Construction Management

1. Sampling of cement & Tests
PREPARED BY:
MAYUR .U. RAHANGDALE -202030018

2. Table of Content
 What is sampling
 Need of sampling
 cement
 Sampling of cement
 Process Inspection
 Lot Inspection
 Test of cement

3. What is sampling?
 Sampling is the removal from a given lot of material a portion that is representative of
the whole yet of convenient size for further analysis.
 It is done either by hand or by an equipment.
 Hand sampling is usually expensive, slow, and inaccurate, (so that it is generally applied
only where the material is not suitable for equipment sampling (slimy ore, for example)
or where machinery is either not available or too expensive to install.)
 Many different sampling devices are available, including shovels, pipe samplers, and
automatic machine samplers.
 For these sampling machines to provide an accurate representation of the whole lot, the
quantity of a single sample, the total number of samples, and the kind of samples taken
are of decisive importance.

4. Need of sampling
 Materials used in construction should be of good quality and to check whether a material
is standard or not, sampling and testing is important.
 Sampling can save time and money. A sample study is usually less expensive than a
census study and produces results at a relatively faster speed.
 Sampling remains the only choice when a test involves the destruction of the item under
study.

5. Sampling of cement
 Process Inspection
 For an in-process quality check for the intermediate and finished product during the
production process.
 Lot Inspection
 Lot Inspection will be generated at the time of production order release.

6. Process Inspection
 By Purchaser- To ensure its conformity to the specification requirements
 By Manufacturer- To ensure uniformity & reduce quality fluctuations to minimum.
 Methods of Drawing samples
Clinker-
a) Every hour from each kiln, immediately after coming out from cooling chamber.
b) After mixing all these hourly samples, a composite sample shall be made for a day.
c) From this small quantity is taken out for the chemical analysis.
d) Remaining clinker if pulverized after mixing it with gypsum & tested for the other
characteristics.

7. Process Inspection
Cement Grinding-
a) From grinding mill, Hourly for testing setting time and every alternate hour for fineness
test.
b) Remaining portions form hourly sample shall be mixed to be a composite sample of the
week & tested for the other characteristics, such as heat of hydration of cement.
Cement Packing-
a) From Packing machine, daily for testing fineness, setting time, soundness, compressive
strength and degree of whiteness.
b) Remaining portions form daily sample shall be mixed to be a composite sample of the week
& tested for the other characteristics, such as heat of hydration of cement.

8. Lot Inspection
 When Process Inspection cannot be made available or when the purchaser so desires, the
procedure of Lot Inspection shall be followed for judging conformity of the lot of
hydraulic cement.
 Recommended- cement should be sampled when it is in motion.
1. Sampling From Conveyors
2. Sampling from bulk storage
3. Sampling from skip’s hold
4. Sampling from wagons
5. Sampling from bags

9. Lot Inspection
 Sampling from conveyors
1. A lot shall be divided into sub lots at the time of discharging over
a conveyor belt.
2. Then a gross sample is drawn from each of the sub lots & shall be
kept separately.
3. The collecting frequency should be one increment for every 10
tons of discharged cement.
4. Mostly a scoop is used for the sampling from moving belts, which
can sweep across the cross section of the material & along the
belt.
5. After taking the increments out of sub lots, they shall be placed
directly on a moisture proof, air tight containers to avoid moisture
absorption & Aeration of sample.
No’s of sub lots into which a lot is to
be divided
Wt. of Lot (Tons) No’s of sub-lots
<100 2
101-200 3
201-300 4
301-500 5
501-1000 6
1001-2000 7

10. Lot Inspection
 Sampling from Bulk Storage i.e. silos
1. A lot shall be divided into sub lots depending upon the weight of the Lot
2. Then a gross sample is drawn from each of the sub lots when the cement is being charged into bulk
storage or at the time of discharging from the bulk storage.
3. Increment shall be taken from each opening.
4. The collecting frequency should be one increment for every 10 tons of discharged cement.

11. Lot Inspection
 Sampling from Ship’s Hold
1. A lot shall be divided into sub lots depending upon the weight of the Lot
2. For collecting samples from ship’s hold, i.e. for depths greater than 2 m, sampling pipe activated by
air jet is used.
3. Then a gross sample is drawn from each of the sub lots.
4. The collecting frequency should be one increment for every 10 tons of cement.
5. The increment shall be weight at least 2 kg.

