Researchers from Hiroshima University and Kyoto University have discovered that concrete contains different microbial zones, with surface bacteria being distinct from those found deeper inside. The microbial communities inside concrete are primarily influenced by the microorganisms introduced through the raw materials used during mixing. Once the concrete hardens, microbial diversity decreases, and they are mostly confined to their original layers.
Even the heat generated by drilling, which can reach temperatures of up to 70°C, does not significantly affect the detectable DNA signature of these microbes. This suggests that microbial traces may remain readable even under the thermal stress of standard sampling procedures.
The findings, published in Case Studies in Construction Materials, have implications for detecting hidden structural damage in concrete. By monitoring the distribution of microbes, unexpected shifts in their presence could serve as early indicators of emerging structural issues.
China Kuratomi, the lead author of the study and a doctoral student at Hiroshima University, expressed the hope that microbial indicators could make concrete maintenance more accessible to a wider range of people. Just as changes in health can be monitored through everyday indicators like body temperature, monitoring building conditions through microbial signals could provide valuable insights for building maintenance.
Researchers explored whether microbes present in concrete could signal deterioration. By studying microbial communities in undamaged concrete and investigating sampling methods, they found that the movement of microbes inside the material is limited. The heat generated during sampling procedures did not significantly alter the microbial profiles, indicating that microbial evidence can survive standard conditions.
The researchers highlighted that microbial migration within concrete can indicate defects such as cracking or increased connectivity, pointing to the potential of microbial information as a novel indicator for diagnosing deterioration in concrete structures.
The research team, including members from Hiroshima University and Kyoto University, will further investigate how damaged concrete impacts microbial migration and what this movement reveals about internal structural issues.
(Source: Hiroshima University)
