Question: While curing concrete, why do people cover it with plastic?
What causes cracking in new concrete? And how do you prevent this cracking? Curing concrete properly while it's fresh can save you a lot of trouble later....
Answer: You've probably seen people cover freshly done concrete work with plastic while it is curing. Why? So that dirt doesn't blow onto the concrete during the curing period? While it's true that covering the curing concrete will keep it cleaner, there's a more essential purpose behind this practice:
Remember, you mix water into concrete mix to activate the cement binding agent within. As the mix dries, it will harden. But the drying, or "curing" should be gradual, otherwise cracking may occur. To prevent cracking, plastic is placed over the curing concrete to trap the water inside, ensuring gradual curing.
For an example of a concrete project that you would need to cover with plastic, see How to Build a Concrete Patio.
