Rapid Hardening Cement (RHC) use cases; Pros and Cons

Articles > Rapid Hardening Cement (RHC) use cases; Pros and Cons

Introduction to RHC:
There are various types of cement on the market, classified according to their characteristics and ingredients. Among them, some types are very common all over the world. All of these types of cement are discussed in our previous article. Each type of cement has been compared to other types in that article. But still, we as an architect, need to fully define each type of cement. In this article, we are going to talk in detail about Rapid Hardening Cement (RHC). RHC Cement is the one that needs the shortest time to set up and consolidate. Once the concrete construction is complete, it begins to solidify suddenly. This type of cement benefits us for many reasons such as fast hardening, high durability, requires minimal adjustment, time-saving, requires incurable, environmental conservation, and savings. Apart from the success of this type of cement, there are also some failures associated with this type of cement. This type of cement cannot be used in many structures like dams, canals, water stations, ponds, and other water retaining structures, etc. As this type of cement releases high hydration temperatures, it can cause cracks and pores due to shrinkage. These cracks and pores can cause leakage. That is why this type of concrete is widely used in road construction, as well as in dry-surrounding constructions. Underground apartments are also not allowed to be built with this type of concrete.

Uses of RHC (Rapid Hardening Cement):

The distinctive property of RHC is its high early strength. This characteristic of RHC makes it very convenient for concrete work. Uses of Rapid Hardening Cement are as under:

Making roads and highways available for use soon after their construction, RHC is used.
RHC has a high rate of heat emission therefore, in cold weather countries RHC is used in almost all purposes constructions.
RHC quickly dries and hardens, therefore, it allows formwork removal early. The cost of shuttering and formwork is saved by the use of RHC.
Slabs, pillars, poles, and other precast structures are made by RHC for efficient development work.
It is resistant to sulfate, therefore, is a site where there is frequent sulfate attack, RHC is beneficial to provide durability to the constructed structure.
Because of its early strength characteristics, the repair work of roads, buildings, drains, etc. is carried out by RHC.

Chemical Composition of RHC:

By analyzing the composition ingredients of the cement, we can see that cement is a mixture of Calcite, Silicate, Clay, and some other substances. Each type of cement has an addition of some substance giving it a particular characteristic. Similarly, the RHC has also some specific type of ingredients in it, which allows it to harden abruptly after setting. The chemical composition of RHC is something like this: About 40 to 60 percent of this type of cement is composed of Tricalcium Silicate (Ca₃O₅Si), 10 percent Tricalcium Aluminate (Ca₃Al₂O₆). Tetracalcium Aluminoferrite (Ca₄Al₂Fe₂O₁₀) constitutes about 8% of the total composition of the cement, the rest of the portion consists of other ingredients. RHC contains the following ingredient proportion.

Sr.No.	Scientific Name	Chemical Formula	Percentage
1.	Tricalcium Silicate	Ca₃O₅Si	60%
2.	Tricalcium Aluminate	Ca₃Al₂O₆	10%
3.	Tetracalcium Aluminoferrite	Ca₄Al₂Fe₂O₁₀	8 %

Advantages of Rapid Hardening Cement:

RHC; the Rapid Hardening Cement has very fine clinkers. It is ground very finely, thus it gives impervious structure, which is resistant to chemical and water attacks.
The setting time of RHC (Rapid Hardening Cement) is very short. It does not need a long time as OPC and PPC need.
RHC (Rapid Hardening Cement) hardens abruptly after setting, therefore it is used in the construction of roads and highways, which need to be soon available for use.
In very cold regions it is used almost all-purpose constructions, because of its early hardening.
RHC (Rapid Hardening Cement) is lighter in weight as compared to OPC and PPC. It is very suitable for mortar and plaster purposes.
A lot of hydration heat is released from RHC, therefore, in very cold regions the masons prefer this cement for construction.
As it develops strength very rapidly, therefore, it does not need a long time of cure.

Disadvantages of Rapid Hardening Cement:

Apart from so many advantages, there are some disadvantages to this type of cement, which can not be overlooked in construction work. The constructors keep in mind all of the pros and cons of a construction material while starting a construction. Although there are significant advantages of RHC, still some of its drawbacks prohibits the constructor from its mass use. These drawbacks are as under.

RHC; the Rapid Hardening Cement is a type of hydraulic cement, which releases a large amount of heat during the process of hydration. The release of the huge amount of heat may cause shrinkage cracks in the structure, therefore, it should not be used underwater or structures in-contact with water and the water retaining structures, likes dams, canals, dikes, water channels, etc.
The storage of this type of cement is very challenging. As it hardens very soon in the presence of very little moisture, therefore, it needs quite a dry place storage.
The cost of Rapid Hardening Cement (RHC) is also higher than OPC and PPC, therefore, keeping the economical advantage of OPC and PPC, this type of cement is seldom suggested by the architects and masons. The cost rises up to 10 percent in the case of RHC.
As it releases a large amount of heat, it creates crakes in the constructed structure, therefore, very large concreting structures should not be built of this type of cement.

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Rapid Hardening Cement (RHC) use cases; Pros and Cons

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