Description
This paper describes the latest design procedures and construction practices used for the construction of bitumen rubber asphalt in rehabilitation projects in South Africa. Bitumen rubber products are normally at a disadvantage as they are placed where the conventional asphalts have already failed or where the existing base courses are in severe distress, and on top of this must now provide additional structural capacity for the next 10 to 15 years under severe traffic conditions.
This paper describes the following aspects:
– Basic constituent materials used in the manufacture of B-R asphalt. The South African materials specification is furnished and discussed.
– The SA asphalt mix design process including the type selection; the volumetric design process as well as the B-R asphalt end point specification.
– Further developments (rutting, fatigue, energy methods, moisture sensitivity, Dynamic Creep).
– B-R structural equivalency.
– Construction of B-R asphalt.
– Potential problems.
– Summary and conclusions.
This paper conclude that the somewhat higher initial construction cost of B-R asphalt are negligible in view of the savings in traffic accommodation, bypasses and the extended life rendered by the B-R asphalt when assessed over the full life cycle. In South Africa B-R asphalt is considered the premier asphalt for rehabilitation purposes.
