Page 80 - Lecture Notes DCC3113

5.1.4 Differentiate the methods of paving rigid pavement

Mechanised paving allows a higher quality concrete finish to be attained. The spreading,
compacting and finishing of the pavement involves use of a fixed form or slip-form paving train.

Fixed-form

Paving uses steel forms or a preconstructed concrete edge-beam to retain the concrete, using machine
rails to support and guide the individual items of plant utilised in the pavement construction process.A
train of machines, each individually operated, run along the rails, executing the basic tasks of:
i. Spreading the concrete
ii. Compacting it by vibration
iii. Finishing the surface.

Machines for dowel and joint forming that leave the surface of the concrete with the required
texture and the addition of curing compounds may also be included within the process. The machines
themselves may be manually propelled, selfpowered or towed along the rail.

Typical types of machinery used in a fixed-form paving train are:
(1) Feeder – receives concrete as it arrives at the required location
(2) Spreader – distributes the concrete across the full width of the pour in question, discharging it at
a controlled rate
(3) Rotary strike-off paddles and compaction beams – regulate the concrete by trimming any
irregularities in the concrete and vibrate its surface
(4) Dowel/tie-bar placers – place these elements in the appropriate joints either manually or by
vibration
(5) Joint groove formers and finishers –
grooves formed by a knife travelling within
the plastic concrete (wet-formed).
Otherwise, a vibrating blade can be used to
form them when the concrete has hardened
sufficiently
(6) Final finishing equipment – additional
compaction and regulation of the concrete
after the dowel and tie-bars have been put
in place. (Machine uses two oblique
finishing beams oscillating in opposite
directions to achieve a uniform finish to the
surface of the concrete)
(7) Curing compound sprayer
(8) Protective tentage. Figure 5-11: Fixed-form Work

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