Tuesday, Oct 02, 2007 at 22:22
Imagine driving along an open highway, pushing a 3m high wall and towing a trailer, at the posted speed limit.
Then, quite suddenly, about 100m away, a traffic light appears, on RED!
You stop, for about 45 seconds, and in that time you have to lower a 300mm plate onto the road surface, and a rail mounted with several seismic sensors. You raise and drop a heavy weight (about 250kg) onto the plate three times, and measure the shock wave received by the seismic sensors. The plate and rail are raised, and suddenly the traffic light turns green. You're off!
But! 700m away there appears another bloody red traffic light, and you repeat the whole sequence again, and again, and again.....
With all the stop-start action, you average about 25-27 Km per hour, and on a really good day you might travel 250-300km. You average about 2500-3000km on a set of brakes, tyres would be lucky to give 15000km, and your fuel consumption is around 45-55litres/100km! (Good thing you have a company credit card, eh!)
And the really annoying thing is..... you're the only one that can see the traffic lights, so you cop abuse from all the other road users.......
Still, the best part is, you stop at a different pub every night, you're paid to be a tourist (albeit a very slow one)
At the end result is, by analysis of the data produced, you can see how well bound-together the understructure of the road is the base course and sub-base). If they're not strongly compacted, or breaking down then there's nothing to support the bitumen and that's when the wheel ruts appear in the seal.....
Wasn't that fun?
FollowupID:
526588