The fatigue properties of asphalts were investigated after various laboratory simulation ageing tests and outdoor natural exposure ultraviolet radiation ageing,by dynamic shear rheometer(DSR) time sweep fatigue test i...The fatigue properties of asphalts were investigated after various laboratory simulation ageing tests and outdoor natural exposure ultraviolet radiation ageing,by dynamic shear rheometer(DSR) time sweep fatigue test in constant strain model and a new type of specimen which was introduced to avoid the problem of adhesion failure between rotor and asphalt binder.The results show that outdoor natural exposure ageing(NEA) causes the decrease of retained fatigue life distinctly,and photodegradation caused by outdoor NEA of 1 250 μm thin films asphalt for three months,is found to be severer than pressure ageing vessel(PAV) with respects to retained fatigue life.The effect of photodegradation increases as the time of outdoor NEA increases.DSR time sweep fatigue test in constant strain indicates that the aged styrene-butadiene-styrene(SBS) modified asphalt still displays better fatigue properties than the corresponding base asphalt after ageing.展开更多
Asphalt-rubber pavements often become dam-aged in high-temperature regions and appear rutted or wavy, and experience slippage. To improve the high-temperature performance of the asphalt-rubber mixture, technical measu...Asphalt-rubber pavements often become dam-aged in high-temperature regions and appear rutted or wavy, and experience slippage. To improve the high-temperature performance of the asphalt-rubber mixture, technical measurements, such as, the optimal adjustment of gradation, technique of composite modification, and control of compaction were investigated. An optimal adjustment of aggregate gradation based on stone matrix asphalt improves the high-temperature stability of the asphaltrubber mixture significantly. Through composite modifi- cation, the effect of asphalt-rubber modification was enhanced, and the dynamic stability and relative defor- mation indices of the asphalt-rubber mixture were improved significantly. Furthermore, compaction parame- ters had a significant influence on the high-temperature stability of the asphalt-rubber mixture. The rolling times for compacting the asphalt-rubber mixture should be controlled to within 18-20 round-trips at a molding temperature at 180℃; if the rolling time is a 12 round-trip, the compaction temperature of the asphalt-rubber mixture should be controlled between 180 and 190℃.展开更多
A new way to improve the tunnel fire protection by using flame-retarded porous asphalt pavement containing ATH powders was introduced. Based on the miniature burning test designed and conducted, the burning time and t...A new way to improve the tunnel fire protection by using flame-retarded porous asphalt pavement containing ATH powders was introduced. Based on the miniature burning test designed and conducted, the burning time and temperature of porous asphalt （PA） and flame-retarded porous asphalt （FRPA） were studied comparing with cement concrete pavement, dense-graded lIMA and SMA. Results of burning test and pavement performance test indicate that FRPA is appropriate and suitable as the pavement material of highway tunnel.展开更多
The objective of this research was to show a way to conduct rejuvenation of aged polymer modified asphalt binder（PMB） successfully.To fully evaluate and understand the rejuvenation of aged PMB,the Penetration grade ...The objective of this research was to show a way to conduct rejuvenation of aged polymer modified asphalt binder（PMB） successfully.To fully evaluate and understand the rejuvenation of aged PMB,the Penetration grade tests including penetration,soften point,ductility and elastic recovery and SuperpaveTM PG grade tests including DSR,BBR and DDT were conducted.The rejuvenation effect of aged PMB by utilizing a fluid recycling agent in common use for binder rejuvenation was evaluated.And then the compound rejuvenation effect of aged PMB by utilizing the recycling agent with a new modifying additive for binder modification was evaluated.The experimental results indicated that the recycling agent in common use currently does not apply to polymer modified asphalt binder rejuvenation.But the recycling agent together with the modifying additive can restore the characteristics of aged polymer modified binder very well.Therefore,compound rejuvenation of polymer modified asphalt binder is recommended.展开更多
Asphalt mixtures exhibit strong viscous properties under repetitive loads. This phenomenon can be simulated in creep and recovery tests. By applying the visco elastoplastic model proposed, data recorded in the tests ...Asphalt mixtures exhibit strong viscous properties under repetitive loads. This phenomenon can be simulated in creep and recovery tests. By applying the visco elastoplastic model proposed, data recorded in the tests are interpreted. It is emphasised that applicability of the visco elastoplastic model depends on the proper method of characterising parameters involved in the constitutive equations. Since two or more strain components of elasticity and viscosity coexist during the loading or unloading, a measuring system of two loggers is introduced to decouple these components. Test data are analysed in three steps as elastic, visco elastic and visco plastic evaluations, using the records collected at the moment of unloading, during the periods of recovery and creep respectively. Factors that may influence the accuracy of data analysis are also discussed.展开更多
The characters of basalt fiber are analyzed and compared with commonly used fibers. The rheological behaviors of the basalt fiber reinforced asphalt mastic are investigated by the dynamic shear rheological tests and t...The characters of basalt fiber are analyzed and compared with commonly used fibers. The rheological behaviors of the basalt fiber reinforced asphalt mastic are investigated by the dynamic shear rheological tests and the repeated creep tests. The results show that basalt fiber has excellent reinforced performances, such as high asphalt absorption ratio, low water absorption ratio, high tensile strength, high elastic modulus and high temperature stability. The rutting factor of the fiber reinforced asphalt mastic is higher than the plain asphalt mastic and the reinforced effects are more remarkable under high temperature. The rheological performances of the asphalt mastic demonstrate a good linear relationship between different temperature and loading frequency. The creep stiffness modulus of the asphalt mastic at different loading time can be expressed by power function. Improved Burgers model is used to represent the rheological behaviors of the asphalt mastic with basalt fiber and the model parameters are estimated.展开更多
基金Projects(2006BAB04A05) supported by the Eleventh Five-Year Plan of the National Key Technology Research and Development Program
文摘The fatigue properties of asphalts were investigated after various laboratory simulation ageing tests and outdoor natural exposure ultraviolet radiation ageing,by dynamic shear rheometer(DSR) time sweep fatigue test in constant strain model and a new type of specimen which was introduced to avoid the problem of adhesion failure between rotor and asphalt binder.The results show that outdoor natural exposure ageing(NEA) causes the decrease of retained fatigue life distinctly,and photodegradation caused by outdoor NEA of 1 250 μm thin films asphalt for three months,is found to be severer than pressure ageing vessel(PAV) with respects to retained fatigue life.The effect of photodegradation increases as the time of outdoor NEA increases.DSR time sweep fatigue test in constant strain indicates that the aged styrene-butadiene-styrene(SBS) modified asphalt still displays better fatigue properties than the corresponding base asphalt after ageing.
