Theory:

Setting means becoming firmed and harder changing from semi-liquid stage to plastic stage and from plastic stage to solid stage.

A.   Initial setting time : It is the time of interval between the time when water is added to the cement and time of partical loss of plasticity as determine by a standard test in which needle 50 mm long and 1 mm in diameter penetrate the block to a depth of 5 mm from bottom.
B.   Final setting time : It is the time interval between the time when water is added to cement and the time that the paste completely lost its plasticity (i.e. the cement paste becomes harder and concrete cannot be placed or deposited).

Application:

As loss of plasticity starts at the time and end at the time of I.S.I. It is necessary that concrete must be mixed, transported and placed in position before I.S.I. The I.S.I. should not be less than 30 min and I.S.I. should not be more than 600 min (1hrs).

Item Required:

1.     Weighing balance
2.     Measuring cylinder 200 ml
3.     Trowel
4.     Stop watch
5.     Clean platform to make a cement paste
6.     Cement sample  ( 1 kg )Clean water

Procedure:

1.     300 gm of cement sample is taken correctly
2.     Water is added to it at the rate of (0.  ) by weight of cement Pn being the water required for making cement pest of standard consistency.
3.     The stop watch is also started at the instant when water is added.
4.     Fill the vicat mould with cement paste and smoothed of the top surface of mould.
5.     Initial setting time needle is attached ( 1 mm ø ) and lowered it gentally to the surface of the test block.
6.     Release the needle quickly without any jerk and allow it to penetrate into the test block and time is noted from stop clock.
7.     The procedure is repeated until the needle is face to surface in block about 5 mm measured from the mould. It is the I.S.I. ( Initial setting time ).Replace the needle by the find setting time needle with an angular attachment.
8.     It is released on the tip surface at angular intervals and the time is recorded.

Precaution:

1.     The cement should be sieved and weighing it correctly.
2.     The stop clock should be started at time of adding water.
3.     Care should be taken that each time needle should be clean and released at new place.
4.     The time from stop watch and reading from the scale should be recorded continuously.


     Diagram:



     Observation Table:
          
                                    
Sr. No.
Perpendicular from              Bottom (mm)
Time Intervals (min)
1
0
5
2
0
10
3
0
15
4
0
20
5
0
25
6
0
30
7
0
35
8
0
40
9
0
50
10
0
55
11
0
60
12
0
65
13
0
70
14
0
75
15
0
80
16
0
85
17
0
90
18
0
95
19
0
100
20
1
110
21
1
115
22
2
120
23
3
125
24
4
130
25
4
135
26
5
140
27
5
145
28
6
150


Observation:

Weight of cement = 300 gm

Weight of water added = 9.3 ml by weight of cement

Result:

Initial setting time (t1) = 115 min

Final setting time (t2) = 480 min