All about concrete
What is concrete?
Concrete is a mixture of cement, water, sand and gravel (stones, crushed rock). The mixture eventually hardens into a stone-like material.
Cement and water are the two ingredients that do all the chemical reaction stuff. The gravel and sand give strength.
If you mix gravel, sand and water together, nothing will happen.
If you mix cement, dry gravel and dry sand together, nothing will happen.
It is only when the cement is mixed with the water that something happens!
For ordinary "around the house" type concrete jobs, the gravel (stone) is usually a mixture of stone sizes up to 20mm (3/4") diameter. Some building supply stores sell bags of gravel and sand (or similar type of aggregate) already mixed. When making a concrete mix, the sand or fine stone is needed to fill the gaps in between the bigger stones, so you have a good binding of the ingredients.
What is cement?
Cement is a powdery type substance made from a mixture of earths materials such as limestone and shale, which is sinteWhat is concrete?
Concrete is a mixture of cement, water, sand and gravel (stones, crushed rock). The mixture eventually hardens into a stone-like material.
Cement and water are the two ingredients that do all the chemical reaction stuff. The gravel and sand give strength.
If you mix gravel, sand and water together, nothing will happen.
If you mix cement, dry gravel and dry sand together, nothing will happen.
It is only when the cement is mixed with the water that something happens!
For ordinary "around the house" type concrete jobs, the gravel (stone) is usually a mixture of stone sizes up to 20mm (3/4") diameter. Some building supply stores sell bags of gravel and sand (or similar type of aggregate) already mixed. When making a concrete mix, the sand or fine stone is needed to fill the gaps in between the bigger stones, so you have a good binding of the ingredients.
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What is cement?
Cement is a powdery type substance made from a mixture of earths materials such as limestone and shale, which is sintered (cause to become solid mass by heating without melting), ground, and mixed with small amounts of calcium sulphate and calcium carbonate.
Cement is activated by water and when mixed with sand and gravel, forms concrete.
Cement is usually grey in color, but white cement can be obtained but is usually more expensive than grey cement
red (cause to become solid mass by heating without melting), ground, and mixed with small amounts of calcium sulphate and calcium carbonate.
Cement is activated by water and when mixed with sand and gravel, forms concrete.
Cement is usually grey in color, but white cement can be obtained but is usually more expensive than grey cement
How to mix concrete.
Small amounts of concrete can be easily mixed in a wheelbarrow with a spade but larger amounts might require a concrete mixer.
Towable concrete mixers, both electrical and mechanical (petrol) can be hired from hire plant depots.
Mix in the wheelbarrow or concrete mixer, cement, gravel, sand and water.
For general purpose concrete the mix can be 1 part cement, 2 parts sand and 3 parts gravel.
Most cement bags will have mixture recommendations written on the bags.
How to mix concrete in a wheelbarrow.
Small amounts of concrete can be mixed easily in a wheelbarrow with a spade or small shovel.
You can make your own concrete mix using 1 part cement, 2 parts sand and 3 parts gravel.
So, to three-quarter-fill the average heavy-duty wheelbarrow, put in 6 spades full of gravel, 4 spades full of sand and 2 spades full of cement. Mix it all together before adding water.
Next add water, approx half a standard household bucket more or less. Add a little of the water at a time. Mix with the spade from underneath and fold over. Keep doing this and adding the water until it is a uniform consistency.
