scholarly journals Shear Properties of Asphalt Mixtures under Triaxial Compression

2019 ◽  
Vol 9 (7) ◽  
pp. 1489 ◽  
Author(s):  
Tuo Huang ◽  
Shuai Qi ◽  
Hongfu Liu ◽  
Huanan Yu ◽  
Sheng Li
Keyword(s):  
Shear Strength ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Friction Angle ◽  
Confining Pressure ◽  
Asphalt Mixtures ◽  
Triaxial Tests ◽  
Cohesion Strength ◽  
Failure Envelope ◽  
Shear Properties

In order to study the influences of confining pressure and temperature on the shear properties of asphalt mixtures, triaxial tests were conducted at 40 °C, 50 °C, and 60 °C, with the confining pressure ranges from 0 to 1 MPa for the widely used continuous-graded AC (Asphalt Concrete)-13, open-graded OGFC (Open-Graded Friction Course)-13, and gap-graded SMA (Stone Mastic Asphalt)-13 asphalt mixtures in China. A nonlinear regression/prediction model of triaxial strength for asphalt mixtures was proposed. The results show that confining pressure and temperature had a significant effect on the shear resistance of asphalt mixtures. With increasing temperature, the shear strength of the asphalt mixture gradually decreased due to the decreasing of cohesion strength; the shear strength of the asphalt mixture increased with the increase of confining pressure. Meanwhile, the cohesion strength increased and the friction angle decreased gradually with the increase of confining pressure. When the confining pressure was close to 0.6 MPa, the Mohr–Coulomb failure envelope bended down, so the linear Mohr–Coulomb criterion is not suitable to describe the failure behavior of asphalt mixtures. Therefore, a power function failure envelope was put forward to characterize the nonlinear shear properties of asphalt mixtures. The nonlinear evolutional laws of shear parameters, which includes cohesion strength and friction angle, were also proposed for asphalt pavement material and structure design. Among these asphalt mixtures, the gap-graded SMA-13 asphalt mixture exhibited better performance on the resistance to shear failure, and it was recommended as the upper layer material to improve the shear performance of asphalt pavement.

scholarly journals Analysis of a Methodology for Torsional Test under Normal Stress and Shear Performance for Asphalt Mixtures

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Jun Xie ◽  
Yiqun Zhan ◽  
Yifan Wang
Keyword(s):  
Shear Strength ◽  
Normal Stress ◽  
Shear Test ◽  
Stress Condition ◽  
Asphalt Mixture ◽  
Friction Angle ◽  
Asphalt Mixtures ◽  
Test Method ◽  
Shear Performance ◽  
Torsional Test

Insufficient shear performance in an asphalt mixture is a primary reason for rutting deformation and pavement surface longitudinal cracking. Thus, it is important to choose a suitable shear test method to evaluate shear performance in an asphalt mixture. Current testing methods mainly evaluate the bonding strength between asphalt layers, and the current shear test method for an asphalt mixture is disadvantaged by high equipment cost and complicated procedures. Our study proposes a torsional test method under normal stress condition, and evaluation was done for four types of asphalt mixture under different temperature conditions. Through the mechanical analysis, the calculation formulas for shear strength and shear parameters (cohesion and internal friction angle) for the torsional test under a normal stress condition were obtained. Testing results were also obtained for shear strength, shear modulus, and cohesion and internal friction angle of the asphalt mixtures. Experimental testing indicated that the method was able to provide repeatable results for the shear resistance of asphalt mixtures at different temperatures and also reflected the difference in shear performance of the various asphalt mixtures and the influence of temperature on shear performance. The failure mode of the specimen was the appearance of an oblique crack of about 45° from the vertical axis after the specimen was destroyed, which accorded with shear failure characteristics. A shear fatigue model was obtained considering different shear stress levels. The torsional test method under normal stress formed a compression-shear action on the specimen by applying torque and normal stress and was used to evaluate the shear performance of the asphalt mixtures.

scholarly journals Using Lightweight Materials to Enhance Thermal Resistance of Asphalt Mixture for Cooling Asphalt Pavement

