scholarly journals Fatigue Equation of Cement-Treated Aggregate Base Materials under a True Stress Ratio

2018 ◽  
Vol 8 (5) ◽  
pp. 691 ◽  
Author(s):  
Songtao Lv ◽  
Chaochao Liu ◽  
Jingting Lan ◽  
Hongwei Zhang ◽  
Jianlong Zheng ◽  
...  
Keyword(s):  
Stress Ratio ◽  
True Stress ◽  
Base Materials ◽  
Aggregate Base ◽  
Fatigue Equation

Visualization and quantification of lab vibratory compacting process for aggregate base materials using accelerometer

2020 ◽  
Vol 25 ◽  
pp. 100393
Author(s):  
Wei Hu ◽  
Pawel Polaczyk ◽  
Xiaoyang Jia ◽  
Hongren Gong ◽  
Baoshan Huang
Keyword(s):  
Base Materials ◽  
Aggregate Base

scholarly journals Standardization of Fatigue Characteristics of Cement-Treated Aggregate Base Materials under Different Stress States

2018 ◽  
Vol 8 (9) ◽  
pp. 1500 ◽  
Author(s):  
Jiawei Xie ◽  
Limin Tang ◽  
Songtao Lv ◽  
Naitian Zhang ◽  
Tuo Huang ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Weibull Distribution ◽  
Interval Analysis ◽  
Cement Content ◽  
Curing Time ◽  
Base Materials ◽  
Test Conditions ◽  
Fatigue Characteristics ◽  
Stress States ◽  
Aggregate Base

In this study, to decrease the evaluation uncertainty of the fatigue characteristics of cement-treated aggregate base materials under different test conditions, unconfined compressive, indirect tensile, flexural tensile strength tests and fatigue tests of these base materials with different cement content and at different curing times were carried out. The Weibull distribution was employed to analyze fatigue test results. The standardization model of fatigue characteristics for cement-treated aggregate base materials under different stress states was established. Based on the interval analysis theory, the fatigue characteristic model under different stress states was established using interval parameters. Results revealed that the curing time and cement content considerably affect the strength and fatigue characteristics of cement-treated aggregate base materials, and with increasing cement content and curing time, the fatigue resistance of cement-treated aggregate base materials can be improved. Clear differences between the fitting parameters a and b of the S-N fatigue equation of cement-treated aggregate base materials under different stress states were observed, which can be eliminated by using the analysis method based on the Weibull distribution and the standardization model, and a unified expression for the cement-treated aggregate base materials under different test conditions was realized. A Standardization model of fatigue characteristics based on the interval analysis new method could solve several problems such as inadequate sampling representation, low precision, and insufficient stability of test equipment; thus, the errors caused by materials, structures, the environment, and loads can be reduced, making the fatigue life interval more reasonable and scientific compared to the point numerical fatigue life. Regression parameters a and be were in intervals [9.0, 10.6] and [9.9, 11.3], respectively, and parameters a and b were similar, which improve the test accuracy and reduce the data error.

scholarly journals Assessment of Field Compaction of Aggregate Base Materials for Permeable Pavements Based on Plate Load Tests

2018 ◽  
Vol 10 (10) ◽  
pp. 3817 ◽  
Author(s):  
Yong-Jin Choi ◽  
Donghyun Ahn ◽  
Tan Nguyen ◽  
Jaehun Ahn
Keyword(s):  
Mechanical Behavior ◽  
Field Experiments ◽  
Low Impact Development ◽  
Base Layer ◽  
Permeable Pavements ◽  
Base Materials ◽  
Major Interest ◽  
Field Compaction ◽  
Load Tests ◽  
Aggregate Base

The permeable pavement is one of Low Impact Development technics that allows stormwater to infiltrate through the pavement surface and the underlying base layer, thereby reducing surface runoff and preventing water contamination. For permeable base layers of permeable pavements, open-graded aggregates are often used to infiltrate and store stormwater in the pore of aggregate base layers. The mechanical behavior of open-graded aggregates has not been a major interest of pavement industry and society, and therefore there is much less information known for behavior of compacted open-graded aggregates comparing to dense-graded materials. This study aims at investigating the mechanical behavior of compacted permeable or open-graded aggregate base materials based on field experiments. Five different open-graded aggregates were selected, and they were compacted in the field up to 12 passes with a 10-ton vibratory compaction roller. The mechanical behaviors of aggregates were evaluated by conducting plate load tests at 2, 4, 8, and 12 passes of roller. For the test conditions considered herein, the strain modulus at the first loading seems to provide more consistent results with respect to aggregate types and level of compaction than other stiffness measures from plate load tests.

Mechanistic Analyses of Geosynthetic Reinforced Aggregate Road Test Sections

2019 ◽  
Vol 2673 (12) ◽  
pp. 783-797
Author(s):  
Jeb S. Tingle
Keyword(s):  
Large Scale ◽  
Full Scale ◽  
Anisotropic Models ◽  
Linear Elastic ◽  
Base Materials ◽  
Scale Test ◽  
Pavement Response ◽  
Aggregate Base ◽  
Nonlinear Elastic ◽  
Development Center

Large-scale laboratory box tests and a full-scale traffic test were performed by the U.S. Army Engineer Research and Development Center to evaluate the performance of geosynthetic reinforced aggregate road sections constructed with marginal base materials over a typical subgrade. The large-scale laboratory testing and full-scale test section included eight different instrumented aggregate road sections including three different aggregate base materials and two different geosynthetics. Mechanistic analyses of each pavement section were conducted using linear elastic, nonlinear elastic, and nonlinear anisotropic models to predict the critical pavement response parameters. The analyses show that mechanistic tools can be effectively used to estimate the critical pavement response parameters for unpaved roads.

