Comparison of the Shear Resistance in the Sliding Joint between Asphalt Belts and Modern PVC Foils

2014 ◽  
Vol 501-504 ◽  
pp. 945-948 ◽  
Author(s):  
Martina Smirakova
Keyword(s):  
Ambient Temperature ◽  
Civil Engineering ◽  
Shear Resistance ◽  
Temperature Dependency ◽  
Horizontal Deformation ◽  
Sliding Joint ◽  
Different Types ◽  
Different Temperatures ◽  
Foundation Structure

This paper deals with sliding joint in the foundation structure. Application of sliding joint into foundation structure is an effective method to reduce effect of horizontal deformation of foundations. These can arise from effect of undermining or from shrinkage or creep of concrete. A different material can be used to create sliding joint but some are advantageous and some are not. It is often used an asphalt belt or newly different modern foils are used too. Different types of asphalt belts are tested at Faculty of Civil Engineering at different loads and at different temperatures. Some foils are tested too. The effect of ambient temperature is monitored to better description of temperature dependency of asphalt belts. Long-term goal of this research is to simplify process of design buildings with sliding joint and to help designer with right choice of the most advantageous material.

Design of Bitumen Asphalt Belt Sliding Joint Based on Experiment Results

2017 ◽  
Vol 738 ◽  
pp. 185-194
Author(s):  
Pavlina Matečková ◽  
Martina Smirakova ◽  
Jan Kubosek ◽  
Radim Čajka
Keyword(s):  
Underground Mining ◽  
Fem Analysis ◽  
Shear Resistance ◽  
Test Results ◽  
Horizontal Deformation ◽  
Normal Forces ◽  
Sliding Joint ◽  
Undermined Area ◽  
Sliding Joints ◽  
Foundation Structure

Foundation structures are usually exposed to dominant vertical load. However, in some cases there is also significant value of horizontal load caused e.g. by horizontal terrain deformation on areas attached with underground mining or by horizontal deformation of foundation structure due to pre-stressing, creep, shrinkage, and temperature variation. Through the friction between subsoil and foundations, the foundation structure must resist significant normal forces. The idea of sliding joints between subsoil and foundation structure, which eliminates the friction in footing bottom, comes from the 1970’s. The bitumen asphalt belt given rheological properties has been proven as an effective material for sliding joints. In the paper there are test results of shear resistance of currently used asphalt belts. The test results are used for subsoil shear stress analysis in model example of strip foundation. Shear resistance is calculated according to Czech code for designing buildings on undermined area and also using advanced FEM analysis.

Bitumen Sliding Joints for Friction Elimination in Footing Bottom

2012 ◽  
Vol 188 ◽  
pp. 247-252 ◽  
Author(s):  
Radim Čajka ◽  
Pavlina Matečková ◽  
Martina Smirakova
Keyword(s):  
Underground Mining ◽  
Shear Resistance ◽  
Temperature Deformation ◽  
Horizontal Deformation ◽  
Shrinkage Temperature ◽  
Stress Strain Relation ◽  
Deformation Velocity ◽  
Sliding Joint ◽  
Sliding Joints ◽  
Foundation Structure

Use of a sliding joint is an effective method to decrease the stress in foundation structure where there is a horizontal deformation of subsoil (areas afflicted with underground mining) or horizontal deformation of a foundation structure (pre-stressed foundations, creep, shrinkage, temperature deformation). A convenient material for a sliding joint is a bitumen asphalt belt. Experiments for different types of bitumen belts were undertaken at the Faculty of Civil Engineering - VSB Technical University of Ostrava in 2008. Since 2011 an extension of the 2008 experiments has been in progress and the shear resistance of a slide joint is being tested as a function of temperature in a temperature controlled room. In this paper experimental results of temperature dependant shear resistance are presented. The result of the experiments should be the sliding joint shear resistance as a function of deformation velocity and temperature. This relationship is used for numerical analysis of stress/strain relation between foundation structure and subsoil.

Sliding Joints from Traditional Asphalt Belts

2014 ◽  
Vol 1020 ◽  
pp. 335-340 ◽  
Author(s):  
Martina Smirakova ◽  
Marie Stara ◽  
Petr Mynarčík
Keyword(s):  
Laboratory Test ◽  
Rheological Properties ◽  
Laboratory Tests ◽  
Base Layer ◽  
Horizontal Deformation ◽  
Existing Building ◽  
Sliding Joint ◽  
Different Temperatures ◽  
Correct Function ◽  
Sliding Joints

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.

