Influence of loading frequency on mechanical properties of unbound granular materials via repeated load tests

2021 ◽  
Vol 301 ◽  
pp. 124098
Author(s):  
Ning Li ◽  
Biao Ma ◽  
Hao Wang ◽  
Jin Tang ◽  
Xiaowei Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Granular Materials ◽  
Loading Frequency ◽  
Unbound Granular Materials ◽  
Load Tests ◽  
Repeated Load

Triaxial Characterization of Minnesota Road Research Project Granular Materials

1997 ◽  
Vol 1577 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Navneet Garg ◽  
Marshall R. Thompson
Keyword(s):  
Shear Strength ◽  
Granular Materials ◽  
Resilient Modulus ◽  
Axial Strain ◽  
Confining Pressure ◽  
Engineering Properties ◽  
Shear Tests ◽  
Road Project ◽  
Load Tests ◽  
Repeated Load

Six granular materials were used as base and subbase materials in the flexible pavement test sections for the Minnesota Road Research (Mn/ROAD) project. Crushed/fractured particles are not allowed in aggregate classes CL-1Fsp, CL-1Csp, CL-3sp, and CL-4sp. Ten to 15 percent crushed/fractured particles are required for CL-5sp. One hundred percent crushed/ fractured particles are required for CL-6sp. A comprehensive laboratory testing program was established to determine pertinent engineering properties of the granular materials. Rapid shear tests and repeated-load tests were conducted to determine the shear strength parameters (friction angle and cohesion), resilient modulus, rutting potential, stress history effects on shear strength, and moisture susceptibility. The results from the rapid shear tests and permanent deformation tests show that the rutting potential of a granular material can be characterized from rapid shear test at a confining pressure of 15 psi (103.35 kPa). The rutting parameter A was a function of the shear strength of the granular materials. The shear strength results obtained from rapid shear tests performed at a confining pressure of 15 psi reflect the rutting trends observed in the low-volume road test sections at the Mn/ROAD project. Results from repeated-load tests were used to develop the parameters for K-θ, UT-Austin, and Uzan’s models for evaluating the resilient modulus of granular materials. The axial strain values calculated from the resilient modulus models appear to be in good agreement with the measured axial strain values, except for the very low shear strength material CL-1Csp.

Assessment of On-Sample Instrumentation for Repeated Load Triaxial Tests

1998 ◽  
Vol 1614 (1) ◽  
pp. 52-60 ◽  
Author(s):  
Andrew R. Dawson ◽  
Simon D. Gillett
Keyword(s):  
Granular Materials ◽  
Comparative Studies ◽  
Measurement Process ◽  
Triaxial Tests ◽  
Triaxial Testing ◽  
Unbound Granular Materials ◽  
Repeated Load ◽  
Pavement Construction ◽  
Repeated Load Triaxial

Five laboratories have been involved in a series of comparative studies of the repeated load triaxial testing of soils and unbound granular materials as found in the lower layers of pavement construction. These comparisons with soil, granular materials, and an artificial specimen are outlined. The performance of the varied types of instruments that measure both axial and radial deformations is assessed, with particular attention to the fixing arrangements, instrument limitations, and weight. On the basis of the information presented, recommendations are given about the most appropriate types of instrument. No universal type is recommended, and it is clear that some variation in performance is an inevitable consequence of the measurement process.

scholarly journals Two unbound granular materials stiffness analysis with staged repeated load CBR test

2019 ◽  
Vol 286 ◽  
pp. 06003
Author(s):  
Abdelaziz Salmi ◽  
Lahbib Bousshine ◽  
Khaled Lahlou
Keyword(s):  
Granular Materials ◽  
Poisson Ratio ◽  
Elastic Behaviour ◽  
Unbound Granular Materials ◽  
Material Stiffness ◽  
Cbr Test ◽  
Repeated Load ◽  
Stress States ◽  
Equivalent Modulus ◽  
Linear Elastic Behaviour

Design methods of flexible pavements in many countries are based on linear elastic behaviour model for Unbound Granular Materials (UGM). In this context, parameters required to characterize an UGM in structural analysis of pavements are Stiffness modulus and Poisson ratio (E and ν). This paper presents a study of two UGM stiffness. Finite element simulation of repeated load CBR (RL-CBR) test has allowed to derive equation used in calculation of materials equivalent modulus based on laboratory RL-CBR Outputs. The staged RL-CBR test is used to evaluate material stiffness for different stress states to highlight its influence on UGM stiffness and compare studied materials. Also, this paper shows that even if two materials are different according to the current road authority specifications, they can represent similar stiffness.

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