Effects of stress conditions on rheological properties of granular soil in large triaxial rheology laboratory tests

Problems with horizontal deformation in the subsoil are often solved for building on undermined areas not only in our region. There are many ways to solve this problem. The existing building can be draw together in total or stiffened belt can be carried out around the structure foundation. But the best solution is that which is carried out beforehand. One of the methods which can be applied beforehand is using of sliding joint with using of rheological properties of asphalt. The basic principle of this method lies on application an asphalt belts or another material between foundation and subsoil. It is also created concrete base layer between sliding layer and subsoil to ensure base flatness and to protect of sliding layer material. The type of material is important for correct function of sliding joint and there are very often used the rheological properties of traditional asphalt belts. The laboratory tests are carried out at the Faculty of Civil Engineering VŠB-Technical University of Ostrava to verify their rheological behavior at different loads and different temperatures. Following the test there is the effort to use of obtained values to other calculations and there is effort to contribute to innovation of currently method of design which is based on old materials from the 80th. The principle and the results from the laboratory test as well as current conclusions will be presented in this paper.

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Unstable behaviour of sand and its implication for slope instability

Canadian Geotechnical Journal ◽

10.1139/t03-039 ◽

2003 ◽

Vol 40 (5) ◽

pp. 873-885 ◽

Cited By ~ 125

Author(s):

J Chu ◽

S Leroueil ◽

W K Leong

Keyword(s):

Shear Stress ◽

Shear Strength ◽

Critical State ◽

Laboratory Tests ◽

State Parameter ◽

Slope Instability ◽

Granular Soil ◽

Dense Sand ◽

Soil Slopes ◽

New Framework

Results of some constant shear-drained (CSD) tests conducted on both loose and dense sand are presented. Using the critical state line and a modified state parameter, a new framework for analysing the instability of granular soil slopes is proposed. The test data were examined and interpreted using the new framework. Instability lines for sand with different void ratios were established within this framework. The conditions for the occurrence of instability in both contractive and dilative granular soil slopes under various shear stress levels were examined using the proposed framework.Key words: deformation, laboratory tests, liquefaction, sands, shear strength, slope stability.

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Mechanistic-empirical evaluation of specific polymer-modified asphalt binders effect on the rheological performance

Science Progress ◽

10.1177/0036850420959876 ◽

2020 ◽

Vol 103 (4) ◽

pp. 003685042095987

Author(s):

Ghazi G Al-Khateeb ◽

Waleed Zeiada ◽

Mohammed Ismail ◽

Ahmad Shabib ◽

Adel Tayara

Keyword(s):

Rheological Properties ◽

Laboratory Tests ◽

Complex Modulus ◽

Heavy Traffic ◽

Asphalt Binder ◽

Empirical Evaluation ◽

Asphalt Binders ◽

Modified Asphalt ◽

Pavement Structures ◽

Polymer Modified Asphalt

Major distresses such as rutting, fatigue, and thermal cracking are facing asphalt pavement structures due to continuous heavy traffic loading and climate change. The modification of asphalt binders (one of the main components of the asphalt paving mix) has the potential to mitigate distresses through using different additives. Polymer modified asphalt (PMA) binders showed a noticeable resistance to pavement distresses as reported in previous studies. The present study aims to evaluate the effect of polymer modification on the rheological properties of asphalt binders through laboratory tests. The polymers included styrene-butadiene-styrene (SBS) and epolene emulsifiable (EE2) types. The 60/70 binder was used as a control for comparison. The Mechanistic-Empirical Pavement Design Guide (MEPDG) was also utilized to simulate the effect of PMA binders on the rheological properties under different climatic conditions and structural capacities. Additionally, the MEPDG was further utilized to compare the effect of asphalt binders on rheological properties using four different binder input levels. Findings of the study showed that laboratory tests experienced varying outcomes regarding the most efficient asphalt binder by means of distresses resistance. However, the MEPDG evaluation showed that the overall ranking of asphalt binders positively impacting the rheological properties was as following: (1) 4.5% EE2 PMA, (2) 4% EE2 PMA, (3) 60/70 binder, (4) 5% SBS PMA, and (5) 4% SBS PMA binders. Furthermore, statistical analysis illustrated that the effect of using different binder input levels on the performance of pavement varied relatively to the evaluated distresses. The analysis showed that using different binder input levels would affect, to a certain extent, the asphalt binder influence on rheological properties only when evaluating rutting and fatigue distresses. Therefore, it is recommended that precise asphalt binder inputs, that is, shear complex modulus (G*) and phase angle (δ) are used when designing pavement structures in regions with hot and mild climate conditions.

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STUDIES IN HISTOCHEMISTRY: EFFECTS OF STRESS CONDITIONS, ACTH, CORTISONE, DESOXYCORTICOSTERONE AND HYPOPHYSECTOMY ON THE QUANTITATIVE HISTOLOGICAL DISTRIBUTION OF PHENOLSULFATASE AND ACETYLCHOLINESTERASE IN THE RAT ADRENAL12

Endocrinology ◽

10.1210/endo-58-5-573 ◽

1956 ◽

Vol 58 (5) ◽

pp. 573-581 ◽

Cited By ~ 6

Author(s):

DAVID GLICK ◽

HELEN R. STECKLEIN

Keyword(s):

Stress Conditions ◽

Effects Of Stress

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The permeability of natural soft clays. Part I: Methods of laboratory measurement

Canadian Geotechnical Journal ◽

10.1139/t83-072 ◽

1983 ◽

Vol 20 (4) ◽

pp. 629-644 ◽

Cited By ~ 100

Author(s):

F. Tavenas ◽

P. Leblond ◽

P. Jean ◽

S. Leroueil

Keyword(s):

Laboratory Tests ◽

Stress Conditions ◽

Laboratory Measurement ◽

Test Equipment ◽

Large Specimen ◽

Soft Clays ◽

Field Stress ◽

Constant Rate ◽

Natural Clays ◽

Constant Head

The methods of measuring the permeability of clays in the laboratory are investigated. Constant head tests in the triaxial are best suited for testing large specimen under field stress conditions provided the cell is modified to eliminate leakage. Using this type of test, the validity of Darcy's law is confirmed.Falling head tests in the oedometer are very simple to perform and subject to minimal sources of errors. However, small size specimens may not be totally representative.Indirect evaluations of the permeability from consolidation tests are shown to be unreliable particularly in structured natural clays: evaluation of k from cv measurements in step-loaded tests gives much too low values, constant rate of strain tests strongly overestimate k in the vicinity of σp′ and give nonrepresentative e vs. lg k relations; controlled gradient tests tend to underestimate k at all void ratios. Keywords: permeability, clays, laboratory tests, test equipment, consolidation tests.

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