Polymer Modified Bitumen Additive (SBS)
Polymer Modified Bitumen Additive (SBS)
Polymer Modified Bitumen Additive - SBS is the most commonly used additive in mixtures, consisting of Styrene-Butadiene-Styrene (SBS) polymer. It is used as a modifying additive to improve the behavior of bituminous binders and mixtures.
SBS is widely used in the asphalt industry.
When polystyrene is heated above its glass transition temperature of 90 ºC, its molecules soften and become fluid, facilitating its mixing with bitumen. When cooled below 90 ºC, the polybutadiene blocks lock the polystyrene blocks, resulting in physical cross-linking. This bonding is very rigid due to the polystyrene structure but also flexible because of the polybutadiene bridges. The physical locking that occurs during cooling reverts to its original state above 90 ºC, allowing for reversible workability.
The goal is to ensure resistance against adverse conditions such as:
- Wheel tracking deformation
- Aggregate stripping
- Undulation
- Low-temperature cracking
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