Modified bitumen is formulated with additives to improve their service performance by changing such properties as their durability, resistance to ageing, elasticity and/or plasticity. These modifiers may be polymers, crumb rubber, sulphur and polyphosphoric acid.
The most common types of modifiers being used are APP (Atactic Polypropylene) and SBS (Styrene Butadiene Styrene). These two types were discovered in Europe. Normally to create roofing grade asphalt; asphalt flux is air-blown at elevated temperatures which convert the flux to roofing grade asphalt. In the early 1970’s, the Italians, lacking the blowing equipment, were looking for a product that would convert asphalt flux into a usable roofing product. They discovered that if Atactic Polypropylene (APP) - a by-product of propylene polymerization - was added to asphalt then it gave the asphalt some plastic properties. While APP was being looked into in southern Europe, northern Europe was experimenting with a different type of modifier called Styrene Butadiene Styrene (SBS). The French and Germans found that if they added 10%-15% of SBS rubber to asphalt, the asphalt’s characteristics changed to those of the rubber additive.
Modified bitumen is widely used in the production of roofing felt and in paving applications.
Sources: roofhelp.com, bp.com, eurobitume.eu
P.S: Gildatar Bitumen is proud to make possible the supply of Middle East bitumen in multiple grades 60/70, 80/100, 85/100, 85/25, 40/50, and 30/40.
