Very often we need to improve binding properties, elasticity, elastic recovery for the binder, prolong life time for the asphalt pavements, increase their bearing capacity for the heavy transport at different climate – these are the reasons for Bitumen modification.
For these reasons there are plenty of different products to use. These products have to be selected depending on basic bitumen we use, specifications we need to achieve, technological aspects, dosing equipment available and etc.
Perhaps, the most common product for bitumen modification all around the Globe is the modification by SBS (styrene – Butadiene – Styrene) elastomers. SBS elastomers improve bitumen’s elasticity, elastic recovery, inrease bitumen’s softening temperature, reduce penetration, but for best results such benefits may be achieved if we use special equipment, consisting high shear mixer. High shear mixers cut the polymer into very small particles and distribute them within the bitumen, obtaining very good dispersion.
Good dispersion is the key for good PmB (Polymer modified bitumen) properties, storage stability, but the chemical composition of the basic bitumen is the same important for good properties of PmB. More we have aromatics inside the bitumen better we have chemical reaction between bitumen and SBS.
There are several SBS elastomers with different Stirene and Butadiene content, also different molecular structure (linear or radial).
Here below some main SBS elastomers available for bitumen modification:
| Elastomer name | Calprene 401 | Calprene 411 | Calprene 501 | Dyne 128 |
| Structure | radial | radial | linear | radial |
| Styrene, % | 20 | 30 | 31 | 30,5 |
| Vinil, % | 10 | 10 | 10 | 38 |
| Molecular weight | average | high | low | average |
We’d like to draw Your attention to our new elastomer Dyne 128, which has different chemical content and gives exclusive properties to the binder:
– it is better compatible with different bitumen and provides lower viscosity, what is very important in production of high SBS elastomer content PmB;
– improves PmB storability;
– due to higher vynil concentration allows modification also for bitumen with low content of aromatics.
Attention !
For those, who does not have equipment to produce SBS PmB, we have brilliant solution – we can provide granullated PmB. These granulles may be added into the bitumen tank or pug mill, by using dosing equipment or manually. Adding just 5% of PmB granulles, we will increase softening point for the bitumen, reduce penetration and also Fraas temperature.
Move we add granullated PmB, less we need basic bitumen.
If You produce high SBS content PmB, for sure, You will have very high viscosity binder, but for reduction of it , we have another very special additive Sasobit®.
Sasobit® – it is of special structure wax, which modifiers the butumen in double way:
– reduce viscosity at temperatures above 110° C;
– reduce penetration, but increase bearing capacity for the pabement, increase bearing capacity for the pavement at the temperature below 70° C.
.
Just because of double influence this product makes to the binder and the wole asphalt mix, Sasobit is very common in special projects like airports, sea terminals and etc.
The estimated recommended dosage for Sasobit is: 3-4 % from bitumen content.
The best results can be achieved when adding it into the bitumen tank.