12. Lot Inspection
 Sampling from Wagons
1. A lot shall be divided into sub lots depending upon the weight of the Lot
2. For collecting samples from wagons, i.e. for depths smaller than 2 m, Slotted-tube sampler is used.
3. Then a gross sample is drawn from at least six evenly distributed points in each selected wagon.
4. The increment shall be weight at least 2 kg.
5. After taking the increments out of wagons, they shall be placed directly on a moisture proof, air
tight containers to avoid moisture absorption & Aeration of sample.

13. Lot Inspection
 Sampling from Bags
1. A lot shall be divided into sub lots depending upon the weight of the Lot.
2. at least 2 percent of the bags (minimum of five) shall be sampled.
3. Selection of bags should be random.
4. Tube sampler shall be inserted diagonally into the valve of the bag and the thumb placed over the
air hole and then shall be withdrawn.
5. Equal no’s of increments should be taken out from each bags.
6. The increment shall be weight at least 2 kg.

14. Sampling Equipments
Tube Sampler For Bags Slotted Tube sampler for bulk storage

15. Test on Cement
The following tests are conducted on cement in the laboratory are as follows:
1. Fineness Test
2. Consistency Test
3. Setting Time Test
4. Strength Test
5. Soundness Test
6. Heat of Hydration Test
7. Tensile Strength Test
8. Chemical Composition Test

16. Test on Cement
The following tests are conducted on cement in the field are as follows:
1. Colour Test of Cement
2. Presence of Lumps
3. Cement Adulteration Test
4. Float Test
5. Date of Manufacturing

17. Consistency Test of cement
 Aim: To determine consistency of standard Cement paste.
 Apparatus:

18. Consistency Test of cement
Material Used:
Cement material shall be stored in
sealed, airtight containers to avoid
changes in its characteristics due to
absorption or deposition from the
atmosphere.

19. Consistency Test of cement
 Procedure:
• Keep the vicat apparatus on a level base while using vicat apparatus with dashpot, keep the bearing
movable rod to its highest position and pin it. Unscrew the top of the dashpot. Half fill the dashpot
with any suitable oil of viscosity and screw the top. Work the plunger a number of times.
• Attach the plunger for determining standard consistency to the movable rod. Work the plunger a
number of times.
• Take 400 gm of cement in a pan and a weighed quantity of water in a beaker.
• Prepare a paste with the water added to cement. Start a stopwatch at the time of adding water to
cement.
• Keep the vicat mould on a non-porous plate and fill the cement paste in it.

20. Consistency Test of cement
 Procedure:

21. Consistency Test of cement
 Procedure:

22. Consistency Test of cement
 Procedure:
• After completely filling the mould, shake it slightly to expel the air. Smooth off the surface of the
paste making it level with the top of the moulder. The cement pastes thus prepared is the test block.
• Place the test block resting on the non-porous plate under the movable rod, bearing the needle.
• Lower the plunger gently to touch the surface of the cement paste and quickly release.
• Remove the pin holding the movable bearing rod to the surface of the cement paste and quickly
release by pushing down the plunger to sink in to the paste. This operation shall be done
immediately after filling the mould.
• Prepare trial test specimens with varying percentages of water until plunger penetrates to a point 5
to 7mm from the bottom of the vicat mould, which is read on the scale. Express the water required
as percentage by weight of the dry cement.

23. Consistency Test of cement
 Procedure:

24. Consistency Test of cement
 Observation Table:
SR. NO. DESCRIPTION READING
1. Weight of cement taken (g) (W1)
2. Quantity of water added to cement (W2)
3
Standard Consistency of Cement for 5-7 mm
penetration (W2/W1*100)

25. Consistency Test of cement
 Significance and importance of the test:
1. It determines the amount of water needed to make a paste. It is necessary to determine consistency
because the amount of water affects the setting time of the cement.
2. Consistency plays a vital role in the determination of compressive strength of concrete or
workability test for concrete.
3. Less water than this quantity would not complete chemical reaction thus resulting in the reduction
of strength and more water would increase water-cement ratio and so would reduce its strength.

