Concrete becomes more durable. The secret lies in the bacteria

Concrete is a commonly used building material. Thanks to the new search, its results are displayed in pages cleaner production magazinemay become more common.

The many advantages of concrete include low costs, high resistance to overloads, and an uncomplicated production process. However, when it comes to using alternative components to produce recycled concrete, more problems arise. These are especially important in cold climates where temperature fluctuations can lead to damage, putting entire structures at risk.

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To counter this, scientists at Xi’an Jiaotong University-Liverpool introduced bacteria into the recovered coarse aggregate, thus increasing the strength of the concrete. When subjected to such treatment, it can be used in cold climatic regions, as it is able to withstand up to 225 freeze-thaw cycles. This is 75 more than the untreated mix.

The methods used so far to strengthen concrete have included, for example, reducing the water-cement ratio or increasing the amount of chemical additives. Unfortunately, the first method is questionable in the long run, while the second method is harmful to the environment. In this case, it seems that both problems have been solved, as well as the most important one related to the durability of the structure.

Concrete is damaged by freezing water

what is the secret? As one of the study’s authors, Chee Seong Chin, explains, water penetrates through concrete during freezing and thawing, creating cracks that reduce durability. The volume of frozen water increases, which translates to an increased risk of damage. However, bacteria can clog the holes that water can enter. That is why they have been used to increase the compressive strength and tensile strength by 30.3% and 20.3%, respectively.

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However, this is not the end of the advantages. Bacteria consume excess calcium hydroxide during the biomineralization process. This makes concrete more resistant to sub-zero temperatures. Despite promising first research results, the scientists now intend to continue their project to increase resistance, for example through the use of nanomaterials.