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Asphalt Glossary
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Z
A
AASHTO - The American Association of State Highway and Transportation
Officials. An or anization of highway engineers from the
50 states that develops guides and standards.
AGGREGATE - Any hard, inert, mineral material used for mixing
in graduated fragments. It includes sand, gravel, crushed
stone, or slag.
ASPHALT - A dark brown to black cementitious material that
can be solid, semi-solid, or liquid in consistency, in which
the predominant constituents are bitumens that occur in nature
as such or are obtained as residue in refining petroleum.
Asphalt is a constituent in varying proportions of most crude
petroleums.
ASPHALT BASE COURSE - A foundation course consisting of
mineral aggregate, bound together with asphaltic material.
ASPHALT BINDER COURSE - An intermediate course between a
base course and an asphalt surface course. The binder course
is usually a coarse-graded aggregate Asphalt Concrete containing
little or no mineral matter passing through a No. 200 sieve.
ASPHALT CEMENT (AC) - Asphalt that is refined to meet specifications
for paving, industrial, and special purposes. Its penetration
is usually between 40 and 300.
ASPHALT CONCRETE - High quality, thoroughly controlled hot
mixture of asphalt cement and well-graded, high quality aggregate,
thoroughly compacted into a uniform dense mass typified by
the Missouri Department of Transportaion Type B and C and
Superpave mixes.
ASPHALT INTERMEDIATE COURSE - A course between a base course
and asphalt surface course. Sometimes called binder course.
ASPHALT JOINT FILLER - An asphaltic product used for filling
cracks and joints in pavement and other structures.
ASPHALT OVERLAY - One or more courses of asphalt construction
on an existing pavement. The overlay generally includes a
leveling course to correct the contour of the old pavement,
followed by a uniform course or courses to provide needed
thickness.
ASPHALT PAVEMENTS - Pavements consisting of a surface course
of mineral aggregate coated and cemented together with asphalt
cement on supporting courses such as asphalt bases; crushed
stone, slag, or gravel.
ASTM - The American Society for Testing and Materials. A
national organization of users and producers of materials
that establishes standards.
ASPHALT SOIL STABILIZATION (Soil treatment) - Treatment
of naturally occurring nonplastic or moderately plastic soils
with liquid asphalt at normal temperatures. After mixing,
aeration and compaction provide water resistant base and
subbase courses with improved load-bearing qualities.
ASPHALT SURFACE TREATMENTS Applications of asphaltic materials
to any type of road or pavement surface, with or without
a cover of mineral aggregate that produces an increase in
thickness of less than I inch.
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B
BASE COURSE - The layer of material immediately beneath
the surface or intermediate course. It may be composed of
crushed stone; crushed slag; crushed or uncrushed gravel
and sand; or combinations of these materials. It also may
be bound with asphalt (asphalt base course).
BINDER COURSE - A transitional layer of bituminous paving
between the base and the surface course.
BORROW - Suitable material from sources outside the roadway
prism used primarily for embankments.
BITUMINOUS CONCRETE - A designed combination of graded crushed
stone, filler, and bituminous cement mixed in a central plant,
laid and compacted while hot.
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C
CBR (California Bearing Ratio) - A measurement of the strength
and support value of a crushed stone base or subgrade soil.
CAPILLARY ACTION - The rise or movement of water in the
voids of a soil caused by capillary forces.
CEMENT-TREATED BASE - Cement-treated base consists of specified
soil aggregates and Portland Cement Concrete mixed in a pug
mill and deposited on the subgrade to the specified thickness.
COAL TAR SEAL - Coal tar sealer shields asphalt surfaces
from the damaging elements of weather and protects against
the harmful effects of chemicals and petroleum products.
Coal Tar shall meet Federal specification R-P355e and ASTM
Specification D-3320.
COARSE AGGREGATE - Aggregate particles retained on a No.
8 sieve.
COARSE GRADED AGGREGATE - An aggregate having a continuous
grading in size of particles from coarse through fine with
a predominance of coarse sizes.
COMPACTION - The densification of crushed stone base, subgrade
soil, or bituminous material by means of vibration or rolling.
CONTRACT - The written agreement executed between the contractor
and other parties, setting forth the obligations of the parties
thereunder; including, but not limited to the performance
of the work, the furnishing of labor and materials, and a
basis of payment.
