Hello
I am going to build a room using concrete form blocks. The floor slab is about to be completed.
I will be using concrete blocks measuring 50x25x30 cm (20x10x12 inches). Reinforcement is clear. I would like to mix the flowing concrete myself. A concrete mixer is available.
Now the questions: Which aggregate size should I use for the concrete? What is the mixing ratio (aggregate to cement)? What additives are necessary to achieve flowing concrete? Is the concrete truly "self-compacting," or will I need to assist with a tamping rod or a vibration device?
I need 200 liters (53 gallons) of concrete per square meter of wall surface.
Steven
I am going to build a room using concrete form blocks. The floor slab is about to be completed.
I will be using concrete blocks measuring 50x25x30 cm (20x10x12 inches). Reinforcement is clear. I would like to mix the flowing concrete myself. A concrete mixer is available.
Now the questions: Which aggregate size should I use for the concrete? What is the mixing ratio (aggregate to cement)? What additives are necessary to achieve flowing concrete? Is the concrete truly "self-compacting," or will I need to assist with a tamping rod or a vibration device?
I need 200 liters (53 gallons) of concrete per square meter of wall surface.
Steven
S
Sebastian7917 Aug 2016 12:59Funny enough, I’m currently working on that too and ordered some today because I’m using it to create steps in our light well.
It’s a bit different though, as it has to withstand earth pressure here – we used a 0-32 mm (0-1.25 inch) aggregate because the foundation will also be poured with it.
It’s not pure gravel, but the mix ratio remains the classic 3:1 plus an appropriate amount of water (by feel). It’s not self-compacting, so you need a vibrating plate or a tamper, though the latter isn’t that effective. However, since you pour/compact every 50 cm (20 inches), using a tamper might still work.
It’s a bit different though, as it has to withstand earth pressure here – we used a 0-32 mm (0-1.25 inch) aggregate because the foundation will also be poured with it.
It’s not pure gravel, but the mix ratio remains the classic 3:1 plus an appropriate amount of water (by feel). It’s not self-compacting, so you need a vibrating plate or a tamper, though the latter isn’t that effective. However, since you pour/compact every 50 cm (20 inches), using a tamper might still work.
As a layperson, I find 0-32 quite coarse. For concrete, we usually used 0-16 gravel. A mix ratio of 3:1 or 4:1 is generally a safe choice. Start with less water and add a bit more just before finishing. It’s best to use a small bucket for this, so you quickly get a good feel for the amount of water at which the concrete “flows.”
S
Sebastian7917 Aug 2016 14:31Yes, of course ready-mix concrete – hardly damp earth-moist concrete.
But this will be quite a challenge for you – it seems you might be underestimating it a bit. You’ll need about 6 cubic meters (7.8 cubic yards) of concrete – doing it yourself will be cheaper, but fairly demanding.
I would have the material delivered...
@Jochen104
Well, it depends on what you want to do – sure, it’s coarse, but it also holds accordingly. Earth pressure is no joke, so I’m playing it safe here.
But this will be quite a challenge for you – it seems you might be underestimating it a bit. You’ll need about 6 cubic meters (7.8 cubic yards) of concrete – doing it yourself will be cheaper, but fairly demanding.
I would have the material delivered...
@Jochen104
Well, it depends on what you want to do – sure, it’s coarse, but it also holds accordingly. Earth pressure is no joke, so I’m playing it safe here.