Volumetric properties of compacted bituminous mixture

Aggregates attributed to the surface pores normally possess and absorb a certain quantity of bitumen. As a consequence, the remaining bitumen quantity is in fact the one that coats the aggregates, fills the voids and provides cohesion in the mixture. This quantity of bitumen is designated as effective bitumen quantity, and it is always less than the initial quantity of bitumen added, unless the aggregate s absorption is zero (ideal case). 

Provided that the bulk specific gravity (Gji,) and the effective specific gravity (G ) of the total aggregate, as well as the specific gravity of the bitumen (GJ, are known, the volumetric properties of bituminous mixture (asphalt mixture) may be determined. 

Vjnb = volume of compacted mix = volume of air voids Vj, = volume of bitumen 

Vse = volume of mineral aggregate (by effective specific gravity) 

Vjnin = voidless volume of paving mix Vjja = volume of absorbed bitumen 

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