Postcrete is an easier way to secure fence posts than having to mix up concrete. But when using postcrete do you need to mix some ballast in, or is it ready to go?
Do you need ballast with postcrete?
No, you don’t. Simply put: a bag of postcrete has everything in it that you need, just add water.
There are small stones in postcrete already that work as a ballast. This does not mean that you cannot add your own ballast to the mix though.
Adding more stones will help to increase the strength of the postcrete and make it go further. You just need to be sure you don’t add too much ballast to the mix.
What is ballast?
Ballast is a mix of sand and gravel that is then mixed with cement in order to make concrete.
The gravel usually consists of limestone or other stone, this is often recycled stone from other manufacturing procedures.
Why use ballast for concrete?
When mixed with cement ballast creates concrete. But why do we use it, after all, you could just add sand and be done with it, without the need for the stones in ballast.
Adding ballast helps to strengthen concrete, that is why it is added. The aggregate in the ballast helps bind the concrete together and as such increases the overall strength.
Do I need to add gravel to postcrete?
This is the same as ballast in most senses of the word. So no you do not need to add any gravel to postcrete. The stones that are already in the mix do resemble gravel, to be honest.
You can add some gravel if you want and it will probably help to increase the strength of the postcrete as long as you don’t go overboard and add too much gravel.
What is Postcrete made of?
In the bag, there will be a mix of cement, sand and a bit of gravel. This is essentially how people make concrete in a mixer, just with postcrete it is already mixed and just needs water adding.
One of the main differences between postcrete and concrete is the ballast used. In postcrete, it tends to be very small bits of gravel whereas with concrete mixes much larger ballast is used depending on the concrete being made.
Larger ballast can help to increase the strength of the finished concrete but it is obviously hard to get large ballast into a pre-made bag of postcrete. So because of this smaller ballast is used in postcrete bags.
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