Bituminous emulsions for highway pavements. National Cooperative Highway Research Program, synthesis of highway practice 30

Technical Report · Wed Jan 01 00:00:00 EST 1975

OSTI ID:7075104

Bituminous emulsions are used widely in the construction and maintenance of pavements ranging from high-traffic-volume highways and airports to low-volume rural roads and city streets. The use of emulsions can reduce energy requirements through reduction or elimination of the petroleum distillates that are used in liquid asphalts and through lower heating requirements compared to hot plant-mix asphalt concrete. The elimination of distillates also reduces air pollution. Three pavement design methods primarily applicable to dense-graded mixes are discussed briefly. Spray applications of emulsified asphalt are widely used. Applications without cover material include: tack coats, to promote bond between layers; fog seals, to seal existing surfaces; and curing seals, to seal cement- or lime-treated bases. Surface treatments and seal coats are spray applications of asphalt followed by an application of aggregate embedded by rolling. Slurry seals consist of a mixing of slow-setting or quick-setting mixing-type emulsion, fine aggregate, mineral filler, and water applied to a surface to serve as a crack filler and wearing course. For emulsion mixes the important properties of aggregates are mineralogical composition, hardness, abrasion resistance, porosity, durability, particle shape, surface texture, surface chemistry, and gradation. For quality construction, proper controls and good workmanship are required. Construction with emulsified asphalt involves different procedures from those used with cutbacks and asphalt cements. Care should be exercised in the storage and handling of emulsions to avoid breaking them. Emulsion mixes preferably are prepared in a central plant using a pugmill or drum mixer. Some of the important hints for quality construction with asphalt emulsions are included. Emulsions are also used for maintenance operations, such as crack repairs, pothole filling, skin patching, and overlays for skid resistance.

• Research Organization: Transportation Research Board, Washington, D.C. (USA)
• OSTI ID: 7075104
• Report Number(s): PB-246844
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
ASPHALTS
EMULSIFICATION
ROADS
BUILDING MATERIALS
ADDITIVES
AIR POLLUTION
COMPARATIVE EVALUATIONS
EMULSIONS
ENERGY CONSERVATION
MIXING
RUBBERS
SEALS
SLURRIES
WATER
BITUMENS
COLLOIDS
DISPERSIONS
ELASTOMERS
HYDROGEN COMPOUNDS
MATERIALS
MIXTURES
ORGANIC COMPOUNDS
ORGANIC POLYMERS
OTHER ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
POLLUTION
POLYMERS
SUSPENSIONS
TAR
020500* - Petroleum- Products & By-Products