Introduction
Introduction
1 APP (ATACTIC POLYPROPYLENE)
Atactic polypropylene (APP) polymer modifiers are by-products of the polymerization of propylene gas into isotactic polypropylene (used for injection molding and extrusion). APP has a lower melting point and is more compatible with asphalt than isotactic polypropylene.
Bitumens modified with APP can display improved physical and mechanical properties. The improved properties are only possible if the APP is finely dispersed throughout the bitumen to avoid separation during manufacture and service.
APP modification of bitumens can impart the following changes in properties:
- increased softening point
- improved ultraviolet radiation resistance
- improved low temperature flexibility
2 HYBRID BITUMINOUS EPDM SYSTEMS
Manufacturer proprietary EPDM (Ethylene Diene Monomers) membrane systems adhered to various substrates with hot bituminous materials.
Oxidized and modified asphalts are used as waterproofing compounds and as adhesives to adhere reinforcement scrims that are bonded to the underside of EPDM membranes to various substrates.
The use of manufacturers’ proprietary hot-melt modified asphalt requires the use of oil-jacketed kettles, equipped with accurate thermometers and a mechanical agitator to heat the asphalt.