CONTRACTOR - The individual, partnership, corporation, or
joint venture contracting for performance of prescribed work.
CRUSHED STONE - The product resulting from the artificial
crushing of rocks, boulders, or large cobblestones with the
particles resulting from the crushing operation having all
faces fractured.
CRUSHER RUN - Aggregates that have received little or no
screening after initial crushing operations. Crusher run
aggregates are generally more economical than screened aggregates.
CUL-DE-SAC - An area at the terminus of a dead-end street
or road constructed for the purpose of allowing a vehicle
to turn around.
CULVERT - Any structure that is not classified as a bridge
and that provides an opening under any roadway.
CUT - The portion of the roadway formed by excavation below
the surface of the earth.
CUTBACK ASPHALT - Asphalt cement that has been liquefied
by blending with petroleum solvents. Upon exposure to atmospheric
conditions, the solvents evaporate, leaving the asphalt cement
to perform its function
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D
DEEP LIFT ASPHALT PAVEMENT - A pavement in which the asphalt
base course is placed in one or more lifts of 4 or more inches
compacted thickness.
DESIGN THICKNESS - The total pavement structure thickness
above the subgrade.
DENSE GRADED AGGREGATE - A mineral aggregate uniformly graded
from the maximum size down to and including sufficient mineral
dust to reduce the void space in the compacted aggregate
to exceedingly small dimensions approximating the size of
voids in the dust itself.
DRAINAGE - Structures and facilities for collecting and
carrying away water.
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E
EARTHWORK - The work consisting of the construction of the
roadway, excluding bridges, pavement structure, and selected
capping material.
EMBANKMENT - A structure of soil, soil aggregate, or broken
rock between the embankment foundation and the subgrade.
EMULSIFIED ASPHALT - An emulsion of asphalt cement and water
that contains a small amount of an emulsifying agent, a heterogeneous
system containing two normally. immiscible phases (asphalt
and water), in which the water forms the continuous phase
of the emulsion and minute globules of asphalt form the discontinuous
phase. Emulsified asphalts may be either anionic, electro-negatively-charged
asphalt globules or cationic, electro-positively-charged
asphalt globules, depending upon the emulsifying agent.
EQUIPMENT - All machinery, tools, and other apparatus, together
with the necessary supplies for upkeep and maintenance, needed
for the proper construction and acceptable completion of
the work.
EROSION - Removal and transportation of soil by the action
of water or wind.
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F
FINE AGGREGATE - Aggregate particles passing a No. 8 sieve.
FINE GRADED AGGREGATE - An aggregate having a continuous
grading in sizes of particles from coarse through fine with
or predominance of fine sizes.
FLEXIBLE PAVEMENT - A pavement structure that maintains
intimate contact with and distributes loads to the subgrade
and depends on aggregate interlock, particle friction, and
cohesion for stability. Asphalt or bituminous concrete pavements
are flexible pavements; concrete is not.
FOG SEAL - A light application of liquid asphalt without
mineral aggregate cover. Slow-setting asphalt emulsion diluted
with water is the preferred type.
FREE WATER (GROUNDWATER) - Water that is free to move through
a soil mass under the influence of gravity
FRENCH DRAIN - A trench loosely backfilled with stones,
the largest being placed on the bottom with the size decreasing
toward the top.
FULL-DEPTH ASPHALT PAVEMENT - An asphalt pavement in which
asphalt mixtures are employed for all courses above the subgrade
or improved subgrade. A full-depth asphalt pavement is laid
directly on the prepared subgrade.
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G
GRAVEL - A coarse granular material (usually larger than
1/4 inch in diameter) resulting from the natural erosion
and disintegration of rock. Crushed gravel is the result
of artificial crushing with most fragments having at least
one face resulting from fracture.
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H
HYDROSTATIC PRESSURE - The pressure in a liquid under static
conditions; the product of the unit weight of the liquid
and the difference in elevation between the given points
and the free water elevation.
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I
IMPROVED SUBGRADE - Any course or courses of select or improved
material between the foundation soil and the subbase is usually
referred to as the improved subgrade. The improved subgrade
can be made up of two or more courses of different quality
materials.
