As you know, Cracking is one of the major deteriorating causes of concrete, which allows the entrance of chemicals and can lead to the loss of physico-mechanical and durability properties of concrete structures. To protect, repair, and rehabilitate concrete structures, the application of different surface coating agents and sealants, binding agents, as well as adhesives has been commonly practiced. Although such techniques have mostly been applicable, due to their inherent mechanism difference, major challenges such as delamination and lack of cost effectiveness have resulted in searching for alternative methods of crack sealing or self-healing.
One of the novel self-healing mechanisms is using bacterial induced calcite precipitation in concrete mixtures to heal concrete cracks. In this technique, bacterial mineralization (biomineralization) is performed through decomposing urea and calcium to produce calcium carbonate (CaCO3), which can fill cracks. It is found that the biomineralization is mostly dependent on factors such as the applying method and consistent preservation of the living bacteria. In addition, the environmental impact of bacterial concrete is found to be directly linked with the urea content in the concrete mixture.
Think of a wall that can repair itself or harden like the shell of a crustacean. That is the approach that a team of researchers at MIT in the United States has adopted, using a type of bacteria to create an innovative biomaterial – the latest example of an ELM (engineered living material).
This breakthrough is part of a tangible evolution in the development of new eco-friendly building materials, some new and others reinvented, such as:
- Mushroom mycelium
- Cob (mixture of vegetable fibers and clay)
- Transparent wood
- Insulating hydrogels
- Vegetable polyurethane
- Panels with sunflower fibers
- Bioplastics
- Bio-concrete
