It seems that more and more architects are specifying Permeable Concrete (otherwise known as pervious concrete or porous concrete) as a surface in landscape plans in order to comply with Council regulations – normally in tree protection zones (which we covered here). So we thought we’d give you a run-down of the porous concrete we use as a base for our permeable paving, and why you can’t use it by itself for driveways.
First up, any paving anywhere is only as good as its base. So the choice of base will ultimately determine the strength of the paving. We use a no-fines concrete base for our paving, as it is the most stable and strong option available.
What is no fines concrete?
It is a concrete mix without the “fines” (small aggregate, ie. sand). What that leaves is a large aggregate (typically 20 mm screenings) and a cement slurry binding them together. This leaves a large network of voids between the aggregate. The depth of the concrete determines the strength of the pavement. For a domestic driveway, we install the concrete at a minimum depth of 100 mm. For commercial strength applications, we’d seek advice from an engineer on the depth required for the desired loads.
Why can’t porous concrete be used by itself?
Porous concrete has great compressive strength. But the size of the aggregate and brittle nature of the cement slurry binding them means that if you try to use no-fines concrete as a driveway by itself, you quickly get rocks being loosened off the surface. Basically, it’ll turn into a gravel pit.
This is where our permeable paving comes in. With it’s hand trowelled finish, it provides a grippy yet smooth surface that won’t be damaged by vehicle traffic. And as a pavement, it is incredibly strong thanks to the permeable concrete base.
We have worked with our suppliers to develop the perfect concrete mix for permeable paving applications. Pair that with our permeable paving and it’s lifetime warranty, and you’ve got the best choice for your permeable driveway!
So if your plan specifies permeable concrete then get in touch with us today!