How to Make Concrete

Stonewc

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posted on 17 years ago — updated on 1 second ago

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Concrete is a building material that's comprised of fine and coarse materials bound together with cement. If you need to do improvements on your home, you may want to make some concrete yourself. To create your own concrete, you’ll need to make or purchase cement and mix it with other materials to create a soft concrete that you can work with. Alternatively, you can purchase pre-mixed concrete and add water to create workable concrete. Regardless of what you decide to do, creating concrete is easy as long as you have the right materials and tools.

Steps

Making Limestone Cement

Crush limestone into 3-inch (7.62 cm) pieces. Purchase or find limestone on your property and crush it up into small, 3-inch (7.62 cm) pieces with a sledgehammer. You can tell if the stone is limestone if it fizzles or cracks when you put vinegar on it. Industrial grade limestone companies use mechanical crushers or hammer mills to crush the limestone. You can also buy limestone-based Portland cement online, at hardware stores, or at home and gardening centers instead of making it yourself.

Put the limestone in a kiln and raise the heat to 2,700°F (1482.2°C). Preheat the kiln and put your limestone into it. Let the kiln heat the limestone for 3 to 4 hours at 2,700°F (1482.2°C). Use a high-temperature kiln thermometer to determine the level of heat in the kiln. Make sure to wear a respirator and goggles when heating the limestone because it will let off a harmful gas.

Crumble up the pieces of heated limestone once it cools. Let the limestone cool for an hour or two before handling it. Point a fan towards the stone to speed up the cooling process. Wear thick rubber gloves when handling the limestone. Transport the limestone to a wheelbarrow and then use a shovel to break up the limestone pieces until it turns into a fine dust.

Making Concrete from Limestone Cement

Mix two parts all-purpose sand to one part of cement. Mix either fine or coarse all-purpose sand with the cement in a wheelbarrow with a shovel. You can buy all-purpose sand online or at a hardware store. If you have access to a concrete mixer, you can use that instead of a shovel and wheelbarrow. Add two parts of sand for every one part of cement dust that you have and make sure that they are well incorporated. If you are trying to make more than 80 lbs (36.28 k) of concrete you should rent a portable concrete mixer instead of trying to mix it by hand.

Add four parts of gravel or crushed brick to the mixture. Add four parts of gravel or crushed brick for every one part of cement. This coarse material will help bind the concrete together once it dries. If you want a smoother concrete finish, you should use smaller pieces of gravel or crushed brick. Continue to mix all the dry ingredients together to create your concrete mixture.

Slowly add water to the dry ingredients. Fill a 5-gallon (18.9 l) bucket ¾ of the way with water and pour the water into the dry ingredients. Pour slowly so that the water doesn’t splash around, mixing in between and adding more concrete.

Mix the cement together. Use a hoe or a shovel to mix the water and dry concrete mixture together. Continue to stir the concrete mixture together until it’s stiff. If the concrete is still dry and crumbly, you need to add more water. To make sure your concrete cures well, pour the concrete in the morning and wet it throughout the day if it's going to be a very hot day.

Wash off your mixing tools. Use a hose on the strongest setting to spray your tools and blast away any remaining concrete before it sets. If there's anything left after you spray, use a wire brush to remove the last bits.

Mixing Pre-Mixed Concrete

Purchase a bag of pre-mixed concrete. You can get pre-mixed concrete at home centers, lumberyards, and at hardware stores. Once you get the concrete, read the directions on the back of the bag so that you know how much water you need to mix with the concrete dust. An 80 lb (36.28 kg) bag of concrete will fill up .6 cubic feet of space. You may want to rent a small powered mixer.

Empty the bag of concrete in a wheelbarrow. Place the bag of concrete into a wheelbarrow and use a hoe or a shovel to cut the bag in half. Lift off both sides of the bag and empty out the contents into the wheelbarrow. Instead of a wheelbarrow, you could use a concrete tray.

Slowly add water to the concrete mix. Fill up a bucket with the amount of water that you need according to the instructions on the back of the bag. Slowly pour the water into the mix. Be careful not to pour in too much water into the concrete mix. You can always add more, but you can't take away what you've already put in.

Mix the concrete together. Use a hoe, shovel, or powered mixer to mix the concrete mix with the water until it’s the consistency of peanut butter. Work out any lumps until the concrete is as smooth as possible.

Clean off your mixing tools. Once you’re done mixing the concrete together, it’s important that you hose off anything that has concrete paste on it. It will be harder to remove the concrete once it dries.