The modification of bitumen by mixing in crumbed rubber from vehicle tyres using the wet blend method was introduced in South Africa in the early 1980s. The product has since been used extensively in Southern Africa in both seal and asphalt applications. Bitumen rubber seals are well known for their ability to seal and prevent cracks reflecting through overlaid surfaces. A wealth of knowledge has been built up with experience gained in the manufacturing and application of bitumen rubber for use in seals. In order to retain the performance properties of the bitumen rubber blend, South African road engineers have adopted stringent design methods and construction techniques to ensure that only minimal cutter is added to the bitumen rubber blend before application. Since the product is highly viscous at spray temperatures, specialised equipment and techniques are required to manufacture and apply the product. Bitumen rubber has become the premium modified binder with a proven track record which is unequalled in performance by any other modified binder. In this paper, a comparison of different case studies will be used to emphasise the differences in behaviour when bitumen rubber is used in different seal types. (a) For the covering entry of this conference, please see ITRD abstract no. E217100.
Samenvatting