Preliminary tests for application of carbon nanotubes and Bacillus sphaericus bacteria in self-healing cement mortars

Self-healing in concrete is a popular and developing topic, which utilizes both biotic and abiotic mechanisms to close micro-cracks. Nano additives such as carbon nanotubes (CNT) improve the cement material's resistance to cracks but could also influence the survivability of microorganisms in concrete. A combination of CNT and calcium carbonate precipitating bacteria might lead to both improvement of concrete's durability and provide self-healing properties, while increasing the survivability of the microorganisms in the environment of the cement-based material. The presented research focuses on preliminary tests of the influence of the Bacillus sphaericus bacteria and low addition of CNT on the cement mortar's strength and survivability of microorganisms in the environment of cement matrix. Strength tests and biotic control were performed to provide data to modify the mix for further tests concerning mechanical properties and survival of microorganisms.