It has been stated that "unless there was residue of explosives at the site, or evidence of explosive related material, the rest of it is pure conjecture.". There was, in fact, such residue, as can clearly be seen here: http://911research.wtc7.net/wtc/analysis/theories/thermite.html
At the beginning of the article, it states:
Aluminothermic reactions are exothermic chemical reactions in which aluminum is oxidized while an oxide of another metal is reduced. Although high temperatures are required to initiate such reactions, they are easily self-sustaining once started due to the heat they generate. The most common example of an aluminothermic reaction is thermite, in which powdered aluminum reacts with an iron oxide. Because aluminum has a greater affinity for oxygen than iron, oxygen is transferred from the iron oxide to the aluminum, releasing a great deal of energy and leaving behind molten iron and aluminum oxide.
It has been argued that "The building is steel, the aircraft is aluminum, pulverized to a fine mist upon impact, with the fires giving the heat needed to start the reaction, which quickly released enormous heat, melting the steel that carried the building's load."
I have heard this argument before, but from what I gather, even
NIST doesn't support it. Instead, NIST desperately clings to the notion that
the planes and fires did it alone, tweaking its computer models in an attempt
to get the buildings to collapse based on these criteria alone. Despite all
their tweaking, even they don't try to simulate how the fires could have actually
collapsed the buildings, instead leaving the computer simulation at the 'poised
for collapse' stage.
I'm glad that you are considering that aluminothermic reactions did take place, however. The next step is simply in persuading you that those reactions were initiated by thermate that was placed within the building instead of from aluminum. Put simply, the planes didn't leave debris on all the floors and left none at all in WTC 7. Another thing is that steel isn't the same thing as iron oxide. Personally, I would like to know more about how high a temperature is required to initiate a thermite reaction. But the fact there are so few people who believe that aluminothermic reactions could have been induced without the use of thermite/nanothermite leads me to believe that explosives were indeed placed.