Aggregate Base and Sub-Base Course Quantity Estimation
Aggregate course estimating is one conversion done carefully: the drawing gives compacted thickness, the supplier delivers loose material by weight or truckload.
Start from compacted volume
Take area from the layer width in the typical section (base is narrower than sub-base), and thickness from the pavement design (commonly 150–300 mm per layer, placed in ~150 mm lifts).
Convert to delivered quantity
Tonnes = Vcompacted × in-place dry density (2.0–2.3 t/m³ for crushed aggregate base)
Buy by the tonne where the supplier weighs; by loose m³ or truckload where they do not. Confirm which basis the unit rate is on.
Gradation and standards
Specify the class (e.g. DPWH Item 200 aggregate sub-base course, Item 201 aggregate base course, or the local equivalent) so bidders price the correct crushing and gradation. Sub-base tolerates a wider gradation and more fines; base course is a tighter, stronger crushed product and costs more per tonne.
Wastage
- Spreading and trimming loss: 3–5%.
- Extra at widenings, tapers, and against kerbs.
- Test-pit and density-test replacement: nominal.
Placement check
Note the number of lifts (compacted thickness / max lift) — it affects the compaction plant hours and the number of density tests, both of which are separate BOQ or preliminaries items.
EngEst Pro’s Civil Calculator converts compacted design volume to loose and to tonnes with your bulking factor and material density, so the aggregate line items match how your supplier quotes.
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