From pollution absorption to self-healing abilities, a number of innovative building materials that function as self-regulating, living systems are being developed today. Comprised in part from bacteria and other natural biological processes, the materials have the ability to cool, heat, and even repair themselves.
No longer simply inert objects, these engineered materials when combined to form completed structures are transforming buildings into living systems that have the ability to adapt to their surroundings automatically on their own.
Traditional mechanical and plumbing systems such as drainage and venting are being reimagined through the creation of living, breathing building systems that are powered by natural biological processes. The end result could be a significant reduction in emissions and a reduction in the carbon footprint of buildings.
On a larger scale, these innovative building materials have the potential to not only transform individual buildings but entire cities so that infrastructure is less dependent on fossil fuels and instead harnesses the potential energy of natural organisms. Here are seven such building materials that are either in production or in the research stages:
1. Pollution Absorbing Bricks
A project at Newcastle University in the UK is underway to develop bricks that have the ability to generate electricity from solar energy, recycle wastewater, and clean the air all at once. Dubbed Living Architecture (LIAR), the project aims to transform our habitats from inert spaces into programmable sites.
When assembled as modular units, the bricks will form partitions of “bioreactor building blocks” that can be programmed as microbial fuel cells (MFC’s) to either produce electricity or to purify air or water. To achieve this, the MFC’s will be filled with a variety of programmable synthetic microbes.
The microbial fuel cells will work in combination with computers that will be able to sense local conditions within a building and control the bioreactor system in order to optimize the building’s environmental impact.
When exposed to sunlight, the modular partitions will remove pollutants such as carbon dioxide, nitrous oxide, and organic matter from waste products and turn them into sustainable resources including fresh water, polyphosphate, and oxygen.
If implemented on a broad scale, the Living Architecture project has the potential to significantly alter the environmental impact of homes, communities, and cities.
2. Cooling Masonry Units
A composite facade material made of clay and hydrogel, which functions as a passive masonry unit cooling system, is being developed at the Institute for Advanced Architecture of Catalonia (IAAC) in Spain.
Hydroceramic, as it is being called, uses the ability of hydrogel to absorb many times its own weight in water. The cooling effect is achieved through the evaporation of water from the hydrogel pellets spread throughout the surface of the masonry units.
Water evaporation helps decrease the temperature while at the same time increasing the humidity in the surrounding air. The effect is greatest when the outside air is warm. In cold weather, little evaporation occurs, making hydroceramic responsive to its surrounding environment.
The composite facade is capable of passively cooling building interiors by nearly 11 degrees Fareheight (6 degrees Celsius) and increasing humidity by about 15-16 percent. Based on findings by the IAAC, this could result in a reduction of about 28 percent in electricity required for air conditioning in buildings.
3. Self-Healing Concrete
Concrete, with the ability to repair itself, is being developed using Bacillus and/or Sporosarcina bacteria. The bacteria are encapsulated in minuscule pellets and mixed with the concrete as well as an organic nutrient called calcium lactate which they feed on.
They remain dormant until cracks form in the material. Once cracks let water in, the bacteria come to life and begin feeding on the calcium lactate, producing limestone as a byproduct to fill the cracks naturally.
Within a period of 3 weeks, the cracks can be naturally sealed off without the need for human intervention. The bacteria can remain dormant within the cement for as much as 200 years, beyond the typical lifespan of the concrete structure itself.
Developed by microbiologist Henk Jonkers at Deft University of Technology, self-healing concrete has the potential to prolong the life of new concrete structures. For existing concrete structures, a liquid spray containing the same bacteria is also being tested.
4. Self-Repairing Asphalt
A different approach to self-repair is a concept introduced by Dutch civil engineer Erik Schlangen for self-repairing asphalt. By mixing steel wool to the asphalt, the material is capable of repairing itself with a bit of help.
While not as independent from human intervention – it requires heating to melt the strands of steel wool – the technology has the potential to reduce cracking and potholes in pavements on sidewalks, roads, and bridges. This could result in major savings in repair costs.
In order to heat the asphalt, Schlangen’s lab has developed a special vehicle that passes induction coils over roads. The vehicle needs to be run about every four years above roads to repair minor cracking and prevent potholes. Schlangen estimates that this process could double the lifespan of traditional roads.
5. Bendable Concrete
Another innovation involving concrete is the creation of a bendable concrete with plastic qualities. It has the ability to bend but not break. Common concrete tends to be very brittle, and as a result, when it fails it happens abruptly and along a single large crack.
Engineered cementitious concrete (ECC), commonly known as bendable concrete, has the ability to give just enough to allow the material to expand and contract under tension and compression without failure. It is able to achieve this due to the addition of microscopic fibers in the cement.
When subjected to stress, bendable concrete begins to develop numerous micro-cracks. These tiny cracks prevent the concrete from completely breaking or collapsing by absorbing the stress in a more uniformly distributed manner. What’s more, the cracks are so tiny that over time they can self-heal.
6. Metallic Glass
Material scientists at Lawrence Berkeley National Laboratory in California have created a micro-alloy glass made of palladium that is extremely strong and very tough. The glass actually has a better combination of strength and toughness than steel.
What’s more, the glass is lighter than steel and comparable to aluminum in terms of weight. Unlike standard glass which tends to be brittle by nature, metallic glass has a plastic response to stress, allowing it bend but not break.
Because of the infused palladium, metallic glass forms many shear bands when subjected to stress, rather than a large single band – the common cause of failure in float glass. This is what allows it to give before it breaks, unlike standard glass.
The challenge currently to bring the product to mass market is the high cost. However, the material holds promise and variations on the concept are being studied at the lab. Eventually, a more cost-effective version should emerge which will allow designers to use glass in structural applications.
7. Light Generating Cement
Cement that has the ability to absorb sunlight and emit light from the stored energy is another innovative concept in the works. From smart roads to bike paths to public spaces/plazas, the technology has the potential to reduce electrical consumption in outdoor spaces.
Researched and created at UMSNH of Morelia in Mexico, the phosphorescent material is manufactured by adding special additives to the cement through a process of condensation of raw materials.
By modifying the optical properties of Portland cement, Dr. José Carlos Rubio Ávalos and his team were able to increase the capacity of the material to absorb and radiate light. The modified cement allows for a degree of light penetration, something not possible in conventional cement.
In addition to roads and public surfaces, the material has the potential to be used on building facades, swimming pools, parking lots, industrial applications, etc. and anywhere electricity is not available. The material can emit light for up to 12 hours each night after absorbing sunlight and has a potential lifespan of over 100 years.