Why Is Impermeability Significant For Concrete?
What is the connection between concrete’s impermeability, and its service life?
Reinforced concrete is a durable and stable combination for building - however, environmental elements can age concrete structures quicker than expected, and cause corrosion of the reinforcing steel.
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Contamination is carried by moisture.
Contaminants such as carbon dioxide, sulphates and chlorides penetrate into the concrete – this sets up conditions for deterioration and premature ageing.
The more porous the concrete, the faster contaminants get in. Likewise, less porous concrete – i.e. more impermeable – is better at resisting contamination ingress.
"95% of the issues associated with concrete, can be tied back to the fact that it lets moisture migrate through it...
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Strength and Durability
Of course, the concrete industry is well aware of the connection between concrete strength and durability. Generally, the higher the concrete strength, the less permeability as well as higher compressive strength. High strength concrete does, however, still let moisture into the concrete matrix over time. The use of fly ash and other admixtures can help offset this.
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A hydrogel additive, as part of the mix design, will create an impermeable concrete, extending the life of new structures. This method ensures much higher and predictable durability.
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But how to help existing structures?
For existing concrete, improving the concrete’s impermeability is greatly beneficial to extend the structure’s service life. This is especially urgent if the concrete is already showing signs of early ageing – microcracks or surface deterioration.
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Increasing impermeability significantly increases how long the structure can remain in service.
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If you are responsible for the maintenance of an existing concrete structure, there is a practical way of increasing concrete impermeability.
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It is possible to apply a catalytic penetrating hydrogel treatment to existing concrete, increasing the service life. This treatment seeps into the pores using free limes and internal moisture to seal the matrix against more contamination. It solidifies and strengthens the concrete, protecting the rebar zone. This greatly improves the structure's durability.
This system of protection is suitable for concrete structures that are exposed to any amount of contamination. It extends the service life of concrete in high-contamination areas such as treatment plants. The system needs no reapplying from the initial treatment of the structure. It is permanent, and reduces the rate of deterioration by arresting corrosion and blocking contamination.
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The CIVIL-TECT system
For asset owners or maintenance teams, this treatment is found in the CIVIL-TECT system. The long-lasting protection for civil concrete infrastructure makes it a cost-effective approach of protecting large areas of concrete.
Having a composition similar to the ingredients found in concrete makes it very compatible with future coatings and other treatments; and when used in conjunction with patch repairs, the CIVIL-TECT system reduces the risk of Incipient Anode Formation. IAF can cause old concrete adjacent to new concrete to spall away. (More about that in Doug's onsite explanation.)
With the key treatments of the CIVIL-TECT system (colloidal silica hydrogels) being certified Nil-VOC and safe for use around potable water, the system is ideal for use on water treatment projects and sensitive marine environments.
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Have a look at using the CIVIL-TECT system for extending the concrete service life of assets in high-contamination environments!