Microorganisms could help seal cement cracks

UN/DICYT  Isolating microorganisms which form calcite (calcium carbonate crystals), scientists are researching producing material which could provide greater durability to cement.

These types of microorganisms could help seal micro-fissures in the internal structure of bio-cement in an eco-friendly manner. When cement mixture is prepared small air-filled voids remain.

Therefore Sandra Milena Montaño Salazar, UNal-Bogotá Biology student gathered samples from walls and sidewalks from several UNal buildings. Afterwards, at the Microbiology lab, she placed them in saline solution and a stirring process at 10º C (50º F) for 15 days, isolating the material in order to release the microorganisms.

Later she grew these specimens in plates generating calcite precipitation and identifying which microorganisms produced calcite.

“As a result I discovered two strains which produce calcium carbonate, a result which has not been recorded in the scientific literature before; furthermore we discovered a bacteria which could help to improve cement durability and resistance”, said Montaño.

Currently researchers are performing studies to become cognizant of the exact composition of calcite, through molecular identification and crystal characterization.

In the near future researchers will embark on tests such as adding bacteria to cement mixtures and making cement cubes in order to test them against cubes without calcite.