Bulkage of Sand: Causes, Effects, and Testing Methods

What is Bulkage of Sand or Bulkage of Aggregate?

Bulkage of sand or Bulking sand: Bulkage in the sand when dry sand contact atmosphere moisture. Than incense sand volume. After contact atmosphere moisture then sand particles around create a layer. After generating layer sand particles create force. Sand particles make force then particles move aside to each other. This prosses increase in send volume.

Causes of Bulking sand

1. Sand particles small size
2. Atmosphere moisture content

Note for Bulking sand

1. Increase the volume of sand at atmosphere moisture makes concrete lose his strength.
2. This process incense concrete workability but decrease concrete strength.

Relevant IS Code 2386 part 3

This method of test covers the field method for determining the necessary adjustment for the bulking of Send (fine aggregate). From IS Code 2386 part 3 Page: 14 Cl 4.1

General  Point Bulkage of Sand or Bulking sand

Sand brought on to a building site or other works may contain an amount of moisture which will cause it, when loosely filled into a container, to occupy a larger volume than it would occupy if dry. From IS Code 2386 part 3 Page: 14 Cl 4.2

If the sand is measured by loose volume, it is necessary in such a case to increase the measured volume of the sand, in order that the amount of sand. put into the concrete may be the amount intended for the nominal mix used ( based on dry sand ).From IS Code 2386 part 3 Page: 14 Cl 4.2

It will be necessary to increase the volume of sand by the ‘ percentage ’ bulking. The correction to be made is only a rough approximation because the system of measurement by loose volume is a rough method at the best, but a correction of the right order can easily be determined and should be applied in order to keep the concrete uniform. From IS Code 2386 part 3 Page: 14 Cl 4.2

As per IS Code 2386 part 3 Page 14 Cl 4.3 two different methods finding bulkage as below. The procedure to be adopted may be varied, but two methods are suggested in (1) and (2) Both depend on the fact that the volume of inundated sand is the same as if the sand were dry. From  IS Code 2386 part 3 Page 14 Cl 4.3.1

1. Bulkage of send test in Laboratory
2. Bulkage of send test at a site

Let’s look at detailed knowledge about Bulkage of Sand.

1. Bulkage of Send Test in Laboratory 

Apparatus Required for Bulkage of Send Test in Laboratory 

Here, the list of use apparatus required in bulakge of send test are as follows.

1. Measuring Cylinder –
2. Sample sand –

Producer of Bulkage of Send Test in Laboratory 

1. Put a sufficient quantity of the sand loosely into a container.
2. until it is about two-thirds full. Level off the top of the sand and pushing a steel rule vertically down through the sand at the middle to the bottom, measure the height. Suppose this is h cm.
3. Empty the sand out of the container into another container where none of it will be lost.
4. Half fill the first container with water.
5. Put back about half the sand and rod it with a steel rod, about 6 mm in diameter, so that its volume is reduced to a minimum.
6. Then add the remainder of the sand and rod it in the same way.
7. Smooth and level the top surface of the inundated sand and measure its depth at the middle with the steel rule. Suppose this is h’ cm.
8.  The percentage of bulking of the sand due to moisture shall be calculated from the formula

Above all point From  IS Code 2386 part 3 Page 14 Cl 4.3.2

Percentage bulking = (h/h’ – 1) x 100

2. Bulkage of Send Test at a Site  

Apparatus Required

Here, the list of use apparatus required in bulakge of send test are as follows.

1. Measuring Cylinder –
2. Sample sand –

Producer of Bulkage of Send Test at a Site  

1. In a 250-ml measuring cylinder,
2. pour the damp sand ( consolidated by shaking) until it reaches the 200-ml mark.
3. with water and stir the sand well.
4. Then fill the cylinder ( The water shall be sufficient to submerge the sand completely. )
5. It will be seen that the sand surface is now below its original level.
6. Suppose the surface is at the mark y ml.
7. The percentage of bulking of the sand due to moisture shall be calculated

Above all point From  IS Code 2386 part 3 Page 14 Cl 4.3.3

 

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

Bulkage of Send PPT

 

Reporting of Results 

Report the percentage bulking of the sand to the nearest whole number. From  IS Code 2386 part 3 Page 14 Cl 4.3.4

FAQs on Bulkage of Sand

What Is the Bulkage of Sand?

Bulkage of sand refers to the increase in the volume of sand when it absorbs moisture from the atmosphere. This happens because the moisture forms a film around the sand particles, causing them to repel each other and thus occupy more space.

What Causes the Bulkage of Sand?

The primary causes of sand bulkage are:

1. The small size of sand particles.
2. The moisture content in the atmosphere.

How Does Bulkage Affect Concrete Strength?

When sand bulks due to moisture, it can cause concrete to lose strength if not accounted for correctly. This is because the volume of sand in the mix increases, leading to a lower proportion of cement, which in turn reduces the overall strength of the concrete.

What Is the Relevance of Is Code 2386 Part 3?

IS Code 2386 Part 3 provides the standard methods for testing and determining the necessary adjustments for the bulkage of fine aggregates (sand). This code outlines the procedures to ensure that the correct amount of sand is used in concrete mixes, even when bulkage occurs.

How Is the Bulkage of Sand Tested in the Laboratory?

To test bulkage in the laboratory:

1. Measure a specific volume of dry sand.
2. Add water to the sand and rod it to minimize its volume.
3. Measure the new volume and calculate the bulkage percentage using the formula: Percentage bulkage=(hh′−1)×100\text{Percentage bulkage} = \left( \frac{h}{h’} – 1 \right) \times 100Percentage bulkage=(h′h​−1)×100 where $h$ is the initial height of sand and h′h’h′ is the height after adding water.

How Is the Bulkage of Sand Tested at a Construction Site?

To test bulkage on-site:

1. Pour damp sand into a 250-ml measuring cylinder up to the 200-ml mark.
2. Add water to submerge the sand completely.
3. Measure the new level of the sand and calculate the bulkage percentage using the formula: Percentage bulkage=(200y−1)×100\text{Percentage bulkage} = \left( \frac{200}{y} – 1 \right) \times 100Percentage bulkage=(y200​−1)×100 where $y$ is the new volume level of the sand after adding water.

What Are the Effects of Not Accounting for Bulkage in Concrete Mix Design?

Not accounting for bulkage can lead to:

1. Incorrect proportions of sand in the concrete mix.
2. Reduced concrete strength.
3. Potential structural issues due to the weakened concrete.

Can Bulkage of Sand Improve Concrete Workability?

Yes, bulkage can improve the workability of concrete by increasing the volume of sand. However, this comes at the cost of reduced concrete strength if not properly adjusted in the mix design.

Why Is It Necessary to Adjust the Volume of Sand for Bulkage?

Adjusting the volume of sand for bulkage ensures that the correct amount of sand is used in the concrete mix, maintaining the intended proportions and ensuring consistent strength and durability.

How Is the Result of a Bulkage Test Reported?

The result of a bulkage test is reported as the percentage bulking of the sand to the nearest whole number, as per IS Code 2386 Part 3, Page 14, Clause 4.3.4.