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L
LEVELING COURSE - An asphalt/aggregate mixture of variable
thickness used to eliminate irregularities in the contour
of an existing surface before superimposed treatment or construction.
LIQUID ASPHALT - An asphalt material having a soft or fluid
consistency that is beyond the range of measurement by the
normal penetration test, the limit of which is 300 maximum.
Liquid asphalts include cutback asphalt and emulsified asphalts.
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M
MATERIALS - Any substances specified for use in the construction
of the project and its appurtenances.
MEDIUM CURING ASPHALT (MC) - Liquid asphalt composed of
asphalt cement and a kerosene-type diluent of medium volatility.
MINERAL DUST - The portion of the fine aggregate passing
a No. 200 sieve.
MINERAL FILLER - A finely divided mineral product at least
65 percent of which will pass a No. 200 sieve. Pulverized
limestone is the most common manufactured filler, although
other stone dust, hydrated lime, Portland cement, and certain
natural deposits of finely divided mineral matter are also
used.
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N
NATURAL ASPHALT - Asphalt occurring in nature that has been
derived from petroleum by natural processes of evaporation
of volatile fractions leaving the asphalt fractions. The
native asphalts of most importance are found in the Trinidad
and Bermudez Lake deposits. Asphalt from these sources is
called Lake Asphalt.
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O
OPEN GRADED AGGREGATE - An aggregate containing little or
no mineral filler or in which the void spaces in the compacted
aggregate are relatively large.
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P
PAVEMENT STRUCTURE (COMBINATION OR COMPOSITE) - All courses
of selected material placed on the foundation or subgrade
soil, other than any layers or courses constructed in grading
operations. When the asphalt pavement is on an old Portland
Cement Concrete base or other rigid-type base, the pavement
structure is referred to as a combination or composite-type
pavement structure.
PERCOLATION - The movement of free water through soil.
PERMEABILITY - A measure of the rate or volume of flow of
water through a soil.
PETROLEUM ASPHALT - Asphalt refined from crude petroleum.
PLANS - The standard drawings current on the date bids are
received; and the official approved plans, profiles, typical
cross sections, electronic computer output listings, working
drawings and supplemental drawings, or exact reproductions
thereof, current on the date bids are received; and all subsequent
approved revisions thereto, which show the location character,
dimensions, and details of the work to be done.
PLANT MIX - A mixture produced in an asphalt mixing plant,
that consists of mineral aggregate uniformly coated with
asphalt cement or liquid asphalt.
PORTLAND CEMENT CONCRETE (PCC) A composite material that
consists essentially of Portland cement and water as a binding
medium in which is mixed coarse and fine particles of crushed
stone.
PRIME COAT - An application of lowviscosity liquid asphalt
to an absorbent surface. It is used to prepare an untreated
base for an asphalt surface.
PROPOSAL - The offer of a bidder, submitted on the approved
official form, to perform the work and to furnish the labor
and material at prices set forth therein, valid only when
properly signed and guaranteed.
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R
RAPID CURING ASPHALT (RC) - Liquid asphalt composed of asphalt
cement and a naphtha- or gasoline-type diluent of high volatility.
REHABILITATION - The renewal of an existing surface or pavement
structure by repair, recycling, or overlay techniques.
RECLAIMED ASPHALT PAVEMENT (RAP) Removed and/or reprocessed
pavement materials containing asphalt and aggregates.
RESURFACING - Existing surfaces may be improved by resurfacing
(or overlaying) with a plant mix asphalt mat of varying thicknesses.
It may be considered in two categories: (1) overlays to provide
smooth, skid- and waterresistant surfaces or to make improvements
in grade and/or cross section; and (2) overlays to strengthen
existing pavements to handle heavier loads or increased traffic.
Sometimes called overlays.
RIGID PAVEMENT - A pavement structure that distributes loads
to the subgrade, having as one course a Portland Cement Concrete
slab of relatively high bending resistance.
ROAD - A general term denoting a public way for purpose
of vehicular travel, including the entire area within the
right-of-way.
ROADBED - The graded portion of a highway within the top
and side slopes, prepared as a foundation for the pavement
structure and shoulders.
ROCK - From which crushed stone, sand, and gravel are made;
the rock most suitable for making good aggregates.
