A study on the mechanical and self-healing behavior of bio-concrete blocks based on Spirulina algae

The construction industry significantly contributes to global carbon emissions, primarily due to Portland cement production, which is essential for the construction of concrete structures. The growing demand for sustainable materials has prompted research into using algae for bio-concrete blocks. In this study, bio-concrete blocks incorporating algal biomass were cast and evaluated to assess their structural and mechanical performance. Algae, known for rapid growth, can enhance the properties of concrete. This study focuses on integrating Spirulina, a type of blue-green algae, into concrete formulations. Spirulina not only improves mechanical properties but also helps seal cracks, reducing the need for expensive and time-consuming repairs. Experiments tested different percentages of algal incorporation (0.2%, 0.3%, and 0.4%) in cement content, yielding average compressive and split tensile strengths of 7.2 MPa and 1.32 MPa, respectively. Results show that 0.4% algal biomass can increase compressive strength by 8-12% due to its ability to seal micro-cracks and enhance load-bearing capacity. Additionally, bacteria can improve tensile strength by up to 63%, contributing to enhanced mechanical behavioral properties that extend the longevity of bio-concrete.