The bitumen modifying is a technique widely used in road paving and consists in adding an additive, the polymers being the most widely used, offering the bitumen/bituminous mixture improved rheological and mechanical characteristics, such as greater cohesion, better elasticity, greater water resistance, reduced thermal susceptibility, and others.
Polymers are classified according to their structure and properties. It is possible to divide them into three groups: thermoplastics, thermosets and elastomers.
Thermoplastics are polymers which deform easily when subjected to the heating action. By cooling they can mould themselves, preserving most of its intrinsic properties. Examples include EVA (Ethyl Vinyl Copolymer), PE (Polyethylene), PP (Polypropylene), among others.
The thermosetting materials are polymers that in their manufacturing process become a stable solid that cannot be longer soften, and therefore cannot be reprocessed. The resins are part of this group of polymers.
The elastomers or rubbers are polymers that have elastic properties, which after vulcanization obtain a partially cross-linked structure. They bear large deformations before rupture, thus having excellent elastic properties. All types of rubber are included in this category.
SBR (Styrene-Butadiene Rubber) is used for modifying bitumen and it is a thermoplastic rubber, combining the characteristics of natural rubber and the thermoplastic characteristics.
There is also one type of elastomer which has thermoplastic properties. Despite being a conventional polymer, the process of vulcanization is not required. The copolymer SBS (Styrene-Butadiene-Styrene) is included within this group.
Thermoplastic elastomer Styrene-Butadiene-Styrene
Technical Data Sheet SBS
Thermoplastic rubber Styrene-Butadiene-Styrene
Technical Data SBR