I know this is a tough one. I have a concrete patio about 5m x 5m that I
want to cover with a light grain gravel. The reason being that the concrete
looks sh*t. What I want to know is, I think there is a method for laying a
substrate of bitumen adhesive, and then coating it with the gravel to a thin
layer. The reason you would do this is that if you just chuck a load of
gravel on top of concrete it will just slide around and pile up in the
corners.

My question is, what would be the best type of substrate, and I can I buy
tubs of it rather than have a contractor come round with a flippin asphalt
truck...?

Any help gratefully received!