New additive boosts rubber-modified asphalt

Lehigh Technologies, which produces micronized rubber powders, has joined forces with additive specialist Rheopave to come up with a system which will improve the performance of asphalt, while reducing the cost compared to standard polymer modified asphalts. Rheopave had developed its X10 additive, a blend of reactive polymers and other elements, to work with Lehigh’s MicroDyne micronized rubber powder. It overcomes two problems currently experienced with rubber-modified asphalt, according to Lehigh’s direc
September 10, 2014 Read time: 3 mins
The LeHigh product offers high performance in use

7875 Lehigh Technologies, which produces micronized rubber powders, has joined forces with additive specialist Rheopave to come up with a system which will improve the performance of asphalt, while reducing the cost compared to standard polymer modified asphalts.

Rheopave had developed its X10 additive, a blend of reactive polymers and other elements, to work with Lehigh’s MicroDyne micronized rubber powder. It overcomes two problems currently experienced with rubber-modified asphalt, according to Lehigh’s director of coatings, asphalt and construction materials Ryan Alleman.

“The first problem is that rubber does not become part of the asphalt so it settles out. So the contractor needs to be near the plant or to fit his equipment with agitators, which is expensive,” he said. “The second issue is that base asphalts have become more robust because refiners are taking out the aromatic oils for other uses.

This means that ground tyre rubber isn’t able to modify the asphalt as well as it used to.”

Rheopave X10 works by generating active sites on the rubber particles allowing a continuous network structure to be created, suspending the rubber throughout the binder. This means it is stable in storage and transportation.

Performance benefits from using the combination of Lehigh’s MicroDyne and Rheopave X10 are longer fatigue cracking life and also enhanced elastomeric properties allowing the pavement to combat cold cracking, according to Alleman. It is also easier to handle as the mix is less tacky than one made with ground tyre rubber alone.

Though this is a new product, it is already available commercially in Florida, with over 18 companies around the US currently involved in testing it. Lehigh has also begun promoting it in Europe, Japan, Korea and Brazil. “We will initially be targeting countries that have experience of rubber-modified asphalt already,” said Alleman.

In terms of cost, this product could offer savings over conventional SBS-modified bitumen, although that will depend on the prices of SBS and how robust the base asphalt is and therefore how much additive it needs. SBS prices have historically been volatile, although they are currently low as there is no shortage in supply.

Hot mix plants looking to use the combination of Rhepave X10 and Lehigh’s MicroDyne may need to invest in modifications. “It does not require a high shear mixer like that which is needed to process SBS however it does require a terminal blender and a saw-toothed blade such as a Cowles Mixer blade,” said Alleman.

“Companies that have blenders can expect to outlay less than $5K in plant modification to process Rheopave.”

Materials

For more information on companies in this article

Related Content

  • New tests for modified bitumens and mixes with RAP
    December 19, 2014
    This month we learn about a new test which is helping to predict the performance of asphalt mixtures containing recycled materials and modifiers, and we showcase some of the new testing equipment recently launched - writes Kristina Smith Researchers in the US have come up with a new test to help owners and contractors better predict the performance of their roads. “The problem is that the current tests cannot determine the performance of new materials,” said Dr Haleh Azari, manager of the AASHTO Advanced P
    Read More
  • Innovative additive for use in recycled asphalt applications
    August 13, 2014
    Biorefiner Arizona Chemical has spent three years developing a new asphalt additive which it says will revolutionise the use of RAP in road pavements. Sylvaroad RP1000 will allow much higher proportions of RAP to be used and produce a better-performing pavement, according to the manufacturer. “What it essentially does is mobilise the chemical matrix of these aged binders,”
    Read More
  • Ready for rubber: Tarmac’s UK asphalt solution
    August 1, 2019
    A huge surplus of waste tyres and a strengthening commitment towards sustainability from local authorities has prompted asphalt supplier Tarmac to invest in technology to add crumb rubber to its mixes. Around 40 million tyres are worn out every year in the UK. Some are burnt as fuel for cement kilns, others are turned to crumb rubber for use in sports fields and yet more are incorporated into items such as car mats. The surplus – sometimes as much as 120,000 tonnes annually - is often shipped abroad for
    Read More
  • Rubber recycling for South African roads
    November 5, 2012
    South Africa takes crumb rubber use to the next level - *Anders Marschall Jensen The preservation of the environment is a global concept, and in the road construction industry, it is all about preservation of roads. In earlier days, roads were built with the primary goal of moving passenger traffic from one place to another, but these days, roads are very different. Not only is there passenger traffic, and more of it, but roads must also deal with extensive movement of products in heavy vehicles. Therefore,
    Read More

Highlighted Content