DETERMINATION OF COMPACTED / RODDED BULK DENSITY AND VOIDS: FINE & COARSE AGGREGATES
Relevant IS Code – IS: 2386 (Pt. – III) – 1963
Bulk
density or unit weight is the weight of material in a given volume. It is
normally expressed in kg/liter.
A cylindrical measure preferably machined to
accurate internal dimension is used for measuring bulk density. The size of the
container for measuring bulk density is shown as under:
Size of
Container for Bulk Density Test
Size of Largest Particles
|
Nominal Capacity
(liter)
|
Inside Diameter
(cm)
|
Inside Height
(cm)
|
Thick. of Metal
(mm)
|
4.75 mm and under
|
3
|
15
|
17
|
3.15
|
Over 4.75 mm to 40 mm
|
15
|
25
|
30
|
4.00
|
Over 40 mm
|
30
|
35
|
31
|
5.00
|
The cylindrical measure is filled about 1/3 each time with
thoroughly mixed aggregate and tamped with 25 strokes by a bullet ended tamping
rod, 16 mm diameter and 60 cm long.
The measure is carefully struck off level
using tamping rod as a straight edge. The net weight of the aggregate in the
measure is determined and the bulk density is calculated in kg. / Liter.
\[{D.L.B.D.} = {{ Weight ~of~ loose ~aggregate ~in~ the~ mould} \over {Volume~ of~ mould} }\] \[{Percentage ~of ~voids} = {{ G_{s} – Y} \over {G_{s}} }\] \[Where,\] \[G_{s} = ~Specific ~gravity~ of~ aggregates \] \[ Y = DLBD~ in ~kg / ~liter. \]
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