Prestudy Paver Training

1
Prestudy Paver Training Wardenburg 17-18
February 2009 Dipl.-Ing. (FH) Volker
Behrens Volker.Behrens_at_dynapac.com Dipl.-Kfm.
Roland Egervari Roland.Egervari_at_dynapac.com
2
Introductory questions

• Describe the main part of the paver and the
  material distribution process.
• Give a short definition for the floating screed
  principle.
• Which factors influence the floating property of
  the screed?
• Define the purpose of the screed load unload
  systems
• What is the purpose of the tamper? Why do we need
  vibration in the screed bottom plates?
• How do we define angle of attack?
• Specify at least 3 USPs for the new Dynapac
  VB510/600 screeds.
• Levelling
• What is the difference between a GRADE and SLOPE
  controller?
• What does the expression modular means in
  connection with the MOBA-Matic levelling system?
• Name 3 major differences between Dynapac and
  Svedala Demag pavers
• Define the Compactasphalt method and its
  advantages

3
Paving in general Main parts of the paver
Canopy
Foldable hopper
Engine hood
Remote control and screed operator position
Conveyor
Screed
Crawler direct drive
Push roller
Levelling arm
Crawler
4
Material Conveying and Distribution Material
Flow

1. A lorry or other kind of feed vehicle dumps the
   material mix in the hopper.
2. The conveyor belts transport the mix to the rear
   wall of paver.
3. One auger for each side distributes the material
   mix across to the paving direction in front of
   the screed to the complete paving width.
4. Paving speed, paving width and thickness are
   fundamental factors of the required material
   quantity. Sensors at the rear wall in top of the
   conveyor belt and the auger take care of a
   controlled, continuous material flow. The bulk in
   front of the screed is significantly responsible
   for a constant result. The head of the material
   in front of the screed must be constant.

5
Material Conveying and Distribution Material
Supply
6
Screed Free Floating Screed
G
Z
a
W
A
A Buoyancy (upward force from the asphalt) G
Weight of the screed W Resistance from the
head of the material W1 Friction between the
screed plate and the material Z Traction power
A number of forces act on the screed, The force Z
is the tractor unit moving the screed forward and
the forces W and W1 are the resistance from the
head of material and the friction between screed
plate and the asphalt respectively. G is the
weight of the screed and A is the upward force
from the asphalt. A depends on the angle of
attack (a) and the speed of the paver. The layer
thickness is determined by adjusting the
tow-point on the tractor unit.
The angle between the bottom plate of the screed
and the surface being paved is known as the angle
of attack.
7
 
Screed Free Floating Screed

• Forces that influence the balance of the screed
• The screed rises if
• the head of material increases
• the speed of the tractor increases
• the material temperature drops
• The screed settles if
• the head of the material decreases
• the speed of the tractor unit decreases
• the material temperature increases
• The height of the screed remains constant only if
  all forces acting on the screed are in
  equilibrium.

Material bulk in front of screed to high.
Material bulk in front of screed to low.
Auger correct adjusted and material bulk in front
of screed optimal.
7
8
Screed STOP LOAD UNLOAD systems
Screed - Screed Control
Screed stop system This system automatically
locks the screed lift arms when the paver stops
during a paving operation.
Screed unload system This system prevents the
screed from sinking into the material by laying
of extremely soft materials or by traction
problems (controlled by an adjustable hydraulic
pressure on the screed lifting cylinder).
The screed side arms are attached to the
hydraulic levelling cylinders which control the
level of the screed. The tow-point position
affecting the layer thickness.
Screed load system The system provides additional
load to the screed and enables it to maintain the
desired level after a long stoppage (controlled
by an adjustable hydraulic pressure on the screed
lifting cylinder).
The screed lifting cylinder are not active during
the normal paving procedure. Only in function by
screed load unload control.
9
Screed Tamper Vibration

• Vibration
• Compaction effect
• Reduces the friction between screed plate and
  asphalt mix
• Screed floats more easily over the material
• Bitumen raises to the asphalt surface providing
  additional lubrication enhancing the surface
  structure

The tamper facilitates the flow of material
underneath the screed plate. The tamping
mechanism uses a vertical, high-amplitude
movement at comparatively low frequencies.
10
Screeds
New VB 510T(V) / EB 51
New VB 600T(V) / EB 60

1. Low height of construction ? Better view in the
   auger section (head of material)
2. Unique, patented telescopic system
3. 380 mm screed bottom plate depth
4. Excentric lever for the adjustment of the angle
   of attack (next slide)
5. Quick height adjustment for the hydraulically
   extendable parts

11
Screed - Free Floating Screed
Layer thicknesses Position I lt 7 cm Position
II lt 7 cm 14 cm Position III gt 14 cm
Quick adjustment
The angle between bottom plate of screed and
sub base is called angle of attack. By changing
of the position from quick adjustment lever, the
angle of attack will be increased or decreased.
12
Levelling Automatic Levelling System
A grade controller, working off a reference
surface, automatically maintains the height of
the screed and the layer thickness for the
material
Laser Sender LS-250
Digital Remote Control
Ultra-Sonic Sensor SONIC-SKI

• Modular construction
• Regulator automatically recognises the
  connected sensor

Rotary Sensor DIGI ROTARY
Slope Sensor DIGI-SLOPE
The slope controller maintains the specified left
and right-hand cross-slope of the mat during the
laying procedure. It detects any deviations of
the screed from a pre-set cross-slope and
generates the necessary signals to restore the
original setting.
Laser Scanner RSS
3-D Levelling Control System
13
Levelling Automatic Levelling System
Slope Sensor
The slope controller maintains the specified left
and right-hand cross-slope of the mat during the
laying procedure. It detects any deviations of
the screed from a pre-set cross-slope and
generates the necessary signals to restore the
original settings.
14
Brand specific features / Dual branding
15
Brand specific features / Dual branding
Auger drive
Auger drive
16
Brand specific features / Dual branding
Delta crawler
crawler
17
Brand specific features / Dual branding
Hopper design
Hopper design
18
Brand specific features / Dual branding
Canopy type
Canopy type
19
Compactasphalt - Definition
The method was developed in cooperation with the
company Hermann Kirchner GmbH Co. in Bad
Hersfeld and Prof. Dr.-Ing. Elk Richter from the
University of Applied Sciences in Erfurt, to
reliably achieve paving a thin wearing course
with high compaction. According to the German
fact sheet MKA, the Compactasphalt method allows
the laying of the wearing and binder course in
one single process hot on hot, whereas the binder
course is highly pre-compacted and the rolling
process of both layers is carried out in one
single operation. Due to the modular design of
the paver unit, no heavy vehicle has to pass over
the hot binder course.  
20
Compactasphalt - Advantages

• Halved construction time
• Cost savings due to halving of the expensive
  wearing course
• Excellent interlocking of the courses
• Extended time for compaction
• By increasing the laying thickness from 4 cm to
  12 cm, the compaction time is extended 7 times!
• Certified laying process according to the German
  Rule compendium ZTV Asphalt-StB 07
• Asphalt laying at 0C is possible

21
Driven by innovation committed to customer
performance