models by calibrating them with experimental data. Laboratory tests and real-world monitoring can provide valuable benchmarks for validating the numerical approach, ensuring that the simulation parameters reflect true material behavior. Additionally, the potential exists to extend the model by incorporating other environmental factors, such as carbonation or sulfate attack, to create a more comprehensive representation of environmental degradation processes. In doing so, we move toward more holistic models that capture the multifaceted nature of concrete deterioration, which is crucial for designing and maintaining sustainable, long-lasting infrastructure.
Overall, pursuing this fully coupled approach is an exciting opportunity to tackle the challenges inherent in corrosion modeling. It helps us understand not only how chlorides penetrate concrete, but also how the mechanical and chemical responses within the structure evolve over time. With the powerful combination of ABAQUS’s numerical capabilities and well-designed user subroutines, researchers and engineers can confidently drive innovation in corrosion prevention and structural resilience, ultimately ensuring that critical infrastructure remains