In a quality control exercise the engineer in charge cut an

In a quality control exercise, the engineer in charge cut an asphalt core 100 mm diameter and 65 mm deep. The total mass of the core is 1200 g. The engineer ran an extraction test in which bitumen was separated from aggregates, the mass of the aggregate was found to be 1140 g. The specific gravity of the bitumen is 1.05 and the specific gravity of the aggregate is 2.75. If the bitumen absorption is 0.9%,

1. The bitumen content.

2. What is percent of the aggregates in the total mix (%Ps)?

3. What is effective specific gravity of aggregates

4. What is bulk specific gravity of the compacted mix?

5. What is the maximum theoretical specific gravity?

6. What is the percent of the voids in the mineral aggregate (%VMA)?

7. What is the percent of the voids in the total mix (%VTM)?

8. What is the percent of the voids filled with bitumen (%VFB)

9. For a dense graded mix, comment on the calculated air voids.

10.For this dense graded mix, do you expect any problems? What are these problems?

Preferably could you do it with Volumetric Relationships like done in the image below because I do not completely understand how to do it like that?

VMA Effective Bitumen Vmm Vmb Vba Absorbed Bitumen Vse Vsb Solid material

Solution

1. The mass of bitumen or the bitumen content is cearly the total mass - the mass o aggregate, that is 1200-1140= 60

2. percentge of aggregates in the total mix= (mass of aggregate/ total mass )*100 that is (1140/1200)*100 = 95%

3.the effective specific gravity of the aggregate= (100%-% of bitumen)/ (100/specific gravity of aggregate)-(% of bitumen-specific gravity of bitumen)

i.e (100-5)/(100/2.75)-(5/1.05) = 0.549

4. bulk specific gravity of compacted mix= (% wt. of aggregates/ specific gravity of aggregtes)+(% wt. of bitumen/ sp gravity of bitumen = (95/2.75)+(5/1.05) = 100/39.70 = 2.54

5. maximum theoritical specific gravity is the bulk specific gravity of the mixture i.e. 2.54