Deformation characteristics of granular base course in flexible pavements

1986 ◽  
Vol 23 (6) ◽  
pp. 222-223
Keyword(s):  
Flexible Pavements ◽  
Deformation Characteristics ◽  
Base Course ◽  
Granular Base

scholarly journals Modeling Stress-Dependent Anisotropic Elastoplastic Unbound Granular Base in Flexible Pavements

2018 ◽  
Vol 2672 (52) ◽  
pp. 46-56 ◽  
Author(s):  
Yuqing Zhang ◽  
Fan Gu ◽  
Xue Luo ◽  
Bjorn Birgisson ◽  
Robert L. Lytton
Keyword(s):  
Stress Responses ◽  
Compressive Strain ◽  
Flexible Pavements ◽  
Plastic Behavior ◽  
Elastic Model ◽  
Nonlinear Stress ◽  
Anisotropic Elastic ◽  
Base Course ◽  
Granular Base ◽  
Stress Dependent

Unbound granular base (UGB) has a cross-anisotropic and nonlinear (stress-dependent) modulus with a plastic behavior. Existing UGB models address nonlinear cross-anisotropy and plasticity separately. It is unknown how the two characteristics are coupled into a finite element model (FEM) and how this will affect the pavement responses. This study presents a coupled nonlinear cross-anisotropic elastoplastic (NAEP) constitutive model for the UGB and implements it in a weak form equation-based FEM. No material subroutine is needed to address the circular dependence between the stress-dependent anisotropic modulus, structural stress responses, and elastoplastic deformation. The NAEP model was calibrated by triaxial resilient modulus and strength tests and validated using laboratory measurements in a large-scale soil-tank pavement structural test. It is found that the NAEP model is valid and effective in predicting the UGB responses in flexible pavements. The model predicted less horizontal tensile stresses at the base bottom and introduced compressive stresses in the middle and top of the base course. This is caused by an increasing confinement resulting from a horizontal plastic dilation in the base course, which cannot be modeled without considering plasticity. The stress-dependent modulus for the UGB material decreases with depth and the distance from loading centerline. Compared with a nonlinear anisotropic elastic model, the NAEP model predicted the same tensile strain at asphalt layer bottom, a higher base modulus, and a higher subgrade compressive strain. Thus, the nonlinear anisotropic elastic UGB model results in the same fatigue life as the NAEP model but may riskily under-predict rutting damage.

scholarly journals EFFECTS OF FREEZE-THAWING ON BEARING CAPACITY OF GRANULAR BASE COURSE MATERIAL

2012 ◽  
Vol 68 (3) ◽  
pp. I_115-I_122
Author(s):  
Shinichiro KAWABATA ◽  
Tatsuya ISHIKAWA ◽  
Takumi MURAYAMA ◽  
Shuichi KAMEYAMA
Keyword(s):  
Bearing Capacity ◽  
Base Course Material ◽  
Course Material ◽  
Base Course ◽  
Granular Base

scholarly journals Effects of Freeze-thaw History on Bearing Capacity of Granular Base Course Materials

2016 ◽  
Vol 143 ◽  
pp. 828-835 ◽  
Author(s):  
Shinichiro Kawabata ◽  
Tatsuya Ishikawa ◽  
Shuichi Kameyama
Keyword(s):  
Bearing Capacity ◽  
Freeze Thaw ◽  
Course Materials ◽  
Base Course ◽  
Granular Base

Recycling of Waste Originating Form Flexible Pavements for Bound-Base Courses of Flexible Pavements

2020 ◽  
Vol 46 (3) ◽  
pp. 394-408
Author(s):  
Kumari Monu ◽  
G.D. Ransinchung R.N. ◽  
Surender Singh ◽  
Gaurav Singh Raghav
Keyword(s):  
Asphalt Pavement ◽  
Flexible Pavements ◽  
Rutting Resistance ◽  
Reclaimed Asphalt ◽  
Coarse Aggregates ◽  
Long Run ◽  
Indirect Tensile ◽  
Base Course ◽  
The Cost ◽  
Marshall Stability

Reclaimed Asphalt pavement (RAP) is a C&D waste originating from the reclamation of asphalt pavement which has completed its service life. Using RAP would potentially reduce reliance on primary aggregates and lowers the environmental impact of construction. The present study is an attempt made to utilize RAP judiciously as a bound base course of the flexible pavement. Natural coarse aggregates were replaced by RAP in proportions of 50% & 100% with & without Warm Mix Asphalt (WMA), for production of bound-base course mixes. To ensure the long run performance, the aging condition was simulated in the laboratory and mechanical properties such as Marshall Stability, Tensile Strengths, Marshall Stability Retained, Indirect Tensile Ratio, rutting resistance, Fatigue life, and abrasion resistance were considered. With the incorporation of 50-100% coarse RAP, the Marshall Stability, rutting resistance and abrasion were found to be improved by 30-32%, 43-104% and 11-17% respectively. Similarly, total cost saving is about 15-35%, which is quite significant. However, the addition of WMA enhanced the cost by 3-4%, which is insignificant when combined with RAP, furthermore, the reductions in fume emission enhance the sustainability aspect of the technology.

Stabilization of Weak Clay with Strong Sand and Geogrid at Sand-Clay Interface

1998 ◽  
Vol 1611 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Braja M. Das ◽  
Kim H. Khing ◽  
Eun C. Shin
Keyword(s):  
Bearing Capacity ◽  
Model Test ◽  
Soil Layer ◽  
Granular Soil ◽  
Laboratory Model ◽  
Test Results ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Base Course ◽  
Granular Base

The load-bearing capacity of a weak clay subgrade can be increased by placing a strong granular base course of limited thickness on top of the clay layer. The load-bearing capacity can be increased further, or the thickness of the granular base course can be reduced, by separating both layers by a geogrid. Laboratory model test results for the ultimate bearing capacity of a rigid strip loading on the surface of a granular soil underlain by a soft clay with a layer of geogrid at the interface of the two soils are presented. The optimum thickness of the granular soil layer and the critical width of the geogrid layer required to derive the maximum benefit from the reinforcement were determined. Model test results on the permanent settlement of the rigid strip load caused by cyclic loading of low frequency are presented.

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