|
| Types of additives | Purpose | Example |
|
| Filler | (i) To fill the holes
(ii) To increase durability and aggregate-asphalt binder adhesion | Lime
Portland cement
Fly ash |
|
| Elastomers | To increase:
(i) Stiffness at higher temperatures
(ii) Elasticity at temperatures within the average range in order to resist cracking
To decrease:
(i) Stiffness at a lower temperature in order to resist thermal cracking | Natural rubber
Styrene butadiene Styrene (SBS)
Tire rubber (TR)
Styrene butadiene rubber (SBR) |
|
| Fibers | To improve:
(i) Tensile resistance
(ii) Cohesion | Natural fibers
Asbestos
Polyester
Fiberglass |
|
| Plastomers (thermoplastic) | To increase:
(i) Performance at a higher temperature
(ii) Structural strength
(iii) Resistance against rutting | Polyvinyl chloride (PVC)
Ethylene vinyl acetate (EVA)
Ethylene polypropylene (EPDM) |
|
| Waste materials | Substitution of asphalt mixture component with cheaper materials | Recycled rubber
Waste plastics
Waste polymers
Waste engine oil
Waste cooking oil |
|
| Warm mix asphalt | (i) To reduce the production temperatures
(ii) Improve the workability | Evotherm
Sasobit
Rediset
Iterlow T |
|
| Nanomaterials and nanocomposites | To improve mechanical performance and aging characteristics | Nanoclay
Nanosilica
Nanotubes |
|
| Adhesion improvers | To enhance the bonding strength between asphalt and aggregate | Organic amines
Amides
ZycoTherm |
|
| Antioxidants | To minimize the aging effect on asphalt mixture | Organic phenylamines
Zinc dithiocarbonates
Lignin |
|
| Natural asphalt | (i) To construct sustainable pavements
(ii) To reduce the cost of asphalt pavement
(iii) To increase resistance against rutting | Rock asphalt
Gilsonite |
|
