Abstract:
Mineral fillers are known to affect the cracking properties of hot mix asphalt (HMA) significantly.
Therefore, the aim of the study was to investigate the effects of filler concentration on the indirect
tensile cracking indices of hot mix asphalt at an intermediate temperature. To make the test samples,
the standard 100% limestone filler was substituted with the recycled fillers of hollow concrete block
(HCB) powder and brick powder (BP), in three different concentrations (3%, 5%, and 7%). Optimal
concentration levels resulted in superior mixes that could sustain pavement service life and
environmental friendliness. Mixtures with 100 and 150 mm-diameter specimens were evaluated using
the flexibility index (FI), crack tolerance index (CT index), fracture energy index (FEI), toughness index
(TI), cracking resistance index (CRI), and fracture strain tolerance (FST) index from IDT test. The results
indicate that filler concentrations influence the IDT indices significantly and that the 5% filler mixtures
yielded reasonable testing results. The two specimen sizes were found to have moderate to strong
correlation coefficient (R2
) values for the same indices, supporting that both may be used
interchangeably to assess cracking resistance in HMA. Thus, using 100 mm-diameter specimens may
be used to minimise costs and material quantities.
