Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 85
Glossary
AADT. The average annual daily traffic, expressed as the for prioritizing projects, evaluation of the benefits and
24-hour traffic volume counts collected over a number of costs for all projects in a program, and determination of
days greater than 1 but less than a year, at a given location. program trade-offs.
AADT can also be approximated by adjusting the ADT binder. An adhesive composition of asphalt cement, modified
count for daily (weekday versus weekend) and seasonal asphalt cement, or other bituminous materials, which is pri-
(summer versus winter) variations. marily responsible for binding aggregate particles together.
AADTT. The average annual daily truck traffic, expressed Also used to refer to the layer of HMA directly below the
as the 24-hour truck traffic volume counts collected over surface course (i.e., binder course).
a number of days greater than 1 but less than a year, at a block cracking. Cracking of a roadway surface caused by
given location. ADTT may be expressed as a percentage shrinkage of the asphalt concrete and daily temperature
of ADT. cycling, usually developing in a block-shaped pattern.
ADT. The average daily traffic, expressed as the 24-hour traf- cape seal. A surface treatment that involves the application of
fic volume counts collected over a number of days greater a slurry seal to a newly constructed chip seal. Cape seals are
than 1 but less than a year, at a given location. used to provide a dense, waterproof surface with improved
alligator cracking. Cracking of a hot-mix asphalt (HMA) skid resistance.
roadway surface caused by fatigue failure of the HMA sur- chip seal. A surface treatment in which a pavement surface
face under repeated traffic loading. The cracks form many- is sprayed with asphalt (generally emulsified) and then
sided, sharp-angled pieces that develop a pattern similar to immediately covered with aggregate and rolled. Chip seals
the skin of an alligator. are used primarily to seal the surface of a pavement with
alternatives. Available choices or courses of action (e.g., non-load-associated cracks and to improve surface fric-
alternative pavement types or rehabilitation or preserva- tion (skid resistance). Also referred to as seal coat.
tion treatment types) that can be considered at each stage cold in-place recycling (CIR). A process in which a portion
of resource allocation or utilization. of an existing bituminous pavement is pulverized or milled,
asphalt cement. A bituminous material often used as a binder the reclaimed material is mixed with new binder and new
with aggregate to form a cold- or hot-applied paving materials, and the resultant blend is placed as a base for a
material. subsequent overlay.
asphalt concrete. See hot-mix asphalt. cold milling. A process of removing pavement material
asphalt emulsion. A mixture of asphalt cement, water, and from the surface of the pavement either to prepare the
an emulsifying agent used in pavement construction and surface to receive overlays (by removing rutting and sur-
maintenance. face irregularities), to restore pavement cross slopes and
base. The layer of material immediately beneath the pave- profile, or to reestablish the pavement's surface friction
ment surface or binder course. characteristics.
benefit-cost. A comparison analysis of the economic benefit condition. Measure of the physical state of an asset as
of an investment to its cost. The benefit-cost analysis affected by deterioration and past maintenance and repair.
should include all costs and benefits to both the agency condition index. A numeric score determined from pavement
and the users of the facility over an appropriate life-cycle condition data and used to represent the performance of the
period. In asset management, benefit-cost can be applied pavement.
88
OCR for page 86
89
corrective maintenance. Maintenance activities performed full-depth repair. Cast-in-place concrete repairs that extend
in response to the development of a deficiency or deficien- the full depth of the existing slab. The technique involves the
cies that negatively affect the safe, efficient operations of a full-depth removal and replacement of full- or half-lane-
facility and future integrity of pavement sections. Correc- width areas of an existing deteriorated PCC pavement.
tive maintenance (sometimes referred to as reactionary functional distress. Deterioration that affects the ability of
maintenance) is usually performed to fix a localized defect the pavement to provide a safe, smooth, and quiet surface
or defects that arise from unforeseen conditions and restore for driving. Most functional problems can be corrected
a pavement to an acceptable level of service. with preservation treatments if there is no serious under-
crack filling. A maintenance procedure that involves place- lying structural problem.
ment of materials into nonworking cracks to substantially high-traffic-volume roadway. As defined in this study, a
reduce infiltration of water and to reinforce the adjacent rural roadway with ADT greater than 5,000 vpd, or an
pavement. Nonworking cracks are defined as those that urban roadway with ADT greater than 10,000 vpd.
