Posted: Wed Jan 30, 2008 10:14 pm
I agree - it needs to be left. Any compaction always brings the water to the surface.
If you compact when the sub-base/laying course is loaded with water, the vibration brings water to the surface and this water inevitably carries an amount of sediment/silt/fines from the laying course material, which has the unfortunate habit of staining the block surface.
If you've used a pre-compacted laying course, then simply sanding the joints and advising the clients to take it easy until you can get back to complete final compaction, the pavement should be OK. In fact, conditions such as this are the ideal opportunity to try the wet grouting technique.
However, if you've relied on the uncompacted laying course method (or the now outdated partial pre-compaction), trafficking the pavement prior to fimnal compaction carries a risk of the blocks becoming differentially settled, especially if there are vehicles performing turning movements. All of which is just another reason to use the pre-compacted laying course method whenever possible.
Assuming you've at least 100mm of Type 1 and the correct grade of laying course, once we've managed 24 hours without precipitation, it should be safe to undertake final compaction, but, as ever, test a small, out-of-the-way corner first, just to be on the safe side. Nowt worse than stained blocks delaying the customer from putting their moniker on the bottom of that cheque!
