Technologies That Evolve Compaction

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Updated: July 14, 2016

Uniformity, quality and confidence give you an advantage

While compaction science – both asphalt and soil – has made great strides in recent years, field acceptance and practical application of new technologies have lagged behind. For those seeking competitive advantages directly related to project costing and profitability, innovative solutions have arrived. Three game-changing developments from Caterpillar Paving Products can make your compaction processes more productive, more efficient and more profitable.

The three new technologies are:

  1. Auto Adjustable Asphalt Compaction
  2. Machine-to-Machine Asphalt Compaction
  3. Soil Compaction Using Machine Drive Power

Auto Adjustable Asphalt Compaction

Experience teaches you that a compactor which has not been properly set up to perform at an optimum level cannot achieve the target compaction in the quickest, most efficient manner. Even worse, it can damage the mat by breaking aggregate. With Auto Adjustable Compaction (AAC), operators can be confident they are compacting at or near the machine’s full potential, and also preventing unseen, unknown damage that may lead to premature mat failure.

How It Works

The exclusive Cat® Auto Adjustable Compaction (AAC) system maximises the potential of the machine by assessing the capacity of the mat to accept energy and adjusting the amplitude to deliver the optimal energy on each pass. The system utilises both drums, functioning from the leading drum in the direction of travel – to ensure superior compaction as follows:

  1. The eccentric weight generates vibration, and then transmits this energy via the drum into the asphalt layer.
  2. The asphalt mat responds with feedback energy, which is measured by an accelerometer.
  3. The system then quickly adjusts the amplitude by phasing an internal and external eccentric mass, to a near decoupled state. This state represents the highest compaction force the mat can accept on each pass, thereby delivering the quickest density/stiffness growth possible.
  4. As the mat nears maximum density, the system decreases the amount of energy delivered.

Each pass provides a Compaction Measurement Value (CMV). As compaction increases, the CMV value increases by smaller increments, indicating that the mat is nearing target density. While not a density measurement, the CMV number can be correlated to density in this way. Paving contractors utilising AAC have found that it provides a reasonable indication of density for the composite asphalt layers.

Whether working on breakdown, intermediate or finish compacting, the automated system works equally well in both directions. Every pass automatically delivers the best compaction effort.

Key Benefits

  • Ensures amplitude is optimised automatically
  • Reduces risk of inexperienced operators damaging the mat
  • Prevents decoupling/damage to asphalt automatically
  • Sensitivity allows for stiffness of different bitumen mixes
  • Helps produce uniform compaction
  • Reduces risk of over-compaction

Machine-to-Machine Asphalt Compaction

Machine-to-Machine Asphalt Compaction is a simple concept that makes it possible for multiple compactors to perform as if they are one. Tied to GNSS location technology, connected onboard modems create a wireless network that shares data between a primary roller and one or more secondary rollers. As system-equipped machines work, they share their compaction data in real time. This could include pass count, mat temperature and CMV, depending on how the machines are equipped. The real-time data enables all of the operators to understand how the whole job is progressing.

The system is particularly useful for time-constrained, high-speed wide paving or echelon paving on surfaces such as airport runways or taxiways. However, any paving train utilising multiple rollers – breakdown, intermediate or finish – will benefit from this new technology. Working and documenting as one assures that the process remains within the boundaries that determine success. Making compaction more uniform is a key to long structure life.

When density problems occur, it’s likely that the number of passes over a given area is inconsistent. Since all operators share a full picture of the compaction process, they can improve a developing situation by making pattern corrections in real time on the fly.

Seeing where the compactor has been is easy during the first pass in any compaction phase; but when two to four additional passes are applied, it can be difficult for operators to know exactly where they’ve been and how many passes they’ve applied. This task is even tougher at night when you can’t always see your watermark. As the mat cools, temperature mapping enables operators to identify and avoid the tender zone.

While Auto Adjustable Compaction is focused on individual compactor optimisation, Machine-to-Machine Compaction utilises information sharing to tie multiple compactors together as if they were operating as one. The application of both technologies brings asphalt compaction to previously unattainable levels of consistency, efficiency and productivity.

Soil Compaction with Machine Drive Power

Machine Drive Power (MDP) is a machine-integrated soil compaction measurement technology. MDP is one element of Intelligent Compaction (IC), which is gaining acceptance on soil compaction job sites worldwide.

IC is commonly understood to include:

  • An integrated compaction measurement system (an accelerometer, or MDP)
  • The ability to tie measurements with their job site location using positioning technology (GPS, for example)
  • A way to gather and record data for analysis

Machine Drive Power provides indications of soil stiffness by measuring the amount of energy necessary to overcome rolling resistance. It is based on the fact that the looser a soil, the harder it is for the drum to roll over the soil, which then requires more energy to propel through it. That resistance provides an indication of soil stiffness or load-bearing capacity as related to the specifications for supporting the road, parking lot, building – or whatever is planned for the site.

MDP, a proprietary technology developed by Caterpillar, is catching the attention of contractors worldwide for several reasons. It works on all soil types, including cohesives, with the vibratory system active or inactive. And it has the potential of eliminating passes, delivering considerable cost savings.

GPS + MDP = Confidence

As MPD provides stiffness measurements, GPS can correlate them to the locations where they were measured, providing a 1-to-1 picture of the compaction, coverage and the uniformity of the work. This complete picture can confirm that the entire site has been compacted the same way or identify areas with potential weakness.

One word – uniformity – sums up the key benefit to contractors, quality control personnel and taxpayers. Uniformity matters because non-uniform areas have a high likelihood of failing. That can mean costly rework or expensive future repairs. MDP has proven to be an outstanding indicator of soil stiffness, making uniformity achievable.

To learn more about the benefits of the latest compaction technologies from Caterpillar, contact their dealership.