How To Find The Right Concrete Mix
With so many types of concrete, it’s important to know what mix you need to make your project a success. Whether you are setting a fence post or pouring your own driveway, this guide will help you understand the difference between mixes so you can be sure to choose the right type for your project.
Tip: Once you know what type of concrete you need, take careful measurements of the area you are working on to ensure you have enough to finish the job.
One of the first things to know is that concrete and cement are not interchangeable terms. While concrete is a blend of Portland cement, sand and gravel, cement is the dry, powdered substance that is mixed with sand, gravel and water to become a binder for concrete. Mixing sand, gravel, water and cement in the right proportion is essential to producing durable, high-quality concrete. We will break down the differences among the three most common mixes and the different types of ingredients that make up each option.
If you choose not to mix your own concrete, there are plenty of ready-mix options. Typically a premixed combination of cement, sand and gravel, ready-mix concrete can cover a wide range of projects.
There are three types of mixes most commonly used: fast-setting, high-strength and crack-resistant.
- Fast-setting concrete: A blend of fast-setting cement, sand and gravel, this concrete is ideal for setting post or pouring slabs that need to be ready to use quickly. This mix usually sets in about 20-40 minutes.
- High-strength concrete: Pre-mixed of cement, sand, gravel and additives, this concrete blend is perfect to use as a foundation, footer or bases for heavy equipment. It typically sets in about 10-12 hours.
- Crack-resistant cement: A pre-blended mix of cement, sand, gravel and additives, this mix is the most durable, meant to reduce cracking and drying. It is most commonly used on patios, walkways and common areas that are prone to cracking.
Three of the most commonly used mixes are Portland cement, Masonry cement and Mortar mix. Let’s take a look at the key differences among the three.
- Portland cement: The most common ingredient used for making concrete, this cement mix acts as a binder. Made of reinforced limestone, clay and iron, it is used for a variety of projects, from driveways to larger projects.
- Masonry cement mix: Designed for commercial-grade performance and contractor use to set stone, block and brick, this mix acts as a binding agent. It must be mixed with sand, gravel and water.
- Mortar cement mix: A blend of water, Masonry cement and sand, mortar provides a long-lasting, strong bond. Ideal for patching walls, laying brick and setting stone.
So, what makes up concrete? Great question! Concrete mixes are made up of sand, gravel, aggregates and additives. The gravel component in concrete that will hold the mixture together once it is solid is called the aggregate.
Concrete additives are either chemical or mineral. They are added to a concrete mixture to increase durability, make concrete of poor quality better and control settling.
- Chemical: These additives reduce the cost of construction and ensure the quality of concrete during mixing and transport.
- Mineral: These additives increase the strength and permeability of concrete, making mixtures more economical.
Tip: Always use caution when using additives.
To make standard concrete, mix 1 part Portland cement, 1.5 parts gravel and 1 part sand with 0.5 parts water.
Tip: Use water that is clean and free from acid, alkaline, sulfate and oil. Mixing concrete in a wheelbarrow provides an easy way to move it where you need it.
Use the back of a shovel to create a smooth surface, then use the side of the shovel to create a groove. If the surface remains smooth and the sides of the groove hold their shape, your concrete is ready.
- If you cannot create a distinct groove, add more water.
- If the groove caves in, mix in more dry ingredients.
Take precautions to avoid back strain or irritation of the eyes, skin and lungs.
- Use your legs to lift heavy concrete to reduce strain on your back.
- Concrete is caustic, meaning the chemical elements it contains have corrosive properties that can irritate or burn your skin if you come in direct contact with it.
- Use a mask to filter out concrete dust.
- Avoid working in poorly ventilated areas.
- Knee pads will help you stay comfortable over the course of long jobs.
- Wear waterproof gloves and boots to protect your hands and feet.