Comparative Study on the Compressive Strength of Bacterial Concrete using Spirulina and Bacillus Subtilis

Abstract

The bacterial concrete has remarkable advantages over ordinary concrete in self-repairing itself when cracked, and it proves to be an environmentally safe building material to be used. The objective of the present study is to investigate the feasibility of using Spirulina in bacterial concrete. A comparative study on the compressive strength of M30 grade of concrete using Spirulina and Bacillus Subtilis (B.Subtilis) were carried out. Volume of Spirulina and B.Subtilis culture used in the concrete were in the order of 5ml, 10ml, 15ml, 20ml and 25ml. Calcium chloride (CaCl₂) was used as a nutrient for both Spirulina and B.Subtilis. About 10 ml of CaCl₂ was used in each mix. Reference cubes were also casted without the addition of bacteria in the concrete. The increase in compressive strength at 7 and 28 days were found to be 28.53% and 17.21% respectively using Spirulina and 33.99% and 24.67% respectively using B.Subtilis when compared to concrete without bacteria. This study is an initiative to use Spirulina in bacterial concrete. Further studies on the durability aspects of concrete using Spirulina can be done as it is a known non-pathogenic cyanobacterium or algae.