Cons of Using Gipave to Repair and Resurface Road Pavements

Brief 

Research into the use of a graphene-enhanced asphalt ‘supermodifier’ has found that the additional upfront cost is more than compensated for by the increased lifespan of the repaired surface.

Insight

Research into the use of a graphene-enhanced asphalt ‘supermodifier’ has found that the additional upfront cost is more than compensated for by the increased lifespan of the repaired surface.

The University of Nottingham’s Transportation Engineering Centre has been working with Kent County Council (KCC) and its highways contractor Amey to assess the pros and cons of using Gipave to repair and resurface road pavements.

The research, part of the £22.9m Association of Directors of Environment, Economy, Planning & Transport (Adept) Smart Places Live Labs programme, builds on the Gipave trial KCC and Amey undertook in July 2020, where core samples from the Gipave asphalt carriageway showed improvements in many structural factors, including fracture toughness, stiffness modulus and fatigue.

Gipave is a graphene-enhanced polymeric supermodifier comprising pellets containing graphene and recycled plastics that are melted into the aggregate mix with bitumen. The resulting product has been shown to have an extended surface lifetime of up to 25 years – approximately two and a half times that of traditional asphalt.

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To better estimate the longevity of Gipave when used to build or repair pavements, the University of Nottingham carried out pavement design analyses (PDA) to model the product’s structural performance across a range of different road types and surfacing materials.

Working in collaboration with KCC and Amey’s Kent Highways team, the university analysed core samples from a number of recently-resurfaced roads of different construction types, namely stone mastic asphalt (SMA), asphalt concrete (AC) and polymer-modified bitumen (PMB).

Modelling from the PDAs concluded that all of the sites would show some improvement in lifetime extension through the use of Gipave, with one site lasting more than four times longer with Gipave than SMA before top-down cracks started appearing.