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SEMINAR 12/2010

INTRODUCTION HIGH PERFORMANCE ASPHALT CONCRETE

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PROPERTIES OF ASPHALT CONCRETE

asphalt mixture shows severe temperature susceptibility:

high-temperature rutting, media temperature fatiguelow temperature cracking damage.

Therefore, asphalt mixture should be modified in some way to promote its further application.

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SOME TYPES OF THE MODIFIED ASPHALT CONCRETE

Rubber asphaltFiber asphalt:

Polypropylene fiber Polyester fiber Asbestos (mineral) fiber Cellulose fiber Carbon fiber Glass fiber

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CARBON FIBER ASPHALT

Properties of Carbon FiberDiameter 7.5 – 7.8 μmTensile Strength 3.2 GpaBase PolyacrylonitrileTemperature of Carbonization 1400 oCCost 15–35 $/kg

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Influence of carborn fiber on the property of asphalt concrete

Increase the properties of bituminous mixtures stability

improve structural resistance to distress occurring in road pavement due to traffic loads.

Improve fatigue life and permanent deformation of bituminous mixtures by improving mix stiffness.

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Some research shown that: the fiber content of 0.4% by weight of total mix resulted in highest performance in terms of stiffness, resistance to permanent deformation and fatigue;

Significant increases in stiffness and rutting resistance

However, due to the advanced technology involved in their production, use of carbon fibers can be expensive

 

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POLYESTER FIBERProperties of Polyester Fiber

Diameter: 25± 5 um

Gravity: 1.36-1.38 g/cm3

Color: White

Lenth: 6mm, 12mm

Tensile strength:

500Mpa

 

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Influence of polyester fiber on the property of asphalt concrete

due to : their effects of absorbing bitumen The interlacing of the fibres vertically and horizontally increases

the elasticity of the asphalt mix their three-dimensional random distribution in asphalt mixes

improve the high-temperature stability notably, adhering to the mineral aggregates, strengthen the resistance of

asphalt mixes to environmental disruption and water damage. help Asphalt to be flexible at low temperature.. → prevents the onset and propagation of cracks, improves the low-

temperature performance of the asphalt mix significantly. block the propagation of cracks and improve the fatigue

resistance of asphalt mixes.

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CELLULOSE FIBER

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CELLULOSE FIBERimproves the deformation resistanceextends the service life of the pavements considerably fix the binder to the aggregates  surface and therefore

prevent de-mixing during transport and layingCellulose is used in Stone matrix asphalt, Porous asphalt→ application areas include:

Airport Infrastructures Motorways Intersections Bus stops Racing Circuits

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RUBBER ASPHALT CONCRETESome sulfur in rubber reacts with oxygen during heating and mixing into binder→change the structure and composition of binder’molecules→ influence high temperature behavior of asphalt

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Influence of natural rubber on the property of asphalt concrete

increase viscosity helps increase cohesion between aggregates and bitumes binder → reduces stripping for the mixtures.

increase softening point of asphalt cement → reduce deformation, bleeding, rutting and increase road pavement stability at high temperature.

Concentrated latex could help increase elasticity of asphalt cement at low temperature.

reduce aging for asphalt cement according to the amount of concentrated latex added.

reduce temperature susceptibility as penetration index (PI) increases by the amount of concentrated latex added.

→adding concentrated latex made the mixtures work well on service temperature at 70oC

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PROPERTIES OF HIGH PERFORMANCE ASPHALT CONCRETE

Stability in severe temperature

Reduce rutting in high temperature

Flexible at low temperature

High deformation resistance