Intelligent Compaction

Intelligent compaction (IC) is a roller-mounted system that measures and records compaction as it happens, using accelerometers, GPS positioning, temperature sensors and an onboard computer, and gives the operator real-time feedback. It is also called continuous compaction control.

What an IC System Includes

Depending on the system, an intelligent compaction roller may carry:

• accelerometers and a high-accuracy GPS receiver, to track the interaction between the drum and the ground and the position of the roller;
• infrared temperature sensors, to monitor the temperature of the surface being compacted;
• a computer with dedicated software that processes the compaction data and reports measurement values; and
• a display and controls that give feedback to the operator and allow the compaction operation to be adjusted.

As of 2013, the component technologies were considered mature and were offered by several manufacturers, both on new rollers and as retrofits to existing ones.

Where It Is Used

IC can be used on unbound materials (embankment, subgrade and base) and on asphalt layers. It is used mainly with vibratory rollers (see Compaction Equipment): steel-drum rollers for asphalt, and smooth-drum or sheepsfoot rollers for soil.

What It Measures

IC measurement values are based on the stiffness of the material, derived from the drum's response. Each manufacturer calculates its value in its own way. As a result, IC values do not convert directly into density, and they cannot simply replace density tests for quality control or acceptance. They are still considered meaningful indicators of the degree of compaction, and because the roller records every pass, they cover the whole area rather than the few spots a density test samples (compare Compaction Measurement and Reporting).

Uses on the Job

IC helps crews find and deal with problems while compaction is still under way:

• Weak areas. Low stiffness readings can reveal weak soils in an underlying layer, so they can be corrected before the next layer covers them.
• Temperature differentials. Surface temperature mapping shows cold areas in an asphalt mat (see Temperature Differentials).
• Uniformity. Monitoring compaction across the area lets operators reduce variability and achieve more uniform density.
• Vibration control. By sensing drum–ground interaction, some systems can adjust the intensity of vibration to avoid damaging the material.
• Pass tracking. GPS records every pass, so rolling patterns can be followed more precisely and the right compactive effort applied everywhere (see HMA Compaction).

The system also produces a complete record of the compaction effort applied to the project.

Costs

The costs of IC include:

• Equipment. In 2013, an IC roller cost roughly 3 to 5 percent more than a conventional roller, depending on features and manufacturer, and retrofitting an existing roller cost roughly $50,000 to $75,000.
• Upkeep. The equipment needs periodic maintenance and calibration.
• Training. Operators and supervisors need training to use the system.

These costs can be offset by:

• more efficient rolling patterns, which use less fuel;
• shorter construction time, which reduces labor and equipment costs;
• finding compaction problems before the next layer is placed, which avoids rework and improves pavement performance; and
• more uniform compaction, which can help a contractor earn density-related pay incentives, even though IC does not measure density directly.

An IC roller does not necessarily pay for itself on its first project; the payback may take several projects.

Further Reading

FHWA's report on accelerated implementation of IC for soils, aggregate base and asphalt¹, its IC tech brief², and NCHRP Report 676 on intelligent soil compaction systems³ describe the technology and its specification in more detail.

@misc{pavint-intelligent-compaction,
  author = {{Pavement Interactive}},
  title = {Intelligent Compaction},
  year = {2026},
  publisher = {HeadLight},
  howpublished = {\url{https://pavementinteractive.org/reference-desk/construction/compaction/intelligent-compaction/}},
  note = {Accessed [date]}
}