Research On Enhancing Development Process Of Asphalt By Ultrasound

Modified asphalt is a mixture of matrix asphalt and some polymers such as rubber and resin or other fillers,which can improve the performance of matrix asphalt.As one of the most widely used polymer modified asphalt,SBS modified asphalt has been mainly applied in highway construction and preparation of building waterproof material.The perform of SBS modified asphalt need to enhance to apply to the increasing traffic flow and load of vehicles,such as resistance of permanent deformation,resistance of rut,resistance of fatigue,resistance of aging,resistance of cracking at low temperature and stability at high temperature.With the industrial production of SBS modified asphalt,it is an urgent problem to improve the pavement performance.Power ultrasound is widely applied in the field of petroleum and chemical industry in recently tears,such as preparation of catalyst and extraction with ultrasound.When the technology of power ultrasound is applied to the development process of modified asphalt,cavitation effect will produce a kind of local environment with high temperature and high pressure,as well as strong shock wave will produce.The mechanical action generated by sound wave and the energy generated by cavitation effect will improve the dispersion of SBS polymer in the asphalt matrix,refine SBS particles and accelerate the reaction of SBS with asphalt or additives.Therefore,power ultrasound plays an important role in improving the pavement performance SBS modified asphalt.In this paper,the mechanism of enhancing development process of modified asphalt by ultrasound was analyzed.Meanwhile,the corresponding experimental equipment was developed and experiment was carried out to investigate effect of ultrasound on development of modified asphalt.The specific research works are described as follow.The application of ultrasound to different development stages of asphalt was analyzed.The dynamic model of cavitation bubbles in modified asphalt was established.The minimum sound pressure to produce cavitation effect and the energy generated by cavitation effect in matrix asphalt under the condition of 20 kHz were calculated according to the model.Combined with the application of power ultrasonic in chemical industry,the influence of ultrasonic on the development process of modified asphalt was analyzed from two aspects: the energy generated by ultrasonic cavitation effect and ultrasonic dispersion.An ultrasonic transducer was designed and manufactured according to the requirement of experimental environment and the formation condition of cavitation effect.The material of each part was determined according to the above conditions.And the dimension parameters of the sandwich vibrator,horn and tool head were designed calculated by electromechanical equivalent method.Since the temperature of liquid which is disposed by ultrasound reaches 170-180?,the cooling structure of the transducer was designed.Moreover,the modal,harmonic response and the heat transfer of the transducer were analyzed by the multi-physics simulation to verify the correctness of the design.After that,the transducer designed was manufactured and the resistance of high temperature was verified by oil bath experiment.The experimental platform was set up according to the development requirements of modified asphalt.The technological process of SBS modified asphalt prepared in the laboratory was developed in order to ensure that the developed modified asphalt meets the requirements of asphalt.The effect of ultrasound on the basic performance index,resistance of aging,compatibility,stability and thermal stability of modified asphalt were studied based on control experiment.In the end,the effect of ultrasound on pavement performance of SBS modified asphalt was analyzed.