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Asphalt Compaction Calculator

Calculate asphalt compaction from core density and reference (Marshall/refusal) density. Includes SHW Series 900 requirements for AC, SMA, and HRA mixes.

Last updated 23 June 2026

About this tool

Calculate asphalt compaction as a percentage of reference density. Compare field core density against Marshall, refusal, or maximum density from the mix design to verify surfacing layers meet specification.

Includes SHW Series 900 compaction requirements for base, binder, and surface courses (AC, SMA, HRA). Results are colour-coded against the 93% and 92% thresholds.

How to use this tool

1. Enter field core density — from laboratory measurement of extracted cores.

2. Enter reference density — Marshall density, refusal density, or maximum density from the supplier’s mix design.

Technical information

% Compaction = (field density / reference density) × 100

SHW Cl. 929: base/binder/surface (AC) ≥93%, surface (SMA/HRA) ≥92%.

Limitations

The reference density must match the mix design. Using Marshall density vs refusal density will give different compaction percentages for the same core.

This tool checks density ratio only. Full compliance also requires air void content, layer thickness, and surface regularity checks.

Revision history

23 June 2026: Initial release

Disclaimer

This tool is provided for educational and general information purposes only. It is not a substitute for professional engineering advice, design or verification.

Diggy and its contributors are not licensed engineering consultants and no results generated by this tool should be used directly for construction, design or safety-critical decisions.

All values and outputs are based on published empirical correlations and should be independently checked and confirmed by a qualified geotechnical engineer before use.

By using this tool, you accept full responsibility for how you interpret and apply the information provided.

Spotted an error? Let us know.

Field (core) density (Mg/m³)

Reference density (Mg/m³)

Marshall density, refusal density, or maximum density from mix design

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