Blog: SECBE Awards 2022 finalist - Delivering Rubberised Asphalt

12 April 2022

Innovation sponsored by RIFT

Delivering Rubberised Asphalt (submitted by Kier Highways)

Innovation Constructing Excellence SECBE Awards 2022 finalist

Annually, over 4,000,000 tyres go to waste in the UK and this submission outlines a trial carried out by Kier Highways in conjunction with Tarmac Ltd. to evaluate Ultipave-R, an innovative new rubberised asphalt product, and assess the viability of bringing it to TfL’s road network, and in turn use it with other local authorities across the UK, providing a means of recycling this waste product as a useful construction material.

The trial was carried out on a Kier Highways LoHAC scheme in South East London to assess Ultipave-R, a new rubberised asphalt, for its product performance. The road selected has annual average daily flows of 207 buses, alongside 354 commercial vehicles in each direction, making it a good example for the trial, and over a series of shifts nearly 3,900m2 of Ultipave-R was laid.

Rubberised asphalt substitutes part of the cellulose filler in the asphalt mix with granulated rubber. The rubber content of the asphalt used in this trial was 0.6% so with a surface thickness of 40mm (equivalent to 100kg/m2) and an average car tyre weighing 9kg, approximately 67 tyres would be recycled per 1,000m2 of resurfacing. Approximately 500,000m2 of carriageway is resurfaced on the Transport for London Road Network (TLRN) annually, meaning that 33,335 tyres per year or 0.83% of all waste tyres in the UK could be recycled through TfL’s carriageway resurfacing programme.

Ultipave-R and an equivalent control mixture not including granulated rubber were both laid during the trial in areas close to each other, with identical weather conditions, and identical machinery, to compare the new products performance. Laboratory tests were undertaken during installation, alongside visual conditions surveys undertaken post installation. Cores were also extracted to check for voids and other defects in the construction layers.

Testing of the new surfacing was undertaken by Tarmac Ltd through their accredited laboratory and selected accredited third-party laboratories, to ensure that, by replacing the cellulose fibres in the asphalt with crumb rubber, there was no detrimental effect on the performance of the asphalt. Assessing Ultipave-R, it was essential to compare its compaction credentials to standard Clause 942 mixtures. This evaluated whether the rubber changed the viscosity of the asphalt during laying thereby impacting the life of the asset in service.

Visual Condition Surveys undertaken following installation confirmed the carriageway was free from defects whilst Ultipave-R cores compared against the control material were indistinguishable from the norm. BBA were on site to oversee production and installation of the product during the trial and HAPAS certification has been granted for the product.

The research and trial of Ultipave-R rubberised asphalt aimed to provide TfL with confidence in its future use for carriageway maintenance and Kier Highways have proved that a rubber modified SMA mix can be used on London’s Strategic Road Network. The company have shared trial outputs with other TfL suppliers so it can be used on any surfacing activities for TfL going forward and its ongoing ambition is to use it nationally, delivering significant recycling of a waste material.

Key achievements:

• Ultipave-R, is HAPAS certified as a ‘Warm Mix’ surface course with Rubberised asphalt from recycled tyres.

• 500 waste tyres could be recycled in every kilometre of road resurfaced with the ULTIPAVE R solution.

• Ultipave -R is classed as zero CO2 rated.

Client: TFL

Project Partners: Kier Highways, Tarmac

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Find out who wins at the Constructing Excellence SECBE Awards 2022 Ceremony on Thurs 30th June 2022.

About the Innovation Award (sponsored by RIFT): 

Innovation is widely recognised as the critical factor for increased and sustained productivity and growth. It demonstrates an organisation’s confidence, capacity and appetite for improved performance and productivity gains. Innovation is most effective as a holistic approach that identifies both demand and ideas and is most successful when supported by collaboration between customers and the supply chain. More info.

>> Find out more about the other Constructing Excellence SECBE Awards finalists here