What is Biological deterioration?
Biological deterioration of concrete refers to the process by which living organisms, such as bacteria, fungi, algae, and vegetation, contribute to the degradation of concrete structures. As concrete ages, surface alkalinity is reduced by carbonation and environmental moisture creating a more hospitable environment for biological growth
These organisms can thrive in moist and nutrient-rich environments, leading to various forms of damage including microbial-induced corrosion, surface discoloration, cracking, and delamination.
This deterioration compromises the structural integrity and aesthetic appearance of concrete, posing challenges for maintenance and longevity of the structures
What causes Biological deterioration of concrete structures?
Biological deterioration of concrete is primarily caused by factors such as contaminated soils and groundwater, deposits of contaminated water or other matter on concrete surfaces, lack of ventilation, accumulation of sulphur components due to bacteriological activity, low pH, and vegetation growth.
Surface discoloration, like algae or moss growth, not only detracts from the appearance but also traps moisture, hastening deterioration. Roots from vegetation penetrating concrete can lead to cracking and delamination.
Biological deterioration can also increase corrosion if the rebar is exposed through cracks or honeycombing where the metabolic activity of microorganisms, such as bacteria or fungi, either chemically or physically change the conditions on the metal surface to induce corrosion.
What are the signs of Biological deterioration of concrete structures?
Disintegration of concrete cover.
How can I identify Biological deterioration in concrete structures?
Visual survey | Non-destructive testing | Destructive testing |
How can I prevent Biological deterioration in concrete structures?
Regular maintenance of concrete surfaces is crucial to prevent the accumulation of nutrients for bacteria and the growth of vegetation which leads to biological deterioration of concrete structures. This can involve cleaning and treating the surface to inhibit microbial growth or improving ventilation in areas prone to moisture buildup.
At the material level, using concrete with high resistance to microbiological attack, such as a binder with a high content of calcium aluminates, can be beneficial. Additionally, applying surface protection systems, such as coatings or sealants, can provide an extra layer of defence against microbial intrusion and growth.
By implementing these strategies, you can effectively prevent and mitigate biological deterioration in concrete structures, ensuring their durability and longevity.