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Haibin Deng ◽  
Deyi Deng ◽  
Yinfei Du ◽  
Xinmin Lu
Keyword(s):  
Thermal Conductivity ◽  
Shear Strength ◽  
Thermal Resistance ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Lightweight Aggregate ◽  
Asphalt Mixtures ◽  
Shear Strength Test ◽  
Irradiation Test ◽  
Negative Effect

This study aims to enhance the thermal resistance of asphalt mixture to cool asphalt pavement. Four kinds of asphalt mixtures were prepared by replacing basalt aggregate and limestone mineral powder with shale ceramsite (SC) and fly ash cenosphere (FAC), respectively. A series of experiments, including environment scanning electron microscope test, thermophysical parameter test, indoor irradiation test, shear strength test, and rutting test, were performed to verify the purpose of this study. The results show that using low-density SC and FAC could produce lightweight asphalt mixtures, which had lower thermal conductivity than control asphalt mixture. The indoor irradiation test shows that the resultant asphalt mixtures had lower temperatures at the depth of lower than 4 cm. The addition of SC had a negative effect on the shear strength and dynamic stability of asphalt mixture. However, the two indicators increased due to the addition of FAC. The results presented in this study indicate that it is feasible to use lightweight aggregate to prepare low-thermal-conductivity asphalt mixture and use this kind of asphalt mixture to cool asphalt pavement.

Study on Test and Influence of Anti-Shear Strength of Asphalt Mixture

2012 ◽  
Vol 598 ◽  
pp. 580-584
Author(s):  
Yi Wang ◽  
Nan Xiang Zheng ◽  
Xiao Ping Ji
Keyword(s):  
Shear Strength ◽  
Internal Friction ◽  
Impact Factor ◽  
Asphalt Mixture ◽  
Friction Angle ◽  
Asphalt Mixtures ◽  
Internal Friction Angle ◽  
Modified Asphalt ◽  
Shear Property ◽  
Nominal Size

In order to further reveal the shear property of asphalt mixtures, shear device self-developed was used to research the variation and impact factor of anti-shear strength, cohesion and internal friction angle of different asphalt mixture types. The results show that: Modified asphalt can effectively improve the cohesion and anti-shear strength, but little effect on the internal friction angle; the internal friction angle and anti-shear strength of SAC-16 are greater than AC-16, but the cohesion is not significant different; with the nominal size of stone increased, the internal friction angle and anti-shear strength of asphalt mixtures rose, but little change in the cohesion; with temperatures increased, the anti-shear strength and cohesion of asphalt mixtures reduced gradually, but little change in the internal friction angle.

scholarly journals Prediction Models of Shear Parameters and Dynamic Creep Instability for Asphalt Mixture under Different High Temperatures

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2542
Author(s):  
Junxiu Lv ◽  
Xiaoyuan Zhang
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Stress Level ◽  
Prediction Models ◽  
Asphalt Mixture ◽  
Confining Pressure ◽  
Shear Strength Parameters ◽  
Dynamic Creep ◽  
Shear Stress Level ◽  
Creep Instability

This study mainly investigates the prediction models of shear parameters and dynamic creep instability for asphalt mixture under different high temperatures to reveal the instability mechanism of the rutting for asphalt pavement. Cohesive force c and internal friction angle φ in the shear strength parameters for asphalt mixture were obtained by the triaxial compressive strength test. Then, through analyzing the influence of different temperatures on parameters c and φ, the prediction models of shear strength parameters related to temperature were developed. Meanwhile, the corresponding forecast model related to confining pressure and shear strength parameters was obtained by simplifying the calculation method of shear stress level on the failure surface under cyclic loading. Thus, the relationship of shear stress level with temperature was established. Furthermore, the cyclic time FN of dynamic creep instability at 60 °C was obtained by the triaxial dynamic creep test, and the effects of confining pressure and shear stress level were considered. Results showed that FN decreases exponentially with the increase in stress levels under the same confining pressure and increases with the increase in confining pressure. The ratio between shear stress level and corresponding shear strength under the same confining pressure was introduced; thus, the relationship curve of FN with shear stress level can eliminate the effect of different confining pressures. The instability prediction model of FN for asphalt mixture was established using exponential model fitting analysis, and the rationality of the model was verified. Finally, the change rule of the parameters in the instability prediction model was investigated by further changing the temperature, and the instability forecast model in the range of high temperature for the same gradation mixture was established by the interpolation calculation.

