The Research Of Performance And Mechanism On Dry-mixed Waste Plastic Modified-CRP Asphalt Mixture

Waste plastics modifier CRP is produced by row materials as waste plastics,and CRP bitumen mixture by dry process is adding the CRP modifier into mixed bitumen mixture at a proper mixing temperatures,after mixing a certain period of time,then finally mixing with mineral powder..However,Its emergence not only guarantees dry-mixed modified asphalt mixture having a better high temperature stability,low-temperature crack resistance and water stability,to a certain extent,but also solves the problems of waste plastics modified asphalt serious segregation and poor storage stability.The paper focuses on molten state and dispersion of the dry-mixed CRP in the asphalt mixture and pavement performance of dry-mixed CRP-modified asphalt mixture.Main research achievements are as follow:(1)The performance of CRP modified asphalt of different CRP mixing amount are tested through indoor experiments as penetration test?softening point test and the Brookfield viscosity test about A 70# asphalt?B 70# asphalt?C 70# and South Korea SK-70# asphalt,the result shows that the dispersion effect of CRP is vary from different kinds of asphalt,it means that the modified effect of CRP to different kinds of asphalt is difference,in comparison,the better modified effect of CRP to asphalt is CRP to South Korea SK-70#asphalt.(2)Through dry-mixed CRP modified melting test for the same aggregate(13.2mm + 9.5mm limestone),aggregate heating temperature,CRP particle size,mixed time about the effect of CRP and the aggregate melting are comparatively studied.The result shows: The best heating temperature for CRP can main completely melteand encapsulate in aggregates surface is 180?;The best duration of mixing the CRP modified bitumen mixture by dry process for the aggregates' particle size of 2.36 mm is 30 s,The best duration of mixing the CRP modified bitumen mixture by dry process for the aggregates' particle size of 1.18mm?0.6mm?0.3mm is 20 s.(3)Using asphalt mixture by field sampling from the test road and indoor mixing,through regular performance test as penetration test?softening point test of extracted reclaimed asphalt,the dispersion of dry-mixed CRP in the asphalt and modified effect are studied.The results show that dry-mixed CRP has a better uniformly dispersion in the asphalt and the modified effect of dry-mixed CRP on asphalt mixture is obvious.(4)Thermogravimetric analysis(TG)and DSC experiment of South Korea SK-70# asphalt?5.5% CRP modified asphalt of wet process and reclaimed asphalt of dry-mixed CRP modified asphalt mixture(drying mixing time of 20 s and 5.5% CRP content)reveal that uniform dispersion of dry-mixed CRP and asphalt improves the high temperature properties of asphalt and asphalt mixture.With the the basis of these studies,modification mechanism of dry-mixed CRP-modified asphalt mixture is studied.(5)High temperature stability,low temperature cracking resistance,resistance to water damage of dry-mixed modified asphalt mixture are studied through Marshall stability?rutting?freeze-thaw split and cold bending of dry-mixed CRP modified AC-13 asphalt mixture.The results show that dry-mixed CRP can significantly improves pavement performance of high temperature performance,low temperature cracking resistance,resistance to water damage about dry-mixed modified asphalt mixture.The research achievements for construction technology and application of dry-mixed CRP modified asphalt mixture have definite practical values.