What technical requirements define app vs. sbs modified bitumen for asphalt or bitumen modification?

The technical requirements for app (Atactic Polypropylene) and SBS (Styrene-Butadiene-Styrene) modified bitumen differ primarily in their polymer characteristics and performance attributes. APP offers enhanced thermal stability and UV resistance, making it suitable for hot climates. In contrast, SBS provides superior elasticity and flexibility, ideal for varying temperature conditions. Both modifications improve the bitumen’s adhesion, durability, and resistance to aging, but their specific applications depend on environmental conditions and performance needs in asphalt mixtures.