Greetings, Rick!
  On 05 Apr 98, Rick Nolan entered the following ASCII codes for the express 
viewing pleasure of Bill Wunsch:
 RN> 01 Apr 98, Bill Wunsch writes to Jim Sanders:
 RN>
 RN>
 >> , or a new layer of asphalt over an old concrete base.
 RN>
 RN> They do that with roads round here :-( The bits breaking off
 RN> damage my Mercedes,god knows what they do sucked into aircraft
 RN> engines :-(
That brings up a good point for discussion.  Any road/runway engineers 
lurking around here?
The soil conditions we have in this city, combined with seasonal changes, 
take a high toll on the streets.  Quite some years ago the city did a test 
surface of several blocks using concrete instead of asphalt surface generaly 
used.  It has stood up well, but is not comfortable to drive on.  I commented 
to a friend that they should use the concrete for a firm base and a smooth 
layer of asphalt over top.  He replied that wouldn't work, because the 
asphalt would not stick properly to the contrete surface.  He commented that 
the contrete surfaces on highway bridges in this province are not covered 
with asphalt for that reason. That startled me a bit, since I have a concrete 
driveway that had the surface totally eaten away by the action of freezing 
water, and a two inch layer of asphalt on top has stood up well for years.  
But then there is slightly less traffic on my driveway than on the highway.
Meanwhile, back at the airport, if I remember correctly from my flying years, 
the runways seemed to be asphalt.  When new construction was done, it was 
contrete.  And when the time came to improve the surface (because the 
concrete had become uneven and was not a pleasure to land on) it would be 
covered with a thick layer of ashpalt.  It seems to stick there, but that may 
be only because a very thick layer is used, not just a thin two inch cap.
                                             -==-
--- GoldED/386 2.42.G0615+
---------------