Determining Optimum Carbon Nanotubes Content for Asphalt Mixture in Road Pavements

2021 ◽  
Vol 1023 ◽  
pp. 121-126
Author(s):  
Van Bach Le ◽  
Van Phuc Le
Keyword(s):  
Carbon Nanotubes ◽  
Asphalt Pavement ◽  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Construction Cost ◽  
Asphalt Mixtures ◽  
Static Modulus ◽  
Pavement Construction ◽  
Modified Binder ◽  
Marshall Stability

Although small amount of binder in asphalt concrete mixture may commonly range from 3.5 to 5.5% of total mixture as per many international specifications, it has a significant impact on the total cost of pavement construction. Therefore, this paper investigated the effects of five carbon nanotubes contents of 0.05%, 0.1%, 0.15%, 0.2%, 0.25% by asphalt weight as an additive material for binder on performance characteristics of asphalt mixtures. Performance properties of CNTs modified asphalt mixtures were investigated through the Marshall stability (MS) test, indirect tensile (IDT) test, static modulus (SM) test, wheel tracking (WT) test. The results indicated that asphalt mixtures with CNT modified binder can improve both the rutting performance, IDT strength and marshall stability of tested asphalt mixtures significantly at higher percentages of carbon nanotubes. However, the issue that should be considered is the construction cost of asphalt pavement. Based on the asphalt pavement structural analysis and construction cost, it can be concluded that an optimum CNT content of 0.1% by asphalt weight may be used as additive for asphalt binder in asphalt mixtures.

A Change of Undrain Shear Strength of Soft Ground during Consolidation Process

2014 ◽  
Vol 513-517 ◽  
pp. 269-272
Author(s):  
Yeong Mog Park ◽  
Ik Joo Um ◽  
Norihiko Miura ◽  
Seung Cheol Baek
Keyword(s):  
Shear Strength ◽  
Soft Clay ◽  
Confining Pressure ◽  
Triaxial Tests ◽  
Test Results ◽  
Exponential Equation ◽  
Consolidation Process ◽  
Degree Of Consolidation ◽  
Clay Ground ◽  
Strength Increment

The purpose of this study is to investigate the undrain shear strength increment during consolidation process of soft clayey soils. Thirty kinds of laboratory triaxial tests have been performed using undisturbed and remolded Ariake clay samples with different degree of consolidation and 5 kinds of confining pressure. Test results show that well known linear equation proposed by Yamanouchi et al.(1982) is overestimated the strength of undisturbed soft clay ground in the process of consolidation. A new simple and reasonable exponential equation proposed in this paper.

Rubber Modified Asphalt Mixture Properties and Mechanical Testing

2011 ◽  
Vol 105-107 ◽  
pp. 810-817 ◽  
Author(s):  
Rong Hui Zhang ◽  
Jia Liu ◽  
Jian Chao Huang ◽  
Yi Fu
Keyword(s):  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Specimen Preparation ◽  
Twin Screw Extrusion ◽  
Modified Asphalt ◽  
Flexural Tensile Strength ◽  
Screw Extrusion ◽  
Twin Screw ◽  
Compound Particle

To solve the high-temperature rutting problem of asphalt pavement, the old rubber of the tire rubber and plastic of general polyethylene waste composite modified asphalt mixture is proposed. The plastic and rubber compound particle was made by the rubber through efficient desulfurization additives, pre-swelling, twin-screw extrusion equipment. The particles mixed with the asphalt mixtures specimen preparation and the dynamic stability experiments, composite beam fatigue experiments, flexural tensile strength and modulus experiments and anti-reflective pavement cracks and other mechanical experiments are performed. The comparative data obtained by the rubber and plastic composited modified asphalt mixtures and SBS asphalt mixtures prove that the rubber and plastic composited modified asphalt mixtures have excellent rutting resistance and fatigue resistance.

