Total Bitumen and Tarmac – Collaborative resurfacing to minimise disruption
While quality, reliability and cost are imperative to the success of any road resurfacing project, minimising disruption for the public is also important, reducing delays and making sure that noise and vibrations are kept to levels that don’t impact nearby residents.
In October 2018, Total Bitumen, Tarmac and the Highways Agency worked together to overcome these issues and more during the completion of the A66 Eden Valley Scheme, showcasing an industry-leading approach to collaboration that ensured the project’s success.
The A66 Eden Valley Scheme
The £5 million A66 Eden Valley Scheme involved resurfacing a key stretch of road between Penrith and Kirkby Stephen in North Cumbria and was undertaken by Tarmac for Highways England.
The aim was to ensure the carriageway was constructed to modern standards, producing minimal vibration for drivers and much less noise during construction so as not to disturb residents. Due to the importance of the route, the works required completion with minimised interruption for the public – meaning each shift, more asphalt needed to be able to be laid, faster than usual.
This required completing the works under full road closures during weekends throughout October 2018, with around ten thousand tonnes of asphalt being installed at seven locations across the A66.
Logistically, these productivity targets could only be achieved using warm mix asphalt, with problems compounded due to the project’s rural nature. The solutions came from Total in the form of Azalt ECO2 binder, Styrelf® eXtreme 100 Polymer-modified binder (PMB) and Total Emulsis NBC50 bond coat.
How Total ensured an efficient operation
Supplying Tarmac with the three products, Total Bitumen was able to drastically improve the performance of both road-laying operations and the asphalt itself.
The benefits of Total Azalt ECO2
Azalt ECO2 warm-mix binders allow bitumen to be laid at much lower temperatures than many conventional products. This was beneficial for the A66 Scheme as the reduced energy demands for heating and the product’s lowered emissions allowed for to a more environmentally friendly operation. A cooler product also meant less danger to staff and the product’s lack of steam generation during paving operations improved visibility to improve site safety and provide a more comfortable working environment for staff.
The product also improved the efficiency of operations and the final paving. Compared to conventional products, bitumen modified with Azalt ECO2 can be compacted more easily, transported longer distances, worked on for longer periods, exhibits greater tolerance durability and combats premature product ageing, all while allowing surfaces to be re-opened to the public faster.
Pre-blended, the warm-mix binder also removed the need to manually mix additives at Tarmac’s asphalt plant, all while allowing a wide variety of products to be manufactured from a single PMB. Simplifying stock while keeping production levels high, it was able to save the project time and lower costs.
The advantages of Total Styrelf eXtreme 100 PMB
Complementing the environmental benefits of Azalt ECO2, the addition of Total Styrelf eXtreme 100 PMB improved the effectiveness of Tarmac’s bitumen further.
Styrelf’s most impressive features are performance-related. Made by crosslinking elastomeric polymers within bitumen, the product improves the durability of road surfaces, making them far more resistant to fatigue, rutting, fretting and ageing in areas of high stress. The A66, with its large volume of traffic and location exposed to the elements, was a perfect candidate.
Styrelf was also able to ensure the stability of bitumen in storage. Sometimes, producers can be negatively affected by sporadic specialist asphalt supplies, and if binders are stored for long periods between production runs, the polymers within will begin separating from the bitumen, resulting in a head of bitumen at the top of the tank and unmodified bitumen below.
This issue can occur when there are gaps in production for specialist products – a situation that affected the A66 project. Thankfully, Total Bitumen had performed extensive laboratory analysis to boost Styrelf eXtreme 100’s storage stability, ensuring it was fit for purpose after over sixty days in storage, thereby reducing waste and the loss of high-value materials.
How Total Emulsis NBC50 ensured a perfect finish
If the A66 was to be durable and long-lasting, the layers of its base, binder course and surface had to be correctly bonded together to stop water filtering into the pavement and de-bonding its layers.
Total Emulsis NBC50 bond coat provided an innovative solution to this issue. With non-stick properties, the bond coat ensured that delivery vehicles did not pick up any of the bond coat on their wheels. This was unlike conventional bond coats, which can be picked up by wheels, causing the surface layer to de-laminate from the binder course, exposing the road surface to the risk of future potholes. The proof could be seen along the surrounding roads: unlike many projects, black contamination lines were absent as delivery vehicles left the site.
Coupled with a fast, responsive approach to delivery, Total Bitumen’s products were able to improve the operational efficiency of the A66 Eden Valley Scheme, so much that the project saw 1,000 tonnes of asphalt laid per shift, and despite Storm Callum causing havoc across the UK during the works, they were completed on schedule.