The Challenges
If you’re reading this article it’s quite possible you work with concrete in some way, shape or form! And you’ll be well aware of concrete’s extensive use in construction of all types.
You know that concrete is extremely versatile, durable and useful – it has a collection of key benefits in construction, that no other building material can completely replicate.
No doubt you’re also well aware of some of concrete’s vulnerabilities. Despite amazing advances in the industry, particularly since the middle of the last century, there are still challenges in ensuring a concrete structure fulfils its intended service life. And of course some environments are more challenging than others.
The Deterioration Process
Concrete is inherently durable – it does have a natural ageing process but this depends on a number of factors.
We know there are concrete structures still existing on this planet which date from Roman times and earlier. We also know there are concrete structures only decades old which seem to be rapidly heading towards being historical ruins.
There is a comparatively modern tension between costs, construction times, and long-term durability. Structural engineers and mix designers are actively pursuing the ideal concrete mix, to maximise durability and service life, while keeping costs down and not impeding construction schedules.
However given the broad spectrum of environments, localised mix ingredients, and project-specific deadlines and working conditions, there is no simplistic solution which guarantees against premature concrete deterioration in every case.
One commonly monitored early indicator of deterioration is cracking. Major cracking may indicate structural movement and should be investigated urgently. Minor cracking and micro-cracking are much more common and often overlooked as a normal part of concrete’s age.
And it is true that minor cracking in itself is not a serious issue. But, critically, minor cracking provides an avenue for moisture-borne contaminants, which lead to further concrete deterioration and to corrosion of the steel reinforcing.
Once these processes have gained a foothold then the cycle continues to escalate – more minor cracks form, more contaminants enter the matrix of the concrete, more deterioration results.
This is, as we all know, a very simplistic overview of the process, and will be affected by factors such as the composition of the concrete, and the environmental conditions.
The key factor is the movement of moisture. Contaminants are carried by moisture (including moisture vapour) and this is how they move about within the matrix of the concrete. Moisture is also needed for reactions such as ASR or chloride reactivity.
The Options
Bringing this down to actual circumstances, and structures you may be building, repairing, or maintaining – what are the options?
1. Forced to act
Maybe the options are running out for you – the concrete is spalling, or cracking significantly, and rust stains are very evident. You’re forced to act. The major drawback of this ‘option’ is the expense. Next after that comes the question how far you go with the repairs – how can you guarantee the prime underlying issue is not still active?
If at all possible, don’t let the situation deteriorate until you are forced to act.
2. Typical maintenance
We understand that maintenance budgets are limited. Limited budgets are usually the motivator for option 1 (above)! Where structures are being monitored and actively cared for, concrete cracking or minor rust stains will be triggers to taking maintenance action. Typical maintenance may extend to crack-filling or application of a protective coating. These approaches help minimize the ingress of new moisture, but don’t necessarily retard the activity of the existing moisture content and its associated contaminants.
3. Catch it early
An astute property owner or asset manager will catch the deterioration process as early as possible – while cracking is still at the minor or micro stage. As noted above, it is not enough just to seal the outer surface of the concrete.
THE ADVANCED SOLUTION is to apply a penetrating catalytic hydrogel. This has a number of key benefits:
- Penetrates up to 150mm, sealing the porosity and any cracks up to 0.5 mm.
- Protects the rebar zone – immobilises the moisture and moisture-borne contaminants already within the concrete.
- Cannot be worn off, damaged or cracked, unlike a surface coating.
- NEVER needs to be reapplied.
This treatment is holistically effective in arresting the ageing process and preventing the advance of rebar corrosion.
4. Proactive approach
Better still? Be proactive!
Hydrogel treatments can be applied to new and young structures, to give maximum protection from the start of their service lives.
This is a truly cost-effective solution, extending the overall service life of the structure and delaying the onset of costly deterioration.
SOUNDS GOOD? IT’S A WIN-WIN.
Talk to MARKHAM today about adding life to concrete in your care.
