MANUAL 4 - Construction Industry Development Board

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MANUAL 4 – BITUMINOUS PAVEMENT SEALS
Once the rate of application has been calculated, then the total quantities of aggregate
required for a project can be found.
Length of road (m) 3 breadth of road (m) = Area m 2
Area (m²) 3 Rate of application in m3/m 2 = Area (m 2 ) 3 Rate (m3/ m 2 )
= Volume in m3
Having calculated the volume of aggregate required for the ALD, a percentage must be
added for wastage – 5% under ideal conditions and 10% for severe conditions.
If the stone is placed on a clean surface and all the aggregate can be picked up, the 5% will
cover the wastage, but if the stone is placed on a rough shoulder then it will not be possible
to use all the stone from the stockpile, so 10% must be allowed.
Volume calculated = 100% to allow 5% then
Volume adjusted = 105%
Volume calculated 3 1,05 = Adjusted volume to be ordered
Spotting of aggregate
To obtain a uniform application of aggregate by hand labour, it is necessary to place the
heaps of aggregate in predetermined quantities and at uniform intervals, along the side of
the road to be surfaced. This is known as spotting the aggregate quantities. See Photos 4.13
and 4.14.
Photos 4.13 and 4.14: Spotting of aggregate
The aggregate can be placed in heaps along the side of the road that is to be surfaced. A half
210 litre drum with the bottom of the drum removed and two handles attached to the drum
for ease of handling, can be used for this operation.
The spacing of the aggregate heaps can be calculated as follows:
210/2 (half drum) = 105 litres of aggregate
= 0,105 m 3 (1 000 litres = 1 m 3 )
The application rate (R) = m 3 /m 2
(Assuming that the rate of application is 0.0083 m 3 /m 2 determined from the pan and cylinder
test.)
IMPLEMENTING EMPLOYMENT INTENSIVE ROAD WORKS 34