| With the continuous development of Chinese economy and the deepening reform,our country’s road traffic is also developing at a high speed,and road plays a vital role in promoting economic development and reform.However,after being used for more than ten years,many asphalt pavement problems have appeared,which seriously affects the normal use of the road.Presently,China’s highway has entered a period of equal emphasis on construction and maintenance,resulting in a large number of waste asphalt mixtures,if not used properly,it will cause serious waste of resources and environmental pollution.According to this situation,the regeneration of aged asphalt is very important.It can solve the problem of asphalt road problems and alleviate the waste of resources effectively.But at present,many asphalt regenerants can not take into account the high temperature stability and low temperature crack resistance after aged asphalt being regenerated.In this case,this paper focuses on the study of regenerant improvement.The functional regenerant is formed through adding functional raw materials to regenerant to enhance the regenerative effect of the original regenerant,making its regenerative performance to aging asphalt more comprehensive so as to overcome the shortcoming of not considering both high temperature stability and low temperature resistance after regeneration of aging asphalt.Accordingly,a series of comparative studies have been carried out.The main research contents are as follows:Based on the basic structure and components of asphalt and the aging mechanism of asphalt,the mechanism of asphalt regeneration is studied,compensating the missing light oil by adding regenerant,and the solubility parameters of components are adjusted to meet the requirements of stable solution,so as to realize the regeneration of asphalt.In this study,LPIBR(low molecular weight polyisobutylene resin)and APAO(amorphous poly alpha olefin)resin were mixed to improve the performance of SZS type regenerant.The design was carried out according to the mass ratio of 4:1,3:2,1:1,2:3,1:4 respectively.The total amount of functional raw materials was added according to 10% of the amount of regenerant,and the optimum dosage of regenerated asphalt is 6.8% determined by the three indexes,and the optimum proportion of functional raw material is as follow,LPIBR: APAO = 3:2.The gradation composition of AC-13 asphalt mixture is synthesized by calculating the proportion according to the results of mineral screening,and the optimum asphalt content of different asphalt mixtures is determined according to Marshall method.High temperature performance,water stability,low temperature performance and fatigue resistance of different asphalt mixtures were investigated through rutting test,immersion Marshall test,low temperature bending test and four-point bending fatigue life test respectively.The low-temperature regeneration ability of functional regenerant is 28% higher than that of SZS type regenerant,and the high-temperature regeneration ability is improved by 43.5%,achieving the purpose of optimizing SZS type regenerant.Finally,according to efficiency coefficient,the pavement performance of new asphalt mixture mixed is the best mixing 60% base asphalt and 40% functional regenerant.According to the series of tests and analysis given above,compared with SZS type regenerant,functional regenerant solves the problem of considering both low temperature crack resistance and high temperature stability of regenerated asphalt effectively.In the project of repairing the damaged section of G202 National Highway in Anshan using thermal regeneration technology,the asphalt pavement regenerated by functional regenerant has been used for more than half a year,and now the road is in a good condition. |
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