scholarly journals Properties of Crushed Red-Bed Soft Rock Mixtures Used in Subgrade

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Huayan Yao ◽  
Shanpo Jia ◽  
Wenning Gan ◽  
Zhenhua Zhang ◽  
Kunlin Lu
Keyword(s):  
Moisture Content ◽  
Resilient Modulus ◽  
Soft Rock ◽  
Road Construction ◽  
Absorption Capacity ◽  
Test Results ◽  
Soft Rocks ◽  
Red Bed ◽  
Compaction Degree ◽  
Physical And Mechanical Characteristics

Slaking red-bed soft rocks are widely distributed in the south of Anhui Province, China, and several highways will go through this area. It is important to evaluate their physical and mechanical characteristics for the purpose of using this kind of soft rocks as materials for road construction. In this paper, the compacting tests, the resilient modulus tests, the California bearing ratio (CBR) tests, and permeability tests have been carried out on crushed red-bed soft rock mixtures. The test results showed that, for a given degree of compaction, the resilient modulus decreases linearly with the increase of moisture content. For a given moisture content, the resilient modulus and CBR values increase linearly with the increase of compaction degree, while the soaking swelling, water absorption capacity, and permeability coefficient decrease linearly. In other words, the strength and water stability are enhanced with the increase of the degree of compaction. The results demonstrate that the crushed red-bed soft rock mixtures can be directly used as materials for the highway construction by taking corresponding measures.

scholarly journals Experimental Study on Dynamic Resilient Modulus of Lime-Treated Expansive Soil

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Zheng Lu ◽  
Yang Zhao ◽  
Shaohua Xian ◽  
Hailin Yao
Keyword(s):  
Moisture Content ◽  
Environmental Changes ◽  
Resilient Modulus ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Confining Pressure ◽  
Triaxial Tests ◽  
The Stability ◽  
Compaction Degree

Dynamic resilient modulus is the design index of highway subgrade design code in China, which is significantly affected by the traffic loads and environmental changes. In this study, dynamic triaxial tests were conducted to investigate the influence of moisture content, compaction degree, cyclic deviator stress, and confining pressure on lime-treated expansive soil. The suitability of UT-Austin model to lime-treated expansive soils was verified. The results indicate that the dynamic resilient modulus of lime-treated expansive soils increases nonlinearly with the increase of compaction degree, while decreases nonlinearly with the increase of dynamic stress level. The dynamic resilient modulus decreases linearly with the increase of moisture content and increases linearly with the increase of confining pressure. Moreover, the moisture content has a more significant effect on the dynamic resilient modulus of lime-treated expansive soil. Therefore, it is necessary to ensure the stability of soil humidity state and its excellent mechanical properties under long-term cyclic loading for the course of subgrade filling and service. Finally, the calculated results of the UT-Austin model for dynamic resilient modulus show a good agreement with the test results.

scholarly journals Research on Intelligent Compaction Technology of Subgrade Based on Regression Analysis

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Ziyi Hou ◽  
Xiao Dang ◽  
Yezhen Yuan ◽  
Bo Tian ◽  
Sili Li
Keyword(s):  
Resilient Modulus ◽  
Single Point ◽  
Mean Value ◽  
Test Results ◽  
Intelligent Compaction ◽  
One Dimensional ◽  
Remote Monitoring System ◽  
The Mean ◽  
The One ◽  
Compaction Degree

A remote monitoring system with the intelligent compaction index CMV as the core is designed and developed to address the shortcomings of traditional subgrade compaction quality evaluation methods. Based on the actual project, the correlation between the CMV and conventional compaction indexes of compaction degree K and dynamic resilient modulus E is investigated by applying the one-dimensional linear regression equation for three types of subgrade fillers, clayey gravel, pulverized gravel, and soil-rock mixed fill, and the scheme of fitting CMV to the mean value of conventional indexes is adopted, which is compared with the scheme of fitting CMV to the single point of conventional indexes in the existing specification. The test results show that the correlation between the CMV and conventional indexes of clayey gravel and pulverized gravel is much stronger than that of soil-rock mixed subgrades, and the correlation coefficient can be significantly improved by fitting CMV to the mean of conventional indexes compared with single-point fitting, which can be considered as a new method for intelligent rolling correlation verification.