Frost Heave and Water Uptake Relations in Variably Saturated Aggregate Base Materials

2003 ◽  
Vol 1821 (1) ◽  
pp. 13-19 ◽  
Author(s):  
W. Spencer Guthrie ◽  
åke Hermansson
Keyword(s):  
Base Material ◽  
Primary Source ◽  
Frost Heave ◽  
Soil Conditions ◽  
Freezing Process ◽  
Freezing Front ◽  
Base Materials ◽  
Additional Water ◽  
Initial Freezing ◽  
Aggregate Base

The occurrence of frost heave in soils and aggregates can be attributed to the redistribution of water in the soil profile. Frost heave testing performed in this study on 71 variably saturated specimens of aggregate base material indicates that although the uptake of new water from outside the soil body is a primary source of moisture in the formation of segregation ice, internal water residing within the soil or aggregate structure can serve as an important supply of water to the freezing front. Frost heave concepts relating to unsaturated soil conditions were reviewed, and a laboratory methodology was employed to study the relationships between the physical properties of the specimens and their frost heave behavior. Degrees of saturation ranging from 45% to 84% were evaluated, and heave–uptake ratios as high as 2.24 were calculated. Ratios less than 1.09 suggest that sufficient porosity exists in the sample matrix to allow the formation of ice without causing frost heave; higher ratios designate samples that are nearly saturated and that undergo substantial upward redistributions of existing water during the initial freezing process, which gives rise to measurable heave even before additional water is imbibed by the sample. The entry of air into freezing soils and aggregates can play an important role in their frost heave behavior.

Deterioration of Asphalt Pavement at Long-Term Pavement Performance Program Site 49-1001 in Utah

2005 ◽  
Vol 1933 (1) ◽  
pp. 121-125
Author(s):  
Brandon J. Blankenagel ◽  
W. Spencer Guthrie
Keyword(s):  
Base Layer ◽  
Pavement Performance ◽  
Falling Weight Deflectometer ◽  
Water Drainage ◽  
Base Materials ◽  
Pavement Deterioration ◽  
Pavement Base ◽  
Aggregate Base ◽  
Falling Weight

Highway 191 near Bluff, Utah, features a well-monitored section of the long-term pavement performance (LTPP) program. Constructed in 1980, this section of flexible pavement performed well for nearly 13 years. Through this time, cracking of the asphalt layer was minimal. In the fourteenth year, however, the extent of longitudinal cracking in the wheel path increased and necessitated placement of a chip seal on the pavement surface. The purpose of this research was to determine the cause of pavement deterioration using LTPP data. Deflection basins obtained from falling-weight deflectometer testing were analyzed to investigate the extent to which structural degradation influenced deterioration of the pavement. Pavement layer modulus values were plotted against time and clearly show that weakening of the pavement base layer immediately preceded the occurrence of cracking. The geography of the site, as documented in photographs, supports the conclusion that inadequate water drainage at the site permitted saturation of the aggregate base layer during a period of midsummer flooding. This finding emphasizes the importance of specifying non-moisture-susceptible base materials and providing necessary drainage works in pavement design.

scholarly journals Mechanical and Mesoscale Analyses of Cement Stabilized Macadam Prepared by Vibratory and Nonvibratory Mixing Techniques

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Jijing Wang ◽  
Zhihua Tan
Keyword(s):  
Fatigue Life ◽  
Stress Ratio ◽  
Cement Mortar ◽  
Stress Sensitivity ◽  
Fatigue Tests ◽  
X Ray ◽  
Loading Rates ◽  
Stress States ◽  
Mixing Techniques ◽  
Fatigue Equation

The objective of this study is to analyze the effects of mixing techniques on the mechanical behavior and meso-structure of cement-treated aggregate. Different specimens were prepared by vibratory and nonvibratory mixing techniques. X-ray CT scans were performed to illustrate the distribution of cement mortar on aggregate. The strength, modulus, and fatigue tests under different stress states were tested to reveal the impacts of mixing techniques. Then, the relationships between strengths and loading rates and that between moduli and stress levels were established. Hereafter, the S-N fatigue equation that modified with stress ratio related to loading rates was used to describe the fatigue performance. The results indicate that the cement mortar of specimens prepared by vibratory mixing was well-distributed on aggregates. The strength, modulus, and fatigue life of the specimens prepared by vibratory mixing were higher under the test condition threshold. Moreover, the growth rate of strength and modulus with loading for specimens prepared by vibratory mixing was slightly larger than that for specimens prepared by nonvibratory mixing. Compared with the cement-treated aggregates specimens prepared by nonvibratory mixing, the fatigue life of cement-treated aggregates specimens prepared by vibratory mixing had more stable stress sensitivity.

Sign in / Sign up

Export Citation Format

Share Document