experience horizontal movements less than about 2 mm hot in-place recycling (HIR). A process that involves soft-
(0.1 in.). ening an existing bituminous surface with heat, mechani-
crack sealing. A maintenance procedure that involves place- cally removing the surface material, mixing the material
ment of specialized materials, either above or into working with a recycling agent, adding new asphalt or aggregate to
cracks, using unique configurations to reduce the intrusion the material (if required), and then replacing the material
of incompressibles into the crack and to prevent intrusion back on the roadway. There are three types of HIR: surface
of water into the underlying pavement layers. Working recycling, remixing, and repaving.
cracks are defined as those that experience horizontal move- hot-mix asphalt (HMA). A plant-produced, high-quality hot
ments greater than about 2 mm (0.1 in.). mixture of asphalt cement and well-graded, high-quality
diamond grinding. A maintenance procedure for PCC aggregate thoroughly compacted into a uniform dense
pavements that involves the removal of a thin layer of PCC mass.
(generally no more than 6.4 mm [0.25 in.]) from the sur- international roughness index (IRI). A measurement of
face of a pavement to remove surface irregularities (most the roughness of a pavement, expressed as the ratio of the
commonly joint faulting), to restore a smooth riding sur- accumulated suspension motion to the distance traveled.
face, and to increase pavement surface friction. It is obtained from a mathematical model of a standard
diamond grooving. The establishment of discrete grooves in quarter car traversing a measured profile at a speed of
the concrete pavement surface using diamond saw blades 80 km/h (50 mph).
to provide a drainage channel for water and thereby reduce joint resealing. The resealing of transverse joints in PCC
the potential for hydroplaning and wet weather accidents. pavements to minimize the infiltration of surface water
dowel bar retrofit (DBR). See load transfer restoration (LTR). into the underlying pavement structure and to prevent
equivalent single-axle load (ESAL). A concept that equates the intrusion of incompressibles into the joint.
the damage to a pavement structure caused by the passage life cycle. A length of time that spans the stages of asset
of a nonstandard axle load to a standard 80-kN (18-kip) axle construction, operation, maintenance, rehabilitation, and
load, in terms of calculated or measured stress, strain, or reconstruction or disposal or abandonment; when associ-
deflection at some point in the pavement structure, or in ated with analyses, refers to a length of time sufficient to span
terms of equal conditions of distress or loss of serviceability. these several stages and to capture the costs, benefits, and
fatigue cracking. Cracking of a roadway surface caused by long-term performance impacts of different investment
repetitive loading. Fatigue cracking often begins as a sin- options.
gle crack in the wheelpath, develops into parallel cracks, life-cycle cost analysis (LCCA). A method of reducing all of
and then continues as interconnected cracks. Also referred the significant costs of an asset over its lifetime to either a
to as alligator cracking. present worth (today's cost) or an equivalent uniform
faulting. Differential vertical displacement of abutting PCC annual cost (annual cost). As such, LCCA accounts for
pavement slabs at joints or cracks, creating a steplike defor- initial (or in-place) costs, subsequent maintenance and
mation in the pavement. rehabilitation costs, and salvage value. In addition to all
flexible pavement. A pavement structure composed of an of these costs, inputs to an LCCA include the analysis
asphalt concrete (AC) surface (usually HMA) and an aggre- period and the discount rate (reflecting the time value of
gate or stabilized base/subbase. money).
fog seal. A light application of slow-setting asphalt emulsion load transfer restoration (LTR). The placement of load
diluted with water that is used on HMA pavements or chip transfer devices, such as dowel bars, across joints or cracks
seals. in an existing jointed PCC pavement.
OCR for page 87
90
longitudinal cracking. Cracking in a pavement surface that These include, but are not limited to, systematic procedures
is oriented parallel to the direction of travel. for scheduling maintenance and rehabilitation activities
major rehabilitation. Structural enhancements that extend based on optimization of benefits and minimization of
the service life of an existing pavement or improve its load- costs.
carrying capability. pavement management system (PMS). A set of tools or
microsurfacing. A mixture of polymer-modified asphalt methods that assists decision makers in finding optimum
emulsion, mineral aggregate, mineral filler, water, and other strategies for providing, evaluating, and maintaining pave-
additives, properly proportioned, mixed, and spread on a ments in a serviceable condition over a period of time.
pavement (usually bituminous) surface. pavement performance. The condition or serviceability of a
minor rehabilitation. Nonstructural enhancements (e.g., thin pavement, either over time or at a given point in time.
