Nano­Materials in Asphalt Pavement

In this project we have addressed the challenges connected to the need for improved durability, safety and efficiency of asphalt pavements following the continuous increase of traffic volumes and loads. The NaMAP project has successfully produced asphalt/graphene oxide (GO) and asphalt/GO/aggregate mixes both in laboratory and field scale. The goal has been better, more durable and cost-effective pavement. In order to achieve this NaMAP has been focusing on modification of aggregates and asphalt mixture with reduced graphene oxide (rGO) or functionalized rGO. GO, rGO and functionalized rGO are nanomaterials with promising properties and potential for market penetration, primarily in asphalt pavements but also in other applications. Using state-of-the art surface characterization techniques (SEM, XPS,and AFM), we have characterized unmodified aggregates and characterized rGO deposited on aggregates to increase bitumen-aggregate adhesion. Furthermore, we have synthesized and characterized functionalized rGO using state-of-the-art techniques (FTIR, XPS, Raman spectroscopy, NMR (ongoing)) and results show successful functionalization. Functionalized rGO has been produced in quantity and been provided to our Greek partners for mixing into bitumen. Also, the project has actively investigated change in properties from mixing unfunctionalized rGO and GO into bitumen. Relevant formulation candidates were selected to be subjected to standard road tests. With growing global concerns with respect to pollution in mind, NaMAP has also assessed the health impact of the exposure to the new material, and the type of dust generated from GO modified asphalt. As we have been investigating potential energy savings and costs of producing the new material compared to conventional asphalt concrete, we have been looking into other aspects of making the production of asphalt concrete more environmentally friendly as well. Cost remains an issue until GO/rGO will be produced in large volumes.

x

The project objective is the development, analysis, characterization, and testing of graphene-­enforced asphalt concrete for advancing stiffness and durability of asphalt pavements. The development focuses on modifying asphalt concrete with graphene oxide or reduced graphene oxide studying the appropriate mixing proportion and process, the properties of the new material and its potential for market penetration in asphalt pavement construction. Complementary analyses will be performed for energy efficient production, health impact assessment, economic feasibility and sustainability assessment. The main innovation beyond the current stateof­the­art lies on the multi­disciplinary approach followed for exploring alternative material structures and enhancing bonding/adhesion among constituents (nano­material, bitumen, and aggregates) and on the detailed material characterization at all levels from nano/micro­scale to macro­scale and real­life field testing. The consortium includes three R&D partners and two SMEs with expertise on asphalt pavement design and construction, nano-­material production and characterization, and material bonding/adhesion methods at nano/micro and macro­scale.