The Brew Cabin

I'm going to have 2 cubic metres of readymixed concrete delivered and pumped through 60m of pipe to the site for a patio base. At the end the pumping equipment will need to be washed through, resulting in about six wheelbarrow-loads of left-overs, so I'm told.

Do you think this is a reasonable estimate and would it be suitable for a shed floor, or footings for a small retaining wall. If not, what would you suggest I do with it?

I personnally would think that the mix would become quite weak if if wash through with loads of water, and more to the point it would probably take about 2 months to dry (maybe a bit of an over exageration there!!!).

However, I have seen brickies lay in pubbles formed from heavy rain the night before.

Im sure Tony will correct me if Im wrong, but I wouldnt say it be very strong.

You're right, Russ, it'll be rubbish. It's only fit for the skip, to be honest.

The cement content is washed out and the bit that remains is at such a high water/cement ratio that it's only just able to cure, and the cured mass is so friable you can crumble it in your fingers.

If you can't lose it on site or in a skip, mix it with 20 barrows of grit sand, to give a roughly 7:1 reduction, which will be enough to stop it setting as a lump, but will still allow the grit sand to be used for bedding or whatever.

Would you mind clarifying these points for me?:

1) the first stuff to be washed out is a reasonable mix that can be used as normal;
2) the rest will be extremely watery and will set if I don't mix it with sand;
3) if I do let it set, it would break-up very easily and could be used as builder's rubble or hard core in the sub base of a flexible path?

1 - NONE of the washout is suitable for use as anything but a fill material

2 - correct, but there is a world of difference between 'set' and 'strong'. Toffee sets, but you wouldn't build a garage on it!

3 - It would break up quite easily to a loose fill material, similar to a granular sub-base, but smaller in aggregate size.