文摘Asphalt-rubber pavements often become dam-aged in high-temperature regions and appear rutted or wavy, and experience slippage. To improve the high-temperature performance of the asphalt-rubber mixture, technical measurements, such as, the optimal adjustment of gradation, technique of composite modification, and control of compaction were investigated. An optimal adjustment of aggregate gradation based on stone matrix asphalt improves the high-temperature stability of the asphaltrubber mixture significantly. Through composite modifi- cation, the effect of asphalt-rubber modification was enhanced, and the dynamic stability and relative defor- mation indices of the asphalt-rubber mixture were improved significantly. Furthermore, compaction parame- ters had a significant influence on the high-temperature stability of the asphalt-rubber mixture. The rolling times for compacting the asphalt-rubber mixture should be controlled to within 18-20 round-trips at a molding temperature at 180℃; if the rolling time is a 12 round-trip, the compaction temperature of the asphalt-rubber mixture should be controlled between 180 and 190℃.
基金Hi-tech Research and Development Program of China (863 Program of China) (No.2006AA11Z117)
文摘A new way to improve the tunnel fire protection by using flame-retarded porous asphalt pavement containing ATH powders was introduced. Based on the miniature burning test designed and conducted, the burning time and temperature of porous asphalt （PA） and flame-retarded porous asphalt （FRPA） were studied comparing with cement concrete pavement, dense-graded lIMA and SMA. Results of burning test and pavement performance test indicate that FRPA is appropriate and suitable as the pavement material of highway tunnel.
基金Funded in Part by the National Natural Science Foundation of China (No. 50878054)
文摘The objective of this research was to show a way to conduct rejuvenation of aged polymer modified asphalt binder（PMB） successfully.To fully evaluate and understand the rejuvenation of aged PMB,the Penetration grade tests including penetration,soften point,ductility and elastic recovery and SuperpaveTM PG grade tests including DSR,BBR and DDT were conducted.The rejuvenation effect of aged PMB by utilizing a fluid recycling agent in common use for binder rejuvenation was evaluated.And then the compound rejuvenation effect of aged PMB by utilizing the recycling agent with a new modifying additive for binder modification was evaluated.The experimental results indicated that the recycling agent in common use currently does not apply to polymer modified asphalt binder rejuvenation.But the recycling agent together with the modifying additive can restore the characteristics of aged polymer modified binder very well.Therefore,compound rejuvenation of polymer modified asphalt binder is recommended.
文摘Asphalt mixtures exhibit strong viscous properties under repetitive loads. This phenomenon can be simulated in creep and recovery tests. By applying the visco elastoplastic model proposed, data recorded in the tests are interpreted. It is emphasised that applicability of the visco elastoplastic model depends on the proper method of characterising parameters involved in the constitutive equations. Since two or more strain components of elasticity and viscosity coexist during the loading or unloading, a measuring system of two loggers is introduced to decouple these components. Test data are analysed in three steps as elastic, visco elastic and visco plastic evaluations, using the records collected at the moment of unloading, during the periods of recovery and creep respectively. Factors that may influence the accuracy of data analysis are also discussed.
基金Funded by The National Natural Science Foundation of China(No.51108082)
文摘The characters of basalt fiber are analyzed and compared with commonly used fibers. The rheological behaviors of the basalt fiber reinforced asphalt mastic are investigated by the dynamic shear rheological tests and the repeated creep tests. The results show that basalt fiber has excellent reinforced performances, such as high asphalt absorption ratio, low water absorption ratio, high tensile strength, high elastic modulus and high temperature stability. The rutting factor of the fiber reinforced asphalt mastic is higher than the plain asphalt mastic and the reinforced effects are more remarkable under high temperature. The rheological performances of the asphalt mastic demonstrate a good linear relationship between different temperature and loading frequency. The creep stiffness modulus of the asphalt mastic at different loading time can be expressed by power function. Improved Burgers model is used to represent the rheological behaviors of the asphalt mastic with basalt fiber and the model parameters are estimated.