scholarly journals An Experimental Study on the Water-Induced Strength Reduction in Zigong Argillaceous Siltstone with Different Degree of Weathering

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Yu-chuan Yang ◽  
Jia-wen Zhou ◽  
Fu-gang Xu ◽  
Hui-ge Xing
Keyword(s):  
Rock Strength ◽  
Geotechnical Engineering ◽  
Soft Rock ◽  
Water Softening ◽  
Soft Rocks ◽  
Weathering Degree ◽  
Weathered Rocks ◽  
Argillaceous Siltstone ◽  
Rock Specimens ◽  
Red Bed

The water-softening property of soft rocks is a key problem in geotechnical engineering. A typical red-bed soft rock (the Zigong argillaceous siltstones) with different weathering degree is selected as an example to study the water-softening property and the influence of degree of weathering. A series of mechanical and microstructure tests are carried out to analyze the weathering characteristics and mechanism of the Zigong argillaceous siltstones. The results of mechanical experiments reveal that the water content and the weathering degree of rock specimens both have a weakening effect on the compressive and shear strengths. According to the results of present microstructure tests, the mechanical properties of the Zigong argillaceous siltstones are closely correlated with their physical properties, including internal microstructure and material composition for highly weathered rocks or moderately weathered rocks (in both natural and saturation conditions). Finally, experimental results indicate that the changes of microstructure and internal materials are two main factors that influence rock strength parameters after contacting with water and that these properties reflect the rock weathering degree. In a word, when red-bed soft rocks are encountered in geotechnical engineering, special attention should be paid to presence of water.

scholarly journals The Critical Indicator of Red-Bed Soft Rocks in Deterioration Process Induced by Water Basing on Renormalization Group Theory

2021 ◽  
Vol 11 (17) ◽  
pp. 7968
Author(s):  
Chang Xia ◽  
Cuiying Zhou ◽  
Fengxian Zhu ◽  
Zhen Liu ◽  
Guangjun Cui
Keyword(s):  
Renormalization Group ◽  
Group Theory ◽  
Soft Rock ◽  
Renormalization Group Theory ◽  
Silty Mudstone ◽  
Soft Rocks ◽  
Multi Scale ◽  
Unit Model ◽  
Deterioration Process ◽  
Red Bed

The internal damage of red-bed soft rock induced by water is pervasive. The accumulation, growth, and localization of damage is a multi-scale process that can lead to significant strength loss in red-bed soft rock. Yet, research on the critical state of deterioration process considering multi-scale failure is limited due to high degree of system freedom. Renormalization group theory is an effective approach to find critical point of phase transition in a disordered system. To apply renormalization group theory in red-bed soft rocks, this article firstly analyzed their microstructures. Then, the granular unit model and stripy unit model are proposed to describe the self-similar characteristics of red-bed soft rocks. The calculation results based on renormalization group theory are consistent with the experimental results. The critical reductions of strength induced by water are 60% in light-yellow silty mudstone and 80% in grey silty mudstone. In addition, the critical state of damage propagation caused by stress is also studied and the analytical solution is derived. Results show that the renormalization group theory can effectively couple the micro damage and strength deterioration which provides guidance to the engineering.

Experimental Study of the Creep Disturbance Effect and Acoustic Emission Characteristics of Mudstone with Different Moisture Contents

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Yongjiang Yu ◽  
Pengbo Wang ◽  
Shipeng Zhang ◽  
Jingjing Liu
Keyword(s):  
Acoustic Emission ◽  
Moisture Content ◽  
Soft Rock ◽  
Clear Understanding ◽  
Creep Failure ◽  
Soft Rocks ◽  
Moisture Contents ◽  
Accelerated Creep ◽  
The Stability ◽  
The Impact

