Rigden’s and Rigden-Anderson’s methods apply to any fine material used as a filler in hot mixes (e. g., bag-house fines and added filler). Filler air voids make up an air volume occurring among grains of filler compacted with a special apparatus by a standardized method. Test methods according to the EN standard (Rigden) and the U. S. procedure (Rigden-Anderson [Anderson, 1987]) differ markedly, which makes the direct comparison of results impossible. The only feature they have in common is their principle—dry compaction of filler.
8.3.2.1 Rigden’s Method after EN-1097-4
The EN method provides for compaction of a dry sample of filler by 100 strokes of a dead weight every second. The mass of sample is 10 g, and the mass of the dead weight is 350 g.
The volume of air voids is estimated, taking into account the mass of the compacted sample, its volume, and the filler density. European countries have used the EN 13043 standard for aggregates for asphalt mixes. The most frequently adopted requirement for a filler tested according to EN 1097-4 is the category V28/45, which means the content of air voids should be within 28-45% (v/v).
