A
substance used for the purpose of improving the
adhesion between a bituminous binder and the aggregate.
The term generally refers to adhesion in the presence
of water.
Aggregate
A
granular material either natural or processed
from deposits of sand, gravel, rock etc.. Described
as Coarse Aggregate or Fine Aggregate. Refer Coarse
Aggregate or Fine Aggregate.
Anti
Stripping Agent
See
Adhesion Agent
Ascrete
Open
Graded Asphalt with the addition of cement slurry
to provide strong surface resistance to deformation
and oil spillage.
Asphalt
(BC or AC)
A
mixture of bitumen and aggregates (coarse and
fine including sand). Produced as Hot Mix or Cold
Mix. Referred to as BC (Bituminous Concrete) or
AC (Asphaltic Concrete). See also Types N, H,
L, R, T and V.
Asphaltic
Concrete
Refer
Asphalt.
Average
Least Dimension (ALD)
The
average height of the aggregate particles when
they are spread as a single layer with their least
dimensions vertical
Base
Course
A
layer of asphalt below the wearing course.
Batch
Plant/Drum Plant
A
plant used for the manufacture of asphalt. Can
be either a drum mix plant or a batch plant.
Binder
A
material used to bind aggregates. Usually bitumen
and bitumen blends.
Bitumen
A
product of the oil refinery process. Bitumen is
usually stored at approximately 150°C to maintain
it in a liquid form. Used in asphalt and spray
seal applications.
Bituminous
Concrete
Refer
Asphalt.
Blast
Furnace Slag
Refer
Slag.
Bleeding
Is
where the bitumen bleeds to the surface causing
a very smooth, shiny surface.
Bound
Material
A
mixture of fine and coarse aggregates bound together
with bitumen, cement etc..
Brooming
The
use of a broom (normally attached to a tractor)
to remove loose material from the crushed rock
surface prior to laying asphalt or seal.
Bulk
Density
Can
refer to the density of the aggregate or the density
of compacted asphalt. Typically Asphalt is 2.3
to 2.5 t/m³.
Coarse
Aggregate
A
general term for aggregate of such size that it
is substantially retained on a sieve of specified
size, commonly 4.75 mm
Cold
Mix (CM) (Premix/Fullgrade)
An
asphalt which when cold will remain workable for
up to 2 weeks. Contains diesel and kerosene. (Used
for pot holes, general patching, emergency repairs
and temporary road reinstatement.)
Cold
Planing
A
mechanical method of cold milling a pavement surface
to restore the road to a specified grade and profile
by removing corrugations, ruts and other surface
imperfections in preparation for resurfacing.
Compaction
A
process of increasing the density of the Asphalt
by rolling or using other vibrating compactors.
Core
A
sample taken from the compacted asphalt for testing.
Usually for density testing.
Coverage
Refers
to the area (m²) covered by one ton of asphalt
or the volume of seal per square metre.
Cracks
Break
in the surface of the pavement. There are a number
of factors that can cause cracking. Different
types of cracks are; Block, Crocodile, Reflection,
Shrinkage and Slippage.
Crushed
Rock
An
aggregate made from crushed rock, as distinct
from crushed gravel.
Cutter
A
liquid usually kerosene added to bitumen to reduce
it's viscosity. Used in Spray Seal or for priming.
Deep
Strength Asphalt Pavement
A
pavement structure in which the wearing course
and a substantial portion of the base consist
of asphalt.
Deflection
The
vertical movement of a pavement under load. This
is often measured to determine the pavement life
and existing wear rate of the pavement, and can
determine rehabilitation programmes.
Dense
Graded Mix
An
asphalt produced with aggregate that produces
a continual grading. Usually low air voids as
compared with open graded products.
Design
Life
The
design life of the pavement. The amount of traffic
influences the design life.
Double
Seal
A
seal coat (refer seal) consisting of two successive
applications.
Drier
The
section of the plant that heats and dries the
aggregate.
Electric
Arc Furnace Slag
Refer
Slag.
Emulsion
Is
a mixture of water and bitumen used for priming,
sealing and tack coating of asphalt layers. (Refer
Emulsion Prime, Spray Seal Reference Chart.)
Enrichment
Seal
An
application of spraying a bituminous material
of either bitumen and kerosene bituminous emulsion
or formed bitumen to an existing surface to improve
the bonding of the binder and the aggregates (Refer
Spray Seal Reference Chart).
Fatigue
The
deterioration of a pavement or other structure
caused by the action of repetitive vehicle loads
Fatty
Surface
Designated
by areas where the bitumen has bled to the surface.
See also bleeding. Can become soft in hot weather.
Filler
A
fine material, the majority of which passes a
0.075mm sieve, derived from aggregate or other
similar granular material and commonly used in
slurry sealing and asphalt.
Fine
Aggregate
A
general term for aggregate of such size that it
substantially passes a sieve of specified size,
commonly 4.75 mm.
