Contrary to what some might think, concrete and cement are not interchangeable terms. Concrete is actually a mixture of sand, gravel, water and cement.
Gravel is sometimes referred to as crushed rock or aggregate. Mixing these ingredients in the right proportion is essential to producing durable, high-quality concrete. For your convenience, The Home Depot has a number of specialized premixed concretes readily available.SHOP CONCRETE
Choosing the Right Concrete Mix
While regular concrete is ideal for building driveways, sidewalks, and curbs, fast-setting cement may be the better option for setting fence posts and mailboxes. Concrete is an easy substance to work with, but larger jobs can prove to be very labour intensive. Knowing how to handle concrete and which type is right for the job at hand will help you achieve the best possible results.
Assortment and brands vary by region.
Premixed concrete is a simple, economical way to produce concrete. It comes in a variety of specialized mixtures, each of which contains the necessary sand, gravel and cement. All you have to do is add the right amount of water and you're all set to go. Premixed concrete is ideal for smaller jobs. Use the chart below to learn about the wide range of available mixes.
The following chart will help you gain an idea of how many bags of premixed concrete you'll need to purchase for laying 4" and 6" slabs. Other projects may require different calculations, but this is a good point of reference for determining the amount needed.
|Estimating Quantities: Number of bags of concrete mix required to pour a concrete slab|
|Area in sq. ft.||2||3||5||7||9||15||20||35||45||50||100|
|Slab 4" thick||60-lbs. bags||1-1/3||2||3-1/3||4-2/3||6||10||13-1/3||23-1/3||30||33-1/3||66-2/3|
|Slab 6" thick||60-lbs. bags||2||3||5||7||9||15||20||35||45||50||100|
Self-Mixing and Quantity
Mixing your own cement requires time and effort, but it can also save you some money. To make standard concrete, mix 1 part Portland cement, 2.5 parts sand and 2.5 parts gravel with .5 parts water. Use water that's clean and free from acid, alkaline, sulfate and oil. Test consistency by using 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. Mixing concrete in a wheelbarrow provides an easy way to move it around the jobsite.
Take careful measurements of the area you're working on to ensure you have enough concrete to finish the job. A trowel and float can be used to provide a smooth finish, or you can swirl the tools around to create a pattern. A brush or broom can be dragged or worked in circles across the still-wet surface to create a textured pattern, which will make the surface less slippery when wet. Avoid creating a pattern that traps water easily, as standing water is a major contributor to concrete failure. Also avoid putting in concrete on extremely hot days, as it may dry too quickly. Clean equipment immediately after use to prevent concrete from drying on it. The strength of concrete is measured in PSI (pounds per square inch) and indicates the amount of weight it can bear.
While concrete can be easy to work with, it also presents some safety hazards. 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. Always make sure you completely cover and protect skin, eyes and lungs to avoid injury. Knee pads will help keep you comfortable over the course of long jobs.
Colours and Patterns
Cement can mimic the appearance of brick and stone and is available in a range of hues, providing added versatility.
This colouring process can be used on both old and new concrete to provide a mottled, marble-like appearance and to add earthy colours.
Concrete used for sinks and countertops can provide the same performance as stone and solid-surface synthetics at comparable prices while offering a wider range of colours, thicknesses and patterns.
The Home Depot has all the tools you need for either purchase or rental. If mixing concrete is a one-time project, consider renting an electric cement mixer; our tools are clean, well-maintained and job-ready. Our professional-grade electric cement mixer can be used as a wheelbarrow for easy pouring or used with the stand to allow barrow-height mixing and tipping.