Mixing Ready-Mix & Hand-Mixed Concrete?

[chrisctk]

I am getting a delivery of ready-mix concrete (C20) delivered on Saturday morning for my foundations, but my supplier cancelled and the only other supplier I can find for this Saturday cant deliver as much as I need (they only have a 4m3 truck and I need 4.4m3).

Given I am only 0.4m3 short, and I OK to mix this separately with a cement mixer and add this to the ready-mix (I was thinking of doing it immediately after the ready-mix was delivered, so both would still be wet)?

Only other idea I though of was just to start the brickwork one layer lower than planned, as the 0.4m3 is about 1 brick height over the length of the footing. This would mean doing one course of red brick, then two courses of blocks, the back to red brick.

Any thoughts?

 

[^woody^]

Just pour in what they have and make up the rest in brickwork. Its building not engineering.

And two course blocks then all red brick would be more sensible. Unless you need to level out uneven concrete

 

[chrisctk]

Cheers. Only reason I was thinking of doing 1 brick then block then back to brick was because I am joining existing foundations at either end (where I am building an extension onto the house), so one brick would bring things up level with the existing footings, then I can run blockwork along the entire length, then go back to brick when above ground.

 

[^woody^]

Oh, I see, but bear in mind that the foundations are not tied in. You only need to match the existing in terms of coursing, so it should not make any difference if the blocks get laid first as the brick courses would still line up.

Its not a major issue, but its just a lot easier to lay the blocks first if you can

 

[cjard]

Can the concrete co come back with .4 cube faster than you can lay a line of bricks? Can you throw .4 cube worth of crap/old concrete/blocks into the readymix before it sets? (This is building, not engineering )