Hello Guys, I have question about Initial & Final setting time For OPC

[Upkar]

I found this questions in an objective book.
Can anyone help me with right answer and full explanation.

The initial and Final setting times for ordinary portland cement are approximately related as
1] T= 530 + t
2] T= 270 + t
3] T= 90 + 1.2t
4] T= 600 - 1.2t

Where T and t are respectively final and initial times in minutes.

 

[rameshchandrapatel]

A smaller value of the final setting time is always preferred in order to avoid large expenditures on the formwork. According to most of the specifications, the final setting time shall not be greater than 10hrs and shall not be less than ( 90 + 1.2 x (initial setting time) ) min.

Final Time (T) = ( 90 + 1.2 x (initial setting time) ) min < final setting time < 10hrs

 

[Dnyan Deshmukh]

From academic point of view and as per specification stated in IS code for OPC cement

Initial Setting time is 30 minutes minimum

Final setting time is 600 minutes maximum.

So your question answer may be

1] T = 530 + t

which is,

final setting time = 530+ 30
= 560 minutes.

All other relation can be true but it ask for approximate relation and 4 options, so option 1 is more closer to codal guidelines.