MANUAL 4 - Construction Industry Development Board

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MANUAL 4 – BITUMINOUS PAVEMENT SEALS
After the surface has been rolled once (i.e. a complete coverage of the roller), care must be
taken to cover bare patches, or remove any double layers of aggregate by brooming, to
obtain a single layer shoulder to shoulder.
The first roll must be done without vibration but subsequent rolling, when the aggregate is
properly placed with full coverage obtained, can be done with intermediate vibration of the
roller switched on.
The rolling must be done in straight lines, parallel to the centre line or edges of the road. It is
essential that rolling is done uniformly across the width of the road surface. Typically three
passes should be sufficient to seat the aggregate. (Photo 4.11)
4.5 Application of penetration spray
The remainder of the bitumen emulsion that was not applied in the tack coat, is now sprayed
as a penetration spray.
The same precautions regarding joints and protection of kerbs, drains, etc. apply, as was the
case for the tack coat.
If the surface is left open for any period before applying the penetration spray, the following
must be attended to:
• Any dust, dirt or sand blown into the surface voids, must be removed/blown out with
a compressor.
• The surface must be rolled once to reseat any aggregate that may have been disturbed
by unauthorised traffic.
The road can be opened to traffic once the emulsion has broken.
IMPLEMENTING EMPLOYMENT INTENSIVE ROAD WORKS 30