Coupled hygrothermal, electrochemical, and mechanical modelling for deterioration prediction in reinforced cementitious materials

In this paper a coupled hygrothermal, electrochemical, and mechanical modelling approach for the deterioration prediction in cementitious materials is briefly outlined. Deterioration prediction is thereby based on coupled modelling of (i) chemical processes including among others transport of heat and matter as well as phase assemblage on the nano and micro scale, (ii) corrosion of steel including electrochemical processes at the reinforcement surface, and (iii) material performance including corrosion- and load-induced damages on the meso and macro scale. The individual FEM models are fully coupled, i.e. information, such as such as corrosion current density, damage state of concrete cover, etc., are constantly exchanged between the models

Electro active repair of concrete for improved durability of conventional repair

Chloride induced reinforcement corrosion is increasing due to aging of concrete infra structure. Conventional repairs have poor durability and many fail after less than 10 years. For conven tional repair chloride contaminated concrete is removed, steel is cleaned and new concrete is applied. Leaving chiorides, eg. in pits, corrosion may re-activate and the repair fails. The authors have invented a pre-treatment for conventional repair, called Electro Active Repair (EAR) for electrochemical removal of chlorides from corrosion products and pits. After removal of contaminated concrete, a temporary mate rial and a temporary anode are installed and cathodic current is applied for 24 hours. Next. temporary materials are removed and repair is executed as usual. A European was granted and a world wide applied for. The principle was conhrmed in laboratory experiments. A cementitious material was placed between NaOH and FeCl, solutions. More than 90% of the chloride was removed from the catholyte (FeCI,) in 20 hours at 8 A1m2 and the pH increased from 3 to 12, which will prevent re-activation of corrosion and consequently improve the durability of the repair. The method has the advantage that it fits in the conventional repair proces

Coupled hygrothermal, electrochemical, and mechanical modelling for deterioration prediction in reinforced cementitious materials

In this paper a coupled hygrothermal, electrochemical, and mechanical modelling approach for the deterioration prediction in cementitious materials is briefly outlined. Deterioration prediction is thereby based on coupled modelling of (i) chemical processes including among others transport of heat and matter as well as phase assemblage on the nano and micro scale, (ii) corrosion of steel including electrochemical processes at the reinforcement surface, and (iii) material performance including corrosion- and load-induced damages on the meso and macro scale. The individual FEM models are fully coupled, i.e. information, such as such as corrosion current density, damage state of concrete cover, etc., are constantly exchanged between the models