READY MIX CONCRETE
Concrete is a composite construction material composed primarily of aggregate, cement, and water. There are many formulations, which provide varied properties. The aggregate is generally coarse gravel or crushed rocks such as limestone, orgranite, along with a fine aggregate such as sand. The cement, commonly Portland cement, and other cementitious materials such as fly ash and slag cement, serve as a binder for the aggregate.
Various chemical admixtures are also added to achieve varied properties. Water is then mixed with this dry composite, which enables it to be shaped (typically poured) and then solidified and hardened into rock-hard strength through a chemical process called hydration. The water reacts with the cement, which bonds the other components together, eventually creating a robust stone-like material. Concrete has relatively high compressive strength, but much lower tensile strength. For this reason it is usually reinforced with materials that are strong in tension (often steel). Concrete can be damaged by many processes, such as the freezing of trapped water.
Concrete is widely used for making architectural structures, foundations, brick/block walls, pavements, bridges/overpasses, motorways/roads, runways, parking structures, dams, pools/reservoirs, pipes, footings for gates, fences and poles and even boats. Famous concrete structures include the Burj Khalifa (world’s tallest building), the Hoover Dam, the Panama Canal and the Roman Pantheon.
Concrete technology was known by the Ancient Romans and was widely used within the Roman Empire—the Coliseum is largely built of concrete. After the Empire passed, use of concrete became scarce until the technology was re-pioneered in the mid-18th century.
Annual world-wide production of concrete is over 5 billion cubic yards
- A ten-year study of 2000 miles of municipal streets in Kansas revealed that asphalt pavement was nine times more expensive to maintain than concrete. Concrete also proves safer due to better traction.
- The first concrete street was built in 1891 in Bellefontaine, Ohio and is still in service today.
- Due to a smoother surface of less resistance, concrete highways are fuel-efficient, reducing fumes and saving fuel.
- Concrete is composed of water, cement or lime and an aggregate such as sand or gravel and was used in this basic form for decades, back to Roman times.
- Each year, more than 4700 pounds of concrete is produced per each person in the United States.
- Because of concrete’s light color, it reflects much of the sunlight. This concrete benefit has been shown to lower a city’s average temperature by several degrees and improves night driving on highways.
- Concrete is environmentally friendly in many ways: the ingredients are in abundant supply, quarries can easily be reclaimed for further usage and concrete is an ideal product for recycling waste or commercial byproducts.
- Concrete homes boost energy efficiency, sound proofing and pest control. Concrete doesn’t burn or rot.
- The average American house contains 120,528 pounds of concrete.
- Twice as much concrete is used in construction around the world than the total of all other building materials, including wood, steel, plastic and aluminum.
Fine and coarse aggregates make up the bulk of a concrete mixture. Sand, natural gravel and crushed stone are used mainly for this purpose. Recycled aggregates (from construction, demolition and excavation waste) are increasingly used as partial replacements of natural aggregates, while a number of manufactured aggregates, including air-cooled blast furnace slag and bottom ash are also permitted.
Decorative stones such as quartzite, small river stones or crushed glass are sometimes added to the surface of concrete for a decorative “exposed aggregate” finish, popular among landscape designers.
The presence of aggregate greatly increases the robustness of concrete above that of cement, which otherwise is a brittle material and thus concrete is a true composite material.