Durability Monitoring of Infrastructures

Background

Reinforced concrete is the most used building material worldwide, particularly in large infrastructures, e.g., tunnels, garages, bridges, and in many public and private buildings. However, the service life of reinforced concrete structures can be limited due to deterioration related to corrosion of the steel reinforcement.

Parameters playing important roles in the corrosion process (pH, chloride concentration, moisture state, …) can currently only be quantified through destructive testing, which is laborious, expensive and only yields very limited information (e.g. with respect to seasonal variations).

Aims and objectives

This project aims at overcoming the above-mentioned limitations of destructive testing, by delivering a solution to allow monitoring all important durability parameters for reinforced concrete structures in-situ and non-destructively.

Methodology

We develop embeddable sensors that can be directly installed on concrete bridges or other concrete structures. Our combined sensor permits, for the first time, the continuous in-situ monitoring of all relevant parameters for corrosion and durability: pH, chloride concentration, concrete’s electrical resistance, moisture state, steel potential, and temperature.

While these fundamental parameters affect the corrosion state in a complex manner, we develop a smart data analysis based on state-of-the-art corrosion theory to assess the current corrosion risk and to facilitate the interpretation of the raw data for non-specialists. Moreover, we use physics-based numerical models to turn the measured data into a real-time updated prognosis of the future condition evolution.

Our solution can be applied to the following cases:

1. New structures: to monitor the durability performance of new materials and structures under real exposure conditions
2. Existing ageing structures: to monitor their deterioration in-situ and to determine the right time for maintenance and repair interventions
3. Repaired structures: To monitor the performance of repair works, e.g. as quality control or to follow up the durability of different repair principles
4. Research: studying durability processes occurring in traditional and new materials (e.g. low-carbon cements), by the non-destructive in-situ monitoring of parameters so far difficult to access

Field application and outlook

We are currently working on the commercialization of our solution that is planned to be offered through a start-up called “DuraMon”. We have different ongoing pilot projects, including:

• Trial in a bridge constructed in Remedios (Cuba) in collaboration with Universidad Central "Marta Abreu" de Las Villas (new structure, to monitor the performance of the new cement used);
• Trial in a new parking garage constructed in Bludenz (Austria) in collaboration with Sika Technology AG, LafargeHolcim, Tomaselli Gabriel Bau, and ETH (new structure, to monitor the performance of the new cement used);
• Trial in an existing parking garage in Saas-Fee (Switzerland) that was repaired in 2019 (repaired structure, to monitor the performance of the repair works).