A H M 531
The Civil Engineering Center
Objectives:
1. Calculating the bulk density of coarse and fine aggregate samples.
2. Calculating the Apparent Specific Gravity for coarse and fine
aggregate samples.
3. Calculating the water absorption of coarse and fine aggregate
samples.
Standards:
¾ B.S. 812 – 1967
General Discussion:
1. Bulk Density
when dealing with aggregates it is important to know
the voids that presents between the aggregate
particles, so that we decide whether to fill them with
finer aggregate or with cement paste.
We all know that the Density we often deal with
equals the mass divided by the volume, when using
this law to measure the density of aggregates the
volume we use is the volume of aggregate + the
volume of the voids, and in this case we get a new
quantity called the Bulk Density.
Bulk Density = Mass of the aggregate \ Volume of
aggregate particles with voids between them.
This bulk density is used to convert quantities by
mass to quantities by volume.
Bulk density depends on several factors: Size
distribution of aggregates, Shape of particles and
degree of compaction.
There are two methods this quantity is measured by:
1- Loose method.
2-Compaction method.
A H M 531
Bulk Density and Specific Gravity
By: Ahmed Essam Mansour
The Civil Engineering Center
1
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But in our experiment we used the loose method
which is described in the procedures.
2. Specific Gravity:
The specific gravity of a material is defined as:
The ratio of a weight of a material of a specific
volume to the weight of water of the same volume.
And we can distinguish two types of specific gravity:
1- Absolute specific gravity:
Where the volume of the material is taken excluding
all pores.
2- Apparent specific gravity:
Where the volume of the material is taken including
the impermeable pores only.
In our study to aggregates we will care only of the
apparent specific gravity.
The specific gravity for the aggregates indicates the
amount of voids inside the aggregate particle itself.
The apparent specific gravity is measured using the
A H M 531
Bulk Density and Specific Gravity
By: Ahmed Essam Mansour
The Civil Engineering Center
2
Visit www.AHM531.com for more lab reports and lecture notes!
