Maximum quality with warm mix asphalt

• Wirtgen Group's Smart Compact Pro system enables precise real-time density measurement and automatic compaction adjustment for warm mix asphalt, addressing the challenge of a shorter compaction window.

• Warm mix asphalt requires faster and more powerful compaction due to its lower paving temperature, which reduces harmful emissions but demands precise timing.

• The Track Assist and WPT Compacting applications provide operators and site managers with real-time process data, mapping, and detailed quality documentation, enhancing transparency and control.

• This integrated digital approach improves compaction quality, reduces the need for drill core analyses, extends road service life, and increases overall process reliability.

Smart Compact Pro for real-time density measurement

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On the L3161 between Olberode and Christerode, a stretch of some 3.3 kilometres was repaved with a new asphalt surface course. The challenge: The warm mix asphalt being used for the job calls for a much faster compaction process than conventional mixes. This is where the Wirtgen Group machines came in. The material was initially paved and precompacted in the Inline Pave process. Two tandem rollers from Hamm with Smart Compact Pro then compacted the new surface.

Shorter timeframe for compaction

The main difference when compacting with warm mix asphalts is that the paving temperature is at least 20 °C lower than the temperature of conventional asphalt mixes. The benefit: Fewer harmful vapours and aerosols are released. The challenge in terms of asphalt construction: Precision timing is key when using this material, because it cools down faster, reducing the window of time available for optimum compaction.

‘In practice, this means making the compaction lanes shorter and achieving a higher compaction power within a shorter time in order to produce the required asphalt quality. Experience shows that even highly skilled operators cannot consistently meet these challenging requirements the way they can for conventional asphalt paving, at least not without supporting systems,’ says Dr Axel G. Mühlhausen, Senior Product Manager – Digital Solutions Hamm.

Real-time density the secret to success

To achieve homogeneous compaction of the material, the team in Olberode utilised Smart Compact Pro. The system uses the Realtime Density Scan to record the asphalt in real time and automatically adapts the compaction power and mode of each drum. As well as asphalt, other parameters are taken into account, including, for example, the cooling behaviour of the asphalt, local weather data, course type and course thickness, for the automatic control of both drums. This ensures that the optimum density is achieved, irrespective of external influences or the operator’s experience. Extra assistance for the driver: Smart Compact Pro has a presetting specifically for warm mix asphalts, which adjusts the system to the particular parameters at the push of a button. ‘Smart Compact Pro is undoubtedly a huge help in achieving the required quality and for the drivers themselves, it’s great to get that instant feedback, telling them if they need to keep compacting here or not,’ explains Andre Blättner, Head of Construction at Bickhard Bau SE.

High level of process reliability, longer road service life

With its real-time density measurements, Smart Compact Pro reduces the need for drill core analyses. Cracks and other signs of premature damage are a much less frequent occurrence and the roads last longer, reducing the potential for additional expenditure for refurbishment at an early stage. Smart Compact Pro is available for the tandem rollers in the HD+ and HX series.

‘For the first time, the driver has the asphalt density at their disposal in real time – the most important parameter of all. This way, the system automatically controls the entire compaction process, while also considering the asphalt temperature, the asphalt’s cooling behaviour and different material characteristics. With warm-mix asphalts in particular, where we only have a short window of opportunity to compact, this is an enormous benefit. Ultimately, this results in higher quality, more efficiency, fewer double passes and, best of all, process reliability,’ adds Dr Axel G. Mühlhausen.

Track Assist and WPT Compacting: Transparency and control of the compaction

The Track Assist app was also called upon to help on the site between Olberode and Christerode. This gives the operator all process and performance data in real time, displayed on the tablet, including the real-time asphalt density measured by Smart Compact Pro. All data can be visualised with clearly presented mapping. This information was also made immediately available on the construction site, giving the driver a transparent overview of the overall compaction progress at any time.

Further to this, the rollers fitted with WPT Compacting documented all performance data and transferred this to the John Deere Operations Center™. This gives the site management team extensive opportunities to analyse and evaluate – from detailed reports and point analyses to standardised exports for the quality documentation. One particularly valuable feature is the ability to create comprehensive density maps for the first time. Rather than assessing quality solely by means of individual drill cores or random checks, the asphalt density achieved across the entire surface can be traced and documented. As such, Track Assist and WPT Compacting build on the automated compaction of Smart Compact Pro to deliver an entirely digital process chain. While Track Assist helps the driver to produce high-quality compaction results, WPT Compacting delivers flawless analysis, documentation and evidence of the quality achieved. For construction companies, this means more transparency, greater process reliability and a strong basis for quality assurance to present to customers.