为了全面提高废口罩纤维(Waste Mask Fiber, WMF)改性沥青的高低温性能,将其与SBR改性剂共同制备WMF-SBR复合改性沥青,基于MSCR流变性能试验,对未老化、FTROT短期老化和PAV长期老化三种状态下的复合改性沥青,测试分析其蠕变恢复率R、不...为了全面提高废口罩纤维(Waste Mask Fiber, WMF)改性沥青的高低温性能,将其与SBR改性剂共同制备WMF-SBR复合改性沥青,基于MSCR流变性能试验,对未老化、FTROT短期老化和PAV长期老化三种状态下的复合改性沥青,测试分析其蠕变恢复率R、不可恢复蠕变柔量Jnr、应力敏感性Jnrdiff、Rdiff等指标的变化规律。结果表明,其软化点较基质沥青提高了14.6%,较WMF改性沥青降低了5%,延度较WMF改性沥青增加了380%;在0.1 kPa、3.2 kPa应力作用下,WMF-SBR复合改性沥青的R值、Rdiff值、Jnr值、Jnrdiff值随老化程度的增加分别呈增大、减小、减小、减小的趋势变化;与基质沥青、SBR改性沥青相比,WMF-SBR复合改性沥青在相同老化阶段和应力水平条件下,R、Rdiff指标均最大,Jnr、Jnrdiff指标均最小。WMF-SBR复合改性沥青显著提高了WMF改性沥青的低温塑性;相比SBR改性沥青,其高温抗车辙变形稳定性更好,弹性变形恢复能力更强,应力敏感性更小,老化后性能更稳定、更耐久。In order to comprehensively improve the high and low temperature performance of waste mask fiber (Waste Mask Fiber, WMF) modified asphalt, the WMF-SBR composite modified asphalt was prepared with SBR modifying agent. Based on the MSCR rheological performance test, the changes in creep recovery rate R, unrecoverable creep compliance Jnr, stress sensitivity Jnrdiff, and Rdiff of composite modified asphalt under three states of unaged, FTROT short-term aging, and PAV long-term aging were tested and analyzed. The results show that, its softening point is 14.6% higher than the matrix asphalt, is 5% lower than the WMF modified bitumen. The extension is 380% higher than that of WMF modified asphalt;under the action of the 0.1 kPa, 3.2 kPa stress, the R value, Rdiff value, Jnr value and Jnrdiff value of WMF-SBR composite modified asphalt respectively increase, decrease, decrease and decrease with the increase of aging degree;compared with matrix asphalt and SBR modified bitumen, WMF-SBR composite modified bitumen under the same aging stage and stress level conditions, the indicators (R, Rdiff) are the largest and the indicators (Jnr, Jnrdiff) are the minimum. WMF-SBR composite modified asphalt significantly improves the low temperature plasticity of WMF modified asphalt;compared with SBR modified asphalt, it has better high temperature rut deformation stability, more resilient elastic deformation recovery, less stress sensitivity, and more stable and durable performance after aging.展开更多
To determine the fracture characteristics of asphalt mixture a novel fracture test with modified loading modes loading fixtures and the control system of the conventional overlay tester is implemented by the asphalt m...To determine the fracture characteristics of asphalt mixture a novel fracture test with modified loading modes loading fixtures and the control system of the conventional overlay tester is implemented by the asphalt material performance tester AMPT .In order to evaluate the validity of the proposed fracture test four different loading rates including 1 2 3 and 4 mm/min are examined in the AMPT. The results indicate that the fracture behavior is similar to creep at a low loading rate and does not show significant marginal tail extension at a high loading rate.It clearly shows the phase of crack initiation crack propagation and fracture at a loading rate of 3 mm/min. Besides eight fracture parameters such as fracture energy tensile strength and tensile modulus are applied to evaluate the fracture characteristics of asphalt mixture.Development of the overlay tester for the fracture test of asphalt mixture can be considered as a new fracture test of asphalt mixture.展开更多