26. Consistency Test of cement
 Why is Consistency Test Done?
We know that the cement we used on our site is mostly affected by
1. Weather Conditions
2. Excessive combination of Silica. One of the cement ingredients which determines the initial and final
setting time of cement paste.
3. The fineness of cement.
4. Manufacturing Defects
By Standardising the consistency of cement, we know that how much of water is required to produce an
effective cement which will eventually produce good quality of concrete.

27.  Aim :- Determination of the initial and final setting time of cement.
 Reference: - IS 4031 (Part-5):1988
 Appratus :-
Vicat apparatus, vicat mould, needle, gauging trowel, measuring jar, weighing balance,
stop watch, rubber glove, non porous glass plate.
 Material:- Ordinary Portland cement; Water.
Determination of Setting Times of Cement

28. Determination of Setting Times of Cement

29. Determination of Setting Times of Cement
 Theory :-
• The time to which cement can be moulded in any desired shape without losing it’s strength is called Initial setting time of
cement
or
• The time at which cement starts hardens and completely loses its plasticity is called Initial setting time of cement
or
• The time available for mixing the cement and placing it in position is an Initial setting time of cement.
or
• Initial set is a stage where the cement paste stiffens to such an extent that the Vicat needle is not permitted to move
down through the paste within 5 ± 0.5 mm measured from the bottom of the mould. The time elapsed between the
moments that the water is added to the cement to the initial set is regarded as initial setting time.

30. Determination of Setting Times of Cement
• The time at which cement completely loses its plasticity and became hard is a final setting time of
cement.
or
• The time taken by cement to gain its entire strength is a Final setting time of cement.
• For an ordinary Portland cement, the initial setting time should not be less than 30 minutes while the
final setting time should not be more than 600 minutes.

31.  Procedure :-
1) Preparation of Test Block
• Prepare a neat cement paste by gauging the cement with 0.85 times the water required to give a paste of standard
consistency. Potable or distilled water shall be used in preparing the paste. The paste shall be gauged in the manner and
under the conditions prescribed in IS : 4031 (Part 5)- 1988. Start a stop-watch at the instant when water is added to the
cement. Fill the Vicat mould with a cement paste gauged as above, the mould resting on a nonporous plate. Fill the mould
completely and smooth off the surface of the paste making it level with the top of the mould. The cement block thus
prepared in the mould is the test block.
• Immediately after moulding, place the test block in the moist closet or moist room and allow it to remain there except when
determinations of time of setting are being made.
Determination of Setting Times of Cement

32. 2) Determination of Initial Setting Time
• Place the test block confined in the mould and resting on the non-porous plate, under the rod bearing the needle (with cross section
1 mm2 ).
• lower the needle gently until it comes in contact with the surface of the test block and quickly release, allowing it to penetrate into
the test block.
• In the beginning, the needle will completely pierce the test block. Repeat this procedure until the needle, when brought in contact
with the test block and released as described above, fails to pierce the block beyond 5.0 ± 0.5 mm measured from the bottom of the
mould.
• The period elapsing between the time when water is added to the cement and the time at which the needle fails to pierce the test
block to a point 5.0 ± 0.5 mm measured from the bottom of the mould shall be the initial setting time.
Determination of Setting Times of Cement

34. 3) Determination of Final Setting Time —
• Replace the needle of the Vicat apparatus by the needle with an annular attachment .
• The cement shall be considered as finally set when, upon applying the needle gently to the surface of
the test block, the needle makes an impression thereon, while the attachment fails to do so.
• The period elapsing between the time when water is added to the cement and the time at which
,attachment fails to make an impression on the surface of test block shall be the final setting time.
Initial and Final Setting Time of Cement

36.  Observations:-
• Weight of given sample of cement is ___________ g.
• The normal consistency of a given sample of cement is ___________ %
• Volume of water taken(0.85 times the water required to give a paste of standard consistency) for
preparation of test block ____________ ml
Initial and Final Setting Time of Cement

37. Initial and Final Setting Time of Cement
 Precaution for Initial and Final setting time of cement test
• The needle should be cleaned after every use.
• The mould should be slightly moved so that the penetration would not be at the same place.
• The experiment should be carried out at a place where there is no external vibration or
disturbance.
• The mould should not have any type of movement from initial setting time to final setting time.
• The temperature of the room in which the experiment is conducted should be maintained
around 27º-29º C and hydration should be maintained in between 60-70%.

38. The End..!