Study On Applicability And Regeneration Mechanism Of Environmental Friendly SBS Modified Asphalt Regenerant

SBS modified asphalt is widely used in road construction,but it will age in the process of use,including the structural damage of matrix asphalt and SBS modifier molecules.At present,the regeneration technology of aged SBS modified asphalt is mainly through the recovery of matrix asphalt components.There are still many deficiencies in the research on the recovery of molecular structure of SBS modifier.Therefore,the development of a regenerant that can recover the molecular structure of matrix asphalt and SBS modifier at the same time has important theoretical value and practical significance.Waste soybean oil is a kind of waste oil recovered from catering,which has the advantages of low viscosity and high unsaturated degree,and the amount of recycling is huge.After recycling,it can be applied to the regeneration of aged SBS modified asphalt.In order to improve the regeneration and recovery ability of single waste soybean oil,this paper developed an environmental friendly SBS modified asphalt regenerant from waste soybean oil,multi epoxy compound TMPGE(trimethylolpropane triglycidyl ether)and catalyst BDMA(n,n-dimethyl benzylamine),and compared the regeneration effect of aged SBS modified asphalt with asphalt regenerant commonly used in Engineering(hereinafter referred to as "R regenerant").In view of the problem that the regenerated SBS modified asphalt will continue to age in the process of re-service and the performance of the recycled waste soybean oil fluctuates in the actual situation,the applicability of environmental friendly regenerant to the secondary aging SBS modified asphalt and waste soybean oil with different deterioration degrees is studied through the tests of conventional physical properties and rheological properties.The microstructure and molecular structure detection technology(fourier transform infrared spectrum FTIR,fluorescence microscope FM and gel permeation chromatography GPC)were used to analyze the changes of functional groups and their molecular weights before and after the regeneration of aged asphalt,so as to clarify the recovery and regeneration mechanism of environmentally friendly regenerant.Firstly,the optimum ratio of waste soybean oil,TMPGE and BDMA in environmental friendly SBS modified asphalt regenerant and the indoor preparation and production conditions were determined by orthogonal test;Through the test of applying environmental friendly regenerant and R regenerant to the performance recovery of aged SBS modified asphalt,the performance indexes such as conventional physical properties,viscosity and ageing-resistant performance are compared and analyzed.The results show that the environmental friendly regenerant has a better recovery effect on the aged SBS modified asphalt.The penetration at 25℃,ductility at 5℃ and elastic recovery at 25℃ of aged asphalt mixed with environmental friendly regenerant were restored to 117.6%,103.3%and 99%of the original SBS modified asphalt respectively.Through the test and analysis of the conventional physical and rheological properties of the secondary aging SBS modified asphalt restored by the environmental friendly regenerant,The results show that environmental friendly SBS modified asphalt regenerant can reduce the temperature sensitivity of secondary aging SBS modified asphalt,significantly improve its flexibility,restore the low-temperature ductility to the standard level,and maintain the high-temperature grade of the original SBS modified asphalt.Environmental friendly SBS modified asphalt regenerant still has good adaptability to secondary aging SBS modified asphalt.By making waste soybean oil with different deterioration degrees,the corresponding environmental friendly regenerant was prepared and applied to the regeneration of aged SBS modified asphalt.The results show that the regenerants prepared from waste soybean oil with different deterioration degrees can improve the penetration and ductility of aged asphalt,and reduce the softening point and viscosity of aged asphalt.At the same time,the low-temperature complex modulus of aged asphalt is reduced,the low-temperature phase angle of aged asphalt is increased,and the rutting factor of asphalt is reduced at high temperature.The environmental friendly SBS modified asphalt regenerant has good applicability to waste soybean oil with different deterioration degrees,which shows that it has good adaptability to the quality fluctuation of waste soybean oil.The changes of functional groups and molecular weight of SBS modified asphalt before and after regeneration were analyzed by fluorescence microscope,fourier transform infrared spectrum and gel permeation chromatography.The results showed that the carbonyl and sulfoxide indexes decreased from 0.003046 and 0.002014 to 0.000677 and 0.008876,respectively.The fluorescence microscope images showed that the molecular morphology of SBS basically recovered to the non aged level,and the weight average molecular weight of SBS modifier in the gel permeation chromatography test recovered to 76.65%of the original SBS modified asphalt.After adding environmental friendly SBS modified asphalt regenerant,the SBS chain segment of the aged and degraded SBS modifier can be repaired and reconstructed,and its spatial structure can be well restored.