When working with ready mixed concrete for the first time, there are lots of things you need to consider.
Here are our definitive do’s and don’ts when working with ready mixed concrete.
Ordering the concrete …
Before ordering any concrete, you first need to know the strength and consistency of the concrete required for your project.
The consistency is referred to as the “slump class”. Different applications require different levels of workability when it comes to concrete, so it is important that you know this information in advance.
Never add water to ready-mixed concrete on site as this can affect its overall structural integrity. If you’re unsure about the type of concrete you need then most ready-mixed concrete companies can advise you on the recommended concrete for your application. You will also need to know the total volume of concrete you require. In the UK this is worked out in cubic metres.
Maxi’s ready-mix concrete calculator is a helpful tool if you need to work out the amount of concrete needed beforehand.
When ordering ready mixed concrete, always make sure that you choose a fairly local company.
Concrete should be freshly mixed in order for it to be workable, therefore you need the concrete to reach you in as quick a time as possible.
Preparing the site for laying …
It is essential that you prepare the site before laying any concrete. This should be done the day before you’re expected to take delivery of the concrete.
The ground on which you’ll be pouring the concrete should be as level as possible which means you’ll need to remove any debris and lay an appropriate subgrade if necessary, to ensure that the concrete’s foundations are stable.
You also need to make sure the ground has been sufficiently compacted. You should never place concrete on a sub-grade that hasn’t be thoroughly compacted and dampened.
Another important aspect of preparing the site is laying down the proper formwork. This generally consists of a series of timber planks which help support the concrete as it’s setting. You should always use a level when laying down formwork in order to ensure that the site is suitable for laying.
Taking delivery of the concrete …
Ready mixed concrete trucks are very large vehicles. You will need to make sure you have suitable parking space near your site, or alternatively, if the truck cannot be parked adjacent to the work site, then you will need to hire a concrete pump to transport the concrete to the site.
Finishing the concrete …
When pouring and forming the concrete, always make sure the correct tools are used. You will need to tamp (compact) the concrete, then float it to the specified grade, flatness, and level you are looking to achieve. This can be done with a hand trowel or power trowel. Make sure you don’t over-trowel the concrete surface when finishing as this can weaken the surface of the slab leaving it more vulnerable to freeze/thaw damage.