Experiment-3 Using The Weighing in Water Method To Determine Particle Density and Water Absorption of Coarse Aggregate
Experiment-3 Using The Weighing in Water Method To Determine Particle Density and Water Absorption of Coarse Aggregate
Experiment-3 Using The Weighing in Water Method To Determine Particle Density and Water Absorption of Coarse Aggregate
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Experiment-3 Using the weighing in water method to determine particle density and
water absorption of coarse aggregate
Objective:
The aim of this experiment is to determine the absorption of water as well
as the density of coarse aggregate particles of size 10mm by using the
method of weighing in water. A sample of aggregate is tested and the
results from the experiment are used to calculate the apparent particle
density and water absorption. All procedures and formulas used in
conducting the experiment and retrieving results were obtained using the
Australian Standards AS1141.6.1-2000.
Procedure
(a)Tare the scale, put the empty container on it, tare it again then
measure two kilograms of aggregate in a container (m1).
(b)Attach the wire mesh basket to the hook underneath the scales using
the handle on the basket and note the weight (w2).
(c) Put the weighted two kg of aggregate in the wire mesh basket then
wind up platform of the specific gravity frame containing the water
bath until the wire mesh basket is completely covered by the water to
a depth of at least 50mm below the surface. Note the reading on the
scale (w2).
(d)Allow for water absorption and again note the reading on the scale.
(e)Wind down the platform and allow water to drip from the mesh basket
then tip the aggregate onto dry towels and rub the aggregate dry.
Allow for a small amount of moisture covering on the aggregate.
Weigh the damp aggregate (m2).
Figure 2 Wire mesh basket being weighed
m 1∗Ꝿ W
ꝾA= m1−(w 1−w 2)
Where
2000∗0.997992
ꝾA= 2000−(1963−738.9)
ꝾA=2.57 t/m3
( m2−m1 )∗100
WA=
m1
Where
( 2000−1990 )∗100
WA=
1990
WA =0.5%
Figure 3 Lab 3 results
Precautions:
Tare the container so as not to include its weight in that of the
aggregate.
Soaking the sample in a water bath allowed for the filling of pores within the
rock while weighing it in water enabled the elimination of air spaces from
the sample’s weight and provided a moist covering around the particles.
This immersion provided a clearer comparison between the water density
itself and the submerged sample density. A higher density result is
obtained from the experiment due to filling of some pores and the moisture
present on the aggregate surfaces as opposed to a lower value for dry
density when all pores are full of air and no moisture is present.
Conclusion:
The soil sample absorbed some water into it at a very low percentage of
0.5%. This could have been due to the fact that the sample was of granite
rock or because it was simply not immersed for a long enough period to be
able to absorb a more significant amount of water. In a larger sample
however, this 0.5% could prove to be a huge amount of water absorbed.
The higher particle density obtained from the experiment was also to be
expected since all pores and surfaces are filled with water when immersed
in a water bath.
Overall Conclusion:
The aggregate impact value obtained from the experiment was 21.67%
which lies between (10-30) % and from this we came to know that impact
value is satisfactory for road surfacing.
From Los Angeles experiment our los angles value is 48.4%, but American
association of state highway and transportation organization(AASHTO)
states that los angles value should not be greater than 40%.but in our case
it is 48.4%,hence the aggregate is not suitable for pavement design.
Reference:
Standard AS 1141.23 – 2009: Determination of Aggregate Value. – Method
23: Los Angeles Value.