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In a few hours, this sloppy wet concrete will harden into
a solid, which, after a few days will be strong enough to hold many tons of weight.
Pasta also starts in a moist amorphous state, hardens after a few hours, and it can also hold
a lot of weight.
But there’s an important difference between capellini and concrete –\hnoodles dry out
(which you can tell because when you add water, they re-absorb it and become soft again),
while concrete sets (you can pour as much water on it as you want, and it won’t become
soggy - which is good because you don’t want buildings and bridges to get soggy when
it rains).
The distinction is that when pasta is made, water simply evaporates out of the dough,
leaving behind a desiccated, starchy scaffolding with plenty of holes & gaps ready to re-absorb
water in the future and re-soften the dough.
When concrete sets, on the other hand, calcium oxide, silicon dioxide and other molecules
in the cement chemically combine with water molecules to create new compounds like calcium
silicate hydrate. These molecules grow into crystalline fibers that bond with each other
and literally cement together rock, sand, metal or whatever else you put into the mix.
So when concrete hardens, it’s not drying out, because water isn’t leaving it –\hwater
is reacting with and becoming PART of the cement. In fact, concrete continues to set
for months and even years after it’s poured, increasing in strength over time and enabling
the construction of miraculously strong and durable structures, like the 2000 foot tall CN Tower in Toronto
or the 2000 year old Pantheon in Rome.