New Knowledge in the Field of Reduction of Shear Stress in the Foundation Structures of Concrete or Masonry Structures

2014 ◽  
Vol 1082 ◽  
pp. 224-229
Author(s):  
Martina Smirakova
Keyword(s):  
Laboratory Tests ◽  
Mechanical Load ◽  
Thermal Sensitivity ◽  
Masonry Structures ◽  
Horizontal Deformation ◽  
Friction Forces ◽  
Sliding Joint ◽  
Real Behavior ◽  
Sliding Joints ◽  
Foundation Structure

This paper deals with application of sliding joint into foundation structures which can be very helpful in case that the foundation structure is exposed to effect of relative horizontal deformation. These deformations can be created direct in the structure from the effect of creep or shrinkage of concrete, from the effect of pre-stressing of foundation structure or they can arise in the subsoil as a consequence of undermining. Sliding joints are often created from asphalt belts which help to increase of friction forces in the foundation bottom. Due to fact that today ́s market gives a lot of new modern materials, the laboratory tests are carried out to verify their behavior at the Faculty of Civil Engineering VŠB Technical University of Ostrava (Czech Republic). The basic principle of these tests is to simulate real behavior sliding joint in foundation structure and great attention is also focused on thermal sensitivity of majority of used materials. Thermal sensitivity at the action of mechanical load relates closely with their rheological properties. Rheology is the science about deformation of substances in the dependence on time and it helps to describe difficult materials using simpler rheological materials models. A right created rheological model of asphalt belt could be used to prediction of behavior of sliding joint with regard to time of loading and ambient temperature. The knowledge of change of asphalt belt behavior consequently to temperature change could be used in the future to design of this type sliding joint where the temperature will be not only monitored but also managed in the dependence on necessity of increasing or decreasing of shear resistance. Partial results from laboratory tests as well as current conclusion will be presented in this paper.

Behavior of Selected Materials to Create Sliding Joint in the Foundation Structure

2013 ◽  
Vol 838-841 ◽  
pp. 454-457 ◽  
Author(s):  
Martina Smirakova
Keyword(s):  
Shear Stress ◽  
Civil Engineering ◽  
Horizontal Stress ◽  
First Case ◽  
Sliding Joint ◽  
Foundation Structure

Some foundation structures can be loaded with horizontal stress, for example pre-stressed foundation structures or structures on undermining areas. Then it is necessary to solute their effects, because they can have very significant effect on the building. When it is spoken about the foundation structures which are loaded with horizontal stress then it is spoken about two possibilities of this loading. In the first case there are horizontal deformations in the structure and in the second case these deformations can arise in the subsoil. In both of them it can be used the method with using sliding joint to increase of shear stress between foundation structure and subsoil. Asphalt belt is often used to create this sliding joint. At the faculty of Civil Engineering some materials are tested to better knowledge of asphalt belts properties and to more precise design and calculation of sliding joint.

scholarly journals SUITABILITY OF SAGO STARCH BLENDED WITH ACRYLAMIDE AS AN ADDITIVE ON HANDSHEETS MADE FROM RECYCLED PULP FIBERS

2017 ◽  
Vol 22 (4) ◽  
pp. 363
Author(s):  
Wong Sin Yeng ◽  
Paridah Md. Tahir ◽  
Liew Kang Chiang
Keyword(s):  
Ambient Temperature ◽  
Solid Content ◽  
Ceric Ammonium Nitrate ◽  
Superior Performance ◽  
Sago Starch ◽  
Pulp Fibers ◽  
Recycled Pulp ◽  
Different Types ◽  
Folding Endurance ◽  
Different Temperatures

This study was carried out to determine the suitability of sago starch blended with acrylamide as paper additive. Solutions of unmodified and blended sago starch with acrylamide, were prepared at 5% weight over volume (w/v) basis before the basic properties (i.e., pH, viscosity and solid content) were determined. Thestarches were thenused to coat on laboratory made handsheets from recycled pulps. Various effects were studied, namely, modification of sago starch, addition of different types of initiator and further curing at different temperatures. The incorporation of acrylamide into sago starch through blending signif icantly increased the pH and viscosity of the solutions. All the blended starches remained biologically resistant even after 14 days of exposure to ambient temperature. Solutionof sago starch blended with acrylamide, gave superior performance when coated on the handsheets, producing handsheets with high folding endurance (110 times) and crushstrength (128 N) ascompared to the handsheets coated with the unmodified sago starch. Nevertheless, the smoothness and air permeance of these papers were unsatisfactory due to insufficient curing shown by the micrographs. The use of ceric ammonium nitrate (CAN) as initiator and further curing at 50oC however, were able to improve the smoothness and air permeance properties.

