ASPHALTopics | Spring 2018 | VOL 31 | NO 1

3D paving offers
unmatched paving
accuracy
with no strings attached
by James Careless
Compared to other techniques, 3D paving offers unmatched accuracy in providing
consistently smooth paved asphalt surfaces. This incredible accuracy explains why
3D paving is now being used to surface airport runways, high-speed racing tracks,
and playing fields such as the U.S. Bank Stadium in Minneapolis, where the NFL’s
Super Bowl LII was held on February 4, 2018.
3D
paving comes with no strings
attached, literally. This technology
does not rely on stringlines or other
physical reference markers to guide
the laying down of asphalt. Instead,
the 3D paving system uses 3D engineering models of
the site or job files loaded within the paver’s machine
control system in tandem with on-site 3D positioning
systems.
“In a sense, the stringlines become ‘virtual’ on a 3D
paving job site,” says Spencer Wykes, Construction
Technology Specialist with SITECH Mid-Canada Ltd. in
Woodbridge, Ontario. “With the electronic referencing
aids providing the necessary locational information for
the paver’s machine control system, the actual strings
are gone. The savings in time spent setting up stringlines,
and manoeuvring around them in trucks and pavers,
is huge.”
At present, there are two kinds of 3D positioning
systems being used in 3D paving. Both of these
systems constantly match the paver’s position in
three dimensions to the 3D paving job file loaded
into its machine control system.
The first 3D paving locational aid is a highly accurate
millimetre GPS tracking unit that is mounted on the
paver itself. The millimetre GPS unit uses the overhead
constellation of GPS satellites to continuously track
the paver’s latitude and longitude. A series of lasers
holds the system’s elevation to within an accuracy of
+/- 3 millimetres, and supplies the job file data to the
paver’s machine control system. (GPS technology cannot
achieve millimetre precision without some sort of laser
augmentation.) This device works well on job sites where
there are no obstructions that could block reception of
GPS signals, such as overhead bridges and high earthen
or stone walls.
26 OAPC | ASPHALTOPICS