“We shape our buildings; thereafter, they shape us.”
– Winston Churchill
This is a very profound thought said by the former Prime Minister of England. The gist of this is “Our mind is affected by the place we live in and the shapes we see – and buildings are some of the most common things we see”
Needless to say, this statement highlights the importance of having good buildings around us. But what makes a good building? The answers can vary depending on whom you ask. Engineers may say “it is the design” the builders will definitely say “the building materials”.
Both of these are correct and both of these are important. A building without a good design is just bad-looking and can crumble anytime. The same goes for building materials as well. Today we will be looking at one of the Most important building Materials of Modern time – Cement. But, What is a Cement?
What Is a Cement?
The basic definition of Cement is “a construction material that is used to bind various building materials such as Bricks and Stones to bond together and form a single unit”. This definition is simple and tells two things:
Function – To Bind materials and increase the bond between the fragmented parts i.e different pieces of bricks and or rocks, so that they can be used in different fields.
Area of Use – In constructions such as Houses, Roads, Dams, Ports, and Bridges
This is the basic gist of what it is and what it does. Now as this material is used in a lot of things, there are a few things you need to consider before buying cement.
Things to know before buying cement
The first thing that we should know is that it is not a natural product but rather a man-made one. While there are natural binding powders that function the same as cement, they are either not as efficient as cement or are hard to get.
Clay is a good example of natural material that has the same function. It is used to bind materials and increase the bond between fragmented parts. In fact, Clay was used instead of cement in the past and is still used in some rural areas that don’t have access to this product. The reason why we don’t use clay anymore is that its binding power is very low when compared to Cement.
Along with this, there are a lot of other things that we know. So let’s see what they are, shall we?
1. Types of cement
As we mentioned cement is a man-made product and as with everything that we create, there are different types of Cement. “Why,” you ask? Well, it is because we need different types of cement for different needs. While the function of the cement remains the same, the feature and area of use change. So to answer the needs of different areas of use, we need different types of cement. So before buying cement you need to know its types.
There are 10 major types of Cement which are:
Ordinary Portland Cement (OPC)
This is the most common cement used around the world. It is made from a mix of limestone with other raw materials such as gypsum and argillaceous. The best feature of this cement is that it is easy to make and sets fast. It takes an average of 43 to 74 hours from the time of application for this type of cement to harden enough for an average-sized human to walk on.
Portland Pozzolana Cement (PPC)
PPC cement is basically OPC cement with some slight variations. These variations include things like manufacturing ingredients, hardness, setting duration, drying period, and strength. Basically, PPC cement is OPC that takes longer to set and is sturdier.
Portland Slag Cement (PSC)
This cement is made from the mixture of Portland Cement clinker (PPC and OPC) with gypsum and granulated blast furnace Slag in an appropriate amount and griding till the texture is uniform between all its components.
Side notes* Clinker is a solid intermediary product that we get while making Portland Cement
Slag in normal terms is a byproduct that you get while smelting metals composed of dirt and other impurities. In this case, slag refers to a mixture of line, silica, and alumina.
Rapid Hardening Cement (RHC)
It is a specific type of portland cement that sets at a similar pace to OPC but has a hardness similar to PPC. While this may seem all good, its production is expensive and harder than the formers. Along with that, not all uses of cement need to be hard. Remember that hardness the harder the material, the less flexible it is.
Extra Hardening Cement
This cement is made by combining inter grinding Calcium Chloride with Rapid Hardening cement. This process makes it set faster and has more hardening which makes it perfect to use in cold weather.
Low Heat Cement
It is a portland Cement that produces a low heat of hydration during the setting and hardening period
Sulphate Resisting Cement
It is designed to improve the performance where the risk of sulfate is present. This is used at places where the environment is harsh to reduce the risk of structural deterioration.
Quick Setting Cement
it is a special type that sets quickly and hardens fast when there is less amount applied. To do this, clinkers are ground with aluminum sulfate.
High Alumina Cement (HAC)
It is also known as Calcium Aluminate Cement (CAC) and is made from Calcium Aluminates. It is made from Limestone or Chalks having Bauxite.
