Concrete Technology, Construction material, Cement

1. University of Salahaddin/ College of Engineering 2015-2016
Dept. Of Dams & Water resources Engineering By: Goran Adil
Construction Material 1
Test No. 3
Test Name: Setting Time of Cement.
Introduction:
When cement mixed with water to form a paste the chemical reaction starts which is known
as hydration, due to hydration the mixture starts changing from fluid state to a solid state this
is known as initial setting of cement and continuous reaction of cement with water will
increase the temperature of the paste because of heat of hydration, when the paste reached to
the maximum peak of temperature this is known as final setting of cement. So it is required
to find the minimum initial setting time necessary for mixing, transporting, placing and
compacting the concrete, and finding maximum final setting time necessary to asses the
reaction rate of cement with water.
The initial and final setting time are approximately related:
Final time (min.) = 90 + 1.2 [initial time (min.)]
Purpose:
To find the initial and final setting time of cement.
Materials:
1- Ordinary Portland cement.
2- Water.
Apparatus:
1- Vicat apparatus with the mould and its initial and final setting needles.
2- Weighing balance with capacity at least 2000 gram.
3- Trowel, Scoop, Container, Hand gloves, Glass Graduates.
Procedure:
1. Prepare the paste by adding the amount of water required for standard consistency of the
paste to 500 gm of cement.
2. Mixing for 4±1/4 minutes.
3. Form the cement paste into the approximate shape of ball with gloved hands. Then toss
six times through a free path of a bout 150 mm from one hand to another. Press the ball
resting on the palm of one hand into the mould, and then remove the excess.
4. Zeroing Vicat apparatus (the initial setting needle attaches the base of the mould and
gauge read zero).
5. Place the mould under the Vicat device.
6. Let the initial setting needle to attach surface of the paste.
7. Let the needle to fall under its own weight to penetrate the paste (this must not exceed 30
seconds after completion of mixing).
8. Read the gauge or the penetration depth taking the distance from the base plate to the tip
of the needle.
9. Repeat step 8 each 5-10 minutes time on different points of the paste.
10. When the reading on the gauge equal to 5 mm or higher, initial set has occurred and the
time taken from the moment of addition of water to cement up to this gauge reading.
11. Replace initial setting needle by final setting needle.
12. Repeat steps 6 and 7 for each 15 minutes times interval.

2. University of Salahaddin/ College of Engineering 2015-2016
Dept. Of Dams & Water resources Engineering By: Goran Adil
Construction Material 2
13. When the set of needle behind the tip of needle made an impression on the paste while the
circular cutting edge failed to do so this is by visual inspection, final set has occurred. The
time taken from the moment of addition of water to cement.
Specification:
Specification I.S.S. (5/1984) BS 12:1991 ASTM (C150)
Initial setting time ≥ 45 minutes ≥ 45 minutes ≥ 45 minutes
Final setting time ≤ 10 hours ≤ 10 hours ≤ 375 minutes
Precautions:
1- Needle must be cleaned each time before use.
2- After recording the penetration of the needle, the mould should be shifted (change its
position) so that penetration of needle may not take place at the same place.
3- The mixing has to be undertaken at a temperature of 20±2 o
C and minimum relative
humidity of 65%, and cement paste stored at 20±1 o
C and maximum relative humidity of
90%.
4- The initial and final setting time are approximately related:
Final time (min.) = 90 + 1.2 [initial time (min.)]
Discussion:
- Compare the test results with the standard specifications.
- What is the significance of this test?
- What is the effect of temperature and finesse of cement on the test results?

3. University of Salahaddin/ College of Engineering 2015-2016
Dept. Of Dams & Water resources Engineering By: Goran Adil
Construction Material 3
Data Sheet
Setting Time of Cement
Test No.: 3
Test name: Setting Time of Cement
Name of the student:
Group No.:
Date:
Group No.:
Time
minutes
Penetration depth for
initial setting
mm
Visual inspection for
final setting
Remarks
5
Results: