Bacteria based self healing concrete
A paper reviews the types of bacteria used in concrete and the ways it can be applied as healing agent. It also gives a brief description of the properties of concrete which vary with the addition of bacteria.
Micro-cracks are inherently present in concrete. This causes degradation of concrete leading to ingress of deleterious substances into concrete, resulting in deterioration of structures. Due to this concrete needs to be rehabilitated. To surmount these situations self-healing techniques are adopted.
Promising results in sealing micro-cracks
The addition of urease engendering bacteria along with calcium source results in calcite precipitation in concrete. Bio-mineralisation techniques give promising results in sealing the micro-cracks in concrete. The freshly composed micro-cracks can be sealed up by perpetual hydration process in concrete. The ureolytic bacteria which include Bacillus Pasteurii and Bacillus Subtilis are integrated along with the calcium source to seal the freshly composed micro cracks by CaCO3 precipitation.
Sustainable improvement of concrete
For the amelioration of pore structure in concrete, the bacterial concentrations were optimised for better results. The literature shows that the encapsulation method will give better results than direct application method and that the use of bacteria can increase the strength and durability properties of concrete.
The study is published in: Construction and Building Materials, Volume 152, 15 October 2017, Pages 1008-1014
