Generally, we use cement and concrete as synonyms which is quite not true. Today we will see the clear difference between the two- Concrete vs cement. As per Merriam Webster -Cement is defined as “a powder of alumina, silica, lime, iron oxide, and magnesium oxide burned together in a kiln and finely pulverized and used as an ingredient of mortar and concrete”. On the other hand, concrete means -“to form into a solid mass” basically to solidify.
So Cement is one of the ingredients of Concrete.
Concrete has much more than cement, it has cement itself and other inert material like sand and coarse aggregate, and more importantly water.
What is Cement?
Cement is a product, obtained from the pulverization of the clinkers. Clinkers are formed, by the calcification of a mixture of Argillaceous and Calcareous material. Basically, raw materials like Lime, Silica, Alumina, Iron oxide, etc., are mixed together.
Subsequently, the mixture is then heated at high temperatures in a kiln, where they will get converted into a solid nodule-like thing called clinkers. These clinkers are then converted to a fine powder by using called cement.
This cement has flash-setting properties. So we have to add some substances for instance gypsum to prevent it from immediate setting after the addition of water.
Who discovered cement?
Joseph Aspdin discovered this amazing thing called cement. It is called Portland Cement because when it gets hardens, it resembles the stone quarried from the quarries near Portland in England.
Manufacturing of Cement?
Firstly, calcareous material like lime and argillaceous material like Clay or shale is broken into a small piece of size around 20-25 mm in ball mill separately.
After grinding, they are then mixed together in a certain proportion. After that left to preheat at 850-degree Celsius for 2-3 hours. Then the material is fed into a rotary kiln and burnt at high temperature.
At the end of this process, we get a small solid round stone-like thing called clinkers. This clinker is then ground to a very fine powder. This cement has a flash setting property, which means the addition of water will convert into a solid thing immediately.
This flash setting is prevented by the addition of retarders like Gypsum, which prolongs the setting time of Cement.
By making little variations in components of the cement we can produce different types of cement-like ordinary Portland cement, Portland Pozzolona Cement, Expanding Cement, Acid Resistant Cement, Rapid hardening Cement, High Alumina Cement, and Low Heat Cement.
What is Concrete?
When this Cement is mixed with water and other materials. Like sand and aggregates, and most importantly water, the final product we get is called Concrete- Material of the 21st Century.
So cement is a material having cohesive and adhesive properties which bind discrete ingredients like sand and concrete.
Properties of Cement Concrete
- High Compressive Strength- Concrete should have a compressive strength that fulfills the strength requirement of the component (like building, bridges, roads, etc.)
- Free from Corrosion- It should not get affected much by the atmospheric agencies ( weathering agencies).
- It should have sufficient plasticity, which means it should not be very hard to work with. It should be sufficiently flowable.
How Concrete is Manufactured?
- The first thing in manufacturing concrete is that at what ratio or at what quantity we should mix cement water and aggregate. So there are two prevalent methods for this. The first is to measure all quantities in Volume and the second is to measure it in Weights. The second method is more accurate.
- Then the ingredients, Cement, sand, and Coarse aggregates are mixed dry first and then water is added. Mixing ensures homogeneous, uniform, and consistent concrete.
- The third step is the transportation of this concrete to the desired place of pouring.
- Care should be taken in transportation that is should not get set before placement basically transporting time should not be more than 30 minutes although we can change the setting time by altering the ingredient of cement.
- The fourth step is the placement of concrete at its place and then compaction, which is very important to reduce the pores in concrete.
- An estimated increase of 5 to 10% of pores can reduce the strength of concrete to about 30 to 60 %.
- The last step is curing, concrete should be continuously cured for the curing period it will increase the strength of concrete.