It is important to have a clear understanding of the creep characteristics of water-rich soft rocks under a dynamic load and the evolution of cracks because soft rock roadways in deep mines are very sensitive to disturbances, and instability and damage can easily occur under the impact of disturbances such as mining and blasting. In this study, a self-developed disturbed creep test bench was used to conduct graded loading creep disturbance tests on mudstone specimens with different moisture contents. The results show that an increase in the moisture content leads to a significant increase in the creep failure strain of mudstone, and the accelerated creep rate is greatly accelerated. Moreover, as the moisture content increases, the type of mudstone creep disturbance failure gradually changes from accelerated creep failure to disturbance failure. By analyzing the acoustic emission (AE) characteristics of the mudstone creep disturbance tests, it was found that the increase in the moisture content greatly weakens the AE count and the accumulated energy. In each stage of disturbance, the AE signals jumped, and the stability was restored at the end of the disturbance. As the load increased, the specimen entered the accelerated creep stage, the AE signal increased exponentially, and the internal cracks expanded rapidly until failure occurred. It is of great significance to carry out creep disturbance experiments and to analyze the evolution of the internal cracks in specimens with different moisture contents to maintain the long-term stability of deep soft rocks.

A Repeated Loading Triaxial Test Study on Resilient Modulus of Graded Crushed Stone

2012 ◽  
Vol 503-504 ◽  
pp. 280-283
Author(s):  
Sui Yuan Wang ◽  
Zhi Gang Luo
Keyword(s):  
Stress State ◽  
Moisture Content ◽  
Triaxial Test ◽  
Resilient Modulus ◽  
Optimum Moisture Content ◽  
Crushed Stone ◽  
Repeated Loading ◽  
Test Results ◽  
Confining Stress ◽  
Test Study

To investigate the effect of confining stress, deviation stress, moisture content and gradation type on resilient modulus of graded crushed stones, three types of graded crushed stone with three moisture content levels(optimum moisture content and ±2% of the optimum moisture content, respectively ) were used, and repeated loading triaxial (RLT) tests with twenty five stress levels were carried out. The RLT test results demonstrate that resilient modulus of graded crushed stone remarkably increases with decreasing moisture content and/or increasing confining stress; resilient modulus of graded crushed stone slowly increases, or minor decreases at the beginning and then slowly increases with increasing deviation stress at low stress state. Results also indicate that gradation type has a certain impact on resilient modulus of graded crushed stone.

scholarly journals A system and analytical method for testing the electrical parameters of soil

2020 ◽  
Author(s):  
Yue Han ◽  
Ailan Che ◽  
Shaokong Feng
Keyword(s):  
Moisture Content ◽  
Time Factors ◽  
Test Tube ◽  
Test Method ◽  
Physical Parameters ◽  
Test Results ◽  
Electrical Parameters ◽  
Water Addition ◽  
Rock And Soil ◽  
Compaction Degree

Abstract The electrical parameters of the rock and soil are closely related to the physical parameters. By measuring the resistivity and polarizability of rock and soil reasonably, information on physical parameters such as moisture content, pore ratio and compaction degree can be obtained. A system for testing the electrical parameters of soil samples based on the middle step quadrupole method is developed in this article. The system uses a series of copper needles as the electrodes of the soil-mounted test tube, and uses a multi-point multi-layer test method for layered data acquisition, which can solve the problems caused by the capacitance phenomenon and the heterogeneity of the soil sample. At the same time, factors affecting the test results, such as uneven soil preparation and water addition and electrode disturbance, are regarded as noise. A data-analysis method based on median filtering is proposed to process and analyse the test results, and the relationships between resistivity, polarizability, moisture content and compaction degree of the sample are obtained. The results show that the resistivity decreases nonlinearly as moisture content increases, and the correlation with compaction is not strong; the polarizability increases as moisture content increases with fluctuation, and it first increases and then decreases with an increase in compaction.

scholarly journals Performance Evaluation of WMA Containing Re-Refined Acidic Sludge and Amorphous Poly Alpha Olefin (APAO)

2021 ◽  
Vol 13 (6) ◽  
pp. 3315
Author(s):  
Mansour Fakhri ◽  
Danial Arzjani ◽  
Pooyan Ayar ◽  
Maede Mottaghi ◽  
Nima Arzjani
Keyword(s):  
Resilient Modulus ◽  
Permanent Deformation ◽  
Road Construction ◽  
Moisture Damage ◽  
Asphalt Mixtures ◽  
Modified Bitumen ◽  
Alternative Source ◽  
The Road ◽  
Marshall Test ◽  
Alpha Olefin

