原物料大妙用：水泥.docVIP

Megastructures: How Its Built: Concrete NGC全民英檢:原物料大妙用－水泥 播出時間:07月25日 星期六 @11:00-12:00 Concrete. Its the most-used building material on earth.It was the building block of the Roman Empire.Today, its the material for a new generation of gravity-defying skyscrapers. The raw ingredients that create this magic formula can be found in nearly every country on earth.Yet, how these simple components are mixed together can make the difference between tragedy and triumph. From the mundane to the massive. From the ordinary, to the extraordinary,concrete helped paved the way for innovation and laid the foundationfor the worlds greatest civilizations.Now, go inside the science of concrete... It starts out like liquid.When it dries. It becomes stone hard.This amazing metamorphosis has earned concrete the nickname liquid rock.it has served as the cornerstone of engineering for centuries. And its a highly prized tool of construction for a reason.Its easy to take concrete for granted.People see it in sidewalks and roadsall the time, everyday but in fact it is the closest thing to a miraculous material in construction that weve ever had. Concrete is everywhere. It has an almost unlimited engineering potential.It can take on nearly any shape.And forms the backbone of a variety of the worlds construction: super-highways,massive bridges,man made waterways,mega dams,the worlds tallest skyscrapers.This miracle material begs the question,how does it do it all? I worked on a lot of jobs and basically they all have a different formula for their concrete. I cant imagine a world without concrete. The basic formula for concrete is simple: sand, crushed rock called aggregate, water and the heart of the concrete mix, cement. Cement is the grey powder material that acts as a glue that sticks all of the concrete together. It covers and coats all of the gravel, the sand and the rock as a way of gluing and binding the whole material together.To make cement, you need lime stone,clay and other elements