Beginners Guide to mixing Concrete

When it comes to tools you basically only need a shovel or spade for mixing the ingredients gravel, sand and cement. The only other thing you need is a bucket and you are ready to mix your concrete.
Right as if it would be just so easy and in principal it is.

First question: What am I using the concrete for and how much do I need to make?

Lets say you want to make pavers, just like i did and you have just one mold ( I'll make another lens on mold making) you can mix it in a bucket, depending on the size of your paver.

You need:

A Bucket or a plastic dish
A container to measure ingredients
small trowel
or if worse comes to worse you put on a pair of gloves and mixing concrete it by hand.

A little tip here: work out how much you need for the paver and if its more then a third to half a bucket full, go to the next level

I like to point out that it is best to work out everything by volume not by weight

What does volume mean? very simple a 10 liter bucket has a volume of 10 liters. It doesn't matter if you fill it with sand, stone ,water or feathers in there it will always be 10 liters. If you take the same ingredients and weigh them, you find they are all different. Of course silly I hear you say, feathers are always going to be lighter then stone or sand.
You are absolutely right. What about sand when its wet or dry? Wet sand is heavier the light sand. Can you see where I'm coming from. That is why it is important to measure by volume.

Volume= Length x width x depth

Lets get on with it.
One mold you can do in a bucket. what about 10?

Well you could use a bucket 10 times over or mix it in a wheel borrow or you could mix it on the ground.

You need:

A wheel borrow
a short handle mortar hoe, a spade or shovel
a 5 or 10 liter bucket to measure ingredients

Tip: Don't overfill the wheel borrow

If it is to much, mix the concrete with the same tools on the ground on some chipboard or a concrete floor.

For bigger jobs you will need to invest in or hire a concrete mixer.

For really big jobs you can order ready made concrete to your site, but that starts costing you more money again.

One other thing I like to point out when it comes to mixing concrete, plan your layout so you don't have to move to much around. Working with concrete is heavy enough without having to cart sand or gravel around.

Now that is easy right? Sand, aggregates (stones) and cement and add water.Thats it we are done.

Wrong

Sand:

Which one, brickies sand, course river sand, play sand. Apparently sands aren't sands. Masonry sand is the most preferred option and I stand to be corrected.

Sands are available from building supply stores and some nurseries have got them

Aggregates:

What size stones 5mm, 10mm or 20mm. surely it can't be that hard. the answer is all depends what you are using the concrete for.
These are available in building supply stores, quarries and some nurseries.

Cement:

Even with the cement you have choices. For one is it can come in white "wow" not just grey. But there are type I, II, III, IV and V. The most common one people are using is the type II cement also known as general purpose cement and available in hardware stores or building supply stores

Water:

The last and most likely the most important part is the water and how much to use. This was the part where i had the most trouble with, because i couldn't find anywhere, where it said how much.
Don't get me wrong I do understand the terms dough like and pancake batter or even squeezing the concrete and it shouldn't crumble. I wanted to know how much in liters, a quantity something I could relate to.
I did also understand that if you had wet sand and wet rock you need less water, but how much as a guide. Finally I found an answer I could work with.
And the answer is: Half of the amount of the cement you use. Bingo I had my answer and I hope this will help many people like me as well.

Now this is not a lot of water to use and it takes a while to get it mixed right, but then I learned another bit about concrete which said the less water you use the better the concrete is going to be. It has something to do with all the chemical reactions which take place when the cement and water combine.
Another point to make is that the water quality is important as well. Use drinking quality water and not contaminated water (muddy , oily etc).

This is the part which didn't make any sense at first. I thought you pour your concrete into a mold or a frame work and 24 hours later it's done.

Not so.Why?

Concrete appears to be hard after 24 hours and it is, but it has got not strength. This happens over the next 7 days and it keeps curing for 28 days. I have a look if I can find the chart for it again and add it in here.

The other thing you may have seen or noticed, is that after concrete is poured for a house slap or drive way or footpath, the builder covers the concrete up with black plastic or wetting it down for a few days.
The reason for this is that the concrete needs to be wet for the chemical reaction to continue. Funny how firstly want only a little water and then you pour it on.
When I make some pavers or pots, I put the pavers or pots into a bath to cure them for a few days.

When it comes to concrete additives the first which comes to mind is colour.

These come in form of powders ( pigments, oxides ) or liquids. Some of the colours are: brown, charcoal, greens and others. You can mix them to achieve a range of other colours. I haven't had a chance to do to much with colours, but as soon as I have I' ll add to here to let you know how I have gone with it.

There also liquid stains available and I'm trying to find out more about them, because I like the way they can change the appearance of a concrete project.

There are also additives to speed up the set time of concrete as well as slowing it down. I'll have to do some more investigating on that one too.
When you thought that was it more of them pop up such as water reducers, latex polymers pozzolans and air entrainers. Because I do not know anything about them I wont expand on them at the moment. Once I know when and how to use them I'll update it in this section.

If someone else know feel free to add it to the comment area. Thank you in advance for your trouble.

Mixture is to wet:

Just add a little more sand and cement.

Mixture to hard to work:

Carefully add a little water.

Concrete drying to quick

Cover the concrete with black platic and wet the area where the concrete is going before pouring it.

Here again we have a lot of choices meaning more then 2.

When we think about mixtures , we need to think about what we using it for.

The most common use of concrete is building foundations ( I'll replace the pictures with a better asap), footings and prefabricated concrete walls. Also there is other prefabricated stuff like concrete pipes.

All this is far to big for us to handle and you have concrete plants producing the high quality concrete required for those jobs

There is another very good lens written on the quality and strength required for the above mentioned jobs and I'll put a link to it.

I'm talking about the small jobs ,the hobby jobs where you make a paver, garden edging, fill in a post hole.

This mixture is good like a general purpose mix to be used in footings, pads or foundations.

It is also a relative cheap mix . because of the larger amounts of gravel (aggregates) used in this mixture.

Very simple 1-2-3

one part cement
two parts sand
three parts gravel

add half part water

Note: careful with adding water as it can make concrete go sloppy very quickly

Here are some links to other things to do with concrete:

Fake Rocks made out of Concrete