Concrete is an extremely durable and versatile building material, which is why it is amongst the most popular man-made materials in construction. Due to its versatility of application, it is used in a multitude of applications, including: sewage systems, tunnels, storage tanks, roads, bridges, building façades, industrial floors, sidewalks to name a few.
However, its common use in often high-traffic areas and environmentally harsh conditions means that concrete can suffer from material degradation, staining and microbial contamination. This microbial contamination can lead to microbially induced corrosion (MIC), which is a major concern within the industries that use concrete. It can mean that the integrity of concrete structures can become compromised, creating a financial burden on companies and authorities as a result of the required cleaning and maintenance.
What is microbially induced concrete corrosion?
Concrete is an inherently porous material that will naturally degrade over time. However, the process of concrete degradation is accelerated by microbially induced corrosion, which is the corrosion of concrete caused or promoted by microorganisms. It affects the long-term durability and mechanical properties of concrete by creating acids that react with ingredients in the concrete mixture, reducing its stability and ultimately leading to early structural failure.
When first produced, concrete has a high pH value that makes it alkaline and naturally inhibits the growth of most microbes. There are however some microbes that thrive in environments of high alkaline pH value and once on the concrete surface will begin the process of biodeterioration. This is the deterioration of materials (e.g. concrete) caused by microbes such as bacteria and mould.
As the alkaline friendly microbes reproduce, they oxidise sulphates and create sulphuric acid – a highly corrosive substance that then causes damage to the concrete. The production of sulphuric acid also reduces the alkaline pH to one more favourable to other microbes, allowing them to survive and reproduce on the concrete surface. Once the surface is contaminated, microbes will continue to grow, producing biogenic acids and causing further deterioration unless the surface is regularly decontaminated with strong disinfectants. Microbially induced corrosion of concrete is rarely caused by just one type of microbe, but a complex ecosystem that each make the conditions more favourable for another microorganism to be introduced.
Measures Against Concrete Biodeterioration
The intensity and rate of bio-corrosive deterioration will vary according to a number of factors, such as substrate porosity and environmental exposure. Controlling the biodeterioration process should start with taking measures to prevent the colonisation of microbes on concrete. Protecting against microbial degradation can extend the usable lifetime of the concrete, introducing potentially huge cost savings for the upkeep, maintenance and replacement of the material.
BioCote® have recently joined forces with Foxfire Enterprises Inc. to deliver innovative antimicrobial concrete sealers and repellents. To tackle material degradation in concrete caused by microbes and the effects of harsh cleaning chemicals, Foxfire can now offer antimicrobial properties to its entire sealer and repellent line.
In comparison to products that have to be added during manufacture of concrete, the Firefox antimicrobial product line can be applied to new or existing concrete structures as part of their sealer and repellent treatments. Providing first-in-class protection against microbial growth on concrete, masonry and stone, the Foxfire range can add protection against concrete degradation, as well as odour and stain causing microbes. This effectively addresses issues faced by municipalities, institutions, hospitals, hotels, parking garages and agricultural facilities. Find out more about Foxfire’s new product line.
To find out more about our range of antimicrobial additives, or if you are interested in protecting your own products with proven BioCote® antimicrobial technology, get in touch with a member of the team on +44 (0)2477 712 489. Alternatively, you can contact us via the form below.