Transcript Polymer Modified Bitumen

Polymer Modified Bitumen
Oscar Ellison
Contents of presentation
•
•
•
•
•
Why do we use polymers
What are polymers
History in NZ and internationally
Types and effects of different polymers
Thermoplastic
– Plastomer
– Elastomer
• Thermoset and others
• The future
Why do we use polymers
• Increase demand from the road network
• Search for new ideas and technologies
• Polymers are an effective solution
What is required
•
•
•
•
Enhance important properties of asphalt
Not detrimental to basic properties
Workable and able to process
Cost effective
What are polymers
• Very large molecules
• Made up of smaller monomers
• Common both in nature and everyday
life
• First synthetic polymers created
around 1910
• Varying molecules and lengths
The Chemistry: Styrene-butadiene
Butadiene
C4H6
Styrene
C6H5CH=CH2
Use in New Zealand
• Natural Latex in sealing
• SBS, EVA and PBD in sealing
• SBS and EVA in asphalt
Types of Polymer Used
Elastomers
Thermoplastic
Plastomers
Thermoset
Elastomers
• Natural Rubber
Long flexible chains
• SBR (Styrene Butadiene Rubber)
Random co-polymer
Hard styrene and rubbery butadiene
Both monomers compatible with bitumen
SBS (Styrene Butadiene Styrene)
• Most commonly used polymer
• Block co-polymer
• Entropic – structural
• Enthalpic - energy
Plastomers
• EVA
Ethylene Vinyl Acetate
Random co-polymer
Not crossed-linked
Raises stiffness and toughness at low temperatures
Effect of Polymers
1.00E+08
1.00E+07
1.00E+06
Modulus
1.00E+05
1.00E+04
1.00E+03
50 pen bitumen
1.00E+02
Plastomer Modified bitumen
1.00E+01
Elastomer Modified bitumen
1.00E+00
0
5
10
20
30
40
Temperature °C
50
60
70
80
Thermoset
•
•
•
•
•
•
Uncommon
Epoxy, Polyurethane
Once cured are not affected by temp
Difficult to handle
Created in situ – cross linked polymer network
Increased stiffness, rutting resistance, fuel resistance
• Embrace the use of polymers
• Sustainability etc. peak oil
• Price of bitumen trending upwards need to find ways to
reduce cost. Polymers can do this. Thinner layers etc.
• New polymers. New technologies for mixing.
• New thinking…