Encapsulation of polymeric healing agents in self-healing concrete: Capsule design - CAPDESIGN

We consider that € 40–120 million of the maintenance costs for concrete bridges, tunnels and retaining walls in the European Union could be saved by application of self-healing concrete. The encapsulation technique is however a bottleneck for valorisation since the capsules must possess multifunctional properties for self-healing concrete containing polymeric healing agents. The challenging objective of this project was to develop capsules which can easily survive the concrete mixing/casting process at the one hand but break immediately when cracks appear in a hardened concrete matrix.

In the CAPDESIGN project, several encapsulation techniques and materials have been investigated. The most appropriate durable capsules were applied to evaluate their self-healing efficiency compared with their mechanical behaviour and liquid tightness. The feasibility of upscaling from laboratory to industrial proof of concept of the most promising capsule was also studied. The main achievements of the project include:

• The most promising materials which can survive the concrete mixing and break upon crack have been identified
• Promising capsules that are compatible with healing agents have been selected
• A low water uptake was measured in cracked samples containing capsules with healing agent, suggesting that a self-healing effect was obtained in concrete
• Upscaling of one selected type of capsule was realised

In addition, during the project period, the partners have published 7 papers in scientific journals and 20 presentations (oral and poster) in international conferences.

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