The name’s Bond, SAMIBond

SAMI Bitumen Technologies’ SAMIbond 007 trackless tack coat emulsion has been designed for high stress impacts and applications. Roads & Infrastructure speaks with SAMI to learn more.

Tough, effective and calm in high stress environments. These are words commonly associated with the title of 007.

SAMI Bitumen Technologies’ take on the 007 label maintains the sophistication while removing the cheesy one liners.

But what does it take to earn double 00 status? 

Kanjana Yindee, Laboratory and R&D Manager – SAMI Bitumen Technologies, says the company’s development of non-tracking tack coat emulsions began in 2019. Ultimately leading to the production of the SAMIbond 007 trackless tack coat emulsion.

“To ensure a sufficient bond between layers, a tack material should remain intact after application. However, a conventional tack coat is likely to track under paving equipment and asphalt delivery vehicles,” Yindee says. “Even if the tack coat is appropriately sprayed, the tack coat binder can be removed in a wheel path due to its pickup by the construction vehicle tyres.

“This is why our customers frequently ask if we have trackless tack coat emulsion, the main reason why we’ve developed such a product.”

A tack coat refers to a thin layer of bitumen that is applied between the layers of a multilayer asphalt pavement, to bond them together, improving the overall strength and durability of the pavement and surface. One of the many reasons it achieved 00 status.

This is usually applied in the form of an emulsion that is sprayed prior to the application of the next layer of asphalt being laid.

This special emulsion allows delivery trucks and pavers to drive over the new surface without leaving markings or wheel tracks on the adjacent surfaces.

Once applied, the SAMIbond 007 renders a shiny black and hard surface.

As Yindee explains, SAMIbond 007 is a cationic bitumen trackless tack emulsion that has been modified with a polymer. 

“The addition of polymer helps to improve the emulsion’s performance and durability, making it better able to withstand high horizontal stresses from traffic during the life of the pavement. This makes the emulsion ideal for use in pavements associated with heavy traffic and high stresses,” she says.

Behind the scenes

Development of SAMIbond 007 focused not only on the trackless component, but also overall durability. 

Brad Richards, State Manager Southern Region – SAMI Bitumen Technologies, says this development has also caught the eye of Victoria Department of Transport (VDoT).

“The concept really started with VDoT who were looking to tack coating products that weren’t going to be picked up by the tyres of machinery that were laying the asphalt on top of it,” he says.

“Their thinking was ‘what’s the point of putting down a tack coat if it’s just going to be picked up by the wheels of the equipment?’ It’s just messy.”

He adds that the product has already been used in projects with high-stresses, such as highways and airports.

“Sometimes, like on an airport, there are only short windows of time that the crew is allowed to be on site so careful planning and specialty products are key to productivity,” Richards says.

“SAMIbond 007 has been used successfully in several applications to date, including cold environments and at night. Paving equipment can drive on the sprayed surface with no pickup on the paving equipment wheels.

“Time is money and the faster the asphalting equipment can get onto the job, the better.”

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Richards says SAMI Bitumen Technologies’ direction from both industry and government were large influencers during development.

“Our technical experts have refined the product over recent years balancing the ease of handling, speed of curing and trackless behaviour, to now have a product that is being used successfully in calibrated sprayers and through pressurised crew trucks,” Richards says.

Yindee concedes that one of the biggest challenges during the product’s development was establishing an emulsion product that catered for Australia’s variety of spraying machinery.

“There is a wide variety of sprayers on the market and it is difficult to anticipate how the product will react with each one,” Yindee says.

“Over a long development period we worked hard to achieve the final formulation with all of the properties that we were aiming for. SAMIbond 007 can now be applied without heating with some sprayers. It’s also energy-efficient, making it a sustainable product.”

Firsthand experience 

One company that has already benefitted from using SAMIbond 007 is Centre State Asphalting.

The Victoria-based contracting business carries out works across the state for clients of all sizes, from private works, to leading contracting on resurfacing works for the Victorian Department of Transport.

Scott Bowley, Project Engineer – Centre State Asphalting, says delivering quality outcomes is the company’s number one priority. 

“By having our crews fully fitted out, asphalt sourced from our production facility and binders from SAMI, we can ensure at every point along the asphalt production and placement process that quality is maintained allowing us to provide the highest quality service possible,” he says.

The company recently used SAMIbond 007 as part of minor works around central Victoria, as well as the Calder Highway for the Victorian Department of Transport.

Bowley says the product has shown potential for use in future projects.

“Having a product that allows delivery trucks and paving equipment to drive over and keep the tack coat on the pavement, is better for the long performance of the pavement and better for stopping tracking of the fresh binder on the site where the works are being undertaken,” Bowley says.

“Due to the quick breaking nature of SAMI bond 007, this product is perfect for all conditions, including low temperatures where the quick breaking nature reduces pick up under vehicle tyres when compared with a typical tack coat.

“Combined with the quicker breaking, reducing the concern of emulsion wash off, it is a lower risk product to be applying at any time of year.”

Richards says that based on the performance and feedback received, there are expectations that SAMIbond 007 could be widely adopted in the near future.

“As more customers get to use the product and see the benefit of how it performs, it is expected that it will become the bond coat of choice not only because it has been specified, but because of the efficiencies that it provides the contractors that use it,” he says. 

This article was originally published in the July edition of our magazine. To read the magazine, click here.