Paper presented at the 21st Annual South African Transport Conference 15 - 18 July 2002 "Towards building capacity and accelerating delivery", CSIR International Convention Centre, Pretoria, South Africa.
In the manufacture of asphalt great emphasis is placed on the bitumen content of the material. Bitumen content tests are undertaken regularly at predetermined intervals and results are analysed statistically during the manufacture of the asphalt and the construction of the asphalt pavements. This is undertaken in order to ensure that the desired quality is obtained as well as to detect any problems in the asphalt manufacturing process timeously. It is therefore necessary to ensure that bitumen content test results are accurate and reliable. In practice bitumen content tests are generally sufficiently accurate and reliable. However, this is not always the case and a rapid and efficient method of verifying the bitumen content is desirable. This applies especially in cases where conflicting test results are reported by two independent laboratories (process control and acceptance control laboratories), or when unexpected trends are observed in the test results.
