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oncrete is amazing these days," says Baker. "We should call it something new, since it's so different than concrete from a few decades ago." More workable and up to five times stronger, concrete today has gained these powers due to a more complex chemical composition. In many cases, industrial by-products, such as fly ash, slag from steel mills and microsilica left over from silicon manufacturing, are added to strengthen the mix, allowing it to be stiffer and support heavier loads.

echnological advances means the elemental ingredients of skyscrapers can support much larger loads with much less material.

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