Burning trash for science - using waste to monitor wildfire energies

2020 ◽  
Author(s):  
Anna Losiak ◽  
Amber Avery ◽  
Andy Elliott ◽  
Sarah Baker ◽  
Claire Belcher
Keyword(s):  
Fire Severity ◽  
Burned Area ◽  
Proof Of Concept ◽  
New Approach ◽  
Data Loggers ◽  
Different Types ◽  
Different Temperatures ◽  
In The Beginning ◽  
Reflectance Measurements

<p>     Properties of the wildfires are hard to precisely and accurately measure during the event. This limits our ability to estimate effects of the event on the environment (e.g., how quickly will the area be able to recover, and what will be the long-term carbon storage in an ecosystem Hurteau and Brooks, 2011). Currently used methods of estimating of the ‘fire severity’ (the amount of vegetation and carbon loss from an ecosystem following a fire) are either subjective (fire severity scales Ryan and Noste 1985), time consuming (charcoal reflectance Belcher et al. 2019) or expensive (thermocouples with data-loggers).</p><p>     Here we present results of our proof of concept tests of a new approach that may allow ecologists to monitor fire severity and the energy distribution across a burned area by looking at the effects of the fire on litter such as tin cans, bottles and plastic items, that are often revealed following wildfire events. The approach is based on the fact that different types of packages and materials are known to decompose at different temperatures. We will present results from: 1) Field observations of burned litter compared with the charcoal reflectance measurements based on samples collected in the same spot from the 2018 Ferndown, UK. 2) experimental heating of a range of typical litter based elements in the wildFIRE Lab, using it’s state-of-the-art fire testing equipment; 3) results of the field-scale experiments performed during the controlled burns in Dorset in the beginning of 2020.</p>

The Acute Effect of Alcohol on Various Memory Processes

2010 ◽  
Vol 24 (4) ◽  
pp. 249-252 ◽  
Author(s):  
Márk Molnár ◽  
Roland Boha ◽  
Balázs Czigler ◽  
Zsófia Anna Gaál
Keyword(s):  
Low Dose ◽  
Short Term Memory ◽  
Acute Effect ◽  
Long Term Memory ◽  
Term Memory ◽  
Memory Processes ◽  
Different Types ◽  
The Brain ◽  
Legal Consequences

This review surveys relevant and recent data of the pertinent literature regarding the acute effect of alcohol on various kinds of memory processes with special emphasis on working memory. The characteristics of different types of long-term memory (LTM) and short-term memory (STM) processes are summarized with an attempt to relate these to various structures in the brain. LTM is typically impaired by chronic alcohol intake but according to some data a single dose of ethanol may have long lasting effects if administered at a critically important age. The most commonly seen deleterious acute effect of alcohol to STM appears following large doses of ethanol in conditions of “binge drinking” causing the “blackout” phenomenon. However, with the application of various techniques and well-structured behavioral paradigms it is possible to detect, albeit occasionally, subtle changes of cognitive processes even as a result of a low dose of alcohol. These data may be important for the consideration of legal consequences of low-dose ethanol intake in conditions such as driving, etc.

Comparative Labelling and Biokinetic Studies of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn)

1977 ◽  
Vol 16 (01) ◽  
pp. 30-35 ◽  
Author(s):  
N. Agha ◽  
R. B. R. Persson
Keyword(s):  
Complex Formation ◽  
Significant Influence ◽  
Room Temperature ◽  
Ph Value ◽  
Maximum Activity ◽  
Reduction Step ◽  
Labelling Yield ◽  
Different Temperatures ◽  
Kinetics Of

SummaryGelchromatography column scanning has been used to study the fractions of 99mTc-pertechnetate, 99mTcchelate and reduced hydrolyzed 99mTc in preparations of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn). The labelling yield of 99mTc-EDTA(Sn) chelate was as high as 90—95% when 100 μmol EDTA · H4 and 0.5 (Amol SnCl2 was incubated with 10 ml 99mTceluate for 30—60 min at room temperature. The study of the influence of the pH-value on the fraction of 99mTc-EDTA shows that pH 2.8—2.9 gave the best labelling yield. In a comparative study of the labelling kinetics of 99mTc-EDTA(Sn) and 99mTc- DTPA(Sn) at different temperatures (7, 22 and 37°C), no significant influence on the reduction step was found. The rate constant for complex formation, however, increased more rapidly with increased temperature for 99mTc-DTPA(Sn). At room temperature only a few minutes was required to achieve a high labelling yield with 99mTc-DTPA(Sn) whereas about 60 min was required for 99mTc-EDTA(Sn). Comparative biokinetic studies in rabbits showed that the maximum activity in kidneys is achieved after 12 min with 99mTc-EDTA(Sn) but already after 6 min with 99mTc-DTPA(Sn). The long-term disappearance of 99mTc-DTPA(Sn) from the kidneys is about five times faster than that for 99mTc-EDTA(Sn).

Sign in / Sign up

Export Citation Format

Share Document