This one is made from materials that have very low iron compounds. This in turn makes the cement color white which is why it is called “White Cement”.
So these are all of the major types of Cement. While there are other variants of cement. Along with this, in recent times a few new types has been created as well. There are called Air Entertaining Cement, Expansive Cement, and Hydrographic Cement.
2. Features/Properties of Cement
As we already mentioned, not all cement is the same and they have different properties depending on their types. These said properties determine how and where the cement is to be used. They are:
This property is the size of cement particles. The fineness of cement directly affects the hydration rate i.e the rate of water absorption which in turn influences other properties like setting time and Consistency.
This property is the ability of the cement to retain its shape and volume upon hardening. Good cement retains both the shape and volume even after hardening.
Consistency of Flow
As the name says, this property of the cement is its fluidity at different hydration levels. A standard should be met at a set hydration level for cement to be considered to be of good consistency.
The strength of the cement can refer to different things such as Compressive strength, tensile strength, and Flexural Strength. Different types of cement have different levels of tensile, compressive, and flexural strength which then determine which area the cement is used.
This property of the cement is the time taken for it to harden after being hydrated. This can vary on multiple factors including the fineness, water to cement ratio, and chemical contents.
The heat of Hydration
When cement is mixed in with the water, a small amount of heat is produced. This can affect the quality of the cement. This is an important property as it determines whether or not cement can be used in a certain climate or not.
These are some general properties that you should know about. Besides these, there are also some properties that are specific to a particular type of cement as well. However, knowing the listed ones before buying cement is usually enough for general purposes.
3. Knowing the Types and Brands Available in your area
After you know the types of cement and features, the next thing that you have to know is the types of cement available in your area and the best brands among them. In Nepal, the Most Common Types of Cement are OPC, PPC, and PSC Cement.
While there are other types of cement available in Nepal, they are only available through Specific Dealers.
Along with this, it is important to know the top brands of Cement in your area as well. The order may vary as per your location, the brands such as Shivam Cement, Jagadamga Cement, and Sarbottam Cements are considered among the top ones in the Cement industry. This is one of those few things that general people consider a lot before buying cement as people who build generally have their preferred brands.
If you want to know the top 10 cement Brands of Nepal, you can check out the links attached at the end of this article.
4. Additional informations you should know
While the information that we have mentioned so far are the major ones that affect the building, as a buyer there are a few more things that you have to keep in mind. These are the information that you need to consider after you have chosen the right type of cement from the brand you trust. They are:
- Pack Seal – If the package is not sealed, then the quality has already been compromised. Always buy Sealed Cement package
- Date of Manufacture – The shelf life of cement is 3 months after which the quality will degrade over time. Always check the date of manufacture to get the optimum quality.
- Quantity/weight – If you are buying cement you need to consider the amount you need. Too much and you don’t know what to do with it, too little and you have to buy again.
- Registered Trademark – By looking at the trademark you know whose product is the Cement Brand. If it is from a trusted company you will be likely to buy it more.
- Grade of a Cement – they determine the comprehensive strength of a cement. The higher the Grade the more strength they have.
- Cost of cement – While costs in this industry don’t vary much, even a single rupee saved per sack can amount to much as we don’t just buy one sack of cement. That being said, don’t use low quality cement just for the sake of saving a few rupees.
These are the things that you should consider while buying cement. We have to remember that cement is used in places that are meant to last long. If you use the wrong type or ones whose properties don’t match the need, you will regret it for a long time.
Also, you have to know that these things are hard to break once set. You will have to use a chisel and a hammer at the very least to make a basic wall that is made using this material. Along with this, be sure to always buy cement from trusted brands like the ones we mentioned before. If you buy any random brands that are not trusted in the market, you are likely to get low-quality cement. There is a reason why some cement brands are at the top and some are never heard of – it’s their quality and service.
Hope that this was helpful for you. And as always, thank you for reading till the end. If you have any suggestions for us, do let us know them down in the comments below.