THE BENAZIR BHUTTO SHAHEED
UNIVERSITY OF TECHNOLOGY AND SKILL DEVELOPMENT
(BBSUTSD), KHAIRPUR MIRS
Department of Civil Engineering Technology
EXPERIMENT NO. 13
BULKING OF SAND
(IS: 2386 PART III)
Object: The main purpose of adding sand in concrete is to minimize the segregation of concrete and to fill out the pores
between the cement and coarse aggregate. This test (bulking of sand or bulking of fine aggregate) is to ensure that we are
using the right amount of sand while concreting.
Apparatus:
Measuring Cylinder 250 ml
Container
Steel Rule
Steel Rod (6mm Dia)
Sample sand
Discussion:
Increase in volume of sand due to presence of moisture is known as bulking of sand. Other word, Sand when
wet or moist shows more volume than is dry form. Thus, if a certain volume of dry sand is made moist by adding
water, it will show on increase in volume. This is the fact that water forms a film around each sand particle, therefore
by causing the increase in volume. This phenomenon is called Bulking of Sand. It is of importance because certain
fixed proportions of dry sand are to be mixed for making mortars of different specification necessary allowance is;
therefore, to be kept for wet sand. Though the increase in volume for certain percentage of moisture varies with the
grade gain size of sand, in general. It is found that 5 to 8 percent moisture causes 20 to 40 percent volume increase. As
the volume of sand increase with the increase in moisture, a stage comes when with any further increase in moisture
content the volume suddenly falls back to its original volume in dry form.
Bulking of sand Means Increase in its volume due to presence of surface moisture.
The volume increases with increase in moisture content till a certain level then vol. decreases.
It is found that 5 to 8 percent moisture causes 20 to 40 percent volume increase, a stage comes when with any
further increase in moisture content the volume suddenly falls back to its original volume in dry form.
There is a thin layer of water around the sand grains which causes the bulking.
As fine grained sands have higher voids than medium and coarse grained sands, the percentage of moisture
absorbed and the percentage volume increase is the highest.
A find aggregate does not show any bulking when it is absolutely dry or completely saturated.
Prepared by: Mr. Yasir Ali Course Teacher: Dr. Sadam Hussain
Lab Assistant, CET Assistant Professor, CET
THE BENAZIR BHUTTO SHAHEED
UNIVERSITY OF TECHNOLOGY AND SKILL DEVELOPMENT
(BBSUTSD), KHAIRPUR MIRS
Department of Civil Engineering Technology
Causes of Bulking of Sand: The moisture content in the sand makes thin films around sand particles.
Hence, each particle exerts pressure. Thus they move away from each other causing increasing in volume. The bulking
of the aggregates is dependent on two factors:
1. The fineness of the aggregates
2. Percentage moisture content
Procedure:
1. Put sufficient quantity of dry sand into the measuring Cylinder 250 ml until it is about one-thirds full.
2. Level off the top of the sand and measure the height (H1).
3. Remove the Sand from the measuring Cylinder by pushing vertically down and Measure weight of the sand.
4. Add 2% of water; mix it thoroughly in the container. Then refill the measuring cylinder and Smooth the level of top
surface and measure the height (H2) of soil.
5. Find the height percentage increment.
4. Repeat the same procedure with increasing amount of water by 2% until percentage increment of sand height is
reduced and attends original level.
5. Plot a graph of percentage increment of sand height against percentage of water.
Volume of dry % moisture Volume of wet
Sample No % Bulking = H2 – H1 / H1
loose sand H1 content added loose sand H2
1
2
3
Moisture Content in Sand Increase in Volume of Sand
2% 15%
3% 20%
4% 25%
5% 30%
Prepared by: Mr. Yasir Ali Course Teacher: Dr. Sadam Hussain
Lab Assistant, CET Assistant Professor, CET
THE BENAZIR BHUTTO SHAHEED
UNIVERSITY OF TECHNOLOGY AND SKILL DEVELOPMENT
(BBSUTSD), KHAIRPUR MIRS
Department of Civil Engineering Technology
GRAPH: Draw a graph between percentage moisture content on X-axis and percentage bulking On Y-axis.
The points on the graph should be added as a smooth curve. Then from the graph, determine maximum percentage of
bulking and the corresponding moisture content.
Precautions:
1) While mixing water with sand grains, mixing should be thorough and uniform.
2) The sample should not be compressed while being filled in jar.
3) The sample must be slowly and gradually poured into measuring jar from its top.
4) Increase in volume of sand due to bulking should be measured accurately.
Result:
1. The bulking % of the sand is ………………………….
Prepared by: Mr. Yasir Ali Course Teacher: Dr. Sadam Hussain
Lab Assistant, CET Assistant Professor, CET
THE BENAZIR BHUTTO SHAHEED
UNIVERSITY OF TECHNOLOGY AND SKILL DEVELOPMENT
(BBSUTSD), KHAIRPUR MIRS
Department of Civil Engineering Technology
Review Questions:
What is meant by bulking of sand?
What is the significance of bulking of Sand experiment.
Define bulking factor?
?What is the effect of moisture on bulking
Prepared by: Mr. Yasir Ali Course Teacher: Dr. Sadam Hussain
Lab Assistant, CET Assistant Professor, CET
