Utilization of Automation and Real-Time Testing to Imrpove QC/QA Procedures for Hot Mix Asphalt

摘要

This project was initiated to evaluate the potential of several new technologies for automated sampling and testing of component materials during HMA production. The automation devices evaluated in this project included: (1) microwave based moisture content probes on the aggregate and RAP feed belts, (2) belt sweepers for obtaining samples of aggregate and RAP, (3) sample drying units to remove moisture from the materials, (4) a sieve-based gradation device for the virgin aggregate, (5) an asphalt calibration tank for checking the accuracy of the asphalt meter, and (6) an in-line asphalt viscometer. Other existing plant control components, such as the asphalt metering system and the mix temperature sensor, were also included in the evaluation. Results of this preliminary project indicate that some of these automated technologies appear to have promise for use in gathering unbiased QC data at a higher frequency than the traditional technician/laboratory testing approach. Several refinements are recommended for improving these automated testing systems. However, it is also evident that the data available with the above automation technologies only provides part of the information necessary to fully evaluate the composition and quality of HMA mixtures during production. More work is needed to develop and evaluate ways to determine the composition of RAP and the quantity of baghouse fines or other mineral fillers added to the mix during production.