This paper reports on the experiences with Styrene Butadiene Rubber (SBR) and Styrene Butadiene Styrene (SBS) modified bitumens in South Africa over the last 20 years. SBR and SBS are the most widely used polymers for the modification of bitumen for spray sealing in South Africa. The distinct differences in the physical properties of bitumen modified with these two polymers are discussed as well as the differences in storage stability. Bitumen emulsions modified with cationic latex modifier are also frequently used for construction of chip seals, especially during colder periods. The techniques and problems associated with the use and handling of latex modified bitumen emulsions are discussed in detail. In conclusion, guidelines are given for the design and construction of seals using SBR and SBS modified bitumens. (a) For the covering entry of this conference, please see ITRD abstract no. E217100.
Samenvatting