Bituminous Materials — Worked Examples

These examples connect binder characterization and asphalt-mixture volumetrics with laboratory and field quality control. Final acceptance depends on the governing agency or project mix-design and construction specification.

Example 1 — Asphalt-binder relative density

A pycnometer test records: empty pycnometer W1=35.0 gW_1=35.0\text{ g}; pycnometer + water W2=85.0 gW_2=85.0\text{ g}; pycnometer + binder W3=60.0 gW_3=60.0\text{ g}; and pycnometer + binder + water W4=86.5 gW_4=86.5\text{ g}. Using the stated displacement relationship, determine binder relative density.

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Example 2 — Air voids in a compacted asphalt mixture

A compacted specimen has bulk relative density Gmb=2.380G_{mb}=2.380 and the same mixture has theoretical maximum relative density Gmm=2.490G_{mm}=2.490. Determine air voids.

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Example 3 — VMA and VFA calculation

For the same specimen, binder content is 5.5% by total mixture mass, so aggregate percentage Ps=94.5P_s=94.5. Aggregate bulk relative density is Gsb=2.650G_{sb}=2.650. Determine VMA and VFA using the percentage convention shown.

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Example 4 — Distinguish Marshall specimen preparation from testing

A technician says “ASTM D6926 is the Marshall Stability test” while preparing compacted specimens. Correct the workflow.

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Example 5 — Mean penetration result

Three valid binder penetration determinations are 62, 65, and 64 penetration units under the specified test conditions. Determine the mean and state its limitation.

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Example 6 — Performance-grade selection logic

A pavement binder must perform through very hot summer pavement temperatures and cold-season thermal contraction. Determine how a PG-type selection should be approached without choosing a grade from air temperature alone.

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Example 7 — Field relative compaction

A field core has bulk relative density Gmb,field=2.330G_{mb,field}=2.330. The approved laboratory reference bulk relative density for the contract's comparison is 2.390. Calculate relative compaction.

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Example 8 — Moisture-susceptibility diagnosis

A laboratory mixture meets density and volumetric targets but loses substantial strength after the specified moisture-conditioning procedure. Determine the engineering response.

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