HMA overlay, mill and thin HMA overlay) made to an exist- pavement preservation. A network-level, long-term strategy
ing pavement section to either eliminate age-related, top- that enhances pavement performance by using an inte-
down surface cracking that develops in flexible pavements grated, cost-effective set of practices to extend pavement
due to environmental exposure, or to restore functionality life, improve safety, and meet motorist expectations. Pave-
of concrete pavements. Because of the nonstructural nature ment preservation programs normally include a combina-
of minor rehabilitation techniques, they are placed in the cat- tion of preventive maintenance, minor rehabilitation, and
egory of pavement preservation. routine maintenance work. However, the majority of work
open-graded friction course (OGFC). A bituminous paving under typical pavement preservation programs is focused
layer consisting of a mix of asphalt cement and open-graded on preventive maintenance.
(also called uniformly graded) aggregate. An open-graded pavement preventive maintenance. A planned strategy of
aggregate consists of particles of predominantly a single-size cost-effective treatments to an existing roadway system
aggregate. and its appurtenances that preserves the system, retards
oxidation. Chemical reaction between the asphalt in an future deterioration, maintains or improves the functional
HMA pavement and air, causing the bituminous surface condition of the system, and extends the life of the exist-
to become discolored and stiffer. ing pavement (without increasing the structural capacity).
partial-depth repairs. Removal of small, shallow areas of pavement reconstruction. The replacement of an entire
deteriorated PCC and replacement with a suitable repair pavement structure with an equivalent or better pavement
material. It cannot accommodate the movements of work- structure. Reconstruction usually requires the complete
ing joints and cracks, load transfer devices, or reinforcing removal and replacement of the existing pavement struc-
steel without experiencing high stresses and material ture. Reconstruction may incorporate either new or recy-
damage. cled materials into the materials used for the reconstruction
pavement condition index (PCI). A condition index with a of the complete pavement section. Reconstruction is
scale of 0 to 100, where 0 represents a failed pavement and required when a pavement has either failed or has become
100 represents a pavement that is in excellent condition. functionally obsolete.
See American Society for Testing and Material Standard pavement rehabilitation. Structural enhancements that
D6433, Standard Practice for Roads and Parking Lots Pave- extend the service life of an existing pavement or improve
ment Condition Index Surveys. its load-carrying capacity. Rehabilitation techniques include
pavement friction. The retarding force developed at the restoration treatments and structural overlays.
tirepavement interface that resists sliding when braking pavement texture. The characteristics of the pavement sur-
forces are applied to the vehicle tires. face that contribute to both surface fiction and noise. Sur-
pavement maintenance. Work that is planned and per- face texture consists of microtexture and macrotexture.
formed on a routine basis to maintain and preserve the performance measure. An indicator, preferably quantita-
condition of the highway system or to respond to specific tive, of service provided by the transportation system to
conditions and events that restore the highway system to users; the service may be gauged in several ways (e.g., qual-
an adequate level of service. ity of ride, efficiency and safety of traffic movements, ser-
pavement management. All the activities involved in the vices at rest areas, quality of system condition).
planning, programming, design, construction, mainte- performance period. Length of time a pavement is expected
nance, and rehabilitation of the pavement portion of a pub- to provide a minimum level of serviceability before major
lic works program. A system that involves the identification rehabilitation is required.
of optimum strategies at various management levels and performance target. Threshold value of a performance
maintains pavements at an adequate level of serviceability. measure.
OCR for page 88
91
preoverlay repair. Improvements performed on an existing serviceability. The ability of a pavement to serve the purpose
pavement prior to the placement of an overlay. for which it was designed and constructed.
present serviceability index (PSI). A subjective rating of skid resistance. See pavement friction.
the pavement condition made by a group of individuals slurry seal. A mixture of quick- or slow-setting emulsified
riding over the pavement, ranging from 0 (impassable) to asphalt, well-graded fine aggregate, mineral filler, and
5 (perfect). water. It is used to fill cracks and seal areas of bituminous
punchout. A major structural distress in continuously re- pavements, to restore a uniform surface texture, to seal the
inforced concrete pavement (CRCP) caused by loss of surface to prevent moisture and air intrusion into the pave-
materials under the slab and loss of aggregate interlock at ment, and to provide skid resistance.
