The effect of filler type and shape on HMA energy dissipation performance.

Abstract:

Hot mix asphalt pavements require adequate compaction to achieve

the required density to resist rutting. The amount of energy required to achieve the

optimum degree of compaction depends on the type of gradation, bitumen content,

filler type and shape, type of compaction equipment etc. In this study, the net energy

required to reduce the specimen volume (size) after each gyration of the superpave

gyratory compactor is used as the compaction energy index (CEI) to measure the

compactability of the samples. Samples with different filler types and content are used

for the analysis.

Effect of fillers on the viscosity of the mastic has been studied previously. Viscosity

of mastics in return affects the compactability of the mix in general. In this regard this

paper tries to study the effect of fillers on the compaction of hot mix asphalt with the

help of the superpave gyratory compactor. Moreover, resistance of the asphalt mix

samples against rutting is evaluated using the simple performance test. In this test, the

sample is subjected to a hydraulic loading while strain transducers attached to the

sample measure the displacement. A computer program receives the displacement

data at various frequencies and calculates the dynamic modulus and flow number

which are used for the evaluation of the pavement performance.

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