Gentle Treatment Of Rap Pays Big Dividends

Preserving Bitumen Reduces Operating Costs

An innovative RAP-processing machine is preserving unprecedented levels of bitumen, helping Asphalt producers drastically reduce operating costs.

The Ammann RSS 120-M with Primary Shredder, Screen and Secondary Shredder handles recycled material more gently than a traditional crusher. That special treatment has a substantial benefit. “The advantage of this machine is that we can reuse the recycling material without damaging the bitumen coating on the stone surface,” said Gerrit Lennips, Territory Manager Plants Benelux. “We have a residue of approximately 5%, while the competition has residue of 20%.”.

What makes the RSS 120-M different from traditional crushers? The Ammann machine disaggregate the bitumen-coated stones instead of crushing it, minimising the need for reapplication of the petroleum-based material.

BAM, the largest construction contractor in the Netherlands, has been quick to take advantage of the RSS 120-M. The contractor has utilised the machine on a variety of jobsites as it incorporates high percentages of RAP into its mix.

Using less bitumen reduces costs, as does using RAP instead of new aggregate.

Additional Benefits

The RSS 120-M also greatly reduces fines, leading to a host of advantages. “With fewer fines, you have better control of your RAP quality and obviously you have better control of your emission quality,” said Jian Qiu, Research and Development Adviser at BAM. Fines tend to be sticky – especially in the RAH dryer – which hinders efficiency and leads to increased maintenance costs.

“The amount of material you put into the machine and the waste you get from this machine is a lot less than if you compare it to other machines on the market,” Lennips said. “We are not breaking stones but we are tearing it apart, and that’s a big benefit.”

Qiu said this process can provide control of the mixture grading with less variation during the recycling process. This is very beneficial to the performance of the mixture during service.

Using the Ammann shredder reduces another operating cost: fuel consumption. “The fuel consumption of the RSS 120-M is very low compared to other crushers,” said Arie Van Dodewaard, Service Partner at Ammann Benelux. “Our average fuel consumption is 15 litres per hour.”

Utilising the RSS 120-M is extremely straightforward, Heijmans said. “This machine is very suitable for asphalt granulates because all handling is completed in a single operation,” he said. “Simply put in the raw material and it’s reduced and screened to the requested fractions.”

Production is notable, with the machine processing an average between 80 tonnes (slabs) and 120 tonnes (milled) of material per hour.

The shredder is ready to work soon after arriving on the jobsite. “Setting up this machine takes between 15 minutes and half an hour,” said Van Dodewaard. Mobility is an additional key feature. Operators use a remote control to relocate the machine around the jobsite. “The machine is completely mobile due to its tracks, remote control and easy transport operation,” said Arjan Heijmans, Plant Manager of BAM Helmond. “It’s actually quite simple.”

Longer travel distances between jobsites require haul trucks. The mobility makes the loading process extremely easy. “The machine is able to drive itself onto the low-load trailer,” Van Dodewaard said. No special transport permissions are needed.

Steps to minimise maintenance time and costs were taken during the design of the RSS 120-M. “Replacing the screen inserts is a very simple process,” Van Dodewaard said. “This was a priority during development of the machine. The replacements can be made in a very short time. Maintenance of the machine is very easy.”

All service points and fluid ports are easy to access. “In addition, there are long service intervals for wearing parts,” Van Dodewaard said.

The Ammann machine disaggregate the bitumen-coated stones instead of crushing it.

Source: Ammann