Self-Healing Materials in Civil Engineering

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Self-Healing Materials in Civil Engineering

Self Healing Materials are a type of smart materials that have the built in capability to repair the early stage damage that would finally lead to material failure. This research is inspired by nature as living organisms already possess the capability of self healing (repair of damage like wound healing, recovery of broken limbs). This research is being carried out at The Delft Centre for Materials, at Delft University of Technology, The Netherlands.

The topics that are selected for the research in Self Healing Materials are:

• Asphaltic materials
• Bio-inspired technical materials
• Cementitious materials
• Composites and hybrids
• Metals
• Paints and other coatings
• Structural polymers
• Biological systems
• Theoretical models related to Self Healing
• Characterisation of Self Healing behaviour

It was only recently that the property of Self Healing was seriously considered as a desirable function for man-made materials. The first successful incorporation of self healing functionality in a (man-made) epoxy-system was via micro-encapsulation by Scott White and collaborators at the University of Illinois. Now research groups throughout the world have started to explore these concepts and materials systems that impart self- healing properties for a variety of applications.

Figure: Self healing action of self healing materials

Usually, cracks are repaired by hand, which is difficult because cracks are often hard to detect. A material (polymers, ceramics, etc.) that can repair damage caused by normal usage could lower production costs of a number of different industrial processes through longer part lifetime, reduction of inefficiency over time caused by degradation, as well as prevent costs incurred by material failure. For a material to be defined as self-healing, it is necessary that the healing process occurs without human intervention.

Some basic questions and answers on Self Healing Materials:

What self healing materials can do?

When a crack forms in the material, it can recover the plastic deformation and heal itself. It does that without the human intervention.

Where Self Healing Materials can be used?

It can be used in satellites or aircrafts. It can also be used in civil infrastructure and be used in prosthetics so a simple crack won’t result in another surgery. If a crack starts moving through material, it should be stopped immediately, otherwise some accident may occur. Propagation of damage should be stopped to prevent failure, but the damage or crack is very hard to detect when you don’t have access. This is where this material can be used.

What’s the importance of this research on Self Healing Materials?

The failure of structural materials is a huge problem. This research will help in structural health monitoring with self-healing. This material can sense damage and then respond to it. It only takes seconds to stop the damage.