Instead, they just started tossing shovelfuls out into the field to get the spreading process started. |
Further distribution was done by simply pushing piles of the chipstone with the back of a rake, all the way down to the other end and obviously losing some portion down into the still-empty slots. |
The subtlety here is that once the slots are full, sweeping in any
direction tends to pull stone back *out* of them and scatter it across
the surface, where blowing at a shallow angle tends to push the isolated
stuff on top away and leave whatever's trapped in the slots alone. There's
a definite sweet-spot of air velocity that gives the best separation here,
and it gets even more interesting when stuff fallen from the trees
gets mixed into the picture too.
The next stage of compaction was rather magic. It wasn't really to squash layers down anymore, as plenty of that had happened, it was to settle the chipstone down as far as it would go into the slots. The best way to express how this worked is a video clip (743K) from the process. Watch closely right next to the compactor plate and you see the chipstone simply melt away and vanish down into the slots. I wonder how they did this back in the days before vibrational compactors? Time, I suppose, would eventually tend to settle material as we know all too well that gravity sucks, but probably far less optimally than giving it all a good shake like this. A few of the chipstone pieces were just long enough to bridge across the gaps, particularly where the locking nubs were, and this would clearly bang those loose and let them fall. I suppose you could do it by hand with a lot of rubber-mallet work, but that would be incredibly tedious and possibly leave the pavers more misaligned than they should be. |
This left the slots nicely settled down but now not quite full. I went around and thunked on a few with the rubber hammer just to test if any of it would settle even more, and it really didn't. |
Besides, they needed the trailer again to go fetch the asphalt for
the street connection. The head guy was originally thinking that
asphalting would wait for the next day, but there was still quite
a bit left of this one so he decided to do it that very afternoon.
Now, the thing about hot-top is you have to buy it by the ton, as that's the minumum amount they'll sell you. We wouldn't need nearly that much, so I was trying to think of anywhere else we could use more of it -- extra surround on either side of the driveway, or maybe even to bulk up the neighbor's little water berm for him. The project manager had been by in the morning, and we'd discussed a few different ideas. |
Time to oil up the Magic Shoes! These looked distinctly home-built, out
of wood, but like the pair that was used on the street job they'd be the
right tool for compacting down small runs of asphalt. The little squirt
bottle of diesel was plenty to lube up all the tools they'd need here.
If you're finding yourself asking "...diesel??", my revelation about its use in asphalt work came from the roadwork page. Basically, a release agent. |
The berm material was laid just slightly high, and then carefully "walked down" to create the match and slope we wanted. |
So at this point the driveway itself was pretty much done, and all that remained was for concrete to finish curing and asphalt to cool and harden. Ribbons were left up across the entrance so nobody would happen to nose in across the fresh hot-top, and I wouldn't be parking on this for another night. No problem, we all wanted it to be as perfect as possible. |
Day 6
But if I needed any more of it later, I could easily go buy it in bags from a nearby stone and masonry supply place. The PM showed me this and his recommendation on efflorescence cleaner, in case I wanted to attack the random whitish patches on some of the pavers. [Basically, weak nitric acid.] Techniseal markets a whole line of paver care products [as does Unilock themselves], most of them geared toward the impermeable type of setups where the aim is to have a *sealed* structure so I'd have to be a little cautious about any sort of cleaning effort. The efflorescence is just a natural result of concrete curing, and after a little research it seems like the best strategy is to just let time take its course and it'll go away by itself in a year or two as long as salts are kept off the driveway. All of the pavers would eventually lighten in color anyway once out of their factory-fresh bundles, so I wasn't too worried about it. |
In fact, efflorescence or no, it all looked gorgeous. Several neighbors
had passed by the ongoing project and stopped to admire, as it's such a
radical and frankly upscale change to my old patch o' dirt. "It's totally
Hollywood Boulevard", commented one. And as mentioned before the
graceful curved bit, now clean and bordered by rich dark loam, really
added a nice touch.
One caveat about the permeable system is that under normal circumstances you don't really want to sweep or rake at all, because it will easily dislodge the joint stone. I was glad I'd already researched the whole leaf-blower thing a couple of months before, as that would be an important tool in ongoing care of this. I wound up getting one of these, a nice lightweight cordless unit with variable speed. With that I'd be able to dial in that delicate sweet-spot between pushing organic stuff and pushing chipstone, and while I don't actually mind trailing a cord around for some things it would also be much nicer to take an un-tethered tool up around the roof and gutters when it came time to launch all the oak crap overboard. |
Then he started on the road, and the spray did lift a lot of the ground-in stuff away nicely but it took a bit of persistence. Not like it covers a large area at a time. |
The geekdom never stops
Bonus section: extraction technique
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