We would recommend the use of the Power-Sprays Lightweight Mist Coat Spray Gun, which is probably the most popular pump-fed facing coat spray gun used in the GRC/GFRC industry worldwide. You could also consider the Mk 3 Powertex Spray Gun from Power-Sprays, which is ideal for application of special aggregates/pigmented facing coats up to 7mm maximum particle size. Check out http://www.power-sprays.com to download brochures.
The use of GFRC as permanent formwork is still in use, both for bridge deckings and architectural applications. Unfortunately it is not usually used in particularly attractive/photogenic applications, so there aren’t many photos available.
We agree with you that it is a fantastic use of GFRC. Are you planning on doing this yourself?
It is normal practice to demould after a day and then moist-cure the product afterwards, however it won’t be a big problem to leave the GFRC in the mould a little longer. Many manufacturers will have no choice but to leave the product in the mould over the weekend, for example.
To repair imperfections, the easiest way to get a similar finish is to use the same mix design minus the fibres, with less water to make it stiffer, and preferably add some acrylic polymer (more than you would use in a normal mix) to help it stick.
Hope this helps,
Graham, compared to precast concrete, GFRC is certainly a more environmentally friendly material, as the cross section (and weight) of a GFRC panel is substantially less than a concrete one. If you want a more in depth answer, see http://www.grca.org.uk/congress/downloads/3%20Is%20GRC%20a%20Green%20Building%20Material.pdf