The effect of filler asphalt ratio on voids in mineral aggregate and asphalt film thickness in hot mix asphalt

Abstract EN

Asphalt durability is often linked to the thickness of the asphalt coating on the aggregate particles.

In order for a pavement to have adequate film thickness, there must be sufficient space between the aggregate particles in the compacted pavement.

This void space is referred to as Voids in the Mineral Aggregate (VMA).

It must be sufficient to allow adequate effective asphalt (that which is not absorbed into the aggregate particles) and air voids.

Marshall mix design was used, first to determine the optimum bitumen binder content and then further to test the mixtures properties of the various filler / asphalt ratio asphalt mixtures.

In total, 75 samples were prepared to investigate the optimum asphalt content of the various mixes and to specify properties of them.

Five proportions of asphalt cement binder were used for each mix type and state by weight of the total mix (4, 4.5, 5, 5.5, and 6).

The tests include the determination of bulk specific gravity, maximum (theoretical) specific gravity, stability and flow.

Marshall mix design requires the determination of the percentages of air voids, voids in mineral aggregate, and voids filled with asphalt.

Due to the results, we found out that when the filler asphalt ratio is in the range between 1.2 and 1.5, the mixture's performance are better in all respects.

If some aspects of mixture performance need to be modified, the filler asphalt ratio can adjusted on this basis.