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Project Overview
Project Overview
Chloride-induced corrosion is the predominant cause for premature damage of reinforced/prestressed concrete members in the marine tidal environment. Repairing premature damages incurs significant direct costs and additions indirect costs due to disruption of services. Therefore, having a planned maintenance schedule for structural members/designing them for maintenance-free service life is essential to minimize the maintenance costs of a structure. This would require developing models that can predict the deterioration of structural members as a function of the quality of construction materials and the service environment.
Chloride-induced corrosion is the predominant cause for premature damage of reinforced/prestressed concrete members in the marine tidal environment. Repairing premature damages incurs significant direct costs and additions indirect costs due to disruption of services. Therefore, having a planned maintenance schedule for structural members/designing them for maintenance-free service life is essential to minimize the maintenance costs of a structure. This would require developing models that can predict the deterioration of structural members as a function of the quality of construction materials and the service environment.
The objectives of this study are:
- Development of realistic periodic tide models for marine tidal zone
- Comparative assessment of moisture ingress along the tidal zone
- Comparative assessment of chloride ingress along the tidal zone
- Comparative assessment of moisture and chloride ingress across tidal staitons: A case study of selected Indian stations
Highlights of the tide model
Highlights of the tide model
Proposed a superimposed tide model as a periodic wave approximation for oceanic tides.
The model is developed based on real-time tidal height data. It simulates the fortnightly occurring spring and neap tides, along with the diurnal tides.
The predictions of moisture and chloride penetration indices obtained using the superimposed tide model are found to be significantly greater than those predicted by the conventionally used diurnal tide model.
Refer the following article for more details
Padala, S. K., Bishnoi, S., & Bhattacharjee, B. (2022). Long-term moisture penetration in concrete exposed to marine tidal conditions. Magazine of Concrete Research, 74(14), 740-755. https://doi.org/10.1680/jmacr.21.00188
Moisture Transport Model
Moisture Transport Model
Developed a moisture transport model for the prediction of moisture profiles in concrete exposed to cyclic wetting and drying based on Richard's equation.
The moisture profiles after every wetting and drying are shown in the figure
The penetration indices used for characterization of the moisture profiles are (i) influential depth of moisture transport (IDMT) and (ii) cyclic water absorption amount (CWAA)
Refer the following article for more details
Padala, S. K., Bishnoi, S., & Bhattacharjee, B. (2022). Long-term moisture penetration in concrete exposed to marine tidal conditions. Magazine of Concrete Research, 74(14), 740-755. https://doi.org/10.1680/jmacr.21.00188
Chloride Transport Model
Chloride Transport Model
Typical chloride profile after a wetting event is shown
The penetration indices used for characterization of the chloride profiles are: (i) peak chloride concentration (PCC), (ii) depth of occurrence of the peak chloride concentration (DPCC), (iii) upper chloride threshold depth (UCTD) and (iv) lower chloride threshold depth (LCTD)
The values of penetration indices at each tidal height are plotted to observe their variation along the tidal zone
Refer the following article for more details
Padala, S. K., Bishnoi, S., & Bhattacharjee, B. (2022). Characterization of the Severity of Tidal Environment on Reinforced Concrete Members Using Moisture and Chloride Penetration Indices. Journal of Materials in Civil Engineering, 34(11), 04022277. https://doi.org/10.1061/(ASCE)MT.1943-5533.0004434
Animation of Moisture and Chloride Profiles
Animation of Moisture and Chloride Profiles
Faster Show.mp4The moisture and chloride profiles with alternating wetting and drying cycles are shown
Case Study
Case Study
Six stations along the Indian Coastline are studied
Real-time tidal height data and meteorological data (temperature, relative humidity, and wind speed) are used in the boundary conditions
The wetting and drying patterns at any tidal height are characterized using a parameter DWTR - cumulative drying to wetting time ratio
DWTR vs. Tidal height was found to give a unique curve for each tidal station
Moisture and Chloride profiles at different tidal height levels at various stations are assessed
Comparison of the critical chloride threshold depths at a given chloride threshold value (mean of UCTD and LCTD) across the tidal stations is shown at different ages of exposure
Refer the following articles for more details
Padala, S. K., Bishnoi, S., Bhattacharjee, B. (2023). Estimation of Safe Cover Thickness to Steel Reinforcement in Coastal Structures addressing several Tidal Stations. Structure and Infrastructure Engineering (Taylor & Francis). Advance Online Publication. https://doi.org/10.1080/15732479.2023.2166537
Padala, S. K., Bishnoi, S., Bhattacharjee, B. (2022). A methodology for comparing the chloride penetration severity across different tidal zones: A case study of two Indian seaports. Materials Today: Proceedings (Elsevier). 65, 697-701. https://doi.org/10.1016/j.matpr.2022.03.266
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