Concrete


 * Concrete**

//(Definition)// The concrete is a mix of cement, water, sand and stones that hardens after a day (If the mix has fast-drying cement it will get hard after a couple of hours), and compleatly drys after exactly 51 days. It is waterproof and fireproof.

//(Reply to the podcast)// Concrete began to be used about three thousand years ago in Ancient Egipt, of course, the concrete used by the egipts was very different from the one we use today, the mix of materials changed along the times. Also the romans used concrete to make difficult structures lake archs and vaults, thanks to the liquid way of pouring it. But, the concrete had much more less importance to architecture until the early 1860's when the reinforced concrete was developed. By putting rods and bars of iron inside the mix or the mold where it was suposed to be poured, the concrete gained the extra strenght it didn't had in tension, making it easier and quiker to build anything.

Reinforced concrete Precast concrete Prestressed Concrete Concrete Shell