What is “Unprotected Concrete”?
It’s possible to argue that there’s no such thing as unprotected concrete. To start with, concrete is inherently durable, and industry improvements in mix designs are actively focused on long-term structural lifespans. Strictly speaking, concrete can be produced which is more or less self-protected against the daily conditions to which it will be exposed.
However, there’s a broad spectrum of reasons why designed life is rarely reflected in real life.
This article is not about those reasons; it simply runs through the deterioration process as it typically occurs when no early protection is undertaken.
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Number 1: Unprotected Concrete Lets in Moisture
Concrete is porous, and some moisture movement will always occur. Yes, mix designs which focus on durability and strength will produce a much less porous concrete. But no, it will still let in moisture (including moisture vapour), and moisture will move around within it.
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Moisture is a vehicle for many deleterious contaminants… little part-molecules of reactive elements are dissolved or suspended in the moisture and carried into and through the concrete. These include obvious contaminants such as chlorides and sulphides, as well as less obvious reactants such as carbon dioxide.
Some of these reactive substances act on the concrete itself, triggering the downward spiral of ASR or carbonation. Others may reach the ‘rebar zone’, the protective passivation layer around the reinforcing steel, and initiate corrosion.
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Number 2: Unprotected Concrete Cracks
ASR, steel corrosion and other issues will cause cracking. It’s the next step in a spiralling cycle of deterioration. The expansion of corroding steel will accelerate this damage. As a result, cracks allow more moisture-borne contamination into the concrete, and the driving causes of the cracking are exacerbated.
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- TEST REPORT: Carbonation of AQURON-treated concrete
Number 3: Unprotected Concrete Falls Apart
Unremediated cracking will worsen to the point where the concrete delaminates or spalls away from the corroding steel.
Somewhere between Number 2 and Number 3, the asset owner usually attempts to fix the problem. Without addressing the underlying cause, these attempts yield mixed results.
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Concrete can be Protected Early!
There’s no need for this cycle of deterioration to prematurely age your concrete assets.
SEAL the porosity of the concrete and IMMOBILISE the moisture so it’s not transporting contaminants!
This is where MARKHAM spray-applied penetrating hydrogel treatments really shine. The catalytic action of the treatment initiates a process that uses the free lime in the concrete, immobilising moisture as a hydrogel in the pores. It’s a comparatively simple process, but enormously effective, with far-reaching benefits.
- REFERENCE: CONQOR PROTECT Technical Data Sheet
In the case of exposed concrete, even in demanding marine or toxic environments, hydrogel treatments have been proven to provide greatly enhanced durability and extend structural service life.
Get in touch if you’d like more information – case studies, technical data or discussion about your particular concrete structure!
For related learning, try our on-demand webinar “Concrete – Waterproofing – Durability“.
