Friday, June 28, 2013

Curbs for the new streets

The curb machine is here putting in curbs for all the new roads.

 
 
In addition to extruding the concrete to form the curb, this machine also has a final stage leveler that precedes the pour.
 
I find it an amazing marvel that the precision work is because this huge machine follows the small string line that has been meticulously laid out beforehand.  How can such a big machine traveling over a round dirt road lay such a precise pour of concrete by following a small string!  Lasers are amazing tools.
 
 
Here you can see the little metal "feelers" that travel along the string line.
 
Imagine what it took to do this kind of work in "the good old days".
 
 
 
Here's the first step after the pour.  This man follows along with a smoothing tool.  (That's not a technical term but its the best way for me to describe it.
 
A fine mist of water keeps it from drying too fast. Our humidity is ridiculously low this week.
 
 
 
 
 
Every so many inches, he makes a mark in the cement.  I'm sure Jim told me exactly but I'm doing the best I can with whatever memory I have left!  :)
 
 
Then he takes another flat tool that has a wedge on the bottom.  It allows him to make a crease in the concrete.
 
Concrete will crack.  These lines help maintain where the cracks can occur.
 
 
The next step along the way is the "sweeper".  He takes a special kind of broom and gently sweeps the concrete to give it that nice smooth surface we see.


Jim explained how the plumb lines were dropped from each metal post so they would be exact.  Measurements start with the wooden stakes driven by the surveyors.

The metal stakes are closer together as they go around a curve to keep everything in line.


Here is an expansion board set into the concrete.  Every 'so many' feet, they chisel out a section and insert a piece of expansion board.



Then "TA DAH..........." (drum roll here) the curb is finished.  The entire crew can take a bow for a job well done.  The curb machine will do about 4,000 feet per day.  That's a lot of cement so the trucks come and go all day.  





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