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Ji X.-P.,Changan University | Hou Y.-Q.,Changan University | Xu H.,Gansu Province Administration Bureau of Highway | Tan X.-Z.,Gansu Highway Construction and Development Co.
Jianzhu Cailiao Xuebao/Journal of Building Materials | Year: 2013

RTFOT aging tests at different aging time for four kinds of asphalt were carried out and the aging test data were fitted to dynamic equation. The aging parameters and aging equation of penetration, ductility, softening point and viscosity of different asphalts were determined. The grey relational theory was utilized to assess the anti-aging performance of different asphalts setting the L and r of penetration, ductility, softening point and viscosity as assessment indicators. The results show that there are nonlinear relationship between penetration, softening point, ductility, viscosity and aging time; the aging rate reaches the peak at the beginning and becomes smaller as the variation of aging time; the aging process of asphalt can be described accurately by dynamic equation and parameters L and r can be a good characterization of aging degree and aging rate, and the sort of aging parameters of different asphalts and indicators is inconsistent. The sort of anti-aging performance of four kinds of asphalt is determined with grey relational theory as following: indoor produced modified asphalt ≤matrix 90# asphalt ≤finished modified asphalt ≤matrix 70# asphalt. Source


Ji X.,Changan University | Xu H.,Gansu Province Administration Bureau of Highway | Hou Y.,Changan University | Tan X.,Gansu Highway Construction and Development Co.
Jianzhu Cailiao Xuebao/Journal of Building Materials | Year: 2014

A method for determining the mixing and compaction temperature of warm mixed reclaimed asphalt mixture(WMRA) was proposed and superpave gyratory compacter(SGC) was used to prepare the specimens. The volume parameters and densification characteristics of SGC densification curve were compared with WMRA and hot mixed reclaimed asphalt mixture(HMRA). Research results indicate that the slopes of densification curve K1 and K2 decrease, and air void(VV), compaction energy index(CEI) and traffic densification index(TDI) gradually increase as the proportion of recycled asphalt pavement(RAP) increasing. The compacting performance and compaction speed gradually decrease and the capacity of resistance from deformation after opening to traffic increases as the proportion of RAP increasing. The VV and CEI of WMRA are smaller than those of HMRA when the compaction temperature is 30°C lower in preparation of the specimens of WMRA, with the result that the warm mix agents can greatly improve the workability of mixtures. The K1, K2 and TDI are almost equivalent between WMRA and HMRA, that is say, the warm mix agents are incapable to improve the compaction speed and resistance from deformation. Source


Hou Y.-Q.,Changan University | Xu H.,Gansu Province Administration Bureau of Highway | Ji X.-P.,Changan University
Chang'an Daxue Xuebao (Ziran Kexue Ban)/Journal of Chang'an University (Natural Science Edition) | Year: 2014

This paper is aimed to solve the temperature control problem of warm mixed reclaimed asphalt mixture (WMRA) in the process of design and construction. A method was proposed for determining the mixing and compaction temperature of WMRA blending with Sasobit, and also for heating temperature of the new aggregates. The laboratory experiments including Marshall test, soaking rutting test, low temperature bending test and water stability test were utilized for analyzing the air void (VV) and road performance. The results show that the mixing and compaction temperature and heating temperature of new aggregates can be accurately determined by the proposed method for WMRA. The VV of WMRA compacted at the temperature lower than 13 °C is approaching to HMRA when the proportion of RAP is much smaller, which indicates the Sasobit can reduce compaction temperature by 13 °C, and significantly improve the blending ratio of RAP by 10.3%. WMRA has better high-temperature stability than HMRA, and the low-temperature bending strain, residual stability degrees and TSR are approximately equal between WMRA and HMRA. The high-temperature stability and low-temperature flexural tensile strength of WMRA and HMRA increase as the RAP increases, but the low-temperature bending strain, residual stability degree and TSR decrease. Source


Zheng N.-X.,Changan University | Hu K.,Changan University | Liu W.-L.,Zhonggonggaoke Maintenance Science and Technology Ltd Company | Xu H.,Gansu Province Administration Bureau of Highway | Deng C.-Y.,Changan University
Wuhan Ligong Daxue Xuebao/Journal of Wuhan University of Technology | Year: 2012

Focusing on the excessive car interior noise on micro-surfacing, twelve mixtures, including different aggregate gradations; mixing processes; fineness and content of rubber powder addition have been measured by sound-absorption test equipment. The results indicate that comparing to ordinary micro-surfacing, low-noise micro-surfacing has a higher absorption coefficient as well as a good abrasion loss. Controlling the aggregate size distribution by adding 7.1 mm sieve to regular gradation design, increasing 1.5 percent of 60 mesh rubber powders, molding in wet method can enhance the absorption coefficient to 0.34. Source

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