Asphalt mixture beams used in bending beam rheometer for quality control: Utah's experience

This paper introduces the use of asphalt mixture beams in the bending beam rheometer (BBR) for quality control with a project in Utah as a case study. A good solution for quality control, the BBR test can be performed by materials laboratory staff at highway agencies and private materials laboratories because it is reasonably priced, is rugged-tested, uses limited material, is conditioned quickly, is available, and is familiar to staff at materials laboratories for everyday mix design and quality control. The paper begins with a literature review of past research work in support of using BBR tests to measure properties of asphalt mixture beams. An asphalt construction project in Utah was selected to demonstrate the applicability of using asphalt mixture beams in the BBR for quality control. Field samples obtained from the project in Utah were shipped to the laboratory, where comparisons of low-temperature properties of asphalt mixtures were done with the BBR. Results easily showed an anomaly on two paving days, when the m value (slope of the curve) was higher than normal. Because of this irregularity, further testing was initiated with the indirect tension test performed at the Asphalt Institute; the test confirmed the results from the BBR. On the basis of results and demonstration, it is clear that using asphalt mixture beams in the BBR is feasible for quality control to evaluate the performance of constructed materials. The application of using asphalt mixture beams in the BBR can be easily adopted by highway agencies to facilitate quality control operations in asphalt construction.