Mixing Concrete: A Guide for Large, Medium, and Small Batches | DIY Gardening Projects

Mixing Concrete: Large, Medium, and Small Batches

Concrete is an essential building material for numerous gardening projects, such as setting curbs or fixing fence posts. This guide will show you how to mix concrete easily using the right method.

How to Mix Concrete Yourself?

Cement, water, and sand or gravel are the central components of concrete. Mixing concrete is as easy as its composition, but the right ratio of the individual components is crucial. The amount required depends on the size of the project.

In the following instructions, you will learn how to calculate the requirements, the mixing ratio of cement, water, and sand or gravel, and the necessary steps.

Determining the Amount

For construction projects requiring large amounts of more than 45 liters of concrete, such as walls or foundations, you will need a wheelbarrow, shovel, and cement mixer. For particularly large projects, it may make sense to consult a structural engineer who will determine the right amount and quality of concrete for you.

For medium amounts of around 12 liters, a mortar mixer, a mortar bucket, a shovel, and a bucket of water are sufficient. This allows you to mix enough material to set individual posts, for example.

Small quantities of less than 12 liters can be easily processed by hand with a trowel in a construction bucket. The concrete is sufficient to repair smaller areas.

Tip: With small quantities, you can save time and effort by using ready-mixed concrete screed. Add the entire amount of water to the mixture and stir until there is no more dry material left.

Determining the Mixing Ratio

Before you begin, collect the necessary tools and have them close at hand near the construction site. Wear work clothes, gloves, and long sleeves to protect your skin from the irritant properties of concrete. Safety goggles are also recommended to protect your eyes from splashes.

In addition to cement and water, sand with a grain size of up to 2 mm or gravel with a grain size of up to 32 mm also belongs in the concrete. The ratio between cement and sand or gravel is 1:4. The higher the proportion of cement, the harder the concrete. Strength class C12/15 is sufficient for most horticultural projects, such as a foundation for a terrace.

When mixing concrete, the correct mixing ratio is important. Mix one full shovelful of cement with four full shovelfuls of sand or gravel. Water is then added as needed. The amount of water determines the subsequent consistency of the concrete. A larger amount of water tends to make the mixture mushy, making it easier to pour a foundation. Less water produces semi-dry concrete that is better suited for pulling a clean back support for a curb.

Mixing Concrete

It is advisable to mix the cement and water with the sand or gravel until the mixture has reached the desired strength. The recommended method depends on the total amount. If you use a concrete mixer, always handle the device carefully, do not reach into it, and ensure stability.

Mixing Large Amounts of Concrete with a Concrete Mixer

1. Press the start button and let the mixer start up.
2. Add four units of gravel.
3. Add a unit of cement.
4. Add water in portions until the mixture reaches a slightly shiny consistency.

Mixing Medium Amounts of Concrete with a Mortar Mixer

1. Put the appropriate amount of gravel or sand and cement in the mortar bucket and mix thoroughly with the mortar mixer.
2. Slowly add water to be able to increase the amount later.
3. Whisk the mixture with the mortar mixer until it reaches the desired consistency.

Mixing Small Amounts of Concrete in a Bucket

1. Put the required amount of gravel or sand and cement in a construction bucket and mix with a plastering trowel until well combined.
2. Slowly add water to the mixture while continuing to mix with the trowel. Be careful not to add too much water, as this can make the mixture too wet and difficult to work with.
3. Mix the concrete until it reaches the desired consistency. You can test the consistency by lifting the trowel out of the mixture and observing how the concrete falls off the trowel. If it falls off in clumps, the mixture is too dry, while if it slides off too easily, the mixture is too wet.

Once you have achieved the desired consistency, you can use the concrete for your project. Remember to clean your tools and equipment thoroughly with water before the concrete sets. Hardened concrete can be very difficult to remove, so it's best to clean up as soon as possible. You can dispose of any leftover concrete in the residual waste bin or mix it into a base layer if one is being created.