The answer to that question is simple; cement is a powder and one of the four ingredients used to make concrete.
Concrete is made from combining the cement with water, sand, and stone. When the cement mixes with water it forms a paste that binds all the materials together.
The surfaces of the stone and sand get coated with the cement paste during the mixing process.
Once the paste sets and hardens, it forms a rock hard mass known as concrete.
When the cement gets mixed with water it forms a paste.
As soon as the two materials are mixed together a chemical reaction takes place that causes "heat".
The chemical reaction is called HYDRATION. As hydration takes place, over time, the paste hardens and gains strength.
A lot of people use the term "cement" when they're really referring to "concrete".
When talking to my customers, they'll say things like cement floor, cement truck, or cement driveway.
Or... people will ask me "Do you pour cement?"
When this happens, I have to politely explain to them the difference between concrete vs cement and for most people, I don't think they really care that much.
No, cement isn't stronger than concrete. The aggregate's (stone) and sand is what make concrete strong.
Cement, when mixed with water, will form a paste that will harden. It's called mortar, but on its own, it's not very strong.
Sometimes sand is mixed with the cement and water to form a stronger mixture of mortar, but it's still not stronger than concrete.
It's the carefully designed portions of each ingredient that make up different concrete strengths.
In it's most basic form, concrete is proportioned at about 15% cement, 70% sand and stone, and 15% water.
It's the ratios of these ingredients when they're all mixed together that make the concrete strong.
The quality and strength of the paste is determined by how much water is mixed with it.
This is called the "water-cement-ratio". The higher the w-c-r, the lower the concrete strength. The lower the w-c-r, the stronger the concrete mix is.
You want the concrete to be workable so it can be properly consolidated and placed. But not too wet or soupy which would produce a lower quality concrete.
Cement is a mixture of materials like limestone, silica, shale, clay, slate, and iron ore.
After being mined from the ground, they get heated to extremely high temperatures in a rotating kiln.
The kiln looks like a large rotating pipe about 10 - 15 feet in diameter and about 300 feet long.
One end of the kiln is raised, this is where the raw materials are placed. As the kiln rotates, the materials move slowly to the lower end.
Jetted flames at the lower end heat all the materials to temperatures between 2700 and 3000 degrees Fahrenheit.
When the materials are exposed to these extremely high temperatures, they form marble sized balls called "clinker".
The clinker is very finely ground into a powder called Portland Cement.
After it's ground into the fine powder, the cement is mixed with small amounts of limestone and gypsum.
This mixture is the cement that's transported to ready-mix concrete plants and used to make concrete.
Did you know there's different types of cement?
Here they are:
This book will teach you all about concrete.
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