MANUAL 4 - Construction Industry Development Board

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MANUAL 4 – BITUMINOUS PAVEMENT SEALS
4. Construction
4.1 Preparation of surface of base
• Sweep the road clean. All loose material and mud that has been brought onto the
surface by traffic must be removed.
• Stake out width of road to be surfaced, marking out the centre and edge of the road
with a chalk line.
• Before any slurry is placed, the spreading team must check and rectify the levels of
the base, before laying the 10 mm thick slurry to give a final thickness of 6 mm for the
slurry surface.
• Place the 10 mm rails along the centre line or quarter points and on edge of the road,
and check the accuracy of the base levels and remove any high spots where a cover of
less than 8 mm is obtained. Isolated low spots can be accommodated with extra slurry,
up to a maximum of 20 mm. Large aggregate in the base can be treated with a 2 kg
hammer to ensure a minimum of 8 mm cover.
• If necessary, lightly spray the surface with a diluted 1: 6 emulsion (1 litre emulsion
to 6 litres water). Normally with an ETB, this should only be necessary if the road has
been exposed to traffic for an extended period. This application of emulsion and water
could be regarded as lightly tacking the surface (only necessary if surface is scuffed
and dry).
• Protect any kerbs, drains, etc. from the emulsion spray. (Photo 4.17)
• Use reinforced paper for the construction joints at the beginning and end of each
spray.
Photo 4.17: Protection of kerbs, drains, etc.
IMPLEMENTING EMPLOYMENT INTENSIVE ROAD WORKS 40