Chemical Attack
If the concrete becomes wet, chemical attack may occur which under certain circumstances could result in almost total loss of strength. There are two forms of chemical attack which may occur, namely sulphate attack and alkaline hydrolysis. Sulphate attack can occur if sulphates present in screed materials or plaster coverings are transferred to the HAC. Alkaline hydrolysis can occur if sodium or potassium hydroxide present in Portland cement screeds or concrete is transferred to the HAC. For both types of chemical attack persistently wet conditions are required.
http://www.quest-tech.co.uk/hac.htmReading this pdf file
http://www.civil.columbia.edu/meyer/publications/2002_03_CIBPaper.pdfwill give you additional insights into US construction during the 70s.
You will recall that the steel showed signs of having undergone a eutectic reaction. The reaction you have described has much bearing n the WTC, but is almost irrelevant when applied to the Pentagon.
To return to the Pentagon.
The pieces of so-called debris all appear to be coated with the low-voc lime-green primer-paint that was qualified for use by Boeing in July 2000.
Catherder says as much in the piece entitled
"Evidence That A Boeing 757 Really Did Impact the Pentagon on 9/11"
Prior to July 2000, Boeing used a dark green primer.
All four 911 planes were built before July 2000.
I have yet to see ANY pieces of Penta-debris that have DARK GREEN primer.
mikelewis says:
The Pentagon would have had fire-proof plenum ceilings that would have delayed the expansion of the fire/heat to the drop ceiling in the office areas. The purpose of the plenum ceiling is to retard the spread of the fire. If a pocket of hydrogen did form, an explosion could have increased the temperature of the fire and melted more of the plane. This seems logical to me.
What? Where?
In everything I have read to date,
and I have read a LOT to date,
I have seen absolutely NOTHING
that would have cause me to ever suspect this was so.
How did you derive this theory?
And then speculate as to how it came to be that the plane melted at about 800 degrees,(?)
and yet the DNA did NOT decompose at about 200 degrees.
Please also explain the fate of the Kevlar and how it came to be that a TIRE managed to retain its tread within this inferno.
Also tell us what happens to limestone
(such as that which comprised the facade of the Pentagon)
when it comes into contact with high temperatures.
As for the alumina-hydrogen-exploding air hypotheses,
call your local firefighter on the non-emergency line
and ask them about combustion.
And maybe also the local high school chemistry teacher.
We also have a conundrum in that the Penta-plane left much of both wedges still standing and a humble wrecking ball then leveled these Penta-walls. Do the math.
If you take JUST ONE ASPECT of the Penta-crash
and focus on it to the exclusion of all else,
then,
and ONLY THEN,
is it is possible to explain it away.
However,
once that single aspect is placed in Penta-context,
the theories invariably fail and accuse diligent researchers to raise their voices to ask
WHERDY GO?