DIY cement mixing
Without question, cement mixing is a fantastic DIY skill to have, greatly expanding your ability to improve your use and enjoyment of your backyard and outdoor areas. As with any endeavour, you will need the correct tools, safety equipment and materials. For the majority of backyard and outdoor area jobs, you will be able to mix your own mortar or concrete. Some bigger or more complicated jobs will require a concrete mixer.
The difference between cement and concrete
People often use the words ‘cement’ and ‘concrete’ interchangeably. But they are not the same thing. There are different kinds of concrete, which is made up of ingredients mixed in different proportions, depending on the end-use for the concrete.Cement
Cement is never used by itself. It is a fine powder, ground from clinker and gypsum. Clinker is quarried or dredged raw materials, which are crushed to a very small size, blended in certain proportions, and then burned in a kiln at very high temperatures. Cement is the binding agent ingredient of concrete, which is also made from aggregates (such as sand, gravel or crushed stone) and water. A cement mix makes up about 10% - 15% of the final concrete mix. The type of cement used as an ingredient in nearly all concretes is called Portland Cement or General Purpose Cement.Aggregates
Aggregates generally make up about 80% of concrete’s volume. They are usually sand, gravel and crushed or uncrushed rocks
How to mix cement
To produce concrete, a chemical reaction must occur between the cement mix and water. This chemical reaction is called hydration, which produces ‘plastic’ concrete (meaning it is soft enough to be moulded into shape) and then ‘hardened’ concrete.Concrete or mortar
Mortar
Manufacturers make mortar out of cement, sand and lime. It’s used to bind bricks, blocks and stones. If you are making mortar, the standard ratio is around three or four parts of building sand to one part of cement mix. You can purchase pre-made Trade Mortar, a quality blend of cement, graded sand and hydrated lime. Pre-made mortars are convenient and easy to use for small jobs, with this one 20kg bag covering 20 house bricks or 10 masonry blocks.Concrete
Concrete is made from cement, sand, aggregate and water. It is a very strong, structural material used to form slabs, foundations and other permanent, built structures. If you are making concrete, the required ratio will depend on the strength you need. The standard ratio is one part cement mix to two parts sand to four parts aggregate. You can purchase pre-made Concrete Mix. This is a quality blend of cement, sand and aggregate suitable for garden edges, mower strips, paths, footings, posts, pergola uprights, garden slabs and foundations. Two 20kg bags will cover a 450mm x 500mm slab of approximately 75mm thickness.
What you need to mix cement
Ingredients
You will need to have on hand:- Cement. A great cement mix for DIY at home is Builders Cement. Combined with sand and aggregate, it creates a concrete mix that is easy to work with for a smooth finish. It’s a good choice for rendering, blockwork masonry, brickwork and as a component of construction mortar.
- Sand.
- Aggregate (if you are making concrete).
- Water.
Safety materials
When you mix your own concrete or mortar, it’s important to protect yourself from respiratory, eye and skin irritation caused by the associated dust and debris. Appropriate personal protective equipment is essential – a good mask, safety goggles and thick gloves.General equipment
You’ll also need:- A wheelbarrow.
- Tarpaulin to protect the ground.
- Plastic buckets – you will need three if mixing mortar (cement mix, sand + water) and four if mixing concrete (cement mix, sand, aggregate + water).
- Builders shovel.
- Power washer + bristle brush.
- Equipment specific to your project, such as a trowel.