scholarly journals Experimental Study of Stress-Seepage Coupling Properties of Sandstone under Different Loading Paths

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Xi Chen ◽  
Wei Wang ◽  
Yajun Cao ◽  
Qizhi Zhu ◽  
Weiya Xu ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Pore Pressure ◽  
Complex Loading ◽  
Friction Angle ◽  
Confining Pressure ◽  
Triaxial Tests ◽  
Compression Tests ◽  
Biot Coefficient ◽  
Cyclic Loading And Unloading ◽  
Loading And Unloading

The study on hydromechanical coupling properties of rocks is of great importance for rock engineering. It is closely related to the stability analysis of structures in rocks under seepage condition. In this study, a series of conventional triaxial tests under drained condition and hydrostatic compression tests under drained or undrained condition on sandstones were conducted. Moreover, complex cyclic loading and unloading tests were also carried out. Based on the experimental results, the following conclusions were obtained. For conventional triaxial tests, the elastic modulus, peak strength, crack initiation stress, and expansion stress increase with increased confining pressure. Pore pressure weakened the effect of the confining pressure under drained condition, which led to a decline in rock mechanical properties. It appeared that cohesion was more sensitive to pore pressure than to the internal friction angle. For complex loading and unloading cyclic tests, in deviatoric stress loading and unloading cycles, elastic modulus increased obviously in first loading stage and increased slowly in next stages. In confining pressure loading and unloading cycles, the Biot coefficient decreased first and then increased, which indicates that damage has a great impact on the Biot coefficient.

The Analyses and Calculation for Thermal Stresses of SBR Modified Asphalt Pavement

2011 ◽  
Vol 243-249 ◽  
pp. 4112-4118
Author(s):  
Min Jiang Zhang ◽  
Gang Chen ◽  
Li Xia Hou ◽  
Li Ping Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thermal Stresses ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
The Finite Element Method ◽  
Temperature Stresses ◽  
Modified Asphalt ◽  
Temperature Performance

Based on the viscoelasticity theory and the data of creep test, Burgers model was established, which was used to study the viscoelastic property of SBR asphalt mixtures, and the viscoelastic constitutive relation was obtained. Using the finite element method, the temperature stresses field was calculated under the environmental conditions and the thermal stresses of SBR modified asphalt pavement was given at the last part of this paper. The study indicated that SBR modified asphalt mixtures have the advantage over common asphalt mixture in low-temperature performance.

Study on Ice Breaking on Crumbed Rubber Asphalt Pavement Based on Self-Stress Method

2012 ◽  
Vol 256-259 ◽  
pp. 1807-1812 ◽  
Author(s):  
Qing Yi Xiao ◽  
Hong Jun Cui ◽  
Ning Li Li ◽  
Cai Li Zhang
Keyword(s):  
Elastic Modulus ◽  
Traffic Safety ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Highway Traffic ◽  
Friction Test ◽  
Rubber Content ◽  
Fem Method ◽  
The Relationship

Ice layer on pavement surface was a serious problem for highway traffic safety. Crumbed rubber asphalt mixture was an effective way to drive ice layer away from surface. Through wheel test asphalt mixture specimen with ice layer at negtive temperature, the paper studied ice breaking performance of asphalt mixtures containing different amount crumbed rubber. Pendulumlike friction test BPN after wheel test was taken as an performance index of crumber rubber asphalt breaking ice. Results shown that the quantity of crumbed rubber and the performance of ice breaking had good linear relationship and more rubber content had better slide resistance recover speed at same wheel arround number.Through numerial model of pavement covered ice based on FEM method, the paper had analyzed the relationship between elastic modulus of crumbed rubber pavement and ice stress-strain on pavement, and put forward the mechanism of ice breaking.

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