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Quick setting cement is the suitable option for constructions requiring fast setting of concrete. This cement type is made by mixing aluminum sulphate, gypsum, and retarder in a less percentage and finely grinding it with cement.
The existence of tricalcium silicate (C3S) and tricalcium aluminate (C3A) decreases the set period of the cement. The lone downside of Quick setting cement is that it is expensive and cannot be available efficiently.
It has a smaller percentage of gypsum and is crushed much finer than that ordinary Portland cement.
The settling process is revved by adding a little percentage of aluminum sulphate, during the period of grinding.
It is costly compared to ordinary Portland cement.
The time required for initial and final setting are 5 minutes and 30 minutes respectively.
The setting process of such a cement begins within 5 minutes and it evolves stone-hard in smaller than half an hour.
1. Working on Quick Setting Cement
When water is mixed with the cement hydration occurs and a chemical reaction takes place which makes the cement set where the initial setting time is 30 mins and the final setting time is 10 hours.
In this special type of cement, where the setting time of the cement is to be small, and the setting of cement is quick. The cement clinkers are mixed with aluminum sulphate, which decreases the setting time of the cement.
Aluminum sulphate is utilized as an accelerating admixture in the amount that ranges from 1% to 3% by weight of cement clinkers.
The work of aluminum sulphate is that it improves the rate of hydration of tricalcium silicate (C3S) and tricalcium aluminate (C3A) stages of cement, thereby giving earlier heat evolution and strength development.
It mainly works as a catalyst in the process of hydration of tricalcium silicate (C3S) and tricalcium aluminate (C3A).
Concrete specimens with differing percentages of aluminum sulphate were sampled for compressive strength, splitting tensile strength, and flexural strength.
The outcomes achieved were compared with the outcomes of standard M20 concrete mix and it was discovered that maximum growth in compressive strength, splitting tensile strength, and flexural strength took place for quick setting cement concrete at 3 days and 7 days.
However, there was no significant rise in compressive strength, splitting tensile strength, and flexural strength at 28 days.
The uses of Quick Setting cement are as follows:
a. Quick Setting Cement can fix damaged structures without disturbing the existing structure
b. Due to its quick setting possessions, it is employed in works where concrete is to be set underwater or in flowing water.
c. The concrete sets extremely quickly. So, cement is employed for underwater construction.
d. The moisture level in the air is very high during cold weather, making it an ideal cement choice during winter.
e. It is also an ideal choice for areas that have fairly high-temperature.
f. It is used for anchoring or rock bolt mining and tunneling, besides constructing concrete steps.
g. Quick-setting cement is an ideal choice to make and carry out repair work for concrete floors.
h. Quick setting cement gains strength very easily in less than five minutes. Therefore, it is used for a structure that has to be completed in a short duration.
3. Properties of Quick Setting Cement
Following are a few of the properties of Quick setting cement that make it an outstanding option for construction:
a. Unlike other cement variants, Quick setting cement has a little yellowish and brown appearance If mixed and applied well, the cement can easily withstand harsh weather conditions.
b. Quick-setting cement works well with materials such as concrete, metals, wood, brick, and plastic.
c. The hardening process of the Quick setting cement begins five minutes after it is put together. Hence, it has to be applied very quickly.
d. Quick-setting cement has waterproof properties, thus acting as a very good hardening material for underwater construction.
e. The concrete made using Quick setting cement reaches final mechanical resistance after 28 days.
f. Quick-setting cement works best both in interior and exterior spaces.
4. Differences between Quick Setting Cement and Rapid hardening Cement
The differences between Quick Setting Cement and Rapid hardening Cement are as follows:
|Factors||Quick setting cement||Rapid hardening cement|
|Admixture||The existence of aluminum sulphate is a very small amount.||It does not possess aluminum sulphate as an admixture|
|Hydration||The hydration process is very quick for Quick setting cement.||The time period of hydration is quick but small than in Quick setting cement.|
|Mixing speed||The cement has to be blended and flowed very quickly as it gains hardness very effortlessly.||The mixing speed requires not to be quick.|
|Setting time||Initial setting time: 5 minutes||Initial setting time: 30 minutes|
|Final setting time: 30 minutes||Final setting time: 600 minutes|
5. Advantages of Quick Settling Cement
The advantages of Quick Settling cement are as follows:
a. It has less setting time but its ultimate strength is the same as OPC.
b. These cement types commonly have high opposition to water.
c. Little water is required at the time of the hydration process.
d. It can be employed for repairs without disturbing the actual structures.
6. Disadvantages of Quick Settling Cement
The disadvantages of Quick Settling cement are as follows:
a. Due to the content of sulphates in the aluminum sulphate, there is a major chance of sulphate attack on the reinforcement corrosion, and durability is compromised.
b. When water is added the work should be completed fast or else it sets and is difficult to mix.
c. It is costly.
d. It is not available effectively in the market.
e. In quick-setting cement, if the heat is not dissipated properly it can result in cracks in the cement after setting.
This was for the Quick Settling Cement.
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