Abstract
The current state of our nation’s infrastructure was given a grade of D+ in 2013, which warrants immediate remedial actions to improve structural integrity and ensure public safety. This has motivated intensive research aimed at enhancing the sustainability of infrastructure with the goal of reducing maintenance cost. Concrete is the most widely used infrastructure materials primarily due to its low cost and wide applicability. However, concrete is brittle and prone to crack formation due to mechanical loads and environmental conditions during its service life. Thus, innovative materials with self-healing capability provide a viable path towards mitigating crack related issues facing concrete infrastructure. In this dissertation, an overview of a bio-inspired self-healing methodology is presented. This methodology is based on microorganism induced calcium carbonate (CaCO3) precipitation filling and binding cracks in the cementitious materials. The effect of addition of microorganisms and related materials on the hydration, compressive strength, transport, and microstructure of cementitious materials is evaluated. The influence of parameters affecting the morphology and chemical structure of CaCO3 is investigated, using microscopy and analytical techniques, to establish the process-microstructure relations of CaCO3.