Hot weather? What’s the impact?
Well, high temperatures do force rapid curing. There’s no doubt everybody wants things sooner than ever before.
With increasing time pressure on precast production lines and construction sites, it may be tempting to hurry the curing process. However, concrete which is cured too quickly, particularly under hot ambient conditions, can result in inherent weakness – permanent heat damage!
And it’s those hot conditions we’d like to talk about now.
Doesn’t heat help the curing process?
As noted, heat may hurry the curing process. This doesn’t mean it’s helping.
Problems can readily result both internally and on the surface.
Within, the concrete may cure unevenly over time. This can result in voids, internal weaknesses, and excess free limes within the concrete. Delayed curing can lead to cracking later in the structure’s life.
On the surface, the most noticeable effect of excess heat is shrinkage cracking. Caused by excess evaporation at the surface, this is so common an occurrence in warmer climates that it is frequently ignored altogether.
Shrinkage cracking isn’t a big deal, right?
Not at first, no. It can be unsightly if extensive, but there are many situations where that doesn’t matter.
HOWEVER, micro-cracking is the start of a long-term cycle of deterioration, a driver for premature decay of the concrete.
Here’s what happens: major cracking is caused by reinforcing steel rusting, or by internal expansive concrete reactions such as ASR. Those processes can’t happen by themselves – they are driven by contamination such as chlorides and other salts. These contaminants travel and react because they are soluble in water – they do not react if totally dry.
Guess how the water gets in? Not into the concrete itself, which is fundamentally waterproof, but via cracks.
Little Cracks Cause Big Cracks. Big Cracks are Death on Concrete.
Hence – there is a direct correlation between poor hydration during curing, and premature deterioration.
Further – high ambient temperatures have a negative effect on hydration quality.
Therefore, these high temperatures during construction will threaten the effective service life of the structure.
Protect the concrete from Day One, right?
So, we understand that the concrete needs the protection of thorough hydration; and that’s a very significant challenge on hot days.
‘Water curing’ has long been the traditional method for maintaining surface moisture. This can be time-consuming and labour-intensive. Curing compounds or coatings also have their drawbacks, sometimes needing removal late in the construction phase.
Presenting hydrogel treatments!
There’s an advanced alternative which is simpler, more versatile, and often cheaper. The application of nanotechnology catalytic silica will induce the formation of a hydrogel within the porosity of the concrete.
Sounds complicated? Let’s just say, specify hydrogels for effective curing.
How do we incorporate hydrogels into the design?
There are two treatments which will assist both hydration quality and long-term durability.
AQURON 300 concrete waterproofing admixture has multiple benefits. It is a superior alternative to crystalline admixture technologies and improves ease of handling. Improved hydration is just another of its many advantages. For more information, here’s a quick overview.
AQURON 2000 spray-applied treatment has a different vantage point. Its curing qualities are equal or superior to 7 days’ water curing (test results available). The resulting concrete hydrogel penetrates to 150mm depth, protecting reinforcing steel, immobilising moisture, waterproofing the concrete, and bonus anti-dust hardening benefits are thrown in.
And there’s more.
The AQURON hydrogels are remarkably useful and cover a range of concrete needs.
And (spoiler alert) there’s a new generation of hydrogels and hybrid hydrogels currently hitting the market …
Intrigued? Faced with a new project or a concrete maintenance challenge? Get in touch!