bulk density

1. DETERMINATION OF BULK DENSITY OF FINE
AGGREGATES IN RODDED STATE
AIM:
To determine the bulk density of the given sample of sand in dense state.
APPARATUS REQUIRED:
 Cylindrical Measure – The measure shall be 3,15 or 30 litres capacity, according
to the maximum nominal size of the coarsest particles of aggregate.
 Weigh Balance – a balance sensitive to 0.5 percent of the weight of the sample to
be weighed.
 Tamping rod- a straight metal tamping rod of cylindrical cross section 16 mm in
diameter and 60 cm long, rounded at one end.
 Shovel
PURPOSE:
For Volume or Weight batching, requirement of material to fill the unit volume of
material can be found if we know the Bulk Density. Also amount of voids present in the
material can be found which is a direct measure of cement to be added in the mix design.
WHAT IS BULK DENSITY?
It is the weight of aggregate material in a given volume of bulk aggregate
material. The term volume includes the volume of the individual particles and the volume
of the voids between the particles. Bulk density is used both in weight and volume
batching.

2. SIGNIFICANCE
 During the concrete mix design, when the aggregate is to be batched by volume or
by weight, then it becomes necessary to know the mass of the aggregates that will
fill the container of unit volume. If we know the bulk density of the aggregate
material then we can easily determine the mass required to fill a unit volume
container.
 This test method is used to determine the bulk density of the given fine grained
specimen.
 Bulk density also indicates the percentage of voids present in the aggregate
material. This percentage of voids affects the grading of the aggregates which is
important in high strength concrete.
 We can get to know the percentage of voids by compacting to loose state and
rodded state.
 Bulk density also indicates the compactive effort required to compact the concrete.
PROCEDURE
 Weight of the empty container is taken as W1
 The measure shall be filled about one-third full with thoroughly mixed aggregate
and tamped with 25 strokes of rounded end of tamping rod.
 A further similar quantity of aggregate shall be added and a further tamping of 25
strokes given.
 The surface shall be filled with over flowing, tamped 25 times.
 The surface of the aggregate shall then be leveled with a straightedge.
 The weight of the container filled with aggregate shall then be determined and is
taken as W3.
 The volume of the container is calculated by taking the weight of the container
filled with water which is taken as W2 and the bulk density calculated in kilogram
per litre.

3. OBSERVATIONS
Serial no Description Observed Values
1 Weight of the empty container, W1 in kg 1.822
2 Weight of the container with water,W2 in kg 3.692
3 Weight of the container and sand in rodded
state, W3 in kg
5.050
CALCULATIONS
Volume of the container V = W2- W1 / 1000
=3.692-1.822 / 1000
=1.87 X 10-3
Bulk density of the sand =W3-W1 / V
=5.050- 1.822 / 1.87 X 10-3
=1726.20kg/m3
RESULT
The bulk density of the given sample of soil in the rodded state = 1726.20kg/m3

4. INFERENCE
The given sample has bulk density of greater than1600kg/m3 which is the
allowable bulk density of sand in rodded state. Hence, it can be used for construction
purposes.