Implementation of AIMS in Measuring Aggregate Resistance to Polishing, Abrasion and Breakage

The report presents efforts undertaken to help in the implementation of the Aggregate Imaging System (AIMS) in Texas Department of Transportation (TXDOT) operations. These effons focus on measuring aggregate shape properties and texture of polishing coupons supplied by TxDOT, compilation of a database of aggregate properties measured at TxDOT and Texas TransportationI nstitute (TTI), and analysis of the aggregate properties. A comparison was conducted between the measurements from the TIT and TxDOT AIMS units, and it was found that there was no statistical difference between the measurements of the two AIMS units. The current method used in the Wet Weather Accident Reduction Program (WWARP) relies on the terminal Polished Value (PV) and magnesium sulfate soundness to classify aggregates. A new method is proposed in this report to better classify aggregates. This method is based on the magnesium sulfate soundness and texture results from AIMS. This method is more sensitive than the cuffent method and allows the aggregates to be spread more evenly in four different categories. The report also includes the development of new methods for measuring aggregate resistance to polishing, abrasion, and breakage. These methods rely on measurements using the Aggregate Imaging System (AIMS) and Micro-Deval. The new method for measuring aggregate resistance to polishing monitors change in aggregate texture as a function of polishing time. The new method for measuring aggregate degradation is capable of distinguishing between breakage and abrasion. The new methods are shown to be rapid and accurate, and they require reasonable training.