Before we tackle the main issue at hand here, we’ll first discuss an inaccuracy in the headline of the article. Namely, this issue about concrete “drying” because concrete doesn’t “dry” it cures.
It’s quite a big difference and it might change your perception about when and how you use it because they’re two completely different processes.
When you dry something out, it does usually get harder. For example, when the moisture leeches from a cake, the cake goes dry, so it would seem the same process is happening with concrete, however “curing” is a chemical process.
Concrete can be laid underwater and cure to a solid quite happily, it’s why we have bridges.
So with that in mind, we’ll now continue under the correct heading…
How to make concrete cure faster
When concrete has cured, it becomes a durable and hard substance that we can walk and drive on easily and build with.
However until it’s set, it’s a relatively volatile substance than can be easily contaminated.
So, we need it to cure quickly.
Now, there’s no super-quick method of drying concrete, you can’t rock up with a device that lasers it or something, but there are some methods that will help the process along somewhat.
Choose your day
The easiest way is to choose a warm, sunny day to get the job done. Granted not entirely helpful in Britain where good weather is at a premium, but if you have a choice of days, check your weather app and go for the nice one.
Use a heater
If you can, use a portable heater near the concrete to warm the ambient temperature and speed up the process.
Easier in buildings, not so useful for pavements.
Use plastic sheeting
If you thought that plastic sheeting over concrete was there to protect it from rain, then you’re only half right.
Moisture (not lots, but some) is an important part of the curing process, and by trapping it in, you’ll help cure it quickly.
Use calcium chloride to accelerate the curing process
Now we get controversial.
Check with your local building regs, but in the 1970s, using calcium chloride was ‘outlawed’ as there were worries that it could be seen to have a detrimental affect on the structural strength of concrete.
Some guidelines give strict levels that can be used, so always check before adding.