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10968: An integral in-situ chloride sensing and monitoring system for concrete structures

In order to come to a reliable chloride sensor a full integral approach is proposed where the sensor development, the chloride induced degradation mechanism and the materials performance are developed simultaneously by three PhD projects. Hence, making sure there is a knowledge chain from materials performance to degradation, up to a sensor level and back. As such three PhD students are foreseen: The first PhD project will be on the development of a Cl sensor that can measure the actual chloride concentration directly from its in-situ condition in a porous network of cement-based materials. The research focuses on the robustness, the stability and on the long term performance of the sensor as this sensor should provide information for a long period (> 20 years). The second PhD project puts emphasis on the various transport mechanisms of Cl in concrete and its relation to damage mechanisms. In order make sure that the sensor is providing reliable data more information is needed on the transport mechanisms of Cl in concrete, e.g., the transport of the ion at various pore levels such as the gel and capillary pores. For this it is needed to measure the transport of the ions non-destructively. The third and last PhD project is on the changing microstructural development and its consequences for the chloride measurements. As concrete ages the porestructure is continuously changing not only due to hydration, but also due to the ingress and settlement of ions, like Cl. Accumulation of chlorides, but also chemical binding may affect the actual morphology of the microstructure, i.e. a changing pore structure inside the cementitious material. In order to come a sensor with long term stability it is foreseen to make use a of sensor technologies such as employed by lab-on-a-chip systems. The three PhDs will work together very closely and research results will be exchanged in order to achieve the desired integral approach.