The rheological properties including the complex modulus G＊ and the phase angle δof matrix and warm mix asphalt （WMA）binders were measured by using the dynamic shear rheometer （DSR ） test at the medium temperatu...The rheological properties including the complex modulus G＊ and the phase angle δof matrix and warm mix asphalt （WMA）binders were measured by using the dynamic shear rheometer （DSR ） test at the medium temperature ranging from 16 to 40 ℃,and the relationships between the fatigue factor G＊ sinδand the matrix binder property,WMA additive and test temperature were established.It is found that G＊ decreases with the increasing temperature while δincreases inversely,and G＊ of the asphalt binder with high WMA additive dosage is large,and δis small.G＊sinδexponentially decreases with the increasing temperature and linearly increases with the increase in additive dosage,and the amplitudes of variation are large at low temperatures and high additive dosages.The effect of WMA additive on the rheological property is more remarkable for the matrix asphalt binder with low G＊.Besides,aging has a great effect on the property of matrix asphalt binder,and a slight effect on the interaction between asphalt and additive.The high additive dosage can increase the fatigue cracking potential of the asphalt binder.展开更多
The performance evaluation and chemical property analysis of the recycled warm mix asphalt （RWMA） binders containing 100% artificial reclaimed asphalt （ RA） are presented, and the combined effects of different p...The performance evaluation and chemical property analysis of the recycled warm mix asphalt （RWMA） binders containing 100% artificial reclaimed asphalt （ RA） are presented, and the combined effects of different percentages of the rejuvenator and warm mix additive （WMA） additives on RWMA binders are analyzed through laboratory tests. Three types of WMA additives ad one commercial rejuvenator named GST were selected to restore the artificial RA. The laboratory performace tests including the penetration test, softening test ad rotary, viscosity （RV） test were carried out. In addition, the Fourier transform infrared spectroscopy （FTIR） test was performed to explore the chemical property of RWMA binders. The results of the performance tests indicate that the rejuvenator GST has the ability to restore the artificial RA; choosing the optimum content of WMA additives and rejuvenator is the key to restoring 100% artificial RA, since the combined effects of them play an important role in determining the basic laboratory performance of RWMA binders. The FTIR tests show that the process of recycling mainly adjusts the chemical component of aged asphalt and no remarkable change is observed in the FTI1R spectra of RWMA binders in terms of chemical functional groups with the introduction of WMA additives.展开更多
Rutting is one of the most damages in the asphalt surfaces for the orthotropic steel bridge decks. With Hamburg wheel tracking device, the suitable test conditions for Gussasphalt in Germany are pointed out, the high ...Rutting is one of the most damages in the asphalt surfaces for the orthotropic steel bridge decks. With Hamburg wheel tracking device, the suitable test conditions for Gussasphalt in Germany are pointed out, the high temperature behaviour of Gussasphalt with different binders are tested and compared. The polymer modified binder has higher resistance stability to rutting. The retained time and mixed frequency have obvious effects on Gussasphalt behaviour during Gussasphalt retained period.展开更多
Rolling Thin Film Oven Test （RTFOT） is the AASHTO T240 standard method to simulate asphalt plant mix aging. But it has proven inadequate in aging polymer-modified asphalts （PMA）. NCHRP 9-10 offered a modified RTF...Rolling Thin Film Oven Test （RTFOT） is the AASHTO T240 standard method to simulate asphalt plant mix aging. But it has proven inadequate in aging polymer-modified asphalts （PMA）. NCHRP 9-10 offered a modified RTFOT （MRTFOT） by adding a steel rod in each bottle. Since construction temperature of PMA mixture is 10 ℃ -20 ℃ higher than that of conventional asphalt mixtures in the field, elevating RTFOT temperature for PMA is necessary for adequate aging and proper simulation. Six PMAs with various PG grades and sources were aged with RTFO at elevated temperatures. Some were also treated with MRTFOT for