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Wang C.,Chang'an University | Wang P.,Chang'an 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.

Zhao Y.,Bureau of Transportation in Shijiazhuang | Wang P.,Chang'an University | Wang C.,Chang'an University | Li Y.,Bureau of Transportation in Shijiazhuang
Advanced Materials Research | Year: 2012

Tourmaline modified asphalt (TMA) was prepared by melt-blending process. The modified effect of tourmaline on base asphalt was studied systematically by penetration test, softening point test, ductility test and bending beam rheometer (BBR) test. Based on this, the chemical components of the samples were tested and the colloidal structures of the asphalt were analyzed. Experimental results showed that the temperature susceptibility of asphalt could be improved significantly with the addition of tourmaline. Softening point test revealed that the softening point of TMA was constantly increased with the increasing amount of tourmaline. BBR test indicated that the low temperature properties of asphalt were improved with the addition of tourmaline. The colloidal structure of the asphalt was not changed due to the addition of tourmaline, remaining Sol-Gel type, and a stronger stability happened with the increasing mixing amount of tourmaline. © (2012) Trans Tech Publications, Switzerland.

Hu S.,Bureau of Transportation in Shijiazhuang | Wang C.,Chang'an University | Du Q.,Bureau of Transportation in Shijiazhuang | Li R.,Chang'an 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.-H.,Chang'an 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.

Li Y.-W.,Tongji University | Mu K.,The First Highway Survey and Design Institute Co. | Mu K.,Chang'an University | Shi X.,Bureau of Transportation in Shijiazhuang | Wang X.-C.,Chang'an 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.

Pei J.,Chang'an University | Fan Z.,Chang'an University | Liu H.,Chang'an University | Zhang J.,Chang'an University | And 2 more authors.
Road Materials and Pavement Design | Year: 2016

The modified Burgers model was selected to develop the nonlinear viscoelastic (NLVE) model of asphalt mixture subjected to repeated load, and the permanent strain was expressed as the summation of residual viscoelastic (RVE) and nonlinear viscous (NLV) strains. It is found that RVE and NLV strains increase with the increasing loading cycles, but RVE strain decreases with the increasing rest period while NLV is not related to the rest period. The proportion of NLV strain to total strain increases with the rest period and loading cycles and the NLV strain is the predominant part if the rest period is long enough. Thus, the NLVE model could be predigested. The repeated load permanent deformation tests of three asphalt mixtures were conducted at different temperatures and stresses for model validation and parameter analysis. It is found that the permanent strain increases with test temperature and stress and the proposed NLVE model can well describe the mechanical behaviour of the asphalt mixture subjected to repeated load. Moreover, fitting results show that the modified Burgers model parameters (Formula presented.), (Formula presented.) and (Formula presented.) decrease with test temperature but increase with stress while parameter (Formula presented.) shows no significant change rule. © 2016 Taylor & Francis

Du Q.L.,Hebei Province | Wang C.H.,Chang'an 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.

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