'Living' concrete bricks can heal and reproduce on their own

Scientists develop "environmentally friendly" concrete by mixing sand, hydrogel and bacteria to create hard construction materials like cement.

The new material contains a primitive form of algae that first evolved on Earth 3.5 billion years ago and absorbs energy from the Sun. Thanks to this algae, the material can heal itself and release less carbon than conventional concrete. Scientists at the University of Colorado Boulder announced their findings today.

Specimens of "live" concrete bricks.(Photo: IFL Science).

The team, led by Dr Wil Srubar, said the material paves the way for "living buildings" in the future, which can repair cracks and absorb harmful substances in the air, thereby revolutionizing the industry. construction industry. According to Dr. Srubar, head of the University of Colorado Boulder Life Materials Laboratory, biomass like wood is being widely used but it is still "dead" material .

Dr. Srubar and his colleagues used cyanobacteria, which live in water to produce their own food, to create living materials. Although these bacteria are relatively small and unicellular, they often grow in clusters large enough to observe and are ideal for producing materials.

The team started by using sand and hydrogel to create a set of rigs for bacteria to grow. Hydrogels contain moisture and nutrients that allow bacteria to reproduce and mineralize similarly to the process of forming shells in the ocean.Bacteria absorb carbon dioxide (CO ₂ ) in the air and form calcium carbonate, the main component of cement.

Cement is the second most consumed building material on Earth after water. Cement industry alone, the powder to mix concrete, emits 6% of the total CO ₂ in the atmosphere. The new production method is a green solution to create building materials, resulting in lower CO2 emissions, according to Dr. Srubar.

Brick hydrogel - sand also has the ability to multiply. When slicing a brick in half, the bacteria can grow into two complete bricks, with just a little more sand, hydrogel and nutrients. Instead of producing individual bricks one by one, Dr. Scrubar's team observed that a single parent brick could lay up to eight offspring after three generations.

Dr. Srubar said the research was in its early stages and there were still a few obstacles to overcome. One of the biggest problems is that the bricks need to dry completely to reach maximum durability, but this puts pressure on the bacteria and reduces their ability to survive. To ensure bacteria survival, maintaining relative humidity and storage temperature is important. Using these conditions as a control switch, the team can decide when the bacteria will grow and when they lie dormant for construction.

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