May 22, 2005 Paving of the south outside lane is almost complete
Sometimes I just get lucky, possibly because I simply cannot sit still.
Just like a high temperature chemical reaction, I am often bouncing around
exploring new ideas. As a kid, I would surely have been
diagnosed with ADD. So today, I bounced up to the bridge and another big
surprise was waiting for me - more paving since yesterday.
So, Friday's, Saturday's and
today's visit yielded big time progress with paving the outside south lane.
Here is a summary of progress since Friday - A lucky view from above
New pavement curing from last (Saturday) night. Note the position of the
5th cable-stay anchor and scroll down to yesterday's (Saturday's) photos
and compare with the launching position of the Bidwell paving machine.
The Bidwell paving machine is in the launching position for the next segment
Cleaning the next segment
I thought I would try to catch the paving this evening. The moon was
full and here is the west pylon bathed in moonlight.
The Bidwell paving machine and the cement mixer were in their
launching positions. The mixer truck is special and can add multiple
components to the resultant concrete.
This is the mixer that mixes the aggregate, sand, cement, latex and water. Each
component is measured (by volume) and dropped onto a src="http://s3.ravenelbridge.net/small conveyor belt near
the back of the truck where it is rapidly mixed. The
Styrafan latex 1186 is manufactured by BASF and adds
flexibility and durability to the road surface.
The BAST article describes the paving process better than I can:
"Cleco employed a straightforward process to install the latex-modified
concrete bridge deck overlay. Modified Concrete Suppliers, LLC, Indianapolis,
Ind., their latex concrete supply contractor for this project, used specially
designed trucks equipped with computerized component metering and augers to
mix the Styrofan 1186 latex, cement, sand, aggregate and water on site for
application to the bridge deck surface. Following application to the bridge
deck, Cleco employees used a Bid-Well finishing machine to spread and trowel
the overlay to achieve thickness and surface smoothness specifications. Once
installation of a section was completed, wet burlap was applied to the surface
of the overlay, covered with polyethylene sheeting, and allowed to moist cure
for 24 hours. This step controlled the rate of water evaporation from the
overlay. After two days of dry cure, the surface was ready for use."
But there was a small problem. In order for the concrete to
cure properly, i.e. no cracks, the evaporation rate must be
below a limit which is determined by the temperature, humidity and wind
velociy. Here Derek (left) has an instrument that measures all this. Here
he and JW (right), from Cleco, are checking the wind
conditions. In general, I am told, winds above 10 mph are problematic.
After a bit of waiting - well it seems that tonight is not the
night for paving ...