Bill,
You set me to thinking. I saw these guys breaking up and removing
another area on the airport ramp some time back, and I don't recall
seeing any sign of rebar in the broken concrete. It was also probably
unreinforced, as well. I guess, if it held up for 70 yrs, they were right.
Jim Nichols
Tullahoma, TN USA
On 2/18/2016 3:11 PM, Bill Pearce wrote:
Interesting, and thinner than I expected. In WWII, it was common to
build runways and taxiways out of unreinforced concrete. The engineers
had conversion charts that said if so think with so much rebar, then
so think with none. When I was working for the airplane factory we did
certain kinds of testing at a nearby former Naval Air Station (Yup in
the middle of Kansas) the Hutchinson Naval Air Station, which was a
base for the navy version of the B24, the one with the single tail.
The son of a local rich oilman bought it for residence and fun, he
lived in the tower structure, the actual glassed in part of the top
had sofas around the outside (yes, this was in the seventies when
parties, sex and drugs happened) and several of the attached buildings
had his collections of various Italian supercars in them. He rented
out the place for us to test, and for gliders and skydiving. Once
while testing, we were constantly irritated by the noise of concrete
being broken up. He had contracted with a local concrete plant to sell
them runways for aggregate. Yes, noiser than jet engines. But the
runways were about one foot thick concrete.
-----Original Message----- From: Jim Nichols
Sent: Thursday, February 18, 2016 2:19 PM
To: LUG@xxxxxxxxxxxxxxx ; Olympus Camera Discussion
Subject: [OM] IMG: Repair of WWII Concrete
I took a walk in the sunshine today at the local airport. Felt good!
This airport was built during WWII as an US Army Air Force training base
for B-24s, hence the concrete was very thick to withstand the wheel
loads. While much of it has held up well, places that received a lot of
traffic have developed cracks. A contractor has been hired to cut out
these broken areas and replace them with new concrete. ( It is
interesting to me that, while concrete made today in our area uses
crushed limestone as the aggregate, I have seen areas of the original
pours that used creek gravel, including a few mussel shells, as the
aggregate.)
This image gives an idea of the thickness of the original concrete.
http://www.gallery.leica-users.org/v/OldNick/Thick+Concrete+3162.tif.html
To tie the new to the old, the old concrete is drilled and rebar is
installed.
http://www.gallery.leica-users.org/v/OldNick/Drilling+for+Rebar+3163.tif.html
About half of this section has been replaced, as the crews work with
manageable pour sections.
http://www.gallery.leica-users.org/v/OldNick/Working+Concrete+3157.tif.html
The rotating mixer drum must be washed out after each pour.
http://www.gallery.leica-users.org/v/OldNick/Wash+Job+3161.tif.html
And then, the truck heads back to the plant for another load. Multiple
trucks were in use, to keep the job moving at a workable pace.
http://www.gallery.leica-users.org/v/OldNick/Going+to+Reload+3165.tif.html
Fuji X-E1 with Fujinon 35/2.0
Comments and critiques welcomed.
--
_________________________________________________________________
Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
Archives: http://lists.thomasclausen.net/mailman/private/olympus/
Themed Olympus Photo Exhibition: http://www.tope.nl/
|