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S
SEAL COAT - A thin asphalt surface treatment used to waterproof
and improve the texture of an asphalt wearing surface. Depending
on the purpose, seal coats may or may not be covered with
aggregate. The main types of seal coats are aggregate seals,
fog seals, emulsion slurry seals, and sand seals.
SELECT MATERIAL - Suitable material obtained from roadway
cuts, borrow areas, or commercial sources and designated
or reserved for use as foundation for the subbase, for subbase
material, shoulder surfacing, or other specific purposes.
SHOULDER - The portion of the roadway contiguous with the
traveled way for accommodation of stopped vehicles, for emergency
use, and for lateral support of base and surface courses.
SLOW CURING ASPHALT (SC) - Liquid asphalt composed of asphalt
cement and oils of low volatility.
SLAG - The air-cooled, non-metallic byproduct of a blast
furnace operation consisting essentially of silicates and
alumino-silicates of lime and other bases that is developed
simultaneously with iron in a blast furnace. Naturally it
is only available in those localities where pig iron is produced.
Crushed slag weighs about 80 pounds per cubic foot.
SLURRY SEAL - A mixture of slow-setting emulsified asphalt,
fine aggregate, and mineral filler with water added to produce
slurry consistency.
SOIL AGGREGATE - Natural or prepared mixtures consisting
predominantly of hard, durable particles or fragments of
stone, slag, gravel, or sand, that contain some soil-clay
or stone dust conforming to specified requirements.
SOIL CEMENT BASE - Consists of a mixture of the natural
subgrade material and Portland cement in the proper amounts.
After thorough mixing, the proper amount of water is added,
and the material is compacted to the required thickness.
SOIL SUPPORT - A term expressing the ability of the roadbed
material, or subgrade soil, to support the traffic loads
transmitted through a flexible pavement structure.
SPECIAL PROVISIONS - Special directions, provisions, or
requirements peculiar to the project under consideration
and not otherwise thoroughly or satisfactorily detailed or
set forth in the specifications. Special provisions set forth
the final contractual intent in the matter involved.
STAGE CONSTRUCTION - The construction of roads and streets
by applying successive layers of Asphalt Concrete according
to design and a predetermined time schedule.
STONE MASTIC ASPHALT - A high performance surface asphalt
mix using high content of asphalt through use of fiber fillers.
Very high quality aggregates are used.
STREET - A general term denoting a public way for purpose
of vehicular travel, including the entire area within the
right-of-way.
SUBBASE - The course in the asphalt pavement structure immediately
below the base course is the subbase. If the subgrade soil
is of adequate quality, it may serve as the subbase.
SUBCONTRACTOR - Any individual, partnership, or corporation
to whom the contractor sublets part of the contract.
SUBDRAIN - A structure placed beneath the ground surface
to collect and carry away underground water.
SUBGRADE - The uppermost material placed in embankments
or unmoved from cuts in the normal grading of the roadbed.
It is the foundation for the asphalt pavement structure.
The subgrade soil sometimes is called basement soil or foundation
soil.
SUBGRADE STABILIZATION - Modification of roadbed soils by
admixing with stabilizing or chemical agents that will increase
load-bearing capacity, firmness, and resistance to weathering
or displacement.
SURFACE COURSE - One or more layers of a pavement structure
designed to accommodate the traffic load, the top layer of
which resists skidding, traffic abrasion, and the disintegrating
effects of climate. The top layer is sometimes called the
'wearing course.'
SUBSURFACE DRAINAGE - Removal of free water from various
structural components of the pavement or the surrounding
soil.
SUPERPAVE - A mix design using volumemetric concepts and
specific performance criteria.
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U
UNDERDRAIN - A perforated or porouswalled pipe placed with
suitable pervious backfill beneath the ground surface to
collect and carry away underground water.
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V
VISCOSITY - This is a measure of the
resistance to flow. The term is used as "high viscosity" or "low
viscosity." A high viscosity material refers to a heavy
or still material that will not flow easily. A low viscosity
material is the opposite. Viscosity is measured in absolute
units called poises. It was formerly measured in empirical
values of time, distance, and temperature. This method was
called Saybolt Furol Viscosity.
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W
WEARING COURSE - The top course of asphalt pavements, also
called the surface course.
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