National Geographic Documentary Megastructures - Science of Concrete - BBC Documentary History
Concrete is a composite material composed of coarse aggregate bonded together with a fluid cement which hardens over time. Most concretes used are lime-based concretes such as Portland cement concrete or concretes made with other hydraulic cements, such as ciment fondu. However, asphalt concrete which is very frequently used for road surfaces is also a type of concrete, where the cement material is bitumen, and polymer concretes are sometimes used where the cementing material is a polymer.
In Portland cement concrete (and other hydraulic cement concretes), when the aggregate is mixed together with the dry cement and water, they form a fluid mass that is easily molded into shape. The cement reacts chemically with the water and other ingredients to form a hard matrix which binds all the materials together into a durable stone-like material that has many uses. Often, additives (such as pozzolans or superplasticizers) are included in the mixture to improve the physical properties of the wet mix or the finished material. Most concrete is poured with reinforcing materials (such as rebar) embedded to provide tensile strength, yielding reinforced concrete.
Megastructures is a documentary television series appearing on the National Geographic Channel in the United States and the United Kingdom, Channel 5 in the United Kingdom, France 5 in France, and 7mate in Australia.
Each episode is an educational look of varying depth into the construction, operation, and staffing of various structures or construction projects, but not ordinary construction products.
Generally containing interviews with designers and project managers, it presents the problems of construction and the methodology or techniques used to overcome obstacles. In some cases (such as the Akashi-Kaikyo Bridge and Petronas Towers) this involved the development of new materials or products that are now in general use within the construction industry.
Megastructures focuses on constructions that are extreme; in the sense that they are the biggest, tallest, longest, or deepest in the world. Alternatively, a project may appear if it had an element of novelty or are a world first (such as Dubai's Palm Islands). This type of project is known as a Megaproject.
The series follows similar subjects as the History Channel's Modern Marvels and Discovery Channel's Extreme Engineering; covering areas of architecture, transport, construction and manufacturing.
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