Autonomous and autogenous healing by bacteria of metakaolin based geopolymer concrete exposed to freeze-thaw

It is known that the most used material as building material in the world is concrete. Cement is the basic material in the production of concrete. The high amount of energy consumption and the emission of harmful gases during cement production have led to the production of different binders that can be used instead of cement. In geopolymer, it is used as a binder of industrial by-products (fly ash, slag, etc.). It is known to produce geopolymers by activating the binders used with alkali. Due to durability effects, cracks occur in concrete and reinforced concrete elements. The durability properties of cracked concrete are adversely affected. Recently, studies on bacterial healing have been carried out to heal cracks in concrete. In this thesis, autonomous and autogenous healing of metakaolin-based geopolymer concrete samples with bacteria was investigated. S. pasteurii, which was strain 33 from the German collection of microorganisms and cell cultures (DSMZ), was used for bacterial healing. In addition, samples were produced using 4% colemanite and 6% aluminum mud in the binder. Produced samples were healed autogenously and autonomously after exposure to freeze-thaw according to TS EN 15177 standard. As a result of the thesis study, the cracks of geopolymer concrete samples exposed to freeze-thaw were successfully healed by using S. pasteurii.