SEMINAR 12/2010 INTRODUCTION HIGH PERFORMANCE ASPHALT CONCRETE

1. SEMINAR 12/2010INTRODUCTION HIGH PERFORMANCE ASPHALT CONCRETE

2. PROPERTIES OF ASPHALT CONCRETE asphalt mixture shows severe temperature susceptibility: • high-temperature rutting, • media temperature fatigue • low temperature cracking damage. Therefore, asphalt mixture should be modified in some way to promote its further application.

3. SOME TYPES OF THE MODIFIED ASPHALT CONCRETE • Rubber asphalt • Fiber asphalt: • Polypropylene fiber • Polyester fiber • Asbestos (mineral) fiber • Cellulose fiber • Carbon fiber • Glass fiber

4. CARBON FIBER ASPHALT • Properties of Carbon Fiber • Diameter 7.5 – 7.8 μm • Tensile Strength 3.2 Gpa • Base Polyacrylonitrile • Temperature of Carbonization 1400 oC • Cost 15–35 $/kg

5. 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.

6. 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

7. POLYESTER FIBER Properties of Polyester Fiber Diameter: 25± 5 um Gravity: 1.36-1.38 g/cm3 Color: White Lenth: 6mm, 12mm Tensile strength: 500Mpa

8. 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.

9. CELLULOSE FIBER

10. CELLULOSE FIBER • improves the deformation resistance • extends the service life of the pavements considerably • fix the binder to the aggregates  surface and therefore prevent de-mixing during transport and laying Cellulose is used in Stone matrix asphalt, Porous asphalt → application areas include: • Airport Infrastructures • Motorways • Intersections • Bus stops • Racing Circuits

11. RUBBER ASPHALT CONCRETE Some 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

12. 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

13. PROPERTIES OF HIGH PERFORMANCE ASPHALT CONCRETE • Stability in severe temperature • Reduce rutting in high temperature • Flexible at low temperature • High deformation resistance