Cement is undeniably one of the most important building materials. It bonds different types of construction elements.
In fact, you can pretty much call it as the backbone of masonry industry.
This fine, inorganic powdery product is mixed with aggregates and water to build structure, roads, bridges and what not.
Whether you plan to build a skywalk or an undersea tunnel, it is hard to conceptualize construction without cement.
Most times cement is lime-based or made of calcium silicate. You can have water-based or hydraulic cement as well as non-hydraulic ones.
Different constructions require different types of cement mixes.
Often, the quality of the concrete is directly dependent on the quality of the cement you use.
Cement Composition
Let us now get into the details of the cement composition. It is actually a combination of several elements.
Cement derives its strength and durability from a mix of several elements.
- Lime – 63%: It is perhaps the most important constituent in cement. The lime in cement is primarily derived from limestone, chalk, shells and any type of calcareous rocks. This calcium oxide gives the cement its strength, but the excess of it will make it disintegrate.
- Silica – 22%: Silica is also known as Silicon Dioxide and comprises 22% of cement. It is mostly derived from a gamut of argillaceous elements. It helps to dicalcium and tricalcium the silicate in aggregates. Moreover, it also imparts strength to cement.
- Alumina – 6%: The chemical name for it is Aluminium Oxide. This is what gives the cement its characteristic quick setting feature. Sufficient amount of alumina is important for bringing down the clinker temperature. However, the excess of alumina can weaken the overall strength of cement.
- Iron Oxide – 3%: Also called Ferrous Oxide, this is what gives the cement its steel grey lustre. Though only 3%, it is a crucial component. It acts as a flux, and this triggers the chemical reaction that eventually lends the strength to cement.
- Magnesium Oxide – 1-3%: The ideal share of Magnesia or Magnesium Oxide should not cross this level. Though it helps in making the cement durable, excess of it will weaken the cement by a huge margin.
- Gypsum – 1-4%: It is added to the burnt cement clinker. This is what controls the time that cement takes to set. As a result, it plays a crucial role in the overall composition of cement. In fact, it is one of the most indispensable items in cement.
Types Of Cement
1) Ordinary Portland Cement
This is perhaps the most common type of cement used globally.
In fact, Portland Cement is primarily used to create concrete and other construction needs.
Be it plastering or grouting; Portland cement is almost indispensable for construction.
However, make sure there is no sulfate exposure from either groundwater or other such sources.
There are 3 classifications of OPC based on its strength test at 28 days according to IS 4031-1988 standard.
- 33 Grade: This is one of the most basic grades of cement. The number indicates the average compression strength of the cement. The 33 Grade cement attains a compression strength of 33 after 28 days curing. Needless, to mention, this is one of the low-grade cement.
- 43 Grade: This is a relatively finer grade of cement compared to the previous one. It also has a much higher compression strength. Overall this is a standard construction cement that is used the world over for plastering, non-RCC structures and also building pathways.
- 53 Grade: This is the finest grade with the highest compression strength. It is commonly used for fast plugging, instant grouting, and manufacturing pre-stressed concrete.
2) Rapid Hardening Cement/ High Early Strength Cement
In many ways, it is similar to Portland cement, but it has a much higher content of tri-calcium silicate. The grinding is also relatively finer in comparison.
In terms of strength it is only slightly more than Portland, but on the whole, it gains strength a lot faster. Hence the name, high early strength cement.
In fact, its strength after 1 day is almost equal to Portland’s 3-day strength. But the amount of heat release is much higher in this case.
As a result, it is not a great option for building huge structures. This is best suited for making roads and bridges.
3) Extra Rapid Hardening Cement
As you can understand from the name, it sets and hardens a lot faster than most other cement variants.
Even compared to the rapid hardening cement, it imparts 25% more strength to the concrete on day one. This is created by grinding Rapid hardening Portland cement with calcium chloride.
It is this calcium chloride that expedites the overall hardening process significantly. But it can’t be mixed and kept for long.
The entire mixing, placing and compacting has to be finished within a 20-minute window.
This is ideal for working in cold weather condition, given the higher heat emission during its evolution.
4) Sulphate Resisting Cement
It is the normal Portland cement but has some unique characteristics. The Tricalcium aluminate content in this is generally less than 5%.
Technically speaking, it can be used anywhere that you use Portland cement. But its unique quality is that it resists sulfate attack.
As a result, basement structures, underground sewers chemical factories and all such potential candidates exposed to sulfate attack prefer this cement.
Construction in coastal areas that are close to the sea, about 50 km radius also uses this specific kind of cement.
5) Quick Setting Cement
A faster setting time is undeniably a key feature of this type of cement. Compared to the normal Portland cement, it sets a lot faster.
The initial setting time is just 5 minutes, and the final setting gets done in 30 minutes sharp. Therefore, this is best suited for constructions that need early setting time.
Think about underwater construction or the ones that are exposed to running water. Given the very fast early setting time, it is generally used only in special cases.
Otherwise, most times the placement and compacting may happen well after the initial set, creating future problems.
6) Low Heat Cement
As the name indicates, the heat evolution is much lower in this cement.
