There are certain situations where the maintenance of a concrete structure becomes a significant ongoing cost and has to be considered frequently. We often talk about the challenges faced by concrete in marine environments. These would be prime specimens: wharf decks and piles, bridges, and other operational infrastructure. Multi-level car parks are another example.
How long has the structure been decaying … really?
When these working structures begin to exhibit decay, several factors need to be considered when selecting a repair or maintenance methodology. There is the question of down-time; and whether appearance is important to the structure. Of course, the severity of decay will be core to the discussion.
One point that is often overlooked, when considering the degree of decay, is the fact that concrete decay mechanisms are usually operating within the concrete well before manifesting on the surface. This means that the real level of decay is almost certainly worse than a visual inspection would suggest. Various non-destructive testing methods should be deployed in most cases, to uncover what’s going on inside the slab.
Fix it with cosmetics?
Because there is almost certainly decay happening within the concrete, simply patching or coating an area on the surface is not an effective response. The reactions which drive the decay will cause the same issues to break out elsewhere.
And that’s not even taking incipient anode formation into account.
In Markham’s experience, we have often observed a short-term, short-cycle attitude to repair work – based on operational and cost demands, and only involving ‘surface’ work. This may be great for the contractor who is called back repeatedly and ever more frequently as the structure ages; but ironically it is more expensive in the long term, than it would be to approach the maintenance holistically.
Response, part 1
For these reasons, Markham strongly recommends including hydrogel durability treatments as a part of the overall methodology. Genuine hydrogel treatment will penetrate deep into the slab, immobilizing the moisture, thereby robbing the decay mechanisms of the moisture and ingredients needed for their progression.
The treatment complements cementitious patching and is compatible with any coating designed for bare concrete. It helps other repair work last longer because it arrests the driving reactions within the concrete that would otherwise break out elsewhere.
And hydrogel treatment prevents incipient anode formation too!
Response, part 2 (but it should be part 1)
Get in early.
Remember that the decay that finally broke out on the surface, had been operating within the concrete well before you were aware of it?
Hydrogel treatment is an excellent preventative measure, and in many cases will prevent or greatly delay the onset of severe cracking or spalling. Break the cycle of repeated repair maintenance with a pro-active maintenance program. Save money – significantly – over the longer term.
This should sit nicely with any big-picture approach to asset management.
If you’re responsible for decisions around concrete asset management, we’d love to hear your stories. Get in touch!