Civil Engineering - Concrete Technology - Discussion

30. 

Setting time of cement increases by adding

[A]. gypsum
[B]. hydrogen peroxide
[C]. calcium chloride
[D]. sodium oxide
[E]. none of these.

Answer: Option A

Explanation:

No answer description available for this question.

Rathi said: (Dec 19, 2013)  
The terms cement and concrete are used interchangeably, although cement is actually an ingredient of concrete. Gypsum is often added to cement and concrete to slow down the drying time. Cement dries quickly. If not added, the cement will set immediately after mixing of water leaving no time for concrete placing.

Snehal Nikam said: (Feb 2, 2015)  
Gypsum is used for decrease the setting time and calcium chloride used for increase the setting time.

Bhadresh Vasoya said: (Jul 15, 2015)  
Gypsum are not accelerator, then is not improve setting time.

Darshan H A said: (Jul 5, 2016)  
Gypsum is added to aviod flash setting. It improves setting time.

Swapnil Pokulwar said: (Nov 19, 2016)  
Gypsum is retarded and calcium chloride acts as an accelerator.

So, calcium chloride is the correct answer.

Aksp said: (Nov 25, 2016)  
@All.

It is talking about setting time not setting!

There is the difference between them!

So, the given answer is Right.

Dilawar Khan said: (Dec 25, 2016)  
Calcium chloride increases the setting time of concrete. So C is the correct answer.

Gopal said: (Feb 2, 2017)  
It should be C.

Rahul said: (Feb 11, 2017)  
Yes, friends gypsum is the right answer. I agree.

Suman said: (Feb 15, 2017)  
Calcium chloride is 100% right answer gypsum is decreasing for setting time of cement.

Akhil said: (Mar 27, 2017)  
Time increase i.e retarder gypsum.

The right answer is A.

Sujit Kumar said: (Jul 26, 2017)  
A is right. I agree.

Ritesh said: (Aug 9, 2017)  
No, @Ssuman.

Because gypsum is a retarder so it prolongs the setting time and calcium chloride is an accelerator and it shortens the setting time.

Dinesh said: (Aug 27, 2017)  
Gypsum is 200% correct answer it increases the setting time because it is a retarder. And calcium chloride decreases the setting time so that conc can be sets early as it is an accelerator.

Karan said: (Sep 9, 2017)  
Which material is used for decreasing the setting time of cement?

Rajesh said: (Sep 11, 2017)  
I agree retarder increase setting time to delay takes place. Where as in accelerator decrease setting time to react fastly.

Arman Malik said: (Sep 30, 2017)  
Gypsum increase setting time of cement.

Madhu said: (Nov 22, 2017)  
Gypsum is a retarder means it is delaying the setting time implies that required the setting time is more that means increasing the setting time. After all, gypsum is the right answer.

Devraj Sablaniya said: (Dec 8, 2017)  
Gypsum used as retarder it's slow down the reaction rate so initial setting time will increase.

Bk Raju said: (Sep 8, 2018)  
Is this adding sugar, increasing concrete setting time?

Shub said: (Sep 25, 2018)  
Gypsum decreases setting action but increases setting time A is the correct answer.

Awanti said: (Oct 11, 2018)  
Gypsum is a retarder. It slows down the reaction of cement with water and increases the setting time of cement. So, A is correct.

Ankit Negi said: (Jan 2, 2019)  
Gypsum is the right answer.

Zia Ur Rehman said: (Mar 26, 2019)  
To increase setting time means that it will take more time, so it means we have to use a retarder to increase the setting time. So the given answer is the right one.

Example: Cement A sets in 30 minutes, What will you use so that it takes time more than 30 minutes?

Saurav Kalouni said: (May 8, 2019)  
Setting time decrease means it takes it will set very fast. So for quick setting of cement cacl2 is added which is a accelerator that accelerates the setting action.

Anomy said: (Jul 10, 2019)  
@All.

Calcium Chloride is an 'accelerator' which means it sets the concrete faster. That means the setting time will decrease.

While gypsum is used as a retarder, that means it will slow down the setting time. Which means the setting time of concrete will increase.

Shayhaq Baloch said: (Oct 30, 2019)  
A is the right answer.

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