It is primarily achieved by reducing the Tri-calcium aluminate content to less than 5%. Meanwhile, the di-calcium silicate content is raised to nearly 46%.
The low heat evolution makes this cement the ideal choice for massive construction. These also are very resistant to ruptures, so that’s a popular avenue too.
This is, however, not very suitable in cold weather areas. The compressive strength too is much lower in this cement variant. As a result, this too is something that is reserved for the specific purpose. The time for optimizing the curing process is also much higher in this case.
7) Portland Pozzolana Cement
When Portland Cement marries Pozzolana, you get Portland Pozzolana cement.
Needless, to mention that this has many properties that are similar to Portland Cement. So it can be used for any type of general construction that you may want. But then the question is why make this?
Well, the relative heat evolution is much lower in this, and it also resists sulfate attack and other contamination prone cracks in concrete very effectively. That means it gives you the Portland advantage with the Pozzolana edge.
This is why this is amongst the top choices for many marine constructions. The strength of this cement is also much higher than conventional Portland Cement.
8) Portland Slag Cement
As the name suggests, slag is an important element in this cement.
Granulated slag is mixed in equal proportion with gypsum and clinker to get this mix.
In terms of construction strength and quality, it has properties similar to Portland cement. It has good resistance against sulfate attacks and other soil-related corrosive actions, it emanates low evolution heat and resists reaction to alumina and iron in the environment.
Even in acidic water, this cement variant signals significantly higher resistance. This is why it is a great option for marine constructions in areas where the sulfur level is much higher in natural water.
9) High Alumina Cement
When Bauxite ore and limestone is mixed, burnt at high temperature and ground finely, you get high Alumina cement.
Rapid strength development is the most distinguishing feature of this product. Unlike conventional cement, it is jet black in colour. It works effectively against potential chemical corrosion like sulfate attack.
However, the other big advantage is that it can be used in extremely high-temperature regions like refractories, foundries and workshops.
10) Air Entraining Cement
Air-entraining cement contains millions of air cell in every cubic foot of concrete. By mixing in a surfactant, it will create bubbles in the cement.
This air entraining element comprises of at least 4-7% of the total concrete volume. But that is a general measure. Depending on local conditions, this can be a bit more as well.
For those four seasons countries, these types of cement provide small pockets for the water to expand when it freezes and prevent damage from the freeze-thaw issue. This means there is no additional pressure on the concrete structure when the exterior freezes during the winter season.
Besides, air entraining cement do provide better workability but the concrete strength is weaker due to its air containing formulation.
11) Supersulphated Cement
This is also another popular slag based cement variant.
In this case, about 10-15% of hard-burned gypsum is combined with granulated slag.
In terms of strength and construction quality, it is similar to the Portland cement. The sulfur content is what makes it different from the rest.
This makes it more resistant to a whole list of the chemical attack on concrete. As a result, in areas that are prone to such chemical driven attacks. This surely makes constructions more sustainable in these conditions.
12) Masonry Cement
Whatever be the type of masonry you need, you will find the masonry cement ideal.
This is a mix of the conventional Portland cement with plasticizers and other hydraulic cement blends.
Higher workability, durability and adequate water retention are some of the key features.
The trick is this cement is created in a controlled atmosphere to guarantee quality performance under all condition.
The workability and performance of this special cement type remain undisputed across genres of construction.
It is almost like a pre-mix where you only need to add sand and water on the site. Precious little needs to be added to this beyond it.
13) Expansive Cement
As you can understand from the name, it is a type of cement that tends to increase in volume after you have added water and sand to it.
This water-based hydraulic cement invariably contains a higher amount of alumina and sulphate.
This enhances its hardening abilities after initial set. So essentially it expands as it hardens in volume.
These can be effective in tackling shrinkages after the cement has dried off.
14) Coloured Cement
When a specific pigment is pre-mixed with the cement, it is called coloured cement.
However, this colouring element should be only about 5-10% of the overall volume. This is important as the strength of the cement will be effected otherwise.
They are commonly used for finishing work. Be it the floors, window sills, stairways or panels; you do not want the grey of the cement to be highlighted. By using this coloured cement, you can easily tackle this problem and create a proper finish.
The pigment is achieved through chemical combinations instead of plain colour. For example, if you want green, you can add chromium oxide while cobalt will result in blue.
15) White Cement
In many ways, it is quite similar to the Portland cement.
However, this is white in colour compared to the grey in case of the latter. This too is primarily used for decorative purposes.
In terms of strength and workability, there isn’t much of a difference. The strength of this cement is considered to be at par with the conventional Portland cement.
It also has some unique features that ensure that the limiting factor of a pigment-producing element that is used.
Conclusion
There are many different types of cement. Every variant has its own unique appeal.
The composition is altered to an extent to create specific construction solutions.
Malaysia of lately has seen a huge boom in construction. As a result, the cement industry has got an additional fillip.
The good news is there are many local manufacturers across Malaysia who produce premium quality products. Find out Malaysia Cement Manufacturers here.
Given the steady growth in their business and increasing demand globally, these cement manufacturers are increasing their footprint internationally.
As a result, you now have a much better grade of construction material available across the country. Needless to mention, they enhance the overall demand scenario as well.
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