Calculation of Loose Thickness from Expected Compacted Thickness of Bituminous layers

Calculation of Loose Thickness from Expected Compacted Thickness

SSR items for DBM, BM, BC, OGC etc. specify compacted thickness. However, during laying, material is placed in a loose condition and undergoes compaction due to rollers and future traffic.

Loose Thickness Calculator

\[ \text{Loose Thickness Factor} = \left( \frac{1 - Q_f}{v_i} \right)(1 + C_{LL}) \] \[ \text{Loose Thickness} = \text{Factor} \times \text{Compacted Thickness} \]

Initial Void Ratio \(v_i\) (%)

Filler / Binder Fraction \(Q_f\) (%)

Future Traffic Compaction \(C_{LL}\) (%)

Compacted Thickness (mm)

Loose Thickness Factor: —

Recommended Loose Thickness: — mm

Important Engineering Note:
Future traffic compaction is a performance assumption. It should NOT be deducted from RA bills unless explicitly specified in contract conditions or MoRTH/IRC specifications.

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