The use of waste materials has been increasingly conceived as a sustainable alternative to conventional materials in the road construction industry, as concerns have arisen from the uncontrolled exploitation of natural resources in recent years. Re-refined acidic sludge (RAS) obtained from a waste material—acidic sludge—is an alternative source for bitumen. This study’s primary purpose is to evaluate the resistance of warm mix asphalt (WMA) mixtures containing RAS and a polymeric additive against moisture damage and rutting. The modified bitumen studied in this research is a mixture of virgin bitumen 60/70, RAS (10, 20, and 30%), and amorphous poly alpha olefin (APAO) polymer. To this end, Marshall test, moisture susceptibility tests (i.e., tensile strength ratio (TSR), residual Marshall, and Texas boiling water), resilient modulus, and rutting assessment tests (i.e., dynamic creep, Marshall quotient, and Kim) were carried out. The results showed superior values for modified mixtures compared to the control mix considering the Marshall test. Moreover, the probability of a reduction in mixes’ moisture damage was proved by moisture sensitivity tests. The results showed that modified mixtures could improve asphalt mixtures’ permanent deformation resistance and its resilience modulus. Asphalt mixtures containing 20% RAS (substitute for bitumen) showed a better performance in all the experiments among the samples tested.

Medium Density Particleboard with Addition of Impregnated Paper

2014 ◽  
Vol 1025-1026 ◽  
pp. 543-546
Author(s):  
Juliana Cortez Barbosa ◽  
Anderson Luiz da Silva Michelon ◽  
Elen Aparecida Martines Morales ◽  
Cristiane Inácio de Campos ◽  
André Luis Christoforo ◽  
...  
Keyword(s):  
Moisture Content ◽  
Modulus Of Elasticity ◽  
Mechanical Tests ◽  
Modulus Of Rupture ◽  
Medium Density ◽  
Test Results ◽  
Thickness Swelling ◽  
Adhesion Test ◽  
Layer Medium ◽  
Determine Moisture Content

The aim of this research was to produce three-layer Medium Density Particleboard (MDP), with the addition of impregnated paper, in the inner layer, in proportions of 1; 5 and 20%. In this study, MDP was composed with particles of small size in outer layers, and larger particles in internal layer. After panel manufacturing, physical and mechanical tests based on Brazilian Code ABNT NBR 14.810 were carried out to determine moisture content; density; thickness swelling; water absorption; modulus of rupture (MOR) and modulus of elasticity (MOE) in static bending and internal adhesion. Test results were compared to commercial panels, produced with 100% Eucalyptus, considering the requirements specified by Brazilian Code. Properties presented values close to normative specifications, indicating positively the possibility of production of MDP using addition of waste paper impregnated.

Modelling of Flow Properties of Asphalt Mastics

2013 ◽  
Vol 752 ◽  
pp. 209-216 ◽  
Author(s):  
Róbert Géber ◽  
László A. Gömze
Keyword(s):  
Research Work ◽  
Road Construction ◽  
Test Results ◽  
Flow Properties ◽  
Rheological Models ◽  
Fine Grained ◽  
Mineral Particles ◽  
Asphalt Mastics ◽  
Rheological Modelling ◽  
Mineral Fillers

The present research work deals with the examination and rheological modelling of flow properties of asphalt mastics which are the most important components of asphalt concretes. Asphalt mastics are mixtures of fine grained mineral filler particles (d<0,063 mm) and bitumen, having a stabilizing role in asphalt mixtures and largely determining the cohesion between mineral particles and bitumen. During our examinations two types of mineral fillers – limestone and dolomite – as well as standard bitumen were tested, which are extensively used in Hungarian road construction. Asphalt mastic mixtures were prepared out of these materials and they were tested with dynamic shear rheometer (DSR). According to the test results, rheological models of mastics were determined. It has been established that at different test temperatures and shear rate ranges asphalt mastics behave as Herschel-Bulkley and Bingham-type materials.

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