PAVING MATERIALS
MODULE 5
Pavement Design Terms
and Concepts
Technically, what is a pavement?



“Black Top” or “Tarvy” ?
“to pave” means “to cover with
asphalt, gravel, concrete, macadam,
etc.”
A surface ?
Why build pavements?
Transportation
Originally, footpaths sufficed
 Increasing traffic and loads

Quality
John
Issues: drainage,
subgrade materials
Macadam,
1756 - 1836
5.01 Define the term pavement as it is
given by the MTO's Pavement Design
and Rehabilitation Manual .

"Pavements are layered structures of
selected and processed materials
which have been designed to resist
surficial wear, to support wheel loads
and provide drainage of water."
PAVEMENT TYPES
5.02 Identify the various pavement types
according to the following three
classification methods:
a) Surface Type
b) Load Transmission
c) Composition
a) Surface Type:
Bound or Unbound
b) Load Transmission
FLEXIBLE
40 kN Load
RIGID
40 kN Load
Typical deflection signatures
Stress is
transmitted
through bound
surface layer to
underlying
granular layers
Bound surface (slab)
distributes stress over a
broader area, thus
reducing the amount of
stress transmitted to
underlying material
c) Composition: Type of materials used
and arrangement/installation technique
 Portland Cement Concrete (PCC)

Asphalt Cement Concrete (Hot or Cold Mix)

Surface Treatment

Mulch
5.03 Identify the 3 key components
to a pavement structure.

SURFACE

GRANULAR BASE

GRANULAR SUBBASE
5.04 List the 4 functions of bituminous
surface materials.

provides resistance to surface wear

reduces surface water infiltration

provides a smooth and rideable finish

provides structural support to wheel loads
5.05 Identify the two broad classes of
asphalt pavement surfaces and give
examples for each.
MIX SYSTEMS
 Hot and Cold Mixed Asphaltic Concrete
 Hot and Cold Mixed Stabilized Base
 Recycled Hot and Cold Mixed Asphaltic
Concrete
 Travel Plant Mixes (cold)
 Slurry Seal
LAYERED SYSTEMS
 Penetration Primer
 Surface Treatment
 Macadam
5.06 Describe the materials and
manufacture of Hot Mix Asphaltic
Concrete.
Materials:
 a mixture of fine and coarse aggregate with
asphalt cement
Manufacture:
 components are heated and mixed in a central
plant
 mixture is hauled to site in special trucks and
placed on the road using an asphalt spreader
Manufacture (Continued):
designed, manufactured and placed within
specified tolerances for use on high traffic
volume roads
5.07 Identify the use(s) of the following
MTO designations: HL 1, 2, 3, 4 and 8;
HL 3 Fine; HL 3, 4 and 8 Modified;
Heavy Duty Binder; DFC; OFC; and
Electrically Conductive Mix.
These MTO mixes are described in Table 5.01
5.08 Describe the materials and
manufacture of Cold Mix Asphaltic
Concrete.
Materials:
 a mixture of emulsified asphalt or liquid
(cutback) asphalt and aggregate
Manufacture:
 components are mixed at ambient air
temperature
 can be mixed in a central plant or in-situ on the
road surface with a travelling mixer such as the
Midland Mix Paver or road mix mulch
pavements
Manufacture (Continued):
aggregate and emulsified asphalt are delivered
to Midland Mix Paver separately and blended in
a pug mill
augers distribute mixture to a screed which
uniformly controls the thickness of the cold mix
layer
once the emulsified asphalt in the mixture
surface starts to break or set, the mixture is
compacted
use in Ontario generally restricted to low
volume rural roads, where HMAC surfaced
pavements are not required
5.09 Describe the materials used
and general placement method for
Surface Treatments.

consist of an application of emulsified or liquid
asphalt and select aggregate over a prepared
granular base or existing surface
5.10 List the reasons for applying surface
treatments to:
a) granular road surfaces, and
b) existing surface treatments or asphaltic
concrete
a) to control water
b) to restore frictional
infiltration, provide
resistance and reduce
frictional resistance,
water infiltration
improve ride quality &
control dust and stone
pick-up
in general, on light to medium volume roads
5.11 Describe the materials/placement
and primary application for: Mulch
Pavements, Slurry Seals, Fog Seals,
Primers, Tack Coats and Granular
Seals.

These treatments are described in Table 5.02
5.12 Identify the origin of asphalt
cement and the MTO grade
specifications (test and designations).



the majority of asphalt cements come from
petroleum distillation as do liquid (cutback)
asphalts and asphalt emulsions (see next slide)
MTO has graded asphalt cements by standard
penetration number (PEN); eg: 85/100
(hardest), 150/200, 300/400, 500+ (softest)
SUPERPAVE is a new mix design method that
replaces this grading system
Atkins, 2nd Ed.
5.13 Describe the 2 conflicting
problems related to asphalt cement
grade faced in Ontario.

if a soft grade is used then rutting is a problem
in the hot summers
Before:
After:

if a hard grade is used then low temperature
(transverse) cracking is a problem in the winter