Preparation of effective nanomodified polymer-bitumen adhesives for asphalt concrete

Abstract

The possibilities of modification of BNB 50/70 oil road bitumen, which belongs to the category of viscous bitumen and is used in road works in the hot season, at an average temperature not lower than +5°C have been studied. Copolymers of butadiene and styrene and vinyl acetate and ethylene were used as polymer materials for polymer-bitumen adhesives (PBA). A copolymer of butadiene and styrene (SBS) is a synthetic rubber in which solid styrene blocks are linked by butadiene “springs”. When mixed with bitumen, they create a highly elastic structure. The inclusion of 2.5 - 6.0% SBS in bitumen as a polymer additive increases the softening point and frost resistance of bitumen, gives high flexibility to the organic adhesive, which increases the heat resistance and shear resistance of asphalt concrete. Ethylene vinyl acetate (EVA) copolymer forms a rigid network in modified bitumen and resists deformation. It dissolves very quickly in thermoplastic bitumen at a temperature of 155-180°C, which facilitates the process of preparing PBY for asphalt-concrete. The optimal concentration of polymers for obtaining high heat-resistant and flexible PBY has been determined. Carbon nanotubes act as a functional additive for bitumen. Modified bitumen adhesives and physical-mechanical indicators of asphalt-concrete mixtures made on their basis were studied. It was found that by introducing a small amount of nanocarbon tubes into asphalt-concrete, its shear resistance and strength are significantly increased at different temperatures (from 0 to 50°C).