Research On Weather Resistance Of Resin Rubber Modified Asphalt Binder And Its Mixture

Styrene-butadiene rubber(SBR)modified asphalt has been known for its superior low-temperature performance since it was discovered and applied.However,with the rapid development and increase of traffic load and frequency,the defect of SBR modified asphalt on the high-temperature deformation resistance and aging resistance become obvious.These deficiencies have seriously affected the further development and utilization of SBR modified asphalt.To improve the high-temperature deformation resistance and aging resistance of SBR modified asphalt,and make it suitable to the changing environment and weather,further composited modification research of SBR modified asphalt was carried out.Using the physical blending method,SBR and thermoplastic phenolic resin(PF)were added to the base asphalt to obtained resin-rubber modified asphalt(PSBR).The physical performance tests were conducted to investigate the effect of modifier’s content on the modified asphalt performance;the orthogonal test design method was used to optimize the preparation process parameters of PSBR.The dynamic mechanical analysis method(DMA)and the Christensen-Anderson-Marasteanu(CAM)model were used to analyze the rheological characteristics of PSBR in a wide temperature range,and effect of PF on the permanent deformation resistance of SBR modified asphalt was also studied.Moreover,linear amplitude sweep(LAS)test was also conducted to investigate the durability and aging resistance of PSBR.The rolling thin film oven test(RTFOT)was used to simulate different aging degrees,and the effects of aging on the physical and rheological performance of asphalt binder were studied.Fourier transform infrared spectrometer(FTIR),gel permeation chromatography(GPC),fluorescence microscope(FM)were used to study the thermal stability of asphalt binder from micro-perspective.Furthermore,the morphology evolution characteristics of functional groups and molecular weight distribution of asphalt binder were also analyzed under different aging time.Marshall test and the freeze-thaw split test were carried out on the virgin and aged(short-,long-term aging)PSBR mixture to evaluate the effect of aging(short-,long-term),moisture,and freeze-thaw cycle on the moisture susceptibility of asphalt mixtures.Besides,the damage behavior characteristics of asphalt mixtures were studied by the Logistic damage model.In addition,perform different freeze-thaw cycles(5/10/15,50/100/150)on the virgin,short-,and long-term aging asphalt mixtures.The effects of environmental factors such as aging,temperature changes,freeze-thaw cycles on the durability,and weather resistance of asphalt mixtures were studied and analyzed by a semi-circular bending fatigue(SCB)test.Results shows that:The addition of PF could effectively improve the physical and rheological properties of SBR modified asphalt and extended its using temperature range and the level of traffic load that can be resisted.Besides,the preparation parameters and content of PSBR had a significant impact on its performance.Considering the performance of PSBR and its mixture,the optimum content of PSBR is 3%PF+4%SBR(S4P3),and the reasonable preparation parameters were:shear temperature 175℃,shear time 45 min,and shear rate 3500 rpm.The PSBR had better high-and low-temperature performance,with good thermal stability.During the long-term aging process of PSBR,the formation of carbonyl and sulfoxide compounds is low and the formation rate is low,the butadiene bond broken rate is low,and the chemical system could maintain stable.The content of large molecular size(LMS)in PSBR,SBR modified,and base asphalt had a good correlation with its nonrecoverable creep compliance(Jnr)and percent recovery(R).The higher the content of LMS in asphalt,the smaller the Jnr,the greater the R,and the lower the temperature sensitivity of the asphalt.After adding PF,the high-temperature stability and moisture susceptibility of the SBR modified asphalt mixture were significantly improved.Compared with the SBR modified asphalt mixture,the dynamic stability of the PSBR mixture was increased by 74%,and the cumulative deformation was reduced by 25%;During the freeze-thaw cycle,damage development speed and degree of the PSBR mixture were lower,and the effect of aging on its water stability was relatively slight.The fatigue life equation of the PSBR asphalt mixture was established by considering environmental factors(aging and freeze-thaw cycle).In addition,the results of the SCB fatigue test displayed that PSBR had better durability,and the addition of PF can effectively alleviate the impact of climatic factors such as aging,freeze-thaw cycle,and water immersion on the durability of the mixture.Compared with SBR modified asphalt mixture,the fatigue life of PSBR asphalt mixture at 10℃,15℃,and 20℃ were increased by 65.7%,65.2%,and 75.7%respectively;The fatigue life loss rate of PSBR mixture is smaller,and its loss rate curve slope is low,which means PSBR has better weather resistance.In summary,PSBR and its mixture had good high-and low-temperature performance and weather resistance,which could maintain stable performance for a long time.It is suitable to be used for construction pavements in the area with hot summer and cold winter.The research results can provide a new material that has good technical performance and better weather resistance for the construction of durable pavements.