Why are we waterproofing concrete structures in the first place?
It seems obvious: whatever the structure is sheltering, we want to keep that dry.
At least that’s the reason in most cases.
Sometimes it might appear it doesn’t matter if the structure is not waterproof. Concrete is resilient and can withstand a high degree of weather exposure of itself. If the structure isn’t protecting anything else, perhaps it doesn’t need to be waterproof?
Well, it’s not so simple.
We need to think about the structure’s own durability.
Here’s something not so obvious: the contaminants and reactants that cause concrete to age and break down prematurely are carried in and around the concrete by moisture. Chlorides, sulphates and other contaminants enter and move about the porosity of the concrete as solutions in water or water vapour.
This is why concrete impermeability equates to concrete durability. Block the entrance and movement of moisture, and you successfully protect the concrete from a wide array of negative contaminant attacks.
The hydrogel answer
This is where concrete hydrogels come into play.
The formation of a C-S-H hydrogel can be induced in concrete by the admixture of nanoparticle colloidal silica. This catalyst reacts with free lime and moisture in the concrete, plugging the pores with fresh hydrogel. No foreign element is introduced into the concrete.
Why is this valuable? Because moisture, and therefore the contaminants it carries, can’t enter or move about, they are immobilised within the hydrogel.
The benefits of hydrogel admixtures
For maximum benefit, from day one, make sure to include colloidal silica treatment in the mix during construction!
The treatment is permanent, closing the porosity of the entire concrete as the pour cures.
There are operational benefits too: improved workability, reduced shrinkage, and enhanced flexural and compressive strengths.
Best of all, hydrogel treatments are completely safe for the environment.
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Sustainability and the environment
We’ve ticked a couple of boxes here already.
- We’re making the concrete stronger and last longer, which means less replacement concrete is required. Seeing as the cement manufacturing process is allegedly a major contributor to global carbon emissions, it’s good news if we can reduce our overall concrete usage by successfully maintaining existing structures.
- Hydrogels are safe for the environment. And for the living things in that environment, too!
Let’s move on to a sustainable source of the key ingredient!
Sustainable source of colloidal silica
Silica is found in and under the ground – you are familiar with sand, for instance. Silica is a significant mineral emission from geothermal and volcanic activity.
And in many places where geothermal activity occurs, it has been successfully harnessed for power production. New Zealand is one of those places.
Steam from underground is diverted to drive power turbines.
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There’s a byproduct of that process – a build-up of silica formation, which must be removed to keep the equipment operational.
That byproduct forms the basis of Markham’s new colloidal silica hydrogel treatment!
It’s a win-win situation.
CONQOR B50 waterproofing admixture is a fully sustainable and environmentally friendly product.
Furthermore, it has been extensively tested, with very positive results in pressure tests and increased concrete strengths.
As a bonus, it improves concrete rheology, making placement and handling easier for the teams on site.
- A WIN for the construction designer – helping meet project environmental requirements.</li>
- A WIN
for the construction team – saving time and money. and improving placements. - A WIN for the asset owner – increasing structural durability and holistic concrete waterproofing.
Intrigued? Get in touch, we’re keen to discuss your project!
More learnings! Try our on-demand webinar, “Concrete – Waterproofing – Durability“.
Header photo by Alexander Abero on Unsplash
