To determine specific gravity and void content in a given sample of cement

 

OBJECT: - to determine specific gravity and void content in a given sample of cement (bulk  density of cement - 1.44 gm per cm cube)

 

APPARATUS:- le-chatelier flask, beaker, weight box, empty container (basin\pan), kerosene free of water or naphtha having a specific gravity not less than 0.7313.

 

EXTRACTS FROM I.S. 4031-1968:-

PROCEDURE:-

1. The flask shall be filled with kerosene to a point on the stem between zero and I ml mark. Inside of flask above level of liquid shall be dried if necessary after pouring, the first reading i.e. wt of flask plus kerosene and level of kerosene shall be recorded.

2. Weighed quantity of cement (about 64gm of port and cement) shall than be introduced in small amount into the flask. Care shall be taken to avoid splashing and to see that cement should not adhere to inside flask above the level of kerosene.

3. after all cement has been introduced stopper shall be placed in flask is to be rolled in inclined position or gently whirled in horizontal circle so as to free cement from air, until no further air bubble rise to surface of liquid, if proper amount of cement has been added level of liquid will be in its final position, final reading i.e. wt. of flask plus kerosene plus cement and level of kerosene shall be taken.

OBSERVATION: -

Minimum three set of reading to be taken

 

S. No	Particular	Observation
		1.	2.	3.
1.	Mass of flask + Kerosene                                    (in Gm)
2.	Level of kerosene in flask                                    (in mi)
3.	Mass of flask + Kerosene + Cement                    (in Gm)
4.	Raised/increase level of kerosene in flask           (in mi)
5.	Mass of cement added (3)-(1)                              (in Gm)
6.	Bulk volume of cement = (5)/ Bulk density         (in Cm3)           (V)
7.	Displaced volume of solid particles in cement (4) -(2)   (in Cm3)           (Vs)
8.	Specific gravity of cement = Mass of cement /Vs
9.	Void content in cement = (V-Vs)/V x 100 (6)-(7)         in %

 

 

 

 

PART II: The percentage of bulking of sand due to moisture shall the calculated from the formula:

Percentage bulking = (200/y-1) x 100

 

OBSERVATION TABLE

PART I

S.No.	Moisture content	ht of loose sand in cylinder-before pouring water h cm.	ht sand after pouring water h cm	% bulking = (h/h,-1) x 100.
1.	1%
2.	2%
3.	3%
4.	4%
5.	5%
6.	6%
7.	8%

 

PART II

S. No.	Moisture content	y ml	% bulking (200/y-1) x 100
1.	1%
2.	2%
3.	3%
4.	4%
5.	5%
6.	6%
7.	8%
8.	10%
9.	12%
10.	16%
11.	20%

 

RESULTS: Report the percentage bulking of the sad to the nearest whole number as -----

DISCUSSION: Cover the following points:

1. Importance of bulking and reasons of bulking.

2. Normal results expected.

3. Variations in resulting due to grading of aggregates.

4. Draw a curve representing % bulking with varying of moisture contents and discuss it.

NOTE:

1. Leave the appliances used by you and their surroundings clean.

2. Record your observation in the journal and get them verified by your teacher.

 

RESULT: - Specific gravity of given sample of cement= Void content of given sample of cement=

PRECAUTIONS: -

1. Kerosene must be free from water.

2. Constant temperature is to be maintained while taking observation.

3. Duplicate determination of sp. Gravity should agree within 0.01.

4. Cement should not adhere to walls of stem of the flask above the level of Kerosene.

5. For the first reading, after pouring Kerosene, little time is to be given to maintain a stable level of Kerosene to the flask.

6. Proper handling of the flask care must be taken.