Pavement Preservation Journal - Spring 2018 - 31
Research: Longitudinally Textured PCC
Pavement Most Energy-Efficient Surface
University of Nottingham, U.K., point out
that decreasing rolling resistance by
10 percent can save between one and four
percent of a vehicle's fuel consumption.
To reduce energy loss at the
tire-pavement interface, the researchers
examined ways to control the distortion
and compression of tires and pavement.
They note recent studies have shown that
"the stiffness of the uppermost pavement
layer is much more significant than that of
underlying layers, meaning that a stiffer
upper pavement saves energy...additionally, pavement texture indentations into
the viscoelastic tread compound induce
micro-distortional energy loss."
Because traditional testing methods cannot isolate texture-dependent contributions to rolling resistance, the researchers
developed a 3D numerical multiscale model
to analyze the effect of pavement macrotexture on tires. Computer models focused
uel economy is always a critical
consideration for automobile buyers. But tire manufacturers and
pavement researchers are looking
for additional ways to improve fuel economy, conserve fossil fuels and improve the
sustainability of driving.
Rolling resistance-the force of friction
that must be overcome for a tire to move
forward on the pavement-results in small,
constant amounts of energy loss. These
small amounts add up, resulting in fuel
waste. A study published in Tire Technology
International 2017: The Annual Review of
Tire Materials and Tire Manufacturing
Technology outlines the magnitude of the
effect this can have.
Researchers Dmytro A Mansura and
Hartmut J Beckedahl, Pavement Research
Centre, University of Wuppertal, Germany,
and Nicholas H Thom, Nottingham,
Transportation Engineering Centre,
As promoted by IGGA, the NGCS is a diamond saw-cut surface that provides a consistent profile
with a predominantly negative texture, absent of positive or upward texture elements. The surface
resembles a combination of diamond grinding and longitudinal grooving and is created using 1/8 inch
wide longitudinal grooves saw-cut to a depth of 1/8 to 3/16 at 1/2 to 5/8 inch centers. Prior to diamond
grooving, the surface is flush ground with 1/8 inch wide blades with 0.035 inch spacers, resulting in a
very fine, corduroy-like surface finish
heavily on the indentation that occurs when
asphalt aggregate comes into contact with
tire tread. The researchers compared that
situation to modeled concrete pavements.
Rolling resistance predictions were then
made and adjusted for real-life surfaces
based on laboratory testing.
Micro-distortional rolling resistance
values from multiple test scenarios demonstrated that coarser surfaces cause more
energy loss than finer surfaces, and "the
most environmentally friendly texture
(i.e. least energy loss) was the longitudinally oriented concrete surface...This is
reasonable since each strip distributes a
larger force, giving rise to a smaller compression in the tread."
This, of course, would include diamond
saw-cut textures such as conventional
diamond grinding, longitudinal safety
grooving and the Next Generation Concrete
Surface (NGCS), all of which also provide the
benefits of very low noise characteristics.
Because the effect of pavement texture
on rolling resistance is so pronounced, the
researchers hope their modeling methods
can eventually be included in pavement
For more information on diamond
saw-cut surface textures, please visit
PRESERVING PCC PAVEMENTS
The use of conventional diamond grinding,
safety grooving and the Next Generation
Concrete Surface all provide specifiers with
long-lasting surface textures that will help
keep pavements quieter, safer and smoother.
These methods also allow roadways
to be repaired in phases using short lane
closures during off-peak hours. Performing
targeted concrete pavement preservation
is easier on traffic control, as it eliminates
closing whole roadways at once.
And at the end of the preservation
process, the entire area can be diamond
ground to provide a smooth, safe and
Spring 2018 | PAVEMENT PRESERVATION JOURNAL