Bulk Density & Voids in Aggregate | Jameel Academy

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1. University of Duhok
College of Engineering
Civil Department
Concrete Technology – Practical
Concrete Laboratory



A Report About :


Bulk Density (Unit Weight) and Voids
in Aggregate



Submitted By : Jameel Masoud Jameel

Lab. No. : 6
Group Name : B1

Testing Date : 26 / 11 / 2017
Submitting Date : 3 / 12 / 2017

Supervised By : Youkhanna

2017 – 2018

2. References :

1) ASTM C29/ C29M







Introduction :



Bulk density of aggregate is defined as the mass over a unit volume
of bulk aggregate material, in which the volume includes the
volume of the individual particles without voids and the volume of
the individual particles with voids between the particles. Expressed
in (kg/m
3
), (Ib/ft
3
) and (Ib/in
3
) .

3. Purpose :

This test method is often used to determine bulk density values that are
necessary for use for many methods of selecting proportions for
concrete mixtures. The bulk density also may be used for determining
mass/volume relationships for conversions in purchase agreements.




Materials :

1) Fine Aggregate.
2) Coarse Aggregate.




Equipment :


1) Balance.
2) Tamping Rod: A round, straight steel rod, [16 mm] in diameter and
approximately [600 mm] in length, having the tamping end, or both
ends, rounded to a hemispherical tip, the diameter of which is (16 mm).








3) Measure: A cylindrical metal measure.
4) Shovel or Scoop.

4. Sketches :












Tamping Rod Sensitive balance














Mold & Tamper Scoop




`

5. Procedures :

5-1 Rodding Procedure:

1) Fill the measure one-third full and level the surface with the fingers. Rod the
layer of aggregate with 25 strokes of the tamping rod evenly distributed over the
surface.
2) Fill the measure two-thirds full and again level and rod as above.
3) Finally, fill the measure to overflowing and rod again in the manner previously
mentioned.
4) Level the surface of the aggregate with the fingers or a straightedge in such a
way that any slight projections of the larger pieces of the coarse aggregate
approximately balance the larger voids in the surface below the top of the
measure.
5) Determine the mass of the measure plus its contents, and the mass of the
measure alone, and record the values to the nearest [0.05 kg].


5-2 Shoveling Procedure:


1) Fill the measure to overflowing by means of a shovel or scoop, discharging
the aggregate from a height not to exceed [50 mm] above the top of the
measure.
2) Exercise care to prevent, so far as possible, segregation of the particle sizes
of which the sample is composed. Level the surface of the aggregate with
the fingers or a straightedge in such a way that any slight projections of the
larger pieces of the coarse aggregate approximately balance the larger
voids in the surface below the top of the measure.
3) Determine the mass of the measure plus its contents, and the mass of the
measure alone, and record the values to the nearest [0.05 kg].

6. Calculations and Results :



We will calculate the Density and percentage of voids by using this formula :


?????? (??????�?????? �??????�??????�)=
(??????−�)
??????

?????? (��??????)=?????? (??????�?????? �??????�??????�)×(�+
�
���
)
??????????????????�� (%)=(�−
?????? (??????�?????? �??????�??????�)
??????� ×?????? ??????� ????????????���
)


Note : all Calculation is the average of both group (B1 & B2 – B3 & B4 )


For Fine Aggregate :

Average weight of cylinder (T) =
�.���� +�.���
�
=�.����� ????????????
Average Volume (V) =
0.004959 +0.005092
2
=�.������ ??????
�


A- With Compaction (Rodding Procedure ) :

Average weight of Cylinder and fine aggregate (G) =
13.033 +12.768
2
=��.����� ????????????