one or two closely spaced cracks. spalling. The breakdown of the slab edges within 2 ft (0.6 m)
raveling. The wearing away of a bituminous pavement sur- of the side of the joint caused by excessive stresses at the
face caused by the dislodging of aggregate particles and joint or crack or poor joint forming or sawing practices.
loss of asphalt binder. stone matrix asphalt (SMA). A hot-mix asphalt consisting of
remaining service life (RSL). The number of years before a a mix of asphalt cement, stabilizer material, mineral filler,
pavement reaches an unacceptable serviceability level. and gap-graded aggregate. A gap-graded aggregate is simi-
rigid pavement. A pavement structure composed of a port- lar to an open-graded material but is not quite as open.
land cement concrete (PCC) surface and an aggregate or structural distress. Deterioration caused by excessive load-
stabilized base. ing, insufficient thickness, or lack of structural support.
roughness. Distortions of the road surface that contribute to Pavements with considerable structural distress are not
an undesirable, unsafe, uneconomical, or uncomfortable good candidates for preservation treatments.
ride. subbase. Layer of material in a pavement structure immedi-
routine maintenance. Planned work that is performed on a ately beneath the base course.
routine basis to maintain and preserve the condition of the subgrade soil. The native soil prepared and compacted to
highway system or respond to specific conditions and support a pavement structure.
events that restore the highway system to an adequate level thin HMA overlays. Plant-mixed combinations of asphalt
of service. cement and aggregate that are commonly placed in thick-
rubberized asphalt chip seal. A variation on conventional nesses between about 19 and 38 mm (0.75 and 1.50 in.).
chip seals in which the asphalt emulsion is replaced with a transverse cracking. Cracking in a pavement surface that is
blend of ground tire rubber (or latex rubber) and asphalt oriented perpendicular to the direction of travel.
cement to enhance the elasticity and adhesion characteris- treatment category. A group of treatments with similar
tics of the binder. Aggregate is typically precoated and hot overall objectives and applied at similar times. For exam-
applied. ple, preventive maintenance treatments are intended to
rutting. A surface depression in the wheelpath caused by a preserve pavement integrity and prevent or retard future
permanent deformation in any of the pavement layers or pavement deterioration.
subgrade. treatment type. A specific work activity performed on a road-
sand seal. An application of asphalt emulsion covered with way pavement that is intended to treat one or more of the
fine aggregate. It may be used to improve the skid resistance pavement's deficiencies. Examples include crack sealing,
of slippery pavements and to seal against air and water thin HMA overlay applications, and diamond grinding.
intrusion. ultra-thin bonded wearing course. A preservation treatment
sandwich seal. A surface treatment that consists of application for flexible pavements consisting of a layer of gap-graded,
of a large aggregate, followed by a spray of asphalt emulsion polymer-modified hot-mix asphalt (HMA) material placed
that is in turn covered with an application of smaller aggre- over a heavy, polymer-modified emulsified asphalt tack
gate. Sandwich seals are used to seal the pavement surface coat. Sometimes called ultra-thin friction course.
and to improve skid resistance. ultra-thin whitetopping (UTW). Thin PCC overlays of
scrub seal. The application of a polymer-modified asphalt existing HMA pavements that consist of very thin (50 to
emulsion to the bituminous surface, followed by the broom- 100 mm [2 to 4 in.]) layers of PCC bonded to an existing
scrubbing of the emulsion into cracks and voids, followed by HMA pavement.
the application of an even coat of sand or small aggregate, undersealing. Also called subsealing, pressure grouting, or
and finally a second brooming of the aggregate and asphalt slab stabilization, this process consists of the pressure
mixture. This seal is then rolled with a pneumatic tire insertion of a flowable material used to fill voids beneath
roller. PCC slabs.
OCR for page 89
92
user benefits. Economic gains to transportation users user costs. Costs incurred by highway users traveling on the
resulting from a project or investment strategy. It may facility and the excess costs incurred by those who cannot
include monetary value of travel time savings, accident use the facility because of either agency or self-imposed
reductions, reduced vehicle operating costs, and savings detour requirements. User costs are typically composed of
or advantages gained from more reliable transportation vehicle operating costs, crash costs, and user delay costs.
services. weathering. The hardening and aging of the asphalt binder.
