The effect of carbon nanotubes on the properties of asphalt concrete

Abstract

The method of nanomodification was reviewed and its effect on the properties of polymer-bitumen adhesives (PBA) and asphalt concrete prepared on their basis was studied. It was determined that nanomodified PBA is less sensitive to aging processes, which is the result of the peptization of asphaltene-resin complexes in the structure of modified adhesives and their construction with polymer matrix. It has been found that the nanotubes used as modifiers act as a tailoring agent and an inhibitor of aging processes in PBA. It has been determined that when nano-carbon tubes are applied in a complex form with MasterLife PVA 100, a surface-active agent, the adhesion capacity of bitumen increases and, accordingly, the operational properties of asphalt concrete improve. Studies have shown that the most important process in the application of nanomodifier is ensuring its uniform distribution in the volume of bitumen. The process of diffusion of carbon nanotubes in bitumen is carried out at a temperature of 100°C with the presence of a plasticizer. As a result of this operation, it is possible to achieve a uniform dispersion and distribution of nanoparticles in the volume of the carrier medium (plasticizer), which allows to the intensification of the processes of incorporating carbon nanotubes into the composite matrix. Achieving high performance of nanomodified PBA against layering and aging is explained by the processes occurring at the micro and nano levels. Along with the use of plasticizers, ultrasound is also used to introduce nanotubes into the bitumen to break up the nanotube agglomerates (entangled balls of hundreds of carbon nanotubes of different sizes held together by Van der Waals forces) and ensure their uniform distribution in the bitumen. The effect of nanomodified PBA asphalt concrete on strength and deformation properties was studied. It was found that the use of modified adhesives in asphalt-concrete mixtures increases the water resistance, heat resistance, and shear resistance of asphalt concrete.