Flexible
Pavement
A
Pavement which obtains its load spreading properties
mainly by intergranular pressure, mechanical interlock
and cohesion between the particles of the pavement
material. In the case of an asphalt pavement,
this further depends on the adhesions between
the bitumen binder and the aggregate, and the
cohesion of the binder. Generally, any pavement
in which high strength Portland cement concrete
is not used a construction layer.
Flushed
Seal
A
seal in which the bitumen has bled to the surface.
See also Bleeding and Fatty Surface.
Flux
A
liquid, normally diesel or oil, added to bitumen
to give a long term reduction in viscosity.
Foamed
Bitumen
Hot
bitumen greatly expanded in volume by the introduction
of steam and water. Can be used for spray sealing
in situ stabilisation (Foamstab) and for production
of Foam mixed aggregate products (Foamix).
Fog
Seal
Refer
Enrichment Seal.
Friction
Course
A
specialised wearing course constructed of Open
Graded Asphalt.
Full
Depth Asphalt Pavement
A
pavement in which asphalt is used for all courses
above the subgrade or improved subgrade.
Gap
Graded Aggregate
A
graded aggregate in which one or more of the intermediate
sizes are absent
Grading
Aggregate
The
quantities of the various particle sizes present
in a mineral aggregate, expressed as a percentage
by mass of the whole. Also referred to as particle
size distribution.
Granular
Pavement
Refer
Flexible Pavement.
Grit
Small
size aggregate 5mm or less.
Harsh
Refers
to an asphalt mix that is difficult to compact
and handle.
Heavy
Duty Pavement
Pavement
designed for heavy traffic volumes and heavy loads.
Hot
Mix
Refer
Asphalt.
Intermediate
Course
Any
layer between the wearing course and the base.
Levelling
Course
See
Regulating Course
Light
Duty Pavement
Pavement
designed for low traffic volumes and light loads.
Lock
Down Seal
A
reseal to prevent further loss of aggregate if
original seal is experiencing aggregate loss.
Normally 5mm or 7mm aggregate applied.Also referred
to as Pin Down Seal.
Macadam
Refers
to a pavement type generally consisting of large
single size aggregate with a surface layer of
smaller material with or without binder to lock
the surface together. Can be either a bitumen
based or water based Macadam Pavement.
Mastic
Asphalt
A
mixture of bitumen and fines that can be used
for waterproofing in building and industrial applications.
Maximum
Density
The
maximum density that could be achieved in a sample
of asphalt if it were possible to compact it so
as to exclude all air voids between coated aggregate
particles (also know as void-free density)
Microsurfacing
A
bituminous slurry surfacing, usually containing
polymer, which is capable of being spread in variably
thick layers for rut-filling and correction courses,
and for wearing course applications requiring
good surface texture.
Mixing
Plants
Refer
Batch Plant.
Modified
Asphalt
An
asphalt where a binder has been modified by the
addition of rubber, polymers, fibres etc.. for
specific applications.
Nominal
Size
A
size designation of an aggregate that which gives
an indication of the largest particle size present.
Nuclear
Density Meter
An
instrument for the non-destructive determination
of the density and moisture content of material
using a radioactive source for its operation.
Open
Graded Asphalt (Open Graded Friction Coarse)
Asphalt
with a high percentage of air voids. Used in the
wearing course to reduce surface water and traffic
noise and to provide a higher skid resistance.
Normally one size.
Overlay
The
addition of a layer over an existing pavement.
Can be asphalt or crushed rock. Also referred
to as resheeting.
Particle
Size Distribution
See
grading.
Pavement
The
portion of the road, excluding shoulders, placed
above the design subgrade level for the support
of, and to form a running surface for, vehicular
traffic.
Pavement
Distress
The
deterioration of the pavement evidenced by visible
surface defects.
Paver
A
machine used to spread asphalt (or crushed rock)
to uniform thickness and a level surface.
Polished
Aggregate Friction Value (PAFV)
A
measure, on a scale of 0 to 100, of the resistance
of an aggregate to polishing under the action
of traffic as determined in standard laboratory
tests.
Polished
Stone Value (PSV)
A
measure, similar to PAFV, but based on a British
Standard.
Polymer
Modified Bitumen (PMB)
A
binder consisting of polymeric materials dispersed
in bitumen with enhanced binder performance for
particular applications.
Precoating
The
coating of aggregate with a liquid to improve
adhesion with the bituminous binder and the aggregate.
PreMix
Refer
Cold Mix.
Prime
An
application of a primer to a prepared base, without
cover aggregate, to provide penetration of the
surface, temporary waterproofing and to obtain
a bond between the pavement and the subsequent
seal or asphalt. It is a preliminary treatment
to a more permanent bituminous surfacing.
Primer
A
bituminous material of low viscosity and low surface
tension used in priming.
