Paver Base Compaction Guide

Two different meanings of “compaction”

BaseLayer defaults to a 15% order allowance because a compacted finished volume can require more loose material. The number remains editable. It is not a field-density target, a machine setting or a substitute for the supplier’s loose-to-compacted conversion.

What field compaction must achieve

Adequate subgrade and base compaction limit later settlement and create a uniform platform for the bedding course. CMHA’s application guide states that aggregate base under pedestrian and residential driveway pavements should be compacted to at least 98% of standard Proctor density under the referenced specification. Areas under constant vehicular traffic use a different referenced target. Those values require a defined test method and project specification; they are not visually verified by the calculator.

CMHA’s construction bulletin emphasizes that adequate compaction of the base is critical to minimizing settlement. The responsible installer must match material moisture, lift thickness, equipment and passes to the aggregate and project.

Why lifts matter

A deep loose pile may compact at the surface while remaining unstable below. Placing the base in controlled lifts lets the chosen equipment influence the full layer. The permitted loose lift thickness depends on the aggregate, compactor, access, moisture and specification.

• Confirm the compacted total thickness and allowed lift thickness.
• Use equipment appropriate to the material and confined edges.
• Correct soft or pumping subgrade before covering it.
• Maintain the required grade while compacting.
• Do not use bedding material to hide depressions in the base.
• Record any specified density or proof-roll acceptance.

Set the calculator allowance without double-counting

1. Start from the finished compacted base thickness.
2. Ask whether the supplier’s quote already converts compacted cubic yards to a loose delivered amount.
3. If it does, set BaseLayer’s compaction allowance to zero or use the supplier’s stated method.
4. If it does not, enter the project or supplier planning factor.
5. Add waste only for the separate handling/grade allowance you actually intend.
6. Compare the resulting tons or yards with truck capacity and minimum-order rules.

Read the open formulas on the methodology page. The calculator multiplies geometric base volume by the compaction allowance and then by waste.

Order-allowance example

A 100 ft² area with a 4 in compacted base has a geometric volume of 33.33 ft³. With a 15% base order allowance and 5% waste:

33.33 × 1.15 × 1.05 = 40.25 ft³ = 1.49 yd³

If the supplier already quoted 1.40 loose yd³ for the specified finished layer, adding another 15% in the calculator could double-count the conversion. Resolve the basis of the quote first.

Visible signs are not acceptance tests

A base that looks smooth may still contain weak zones. Conversely, surface movement alone does not identify the correct remedy. When the project requires a density percentage, proof rolling or other acceptance method, use the specified test and qualified personnel.

References

• CMHA PAV-TEC-010 — Application Guide for Interlocking Concrete Pavements
• CMHA PAV-TEC-002 — Construction of Interlocking Concrete Pavements
• CMHA PAV-GSP-011 — Aggregate Base Guide Specification