Cracks are commonly occurring phenomena in concrete structures. Cracks provide paths for the ingress of deleterious substances, therefore endangering the durability of the structure. When cracking gets excessive, manual maintenance and repairs are required, which are both costly and time consuming. The demand for durable structures and materials that limit the need for manual repair and maintenance are leading to innovative solutions, such as the inclusion of the biological self-healing mechanism developed by Dr. Jonkers at the Delft University of Technology. This autonomous self-healing process utilizes mineral producing bacteria to help mend cracking in concrete, thereby enhancing the reliability and lifetime of the material. The bacterial spores are embedded into the concrete, along with organic compounds in capsules of polylactic acid for protection. Once a crack is created and water starts to seep through, the bacterial spores activate from their dormant state and start to metabolize the nutrients, resulting in the formation of calcium carbonate crystals which seal the crack. Self-healing can potentially reduce the necessity for regular maintenance and repair, thereby lowering long-term costs, resulting in more economically viable structures. However, in order for self-healing concrete to become applicable on an industrial scale, some obstacles still need to be overcome, such as the high production cost of the healing agent at present. Moreover, concerns regarding the influence of this novel technology on concrete characteristics need to be evaluated and addressed accordingly. The purpose of this present study is to identify and evaluate the most optimal and cost-effective form and quantity of the self-healing agent, in order to achieve a significant improved self-healing capacity without compromising other concrete characteristics. To assess the effect of the healing agent on the mortar characteristics, material characterization tests were conducted, both on fresh and hardened mortar samples. Three different forms of the healing agent were employed during these experiments: i.e., encapsulated particles, grinded particles and the loose components. The investigated dosages of healing agent used were 5, 10 and 15 kg/m3. The experimental results indicated that the healing agent performed best, in terms of its effects on mortar characteristics, when applied in the form of loose components. The effects on the material characteristics seemed to increase significantly when a higher dosage of the healing agent was used. In order to designate the performance efficiency of the healing agent, attention was paid to three requirements: the presence of mineral formation in the cracks, reduction in crack permeability and evidence of bacterial activity in the mortar. Microscopic techniques, in conjunction with crack permeability tests, revealed that full healing of cracks occurred in the bacteria based specimens, whereas this occurred only partly in the control specimens. The bacterial mediated process resulted in efficient sealing of cracks up to 0.47 mm, after 56 days of water submersion. Optimal performance was observed for the specimens containing the loose components in a dose of 10 kg/m3. That the crack healing potential was indeed bacterial induced is supported by oxygen profile measurements, which revealed bacteria based consumption. The effects of different healing regimes on the healing performance were also investigated. The study reveals that a damp environment is the most stimulating regime for the self-healing mechanism. In sum, the novel healing agent appears to be most efficient when administered in the loose components form, in a dose of 10 kg/m3 and in a wet environment. Under these circumstances, the agent shows the greatest potential for increasing the durability of concrete at an acceptable price.