Table of Contents

Appendix A 3 Fillers

The tests to assess fillers for use in asphalt mixes are usually specified in road authority specifications. Typical filler requirements are also included in AS 2150.

The percentage by mass passing the 75 μm sieve is determined by dry sieving in accordance with Australian Standard AS 1141.0, Methods for sampling and testing aggregates: list of methods. The grading of the filler could be determined by hydrometer analysis but, more commonly, the procedure of determining the ‘surface’ area by measuring the air permeability of the compacted filler is used.

The packing behaviour of the filler particles, which determines the porosity or air voids of the compacted filler is determined in accordance with AS 1141.17 (Figure A 4).

The water soluble fraction is determined in accordance with AS 1141.8, while the active lime content is determined using AS 4489.6.1.

Moisture content of all fillers and the plasticity index of crusher dust or ground limestone are determined in accordance with AS 1289, Testing soils for engineering purposes.

Figure A 4: Rigden device used in AS 1141.17 to assess packing behaviour of fillers