06-09-2017, 02:29 PM
Concrete is a composite composite of coarse aggregate bonded together with a fluid cement that hardens over time. Most of the concrete used are lime-based concretes such as Portland cement concrete or concretes made from other hydraulic cements, such as cement fondu. However, asphalt concrete, which is often used for road surfaces, is also a type of concrete, where the cement material is bitumen, and polymer concrete is sometimes used when the cementing material is a polymer.
When the aggregate is mixed together with dry Portland cement and water, the mixture forms a flowable slurry which is easily poured and shaped into shape. The cement chemically reacts with water and other ingredients to form a hard matrix that bonds the materials together into a durable stone material that has many uses. Often, additives (such as pozzolans or superplasticizers) are included in the blend to improve the physical properties of the wet blend or the finished material. Most of the concrete is poured with reinforcing materials (such as reinforcing bars) embedded to provide tensile strength, producing reinforced concrete.
The famous concrete structures include the Hoover Dam, the Panama Canal and the Roman Pantheon. The first large-scale users of concrete technology were the ancient Romans, and concrete was widely used in the Roman Empire. The Rome Coliseum was largely built of concrete, and the concrete dome of the Pantheon is the largest unreinforced concrete dome in the world. At present, large concrete structures (eg, dams and multi-storey car parks) are usually made of reinforced concrete.
After the Roman Empire collapsed, the use of concrete became rare until the technology was rebuilt in the mid-eighteenth century. Today, concrete is the most widely used artificial material (measured by tonnage).
When the aggregate is mixed together with dry Portland cement and water, the mixture forms a flowable slurry which is easily poured and shaped into shape. The cement chemically reacts with water and other ingredients to form a hard matrix that bonds the materials together into a durable stone material that has many uses. Often, additives (such as pozzolans or superplasticizers) are included in the blend to improve the physical properties of the wet blend or the finished material. Most of the concrete is poured with reinforcing materials (such as reinforcing bars) embedded to provide tensile strength, producing reinforced concrete.
The famous concrete structures include the Hoover Dam, the Panama Canal and the Roman Pantheon. The first large-scale users of concrete technology were the ancient Romans, and concrete was widely used in the Roman Empire. The Rome Coliseum was largely built of concrete, and the concrete dome of the Pantheon is the largest unreinforced concrete dome in the world. At present, large concrete structures (eg, dams and multi-storey car parks) are usually made of reinforced concrete.
After the Roman Empire collapsed, the use of concrete became rare until the technology was rebuilt in the mid-eighteenth century. Today, concrete is the most widely used artificial material (measured by tonnage).