?????? (??????�?????? �??????�??????�)=
(G−T)
V
=
(12.900075 kg−3.51425 kg)
0.005025 m
3
= ����.�
????????????
??????
�
⁄

?????? (??????????????????)=?????? (??????�?????? �??????�??????�)×(1+
�
100
)=1867.9×(1+
1.78
100
)=����.�
????????????
??????
�
⁄
??????????????????�� (%)=(1−
?????? (??????�?????? �??????�??????�)
???????????? × ?????? ??????� ????????????���
)×100=(1−
1867.9
2.55 × 1000
)×100=��.� %

B- Without Compaction (Shoveling Procedure) :


Weight of Cylinder and fine aggregate (G) =
��.��� + ��.���
�
=��.����

?????? (??????�?????? �??????�??????�)=
(G−T)
V
=
(12.3225 kg−3.51425 kg)
0.005025 m
3
= ����.�
????????????
??????
�
⁄

?????? (??????????????????)=?????? (??????�?????? �??????�??????�)×(1+
�
100
)=1752.8×(1+
1.78
100
)=����
????????????
??????
�
⁄

??????????????????�� (%)=(1−
?????? (??????�?????? �??????�??????�)
???????????? × ?????? ??????� ????????????���
)×100=(1−
1752.8
2.55 × 1000
)×100=��.� %

Where:
G: Mass of the aggregate and measure (kg).
T: Mass of the measure (kg).
V: Volume of the measure (??????
3
).
Gs: Bulk specific gravity (dry basis).
A: absorption of aggregate.
??????: Density.

7. For coarse Aggregate :

Average weight of cylinder (T) =
�.����+����
�
=�.����� ????????????
Average volume (V)=
0.010190 +0.010190
2
=�.������ ??????
�


A- With Compaction (Shoveling Procedure) :

Weight of Cylinder and coarse aggregate (G) =
��.���� + ��.����
�
=��.���� ????????????


?????? (??????�?????? �??????�??????�)=
(G−T)
V
=
(26.9245 kg−9.29975 kg)
0.010190 ??????
3
=����.�
????????????
??????
�
⁄

?????? (??????????????????)=?????? (??????�?????? �??????�??????�)×(1+
�
100
)=1729.6×(1+
2.3
100
)=����.�
????????????
??????
�
⁄
??????????????????�� (%)=(1−
?????? (??????�?????? �??????�??????�)
???????????? × ?????? ??????� ????????????���
)×100=(1−
1729.6
2.64 × 1000
)×100=��.�� %

B- Without Compaction (Rodding Procedure ) :


Weight of Cylinder and coarse aggregate (G) =
��.��� + ��.���.�
�
=��.���� ????????????


?????? (??????�?????? �??????�??????�)=
(G−T)
V
=
(25.62725 kg−9.29975 kg)
0.010190 ??????
3
=����.�
????????????
??????
�
⁄

?????? (??????????????????)=?????? (??????�?????? �??????�??????�)×(1+
�
100
)=1602.3×(1+
2.3
100
)=����.�
????????????
??????
�
⁄
??????????????????�� (%)=(1−
?????? (??????�?????? �??????�??????�)
???????????? × ?????? ??????� ????????????���
)×100=(1−
1602.3
2.64 × 1000
)×100=��.� %

Detail's Table :

Type of
Aggregate
Type of
Procedure
Average
Mass of
Aggregate
(kg)
Average
Volume
( ??????
�
)
Average Bulk
Density (
????????????
??????
�
⁄)
Average
Voids
%
(Dry Basis) (SSD)
Fine
Compaction 9.39
0.005025
1867.9 1901.1 26.7
No Compaction 8.81 1752.8 1784 31.3
Coarse
Compaction 17.625
�.������
1729.6 1769.4 34.49
No Compaction 16.33 1602.3 1639.2 39.3

8. Discussion and Conclusion :

In this test we determine the density (Dry basis and SSD) of fine and
coarse aggregate, finally we got a result after doing all procedure
accuracy, which is the bulk density of coarse aggregate is (1746.115 kg/m
3

- 1591.4 kg/m
3
) and for fine aggregate is (1919.1 kg/m
3
- 1824.7 kg/m
3
) for
(Compaction and No compaction) relatively. And our result placed
between the range of aggregate's density (1400 – 1900 kg/m
3
). Therefore
we can use this density. but During the procedure we have some errors.
the reason of this errors is the compaction process or when filling the
mold with aggregate, but as shown in our result the test was correct. or
we can do many test and get average for more accuracy.

In conclusion the purpose of this test is to know how to determine the
Density of aggregate, and the void between particles. finally we measure
the bulk Density and voids in percentage after doing some procedure and
calculation, and we can use density that obtained in test.