Primer
Binder
A
material more viscous than a primer and required
to act both as a primer and binder, and used in
primersealing.
Primer
Seal
An
application of a primerbinder with a fine cover
aggregate to a prepared base to provide penetration
of the surface and retain a light cover of aggregate.
It is used as a preliminary treatment to a more
permanent bituminous surfacing. It is intended
to carry traffic for a longer period than a prime.
Profile
Refers
to shape of the road in cross section.
Profiler
Refer
Cold Planing.
Pugmill
A
device for mixing aggregate, sand and binder.
Quarry
Fines
Refer
Glossary of Terms Quarry and Sand Products.
R-(Type)
Refer
Type R.
RAP
See
reclaimed asphalt pavement
Ravelling
The
loosening of stones from the surface of a pavement.
Recycling
The
reuse of paving material. Processes include Hot
and Cold and can be insitu or off site.
Regulating
Course
An
asphalt course of varying thickness applied to
a pavement surface to adjust its shape preparatory
to overlaying with another course or applying
a sprayed seal.
Rehabilitation
The
process of restoring a distressed pavement, e.g..
overlay, patching.
Reseal
A
seal over an existing bituminous surface. Refer
Spray Seal reference chart.
Residual
Binder
A
binder that remains in service after any volatiles
have evaporated.
Rigid
Pavement
A
pavement which is designed with minimal deflection,
i.e.. concrete pavement.
Roadbase
A
term used to describe crushed rock or natural
gravel used in road construction.
Roller
An
item of equipment used for compacting pavement
material.Types include pneumatic (multi), static,
steel or vibrating.
Roto
Milling
Refer
Cold Planing.
Rubber
Seal
A
seal with a polymer (rubber) modified binder (refer
seal).
Rubberized
Asphalt
An
asphalt in which the binder consists of bitumen
modifed by the incorporation of rubber, either
natural or synthetic or suitable polymer, which
helps resist fatigue of asphalt.
Rubberized
Bitumen Seal
A
sprayed seal where the binder consists of bitumen
modified by the incorporation of rubber, either
natural or synthetic. See also polymer modified
bitumen, SAM and SAMI.
Rutting
The
deformation of the pavement surface generally
in the wheel path.
Sand
Asphalt
Asphalt
consisting of bitumen and sand.
Screed
Part
of the paver that levels and shapes the asphalt
during placing.Also refers to a hand held wooden
leveling device.
Seal
A
process of spraying bitumen followed by the spreading
and rolling of aggregate (refer Spray Seal).
Segregation
Asphalt
where the coarse aggregate has separated from
the fines.
Shoulder
The
outside section of the pavement which is generally
not trafficked.
Shoving
Movement
of the pavement generally caused by heavy traffic.
Single
Size Aggregate
An
aggregate having a major proportion of particles
lying between narrow size limits.
Skid
Resistance
The
measurement of the resistance of a pavement surface
to skidding.
Slag
Byproduct
of steelmaking, crushed and screened as aggregate.
Slurry
Seal
A
road surface treatment involving the application
of a mixture of fine aggregate (5mm or 7mm) and
emulsion in the form of a slurry over an existing
pavement.
Spray
Seal
A
process of spraying bitumen followed by the spreading
and rolling of aggregate (ranging from 5mm to
20mm) which adheres to the bitumen to form a final
trafficable surface. Can be placed directly over
the prime, previous seal (rehabilitation), asphalt
or crushed rock.
Stabilize
The
addition of a material e.g.. cement, lime, fines
etc. to improve the characteristics of the original
material.
Stone
Mastic Asphalt (SMA)
Asphalt
with special grading and binders to produce high
rutting resistance.
Strain
Alleviating Membrane Interlayer
A
modified bituminous layer applied immediately
below the wearing course to absorb reflective
cracking from the underlying layers.
Stripping
The
loss of aggregates from a sprayseal surface or
the loss of binder from the surface of the aggregate
in asphalt.
Subbase
The
material placed immediately over the subgrade.
Subgrade
Refer
Subgrade, Glossary of Terms, Quarry and Sand Products.
Surface
Coarse
See
wearing course.
Tack
Coat
The
spraying of a binder such as bitumen or emulsion
as a thin film to improve the adhesion between
layers of asphalt.
Tar
Residue
obtained from distillation of coal. Sometimes
incorrectly used to describe bitumen or asphalt.
Tar products are no longer used in road making.
Tender
Mix
An
asphalt mix that moves easily and is susceptible
to rutting by traffic.
Two
Coat Seal
A
seal coat consisting of two successive application.
Refer Spray Seal reference chart.
Unbound
Base
A
material which has not had a binder added e.g..cement
or bitumen.
Viscosity
A
measure of the consistency of resistance to flow
of a material, normally specified for bitumen
by Class i.e.. Class 320.
Void-free
Density
Refer
Maximum Theoretical Density.
Wearing
Course
That
part of the pavement upon which traffic travels.
