Nearly mixed enough to fill up the shutter. All in all, it took about 2 really full mixes to complete the job, and had just a little left over. I used nearly one whole bag of vermiculite in this slab, probably using about 120 litres (60L in each mix). Vermiculite is also used by gardeners for its moisture retention properties, and whilst mixing the concrete the amount of water I had to use at least double what I'd previously used for normal mixes.
