Currently the primary method of modifying bitumen for roofing and waterproofing applications is the introduction of polymer additives. Such approach allows to significantly improve flexibility at subzero temperatures, improve heat endurance, aging resistance, as well as fatigue durability. In most cases. up to 30% polymer is enough for modification of bitumen.
Еhe following substances can be used as modifiers:
- Atactic polypropylene (APP);
- styrene butadiene styrene (SBS);
- ethylene-propylene-butene (EPB),
The resulting product properties are determined by several factors. Among them we need to emphasize the following:
- mixture homogeneity;
- initial compatibility of bitumen with modifier;
- the amount of modifier.
The price of bitumen-polymer roofing and waterproofing materials is several times higher than that of usual bitumen products. But their service life can reach 15-20 years, and number of layers does not exceed two (compare with four or five layers of regular bitumen materials).