comparison. SHRP performance grade and phase angle were used as indicators to analyze the effects of RTFOT under different conditions. The results show that elevating the temperature is more effective than using rods. And PMA RTFOT temperature could be determined by equiviscous principle. From limited data, O. 25 Pa ~ s is tentatively proposed as critical viscosity for PMA, but still more work is necessary to validate this. Given the fact that equiviscous principle is seldom used in field practice, a simple approach was proposed： 173 ℃ is used for RTFOT of PG70 PMAs （grading herein from un-aged asphalts） , while 178 ℃ is for PMAs of PG76 or PG82 and 20 ℃ higher than standard 163 ℃ is necessary for PG 88 or stiffer PMAs.展开更多
文摘为了全面提高废口罩纤维(Waste Mask Fiber, WMF)改性沥青的高低温性能,将其与SBR改性剂共同制备WMF-SBR复合改性沥青,基于MSCR流变性能试验,对未老化、FTROT短期老化和PAV长期老化三种状态下的复合改性沥青,测试分析其蠕变恢复率R、不可恢复蠕变柔量Jnr、应力敏感性Jnrdiff、Rdiff等指标的变化规律。结果表明,其软化点较基质沥青提高了14.6%,较WMF改性沥青降低了5%,延度较WMF改性沥青增加了380%;在0.1 kPa、3.2 kPa应力作用下,WMF-SBR复合改性沥青的R值、Rdiff值、Jnr值、Jnrdiff值随老化程度的增加分别呈增大、减小、减小、减小的趋势变化;与基质沥青、SBR改性沥青相比,WMF-SBR复合改性沥青在相同老化阶段和应力水平条件下,R、Rdiff指标均最大,Jnr、Jnrdiff指标均最小。WMF-SBR复合改性沥青显著提高了WMF改性沥青的低温塑性;相比SBR改性沥青,其高温抗车辙变形稳定性更好,弹性变形恢复能力更强,应力敏感性更小,老化后性能更稳定、更耐久。In order to comprehensively improve the high and low temperature performance of waste mask fiber (Waste Mask Fiber, WMF) modified asphalt, the WMF-SBR composite modified asphalt was prepared with SBR modifying agent. Based on the MSCR rheological performance test, the changes in creep recovery rate R, unrecoverable creep compliance Jnr, stress sensitivity Jnrdiff, and Rdiff of composite modified asphalt under three states of unaged, FTROT short-term aging, and PAV long-term aging were tested and analyzed. The results show that, its softening point is 14.6% higher than the matrix asphalt, is 5% lower than the WMF modified bitumen. The extension is 380% higher than that of WMF modified asphalt;under the action of the 0.1 kPa, 3.2 kPa stress, the R value, Rdiff value, Jnr value and Jnrdiff value of WMF-SBR composite modified asphalt respectively increase, decrease, decrease and decrease with the increase of aging degree;compared with matrix asphalt and SBR modified bitumen, WMF-SBR composite modified bitumen under the same aging stage and stress level conditions, the indicators (R, Rdiff) are the largest and the indicators (Jnr, Jnrdiff) are the minimum. WMF-SBR composite modified asphalt significantly improves the low temperature plasticity of WMF modified asphalt;compared with SBR modified asphalt, it has better high temperature rut deformation stability, more resilient elastic deformation recovery, less stress sensitivity, and more stable and durable performance after aging.
基金The National Natural Science Foundation of China(No.51178114)the Chinese Western Transportation Construction Technology Project of Transportation Ministry(No.2009318000086)
文摘To determine the fracture characteristics of asphalt mixture a novel fracture test with modified loading modes loading fixtures and the control system of the conventional overlay tester is implemented by the asphalt material performance tester AMPT .In order to evaluate the validity of the proposed fracture test four different loading rates including 1 2 3 and 4 mm/min are examined in the AMPT. The results indicate that the fracture behavior is similar to creep at a low loading rate and does not show significant marginal tail extension at a high loading rate.It clearly shows the phase of crack initiation crack propagation and fracture at a loading rate of 3 mm/min. Besides eight fracture parameters such as fracture energy tensile strength and tensile modulus are applied to evaluate the fracture characteristics of asphalt mixture.Development of the overlay tester for the fracture test of asphalt mixture can be considered as a new fracture test of asphalt mixture.
