Concrete – it’s everywhere. From the sidewalks we walk on to the office buildings we work in. In fact, concrete is the second most consumed resource on Earth, only behind water. As we need water to survive and grow, infrastructure needs concrete to do the same.
Concrete’s dominance as a building material results from its positive physical attributes including longevity, strength, and resilience, as well as its affordability. It will continue to play a key role in global urbanization and industrialization into the future.
The ingredients in concrete’s recipe always include cement, water, sand, and aggregate. The ratios of its components may vary slightly depending on the end use of the concrete.
Cement: the powdery glue that binds concrete
Cement and concrete are often incorrectly described as the same material. However, while concrete acts as the foundation for much of our infrastructure, cement is actually the powder like glue that binds components that mix to create concrete.
Cement Manufacturing: the basics
In brief, cement results from the chemical transformation of crushed limestone when heated in large rotating kilns at temperatures up to 1450 C. The calcination produces a marble sized raw material known as clinker. After cooling, the clinker is mixed with other ingredients, and ground into the fine powder we know as cement. Cement production emits approximately 8% of the global anthropogenic carbon dioxide emissions.
Here is a more detailed look at the process:
The basics of what is involved in the manufacture and production of cement are mentioned below.
Extract the limestone that will be used for the cement manufacturing from a quarry located near the cement kiln.
Crush the limestone and transport to the raw mill.
Combine limestone with other materials (clay, shale, etc.) and grind into a raw meal powder.
Add the raw meal and heat to 1450 degrees C in a rotating kiln. Within a 30-minute cycle, the raw meal is transformed into clinker. At this point, calcination of the raw meal releases carbon dioxide as a byproduct.
Clinker is cooled and ground into a fine powder in the cement mill. It can be mixed with certain ingredients, such as gypsum and fly ash, based on the purpose of the mix. The cement is ready to be transported for use in making concrete.