Mixing concrete is a basic skill that every DIY enthusiast should know how to do. Concrete is one of the most common and inexpensive building materials on the planet and is composed primarily of sand, gravel, and cement.

Mixing concrete is similar to baking in that it is best to follow a specific recipe for consistent results. There are a multitude of different concrete mixes for different applications depending on the strength, workability and application of the concrete.

Mixing concrete is a science for professionals, but for the average backyard enthusiast, learning the basics of concrete is enough to get started.

When mixing concrete, you will need to mix aggregates such as sand and gravel together with cementitious powder and water as a catalyst to begin the chemical process of bonding the ingredients. Concrete mix is ​​a function of proportions where you will measure the volume of aggregate used against the volume of cement used.

The most common concrete mix used around the world is the 3-2-1 mix that uses three parts gravel, two parts sand, and one part cement. Water is added with the idea that you should use as little water as possible so that the concrete will work for what you need it to be. The viscosity of concrete refers to the measurement by “slump”, which is a specific test in which the amount that a cone filled with concrete will lose its shape once the cone is removed, is measured in inches or mm. A concrete with a zero slump would be very stiff and dry and inclined to hold its shape, while a concrete with a slump of six inches or more would be extremely wet and not inclined to maintain a shape.

3-2-1 mix is ​​widely used as it can fill large areas with concrete at relatively low cost. You could potentially use just sand and cement, not gravel, to create what’s called mortar. In the 3-2-1 mix, the gravel serves as a filler taking up a large amount of space while retaining a relatively high overall strength. The downside to the 3-2-1 mix is ​​that the larger gravel aggregate will often float to the surface during finishing and is not suitable for thin or detailed concrete applications.

The best overall mix for a DIY enthusiast to memorize and use is a simple 3: 1 mortar mix. By using three parts sand and one part mortar, you can create the strongest concrete possible, as well as concrete that is easy to finish and detail with designs, templates or stamps. By not using the gravel, the mortar will have a smoother overall consistency, but will ultimately take up less volume than concrete made with gravel as well. If you are pouring large volumes of concrete, gravel could prove profitable, however for most DIY projects a 3: 1 mortar mix is ​​the way to go.

The sand you need to use for a 3: 1 mortar mix should be sharp sand, masonry sand, or joint sand. Each place you buy sand will use a different term, so it can be confusing when shopping. All you need to remember is to avoid playing in the sand. Play sand is sand that has been washed and sterilized (this is fine) and then turned over to smooth all the edges of the individual sand grains (this is bad).

The sharp edges of the sand help hold the concrete mix together better than the rounded edges of the tumbled sand. Ideally, you would like to find sand at garden supply stores that will sell you by the cubic yard. With a sturdy trailer, you can collect as much sand as possible for next to nothing, plus the quality of the sand for making cement will be very high.

The applications for a DIY enthusiast to use a 3: 1 mortar mix are huge. Everything from repairing broken exterior steps and stairs, driveways, patios, decks, ponds, waterfalls, man-made rocks, statues, and much more, is possible with a simple mix of sand, cement, and water.

Start with small concrete projects to get a better idea and understanding of how to work with concrete. Since concrete is so popular all over the world and is a very advanced science, you will never run out of interesting concrete applications to learn or try. Combined with being the most affordable building material on the planet and readily available everywhere, learning how to mix basic concrete recipes is a fundamental DIY project.