# Bio-Influenced Self-Healing Mechanism in Concrete and Its Testing: A Review
## 3 Results and Discussion
### Type of Test: Destructive and Non-Destructive
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Method**} & \multirow{2}{*}{**Bacterial Strain**} & \multirow{2}{*}{**Protective Material**} & \multicolumn{2}{c}{**Scale Level of Test**} & \multicolumn{2}{c}{**Type of Test**} & \multirow{2}{*}{**Connect Type**} & \multirow{2}{*}{**Ref**} \\ \cline{3-4} \cline{8-10}  & & & & **Macon** & & & **Milow** & **Namo** & **D** & **NOT** \\ \hline \multirow{9}{*}{**Baselines**} & Spontaneous pasteuri & None & x & x & x & x & GFC & [60] \\  & Bacillus subtilis & None & x & x & & x & NSC & [22] \\  & Bacteria NBR1 & None & x & x & x & x & NSC & [51] \\  & Bacillus subtilis and spherometers & None & x & & x & & NSC & [53] \\  & Sporomakers pasteuri & None & x & x & x & x & NSC & [54] \\  & Bacillus subtilis & None & x & & x & x & NSC & [55] \\  & Bacillus nongeneration and subtilis & None & x & x & & x & NSC & [56] \\  & Bacillus subtilis & None & x & x & & x & NSC & [57] \\  & Sporomakers pasteuri & None & x & x & x & x & NSC & [58] \\  & Bacillus subtilis & None & x & x & x & x & NSC & [58] \\  & Bacillus subtilis & None & x & x & x & x & NSC & [53] \\ \hline \multirow{9}{*}{**Baselines**} & Bacillus subtilis & Inon oxide nano-sized particles (ONPs) limestone powder & & x & x & x & NSC & [60] \\  & Bacillus spherometers & Silica gel & x & & x & x & NSC & [63] \\  & Virus positive bacterium & Block aggregate & x & x & & x & NSC & [62] \\  & Bacillus subtilis & & LWS and CSV & & x & & x & NSC & [22] \\  & Sporomakers pasteuri & Pre-wetted lightweight the expanded shale aggregates & x & & & & NSC & [64] \\  & Sporomakers pasteuri & Ceramic & x & & & NSC & [64] \\  & Bacillus pseudodermous & Cated expanded gentle & x & & & x & NSC & [65] \\  & Bacillus colonial & Expanded gentle & x & & x & x & NSC & [66] \\  & Bacillus and licheniformis & Inon oxide nanoparticle & x & x & x & x & NSC & [61] \\  & Bacillus subtilis & Limestone powder & x & & & x & NSC & [69] \\  & Sporomakers pasteuri & Calcium sulphanumulate connect & x & & & x & NSC & [67] \\  & Sporomakers urea and Sporomakers & Zoolite & x & & x & x & NAM and FEM & [68] \\  & parasitoid & & & & & & & & \\ \hline \multirow{9}{*}{**Baselines**} & Bacillus hamophysics & Bead encapsulating calcium alginate and bacteria & x & x & & x & NAM & [71] \\  & Bacillus pseudodermous & Biomaceous capsule & & & & & & NSC & [22] \\  & Bacillus spherometers & Glass tube encapsulating bacteria and silica gel & x & x & x & x & NAM & [73] \\  & Bacillus pseudodermous and Calcium alginate Beads & x & x & & x & x & FFC & [74] \\  & Darbouxractors introduced & & Hydged & x & & x & x & NM & [23] \\  & Bacillus spherometers & Meantime Microcapsule & x & x & & x & NCM & [75] \\ \hline \hline \end{tabular} Note: For Type of Test: D—Descructive and NDT—Non-Destructive. Concrete Type: Normal strength concrete (NSC), Geopolymer Concrete (GPC), Normal Mortar (NM), Fiber Reinforced Mortar (FROM), Fiber Reinforced Concrete (PRC).  
\end{table} 
Table 2: Application methods of bacteria in cementitious composites with protective materials and the corresponding property tests. Self-healing technology in concrete is one of the possible solutions to prevent the unnecessary repair and maintenance of concrete structures, as well as to reduce carbon dioxide emissions due to cement production. The demand for concrete as a construction material will increase as the demand for infrastructure development increases. The production of concrete emits a lot of carbon footprints and an energy intensive process. In the long run, concrete material may not be sustainable, due to limited resources and environmental issues. Therefore, there is a need to develop a sustainable concrete material in order to meet demand, as well as to protect the environment. The market research results show that highways and infrastructure generally, and water retaining structures, would benefit most from self-healing cementitious materials, with reduced maintenance costs over a structure's lifetime, justifying a premium in the capital material cost [76].