Self-Healing Materials in Construction have the potential to revolutionize the construction industry. They can reduce the amount of maintenance and repair work needed on structures, and they can extend their lifespans by repairing minor damage.
Developing self-healing materials that can protect buildings, bridges and dams from damage should be a priority. These technologies could help prevent accidents caused by the collapse of high-rise buildings and long bridges.
1. Self-healing concrete
Concrete is one of the most pervasive materials used in construction, and it’s not uncommon for cracks to form over time. But these cracks can be costly to repair, and they can also weaken the structural integrity of a building. To address these concerns, researchers are working on self-healing concrete, a material that can seal itself as it develops cracks.
The key to this technology is adding bacteria that converts lime into a paste that fills and heals the cracks in the concrete, according to a study published in the journal Science Advances. The research was conducted by scientists at the USC Viterbi School of Engineering, who replaced some of the rock-like aggregates that help create concrete’s strength with engineered aggregates containing healing agents.
These engineered aggregates were then mixed with cement during traditional concrete mixing methods. The team found that the healing agent, which consists of bacteria encased in a polyurethane shell, was able to fill in and repair cracks about 1mm wide.
To make the system work, the scientists added a trigger mechanism to activate the healing agent. The trigger is a crack that forms in the concrete, and the bacteria are then released to start converting limestone into the concrete’s paste.
Scientists are also experimenting with other ways to heal concrete, including using fungus. Ning Zhang, Congrui Jin and Guangwen Zhou of Rutgers University and David Davies of Binghamton University created a version of self-healing concrete that relies on spores from the Trichoderma reesei fungus. Like the bacterial version, this type of concrete can heal cracks and maintain its strength.
2. Self-healing asphalt
Self-healing asphalt is based on the natural capacity of bituminous materials to repair fractures and cracks on their own, accelerated by an increase in temperature. The healing mechanism is complex and the encapsulation of rejuvenating agents within the asphalt is key for the material to function properly. Various encapsulation methods exist, but polymerization is currently the most common. The encapsulated particles should also have a size that is sufficient to avoid being squeezed or pulverized during the asphalt mixing and compaction processes.
The results of this research could significantly improve road construction and maintenance. The technology has the potential to greatly decrease the deterioration of asphalt pavements and reduce road repairs, which are currently costly for municipalities. It can also decrease traffic disruption and CO2 emissions due to road maintenance activities.
Researchers have developed asphalt with steel fibres that can be triggered to heal by induction. This technology can be used on both new and existing roads to extend their lifespan. The fibres are placed in the surface of the asphalt and act as a guide for the induction process, ensuring that the rejuvenating agent is targeted at the most damaged areas of the road.
The scientometric study showed that the field of self-healing asphalt is highly active in some countries, with China leading the way with 95 documents and a contribution of 43.8%. This research can be useful for academics to explore opportunities for cooperative ventures with other scientists in different regions.
3. Self-healing coatings
Self-healing coatings are one of the most promising solutions for prevention of metal corrosion. The coatings can repair dents and scratches caused by abrasion or impact, and they can also restore the protective barrier of the original coating. These coatings are being developed for a variety of substrates, including concrete and metals. Self-healing coatings can improve the durability of construction materials and help reduce maintenance costs.
The development of self-healing coatings is an important step towards the sustainable and economical production of construction materials. However, many challenges remain. These include the ability to accurately measure and quantify the healing capacity of self-healing coatings, the need for more rigorous long-term and accelerated testing, and the cost of the technology.
In addition to enhancing the durability of construction materials, self-healing coatings can also provide an environmentally friendly solution for corrosion protection. For example, researchers have recently developed transparent self-healing coatings for automobiles that can repair scratches and resist corrosion in just 30 minutes under sunlight. These coatings can save time and money on maintenance, and they can also increase vehicle performance.
The most commonly used method for implementing self-healing mechanisms in anticorrosion coatings is to incorporate polymerizable healing agents into the coatings. These are typically stored in micro/nano-containers that can be released when the coatings experience damage. These healants can then polymerize to fill in the damage and restore the anticorrosion protection.
4. Self-healing composites
Self-healing materials are useful for construction because they allow engineers to build more resilient structures. These materials can detect tiny structural failures and correct them before they become serious. They can also extend the lifespan of existing structures by reducing the frequency of repairs and maintenance. For example, self-healing concrete can repair small cracks and prevent them from getting worse. This technology can be applied to high-rise buildings and long bridges, where minor failures can have serious consequences.
MIT researchers have developed a self-healing material that grows, strengthens and repairs itself using carbon dioxide in the air. The material is designed to replace conventional building and roadway materials, and it can be used as a coating or additive. It can also reduce the need for recurring maintenance work, saving firms time and money.
The self-healing material is based on the natural process of plant growth and regeneration, as well as the healing of animals’ skin. It uses a ruthenium-based catalyst to initiate a chemical reaction that repairs damage. The material is also insensitive to humidity, making it possible to use it in harsh environments.
Despite the promising potential of this new material, researchers are still working to perfect it. In addition to ensuring that the material heals properly, it must also be able to maintain its mechanical properties. If the material loses its ability to withstand physical deformation, it will no longer be able to repair itself.