Evaluation de mélanges asphalte coulé avec diverses sortes de liants au moyen d'essais par oscillation axiale et d'essai à la fatigue (Evaluation of cast asphalt mixes with various binders by axial vibration and fatigue testing) R.GUBLER and H.W.FRITZ EMPA, Dubendorf, Switzerland

1990 ◽  
pp. 461-469
Keyword(s):  
Fatigue Testing ◽  
Axial Vibration ◽  
Asphalt Mixes ◽  
Fatigue Evaluation

A multi-axial vibration fatigue evaluation procedure for welded structures in frequency domain

2022 ◽  
Vol 167 ◽  
pp. 108516
Author(s):  
Xianjun Pei ◽  
Sandipp Krishnan Ravi ◽  
Pingsha Dong ◽  
Xiangwei Li ◽  
Xiaokun Zhou
Keyword(s):  
Frequency Domain ◽  
Evaluation Procedure ◽  
Axial Vibration ◽  
Welded Structures ◽  
Vibration Fatigue ◽  
Fatigue Evaluation

Investigation on use of recycled asphalt shingles in Ontario hot mix asphalt: a Canadian case study

2014 ◽  
Vol 41 (2) ◽  
pp. 136-143 ◽  
Author(s):  
Jun Yang ◽  
Shirley Ddamba ◽  
Riyad UL-Islam ◽  
Md. Safiuddin ◽  
Susan L. Tighe
Keyword(s):  
Hot Mix Asphalt ◽  
Fatigue Testing ◽  
Good Condition ◽  
Mix Design ◽  
Recycled Asphalt ◽  
Asphalt Mixes ◽  
Laboratory Test Results ◽  
Recycled Asphalt Shingles ◽  
Recycled Material ◽  
Asphalt Shingles

The usage