Estimation of shear modulus of asphalt mixture based on the shear strength of the aggregate interface

2020 ◽  
Vol 248 ◽  
pp. 118695
Author(s):  
Xu Cai ◽  
Li Chen ◽  
Ruida Zhang ◽  
Wenke Huang ◽  
Kuanghuai Wu ◽  
...  
Keyword(s):  
Shear Strength ◽  
Shear Modulus ◽  
Asphalt Mixture

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.

Visco-Elasticity of Asphalt Mixture under Broad Temperature and Frequency

2013 ◽  
Vol 838-841 ◽  
pp. 156-161
Author(s):  
Peng Yang ◽  
Hong Zhi Cui ◽  
Wei Lun Wang
Keyword(s):  
High Temperature ◽  
Shear Modulus ◽  
Asphalt Mixture ◽  
Dominant Position ◽  
Nonlinear Curve Fitting ◽  
Lower Temperature ◽  
Improved Model ◽  
And Storage ◽  
Nonlinear Curve ◽  
Cam Model

In this study, the improved model of CAM with clear parameter was introduced. The visco-elasticity of asphalt mixture under broad temperature and frequency was studied and the properties of asphalt mixture at high asphalt and low temperature of was described by fitting the parameters of CAM model. The four equations of CAM model can be utilized in analysis of visco-elasticity of asphalt mixture and the physical meaning of the parameters in equations was very clear; Through nonlinear curve fitting , the CAM model was found to overcome the defect of deviation from the start and the end fitting; For one kind of asphalt mixture, the complex shear modulus and storage shear modulus was higher in same frequency at lower temperature, and the elasticity was in dominant position significantly; At middle temperature, the modulus of asphalt mixture became smaller; At high temperature, although the modulus was lower, the elasticity was higher. At middle-high temperature, the modulus of asphalt mixture remained smaller and the ratio of elasticity was minimum value, and asphalt mixture was recognized as typical visco-elastic body and was destroyed easily by the deformation disease.

Research on Road Performance of Desulfurized Rubber Asphalt and Mixture

2014 ◽  
Vol 525 ◽  
pp. 546-551 ◽  
Author(s):  
Chun Wei Wang ◽  
Fei Wang ◽  
Wen Gang Zhang
Keyword(s):  
Shear Strength ◽  
Rubber Particle ◽  
Asphalt Mixture ◽  
Performance Testing ◽  
High Viscosity ◽  
Cohesive Strength ◽  
The Road ◽  
Swelling Mechanism ◽  
Road Performance ◽  
Asphalt Mortar

In order to discuss the road performance of desulfurized rubber asphalt and mixture, Swelling mechanism of desulfurized rubber asphalt was studied first, and then performance testing of KLMY90#, normal rubber asphalt and desulfurized rubber asphalt were taken, after that, penetration, shear strength and cohesive strength of desulfurized rubber asphalt mortar were test, road performance of desulfurized rubber asphalt mixture were test at last. The results of the study show that, there is no Rubber particle core, but lots of chemical reaction in desulfurized rubber asphalt; the performance of desulfurized rubber asphalt is better than normal rubber asphalt without high viscosity, easy isolation and poor high temperature storage stability; shear strength and cohesive strength of desulfurized rubber asphalt mortar is better; and desulfurized rubber asphalt mixture have good road performance.

Structure characteristics and mechanical properties of kaolinite soils. II. Effects of structure on mechanical properties

2006 ◽  
Vol 43 (6) ◽  
pp. 601-617 ◽  
Author(s):  
Y -H Wang ◽  
W -K Siu
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Shear Modulus ◽  
Critical State ◽  
Soil Structure ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Undrained Shear Strength ◽  
Interparticle Forces ◽  
Undrained Shear

This paper reports the effects of structure on the mechanical responses of kaolinite with known and controlled fabric associations. The dynamic properties and strength were assessed by resonant column tests and undrained triaxial compression tests, respectively. The experimental results demonstrate that interparticle forces and associated fabric arrangements influence the volumetric change under isotropic compression. Soils with different structures have individual consolidation lines, and the merging trend is not readily seen under an isotropic confinement up to 250 kPa. The dynamic properties of kaolinite were found to be intimately related to the soil structure. Stronger interparticle forces or higher degrees of flocculated structure lead to a greater small-strain shear modulus, Gmax, and a lower associated damping ratio, Dmin. The soil structure has no apparent influence on the critical-state friction angle (ϕ′c = 27.5°), which suggests that the critical stress ratio does not depend on interparticle forces. The undrained shear strength of kaolinite is controlled by its initial packing density rather than by any interparticle attractive forces, and yet the influence of the structure on the effective stress path is obvious.Key words: interparticle forces, shear modulus, damping ratio, stress–strain behavior, undrained shear strength, critical state.

Effect of the Strain Rate on the Twisting of Trabecular Bone from Women with Hip Fracture

2013 ◽  
Vol 135 (12) ◽  
Author(s):  
Ana C. Vale ◽  
Jennifer Faustino ◽  
Luís Reis ◽  
Ana Lopes ◽  
Bruno Vidal ◽  
...  
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Hip Fracture ◽  
Shear Modulus ◽  
Strain Rate ◽  
Trabecular Bone ◽  
Axial Load ◽  
Angular Displacement ◽  
Maximum Shear Stress ◽  
Lower Limbs

As one of the major functions of bone is to provide structural support for the musculoskeletal system, it is important to evaluate its mechanical strength. Bones may be subjected to multiaxial stresses due to bone pathologies, accidental loads which may lead to hip, wrist fracture, or to a prosthetic joint replacement. Twist loading may lead to fractures, especially involving long bones from lower limbs. The aim of this work was to study the effect of the strain rate on the shear properties of trabecular bone samples from women with hip fracture (from 65 to 100 years). Cylindrical samples were core drilled from human femoral heads along the primary trabecular direction. The cylinder's ends were polished and embedded in blocks of polymeric material which fit the grips of the testing device. Deformation rates of 0.005, 0.01, 0.015, and 0.05 s−1 were applied. Twisting tests were conducted with or without an applied axial load of 500 N. From the torque-angular displacement curves, the shear stress–strain curves were obtained. The maximum shear strength and the shear modulus (i.e. the slope of the linear region) were determined. A large scatter of the results of the shear strength and the shear modulus was found, which is probably related to the heterogeneity of nonhealthy human bone samples. There is no significant effect of the strain rate on the maximum shear stress and the shear modulus, either in tests undertaken with or without the application of an axial load. The effect of strain rate on nonhealthy bone trabecular twisting properties did not follow the trend observed on the effect of strain rate in healthy bone, where an increase is detected.

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