基金The National Natural Science Foundation of China(No.51408043)the Natural Science Foundation of Shaanxi Province(No.2014JQ7278)
文摘The rheological properties including the complex modulus G＊ and the phase angle δof matrix and warm mix asphalt （WMA）binders were measured by using the dynamic shear rheometer （DSR ） test at the medium temperature ranging from 16 to 40 ℃,and the relationships between the fatigue factor G＊ sinδand the matrix binder property,WMA additive and test temperature were established.It is found that G＊ decreases with the increasing temperature while δincreases inversely,and G＊ of the asphalt binder with high WMA additive dosage is large,and δis small.G＊sinδexponentially decreases with the increasing temperature and linearly increases with the increase in additive dosage,and the amplitudes of variation are large at low temperatures and high additive dosages.The effect of WMA additive on the rheological property is more remarkable for the matrix asphalt binder with low G＊.Besides,aging has a great effect on the property of matrix asphalt binder,and a slight effect on the interaction between asphalt and additive.The high additive dosage can increase the fatigue cracking potential of the asphalt binder.
基金The National Natural Science Foundation of China(No.50578031)
文摘The performance evaluation and chemical property analysis of the recycled warm mix asphalt （RWMA） binders containing 100% artificial reclaimed asphalt （ RA） are presented, and the combined effects of different percentages of the rejuvenator and warm mix additive （WMA） additives on RWMA binders are analyzed through laboratory tests. Three types of WMA additives ad one commercial rejuvenator named GST were selected to restore the artificial RA. The laboratory performace tests including the penetration test, softening test ad rotary, viscosity （RV） test were carried out. In addition, the Fourier transform infrared spectroscopy （FTIR） test was performed to explore the chemical property of RWMA binders. The results of the performance tests indicate that the rejuvenator GST has the ability to restore the artificial RA; choosing the optimum content of WMA additives and rejuvenator is the key to restoring 100% artificial RA, since the combined effects of them play an important role in determining the basic laboratory performance of RWMA binders. The FTIR tests show that the process of recycling mainly adjusts the chemical component of aged asphalt and no remarkable change is observed in the FTI1R spectra of RWMA binders in terms of chemical functional groups with the introduction of WMA additives.
文摘Rutting is one of the most damages in the asphalt surfaces for the orthotropic steel bridge decks. With Hamburg wheel tracking device, the suitable test conditions for Gussasphalt in Germany are pointed out, the high temperature behaviour of Gussasphalt with different binders are tested and compared. The polymer modified binder has higher resistance stability to rutting. The retained time and mixed frequency have obvious effects on Gussasphalt behaviour during Gussasphalt retained period.
文摘Rolling Thin Film Oven Test （RTFOT） is the AASHTO T240 standard method to simulate asphalt plant mix aging. But it has proven inadequate in aging polymer-modified asphalts （PMA）. NCHRP 9-10 offered a modified RTFOT （MRTFOT） by adding a steel rod in each bottle. Since construction temperature of PMA mixture is 10 ℃ -20 ℃ higher than that of conventional asphalt mixtures in the field, elevating RTFOT temperature for PMA is necessary for adequate aging and proper simulation. Six PMAs with various PG grades and sources were aged with RTFO at elevated temperatures. Some were also treated with MRTFOT for comparison. SHRP performance grade and phase angle were used as indicators to analyze the effects of RTFOT under different conditions. The results show that elevating the temperature is more effective than using rods. And PMA RTFOT temperature could be determined by equiviscous principle. From limited data, O. 25 Pa ~ s is tentatively proposed as critical viscosity for PMA, but still more work is necessary to validate this. Given the fact that equiviscous principle is seldom used in field practice, a simple approach was proposed： 173 ℃ is used for RTFOT of PG70 PMAs （grading herein from un-aged asphalts） , while 178 ℃ is for PMAs of PG76 or PG82 and 20 ℃ higher than standard 163 ℃ is necessary for PG 88 or stiffer PMAs.
