I think I've made a massive blunder

Hi all.

If you mix concrete in a big plastic box with a lid, and then just leave it so it stays wet (the lid stops the mositure escaping, while being a split lid allows rainwater to get in), how long will it stay wet?

The reason I ask is that I might have just inadvertantly concreted over a patch of my garden.

When we moved into our new house nearly a year ago, we did notice signs of unfinished projects. There were also two big plastic packing crates, the kind with the hinged lids that sort of meet in the middle. They were full of unidentified filth. I just left them there (there was plenty of other more pressing jobs to do) but put breeze blocks on them so that our inquisitive little lad couldn't open them.

Just now I decided to tackle them, as they are in the way of where I plan to build a patio. One was full of wet sand. No problem there. I just emptied the sand over the area where the patio will be. I still have to level it all off anyway.

The other box appeared to be full of wet mud, so I started to scoop it out with a bucket and slop it onto my freshly dug over garden. It was only when I'd nearly emptied it all when I realised it wasn't the usual mud. It was slightly grey in colour, had gravel in it, traces of sand, and the way it slopped reminded me of freshly mixed concrete.

I then started to think about other little clues. Lots of bricks, breeze blocks and flagstones about, as though somebody was going to build something but never got round to finishing.

So now I'm thinking I might have unwittingly concreted part of my garden. Could that be the case? For it to be possible, concrete would have to be able to stay wet for at least a year in a plastic packing crate with the lid on.

 

No chance, it would be set in a few hours.

However, lime mortar will keep indefinitly if its kept wet, lime putty can be gray, depending what limestone it is made from.

As a precaution, keep your little one away from it, its very caustic.

If you have any ph testing stuff, it will be very alkaline.

 

There is no way concrete will stay wet for long, before setting. The cement you buy these days is Portland cement, and one of its properties it that it will set even when submerged in water. That's why Bazalgette chose it to build the London sewers in the 1860s

 

If it is lime mortar, will it stay caustic for long, or will it head towards pH netral over time?

 

It will, once the air gets to it, it absorbs co2 & turns from calcium hydroxide back into calcium carbonate. Its much softer than cement & if there is a set, it will break up easily.

I put old lime mortar on the veg patch.

 

Thanks all. I'm sure all will turn out ok from what you've all said. The garden has yet to be turned over again when I fetch my compost heap up, so it will all just get mixed in then.

 

Just had a further thought Dave. Its probably not mortar at all, its more lightly to be silver sand. One lot of sand for mixing up, then a finer one for leveling the slabs.