MANUAL 4 - Construction Industry Development Board

MODULE
1
2
3
4
5
6
7
MANUAL 4 – BITUMINOUS PAVEMENT SEALS
Where:
Column Symbol Description Unit
1 AO Control area to be sprayed (width 3 2 m length) m 2 m 2
A1; A2 etc. Subsequent control areas to be sprayed (width 3 length) m 2 m 2
2 Tc Time calculated to spray control area and subsequent control
areas {(A 3 R)/D} where R is the required application rate
Seconds
3 Ta Actual time for spraying control area and subsequent areas Seconds
4 Ta 3 D Volume of binder applied to the control area and subsequent
control areas, based on pump delivery and spray time
5 Rd Rate of application of binder to control area and subsequent
areas, based on pump delivery and spray time
Litres
Litres/m 2
6 & 7 D1 – D2 Volume of binder sprayed, based on dip readings Litres
8 Ra Rate of application of binder, based on dip readings Litres/m 2
Table 4.2 b: Clarification of symbols
Once the time for spraying control section 1 for the 2 m length of road has been calculated
and sprayed, the clock must be set at zero and the time taken for spraying sections 2, 3,
4 (and 5) must be calculated and the spray operator guided for each section by the time
controller.
The time the spray operator actually takes for each section must be recorded in column 3.
The variation of spray application can be checked by comparing the actual application rate
calculated in column 5, with the design spray rate. The recording of the times in column 3
must be done by a separate operator (recording operator) as it cannot be done by the time
controller.
The dipstick readings are done by using a steel rod calibrated/graduated in 10 litre intervals
up to 210 litres. The amount of emulsion sprayed for each cycle of spraying is recorded in
litres.
The time controller, recording operator and spray operator must work very closely together.
Spraying can only commence after the time controller has zeroed the stopwatch and gives
the signal to start spraying.
The recording operator will mark the separate sections for checking at 2 m intervals and
record the time at the end of each 2 m section that is sprayed. From these readings, a double
check of the accuracy of the work can be established by multiplying the pump delivery D by
the time taken to spray each section.
The spray operator must control his rate of moving the spray lance by listening to the time
controller calling out the seconds required for each 2 m section, using his wrist watch (or
preferably a stopwatch) and bearing in mind the number of seconds he has to cover each
2 m section of road.
IMPLEMENTING EMPLOYMENT INTENSIVE ROAD WORKS 22