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Wang C.-H.,Changan University | Li Y.-W.,Bureau of Transportation in Shijiazhuang | Yang L.,Luyang Expressway Corporation in Zhengzhou | Du Q.-L.,Bureau of Transportation in Shijiazhuang | Hu S.-M.,Bureau of Transportation in Shijiazhuang
Gongneng Cailiao/Journal of Functional Materials | Year: 2014

In order to solve the high temperature problem of asphalt pavement in summer, tourmaline modified asphalt was developed and its concrete was prepared. Firstly, the most reasonable pavement temperature test method was determined from several aspects including the specimen preparation, test instruments, temperature measuring position, heat insulation way. Then the influence laws of pavement cooling performance with the outside temperature, the types and mixing amount of tourmaline were systematically studied. Finally, the pavement cooling mechanism and road properties of tourmaline modified asphalt concrete were further analyzed. Experimental results indicate that: tourmaline can significantly reduce the surface temperature of asphalt pavement. The higher outside temperature was, cooling performance of tourmaline modified asphalt concrete was better; in the daytime, cooling effect of tourmaline modified asphalt concrete in high temperature period was better than that of low temperature periods. Pavement cooling performance of tourmaline modified asphalt concrete was improved with the increase of tourmaline mixing amount, and the cooling performance variation become unobvious while the mixing amount of tourmaline was more than 17%. For different types of tourmaline, the cooling performance of tourmaline anion powder was better than tourmaline powder, improved with the increase of anion releasing amount, but the variation was not obvious while anionic releasing amount exceeding 5000 ions. Road properties tests show that the adding of tourmaline can significantly improve the high temperature performance, low temperature performance and the water stability of asphalt concrete.

Du Q.L.,Hebei Province | Wang C.H.,Changan University | Yang L.,Luyang Expressway Corporation in Zhengzhou | Li Y.W.,Bureau of Transportation in Shijiazhuang
Applied Mechanics and Materials | Year: 2013

In order to solve the problem of high dependence on manufacturers or high blindness when warm mix agents are chosen in project. On the basis of the action mechanism that the agents can reduce viscosity of asphalt so that the asphalt mixture can be mixed at low temperature, an investigation on the extent of reducing viscosity on construction temperature of these agents are presented when temperature and the mixing amount of warm mix agents are different. The optional mixing amount of different warm mix agents are recommended, providing a theoretical basis for the selection and application of warm mix agent in our country. © (2013) Trans Tech Publications, Switzerland.

Li Y.-W.,Tongji University | Mu K.,The First Highway Survey and Design Institute Co. | Mu K.,Changan University | Shi X.,Bureau of Transportation in Shijiazhuang | Wang X.-C.,Changan University
Chang'an Daxue Xuebao (Ziran Kexue Ban)/Journal of Chang'an University (Natural Science Edition) | Year: 2014

In order to study the impact of the base-surface contact conditions on pavement performance, the mechanical response of pavement under different bonding conditions between base and surface layer was analyzed. A numerical model based on delamination failure theory was established. Substructure analysis was used to study the bonding state influence on pavement with fine milling, rubber, SBS and conventional asphalt. Direct shear test was used to verify the prediction model. The results show that compared with traditional methods, delamination failure theory can reflect mechanical properties of interlayer with different materials and thicknesses; loss of stiffness in interlayer material can be considered with the increasing wheel load; fine milling and other measures can improve the interlayer stress state under following condition, thin pavement, large horizontal load coefficient and heavy traffic.

Hu S.,Bureau of Transportation in Shijiazhuang | Wang C.,Changan University | Du Q.,Bureau of Transportation in Shijiazhuang | Li R.,Changan University
Advanced Materials Research | Year: 2012

Aging properties of tourmaline modified asphalt prepared by melt blending were studied. The change laws of aging properties of asphalt caused by different types and contents of tourmaline were studied systematically by rotated thin film oven tests (RTFOT), in which the indices of aged residues such as softening point, penetration and ductility were tested. The results showed that the anti-aging performance of asphalt was improved effectually with addition of tourmaline, the ratio of residual penetration and ductility increased, and the softening point increment of aged asphalt decreased. The improvement of anti-aging performance of asphalt reduced with the increasing mixing amount of tourmaline. Tourmaline anion powder (5000ions) was recommended to improve the anti-aging performance of asphalt. © (2012) Trans Tech Publications, Switzerland.

Wang C.,Changan University | Wang P.,Changan University | Li Y.,Bureau of Transportation in Shijiazhuang | Zhao Y.,Bureau of Transportation in Shijiazhuang
Construction and Building Materials | Year: 2015

Tourmaline modified bitumen was prepared by blending base bitumen with tourmaline powder. Effect of temperature, frequency as well as the content of tourmaline powder on the complex modulus and phase angle of the bitumen was investigated by dynamic shear rheometer (DSR). The results indicate that the complex modulus decreased whereas the phase angle increased with the increasing of temperature and frequency, the complex modulus of modified bitumen exhibit good linear relationship with the logarithmic value of loading frequency. Compared with base bitumen, the bitumen containing tourmaline powder exhibit higher rutting factor, indicating that the rutting resistance of bitumen at high temperature was improved by tourmaline, for the rigidity of bitumen was enhanced by tourmaline. © 2015 Elsevier Ltd All rights reserved.

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