I have concrete pieces 10 cm to 10 cm (C60 recipe with 1 water : 3.3 Portland composite cement : 14.4 gravel 0-16 mm with fibre glass reenforcement) which are not especially designed to remain underwater (but will have the usual concrete resistence against water). Will they resolve into a bucket of water within 4 weeks?
I started the process and after some days some pieces have cracks and even fell apart, but I'm not sure if that's just the glass fibre expanding.
I suspect this to work since something has to happen concrete which isn't mixed to remain when constantly under water when put into water permanently and can't imagine anything else than it falling into it's original ingredients (except the concrete having lost it's chemical reaction potential and being dissolved into water).
I realize that it's a lot of effort. It's more of an experiment.