Home » Uses of Rapid Hardening Portland Cement – Fast Setting Concrete

Uses of Rapid Hardening Portland Cement – Fast Setting Concrete

Rapid Hardening Portland Cement (RHPC) is a special purpose cement. It is used in concrete to achieve a higher rate of early strength development, compared to using Normal Cement. The improved early performance of RHPC is achieved principally through increased product fineness. It is also called a quick dry cement.

This cement becomes harder than ordinary cement. Strength that comes in Ordinary Portland Cement comes in 28 days, it is only received within 4 days in Rapid Hardening Cement. In order to make this cement, it is added to a high quantity of good quality Lime and goes fine grinding over ordinary cement.

The initial setting time period of this cement is 30 minutes and Final Setting Time is 10 hours, but at the time of setting, heat exceeds heat. Therefore, this macro concrete is not suitable for the work.

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Its compression strength is 11.5 N / mm2 after one day and 21 N / mm2 after three days and Tensile Strength is 2 N / mm2 after one day and 3 N / mm2 after three days.

Because this cement accepts faster power, the construction work is completed faster and the form work can be removed quickly. Its curing needs to be reduced. It is stored in ordinary cement.

It is also called Early Strength Cement. After adding calcium chloride to 2% in cement it becomes harder. Form work can be removed only after 6 hours and after 16 hours the structure can be weighted. The strength in ordinary cement comes in 7 days. He gets this cement in 3 days. This cement is also called calcium chloride cement.

The raw materials required for the manufacture of Rapid Hardening Portland Cement are:

  • Limestone
  • Shale
  • Gypsum
  • Coke

Rapid Hardening Portland Cement is manufactured by fusing together limestone (which has been finely grounded) and shale, at extremely high temperatures to produce cement clinker. To this cement clinker, gypsum is added in small quantities and then finely grounded to produce Rapid Hardening Portland Cement. It is usually manufactured using the dry process technology.

Also Read: What is OPC and PPC Cement? – How to Make the Right Choice

Following are the uses of the rapid hardening portland cement:-

  • This cement is used in such works where there is a possibility of rapid load, such as bridge, road and repair work. This cement is very useful for military construction work at the time of war.
  • It is used where high early strength is required.
  • It is generally used for constructing road pavements, where it is important to open the road to traffic quickly.
  • It is used in industries which manufacture concrete products like slabs, posts, electric poles, block fence, etc. because moulds can be released quickly.
  • It is used for cold weather concreting because rapid evolution of heat during hydration protects the concrete against freezing.

Advantages of Rapid hardening cement

The advantages of using Rapid hardening cement are –

  • It gains high strength in the early days and the formwork can be removed earlier as compared to other types of cement.
  • It requires a short period of curing.
  • There is a reduced shrinkage during curing and hardening of cement.
  • Rapid hardening cement is resistant to sulphate attacks.
  • Rapid hardening cement is used in areas like road pavements so that the traffic can be opened early. It is also used in manufacturing precast slabs, posts, electric poles, concreting in cold countries.
  • There is a good speed of construction as the cement sets rapidly.
  • It is a very durable cement which matches the fast pace of construction and budgets required to make projects operational.

Disadvantages

It is expensive than Ordinary Portland Cement.

 

Properties

  • Initial Setting Time: 30 minutes
  • Final Setting Time: 600 minutes
  • The specific surface is greater than 3250 cm2/gm.
  • RHC is lighter than OPC.
  • The curing period for RHC is less.

Manufacturing

Rapid hardening cement is burnt at a higher temperature than that of the OPC under more controlled conditions.

 

Strength

The 3 days strength of rapid hardening cement is equivalent to the 7 days strength of OPC when the water-cement ratio for both the cement is taken to be same. The increased rate of strength is due to the fact that higher proportion of tri-calcium silicate (C3S) is contained in RHC along with finer grinding of the cement clinker. Though, the rate at which RHC gains strength is higher than the rate at which OPC gains strength, the ultimate strength is only a bit higher for RHC.

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