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Pavement Terminology

Pavement Terminology: Terms & Definitions

From annual costs to pavement reconstruction to user costs, stay up-to-date the with latest terms, definitions and terminology in the asphalt and pavement industry.

Any costs associated with the annual maintenance and repair of the facility.

A surface treatment that involves the application of a slurry seal to a newly constructed surface treatment or chip seal. Cape seals are used to provide a dense, waterproof surface with improved skid resistance.

A surface treatment in which a pavement surface is sprayed with asphalt (generally emulsified) and then immediately covered with aggregate and rolled. Chip seals are used primarily to seal the surface of a pavement with non load-associated cracks and to improve surface friction, although they also are commonly used as a wearing course on low volume roads.

Process in which a portion of an existing bituminous pavement is pulverized or milled, the reclaimed material is mixed with new bind and, in some instances, virgin aggregates. The resultant blend is placed as a base for a subsequent overlay. Emulsified asphalt is especially suited for cold-in-place recycling. Although not necessarily required, a softening agent may be used along with the emulsified asphalt.

Cold milling is a process of removing pavement material from the surface of the pavement either to prepare the surface (by removing rutting and surface irregularities) to receive overlays, to restore pavement cross slopes and profile, or to re-establish the pavement’s surface friction characteristics.

Maintenance that is performed once a deficiency occurs in the pavement (i.e. loss of friction, moderate to severe rutting, extensive cracking or raveling)

The placement of materials in non-working cracks to substantially reduce infiltration of water and to reinforce the adjacent pavement. Working cracks are defined as those that experience significant horizontal movements, generally greater than about 2 mm (01. in). Crack filling should be distinguished from crack sealing.

A maintenance procedure that involves placement of specialized materials into working cracks using unique configurations to reduce the intrusion of incompressibles into the crack and to prevent intrusion of water in the underlying pavement layers. Working cracks are defined as those that experience significant horizonal movements, generally greater than about 2 mm (0.1 in).

An overlay course consisting of a mix of asphalt cement and a well graded (also called dense-graded) aggregate. A well graded aggregate is uniformly distributed throughout the full range of sieve sizes.

The rate of interest reflecting the investor’s time value of money, used to determine discount factors for converting benefits and costs occurring at different times to a baseline date. Discount rates can incorporate an inflation rate, depending on whether real discount rates or nominal discount rates are used.

An emulsion of asphalt cement and water, which contains a small amount of an emulsifying agent. Emulsified asphalt droplets, which are suspended in water, may be either the anionic (negative charge) or cationic (positive charge) type, depending upon the emulsifying agent.

The net present value of all discounted cost and benefits of an alternative as if they were to occur uniformly throughout the analysis period. Net Present Value (NPV) is the discounted monetary value of expected benefits (i.e. benefits minus costs).

A light application of slow setting asphalt emulsion diluted with water. It is used to renew old asphalt surfaces and to seal small cracks and surface voids.

A form of hot in-place recycling in which the surface of the old pavement is heated, scarified with a set of scarifying teeth, mixed with a recycling agent, and then leveled and compacted.

A process that consists of softening the existing asphalt surface with heat, mechanically removing the surface material, mixing the material with a recycling agent, adding (if required) virgin asphalt and aggregate to the material, and then replacing the material back on the pavement.

A high quality, thoroughly controlled hot mixture of asphalt cement and well graded, high quality aggregate thoroughly compacted into a uniform dense mass.

The rate of increase in the general price levels usually caused by an increase in the volume of money and credit relative to available goods. The inflration rate is also reflective of the rate of decline in the general purchasing power of a currency.

All costs associated with the initial design and construction of a facility, placement of a treatment, or any other activity with a cost component.

A ratio of the accumulated suspension motion to the distance traveled obtained from a mathematical model of a standard quarter car traversing a measured profile as a speed of 80 km/h (50 mph). Expressed in units of meters per kilometer (inches per mile), the IRI summarizes the longitudinal surface profile in the wheel-path.

An economic assessment of an item, system, or facility and competing design alternatives considering all significant costs of ownership over the economic life, expressed in terms of equivalent dollars.

A mixture of polymer modified asphalt emulsion, mineral aggregate, mineral filler, water, and other additives, properly proportioned, mixed and spread on a paved surface.

The present value of future expenditures or costs discounted using an appropriate interest rate.

Dollars of purchasing power in which actual prices are stated, including inflation or deflation. Hence, nominal dollars are dollars whose purchasing power fluctuates over time.

An overlay course consisting of a mix of asphalt cement and open-graded (also called uniformly graded) aggregate. An open-graded aggregate consists of particles of predominantly a single size.

The sum of all activities undertaken to provide and maintain serviceable roadways. This includes corrective maintenance and preventive maintenance, as well as minor rehabilitation projects.

Planned strategy of costeffective treatments to an existing roadway system and its appurtenances that preserves the system, retards future deterioration, and maintains or improves the functional condition of the system (without increasing the structural capacity).

Construction of the equivalent of a new pavement structure which usually involves complete removal and replacement of the existing pavement structure including new and/or recycled materials.

Work undertaken to extend the service life of an existing pavement. This includes the restoration, placing an overlay, and/or other work required to return an existing roadway to a condition of structural and functional adequacy.

A subjective rating of the pavement condition made by a group of individuals riding over the pavement.

Costs associated with rehabilitation activities that must be applied periodically over the life of the facility.

Economic method that requires conversion of costs and benefits by discounting all present and future costs to a single point in time, usually at or around the time of the first expenditure.

Dollars of uniform purchasing power exclusive of general inflation or deflation. Real dollars have a constant purchasing power over time.

Organic materials with chemical and physical characteristics selected to address binder deficiencies and to restored aged asphalt material to desired specifications.

Similar to recycling agents in material composition, these products are added to existing aged or oxidized HMA pavements in order to restore flexibility and retard cracking.

A variation on conventional chip seals in which the asphalt binder is replaced with a blend of ground tire rubber (or latex rubber) and asphalt cement to enhance the elasticity and adhesion characteristics of the binder. This is commonly used in conjunction with an overlay to retard reflection cracking.

The remaining worth of the pavement at the end of the analysis period. There are generally two components of salvage value: residual value, the net value from recycling the pavement, and serviceable life, the remaining life of the pavement at the end of the analysis period.

An application of asphalt material covered with fine aggregate. It may be used to improve the skid resistance of slippery pavements and to seal against air and water intrusion.

A surface treatment that consists of application of a large aggregate, followed by a spray of asphalt emulsion that is in turn covered with an application of smaller aggregate. Sandwich seals are used to seal the surface and improve skid resistance.

The application of a polymer modified asphalt to the pavement surface followed by the broom scrubbing of the asphalt into cracks and voids. Next, the application of an even coat of sand or small aggregate is made. Finally, a second brooming of the aggregate and asphalt mixture is applied. This seal is then rolled with a pneumatic tire roller.

A mixture of slow setting emulsified asphalt, well graded fine aggregate, mineral filler, and water, It is used to fill cracks and seal areas of old pavements, to restore a uniform surface texture, to seal the surface to prevent moisture and air intrusion into the pavement, and to provide skid resistance.

The result of water entering brick, concrete or natural stone and forcing the surface to peel, pop out or flake off. This is caused by salt in water pushing outward from the inside. Eventually, spalling can cause crumbling and destruction of a structure.

An overlay course consisting of a mix of asphalt cement, stabilizer material, mineral filler, and gap-graded aggregate. The gap-graded aggregate is similar to an open-graded material but is not quite as open.

The characteristics of the pavement surface that contribute to both surface friction and noise.

Costs that are incurred by highway users traveling on the facility and the excess costs incurred by those who cannot use the facility because of either agency or self-imposed detour requirements. User costs typically are comprised of vehicle operating costs (VOC), accident costs, and user delay costs.