Capable of mixing up to 90 litres, this should produce around a wheelbarrow full. To test a concrete mix a mm high cone made of steel is used that features a top opening of mm diameter and a bottom opening of mm diameter.
The mixed concrete is placed into the cone through the top, a bar is used to compact the concrete and remove any air voids within the cone. The cone is then lifted clear. By laying the bar on top of the cone, it is possible to measure how far the concrete "slumps". A slump of approx 50mm is acceptable for C20 mix.
If you are mixing up several batches of concrete to form the floor slab of a new extension then it is absolutley essential that each mix is exactly the same as the last. For example, if the second batch that you mix is wetter than the first batch, both will dry at a different rate. When this happens you will get shrinkage and cracking.
The strengths of each mix will also be different as they will dry at different rates. Generally, the slower a mix is allowed to cure the stronger and more flexible it will be. Ultimately, the slower your concrete dries out or cures, the stronger and more resistant it will be. If you are working in very hot conditions or there are strong, dry winds then this will most likely dry your concrete out too fast and it will become brittle and crack, weakening it.
Likewise, if you are working in very cold conditions e. As we know, when water freezes it expands and this expansion will force the mix apart preventing the components from bonding together correctly.
When the temperature rises again and the ice melts, thousand of tiny cavities are left which can severely weaken your concrete. In an ideal world, the best conditions to concrete in are mild weather conditions, slightly overcast, not too hot and not too cold.
If you have no choice but to work in slightly extreme conditions then there are ways that we can minimise any potential damage:. All project content written and produced by Mike Edwards , founder of DIY Doctor and industry expert in building technology. Find a tradesman now! We love feedback on our DIY tutorials it helps us to make them the best they possibly can be so if you have any comments you would like to share with us, click the button below and let us know.
Skip to primary navigation Skip to main content Skip to primary sidebar Skip to footer Main navigation. Search this website. Blog DIY Competitions. Twitter Facebook Pin It Buffer. Project Page Menu. What is Concrete? This calculator is for a C20 mix Enter your dimensions to calculate the volume of concrete needed for your project, then enter this total into the second calculator for the materials necessary. Back to the Top.
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All three options offer the same 85 litre mixing capacity but each offers slightly different benefits depending on your needs. Non towable — Electric. For sites with difficult access. At only Towable - Electric. Towable - Petrol. Make sure you have read the operating and safety instructions and are wearing the correct safety gear — glasses, gloves, ear muffs and covered shoes.
Get your concrete mixer ready to roll. If electric, plug it in and if petrol, make sure the petrol tank is full. Have a read of the instructions on the back of your concrete mix bag - take careful note of the recommended water to mix ratio!
Load your dry concrete mix into the concrete mixer. Add the required amount of water to your concrete mix. Measure your water - it can be tempting to just add water with a hose, but it can result in a very sloppy batch of concrete! A measuring bucket is ideal for this.
If there is too much water added, the cement mix will come out too thin, become unmanageable, and not dry properly. If there is not enough water, the mix will become too thick, it will not combine thoroughly, and will become unusable.
Turn your concrete mixer on and let it do the hard work for you! Most cement mixers will tip and turn to the appropriate location in order to do this with ease. If a novice user, Hirepool recommends turning the concrete mixer off for safety before pouring. Like any recipe, if you get the ingredients wrong it will either be too runny or too dry. Sloppy or too wet concrete is only about half as strong as a proper mix and is more likely to crack. While less water can add to the strength of your concrete, if it is too dry it becomes very hard to work with.
Again, have a look at how your concrete mix is moving in your concrete mixer. If your concrete mix reaches the top of the concrete mixer before it falls, then this tells you that your concrete mix is too dry. It is important to aim for the same mixture consistency with every load so that your project has the same level of strength and durability throughout.
Take a look around our Concrete and Masonry section to see what other tools we have that may help make light work of your concreting project. Hiring rather than buying tools that largely go unused year round is a cost effective way to stay on top of your maintenance and DIY jobs.
Hiring comes with the added bonus that someone else is in charge of maintenance and storage. Saving you more time, money and space in the shed! Whatever you need to hire you can easily book your concrete mixing equipment online or get in touch with your local Hirepool branch who will be happy to advise on the best equipment and book these for you.
Easy as! For foundations, a mix of 1 part cement to 3 parts sand to 6 parts aggregates can be used. Using half now will prevent the mix from drying out before you get chance to use all of it — you can mix the other half later. Tip the sand and aggregates if making a concrete mix onto your mixing board or into your container. If using a board, form a crater in the middle of the pile. This will kick-up dust when you pour the cement out, so ensure your protective mask or mouth protector is in place.
Using your shovel, mix your ingredients together, working the shovel around the pile of cement, sand and aggregates if making concrete mix. There is no specific method here, simply turn the pile over around three to four times to evenly mix everything and get a consistent colour throughout your pile.
Bring your pile together again in a cone-like shape and create another crater in the middle. Size-wise, the crater should be around half the diameter of the mound itself.
Move the sides of your crater into the mixture and turn it over to evenly distribute the water throughout your mixture. Keep on turning your mix until the mixture is wet. When the mix becomes wet enough, use the edges of the shovel to make imprints in the top of your mixture to test its consistency, creating ridges as you go. Try adding more dry ingredients to solidify your mix.
Mortar is normally used for walling and laying paving flags so the mix is simply troweled or shoveled out of a container. Concrete may be poured or shoveled into the desired area and then screeded if necessary, to get a smooth even finish.
Use a power washer or hosepipe to clean excess mortar or concrete mix off your mixing board and tools, scrubbing them with your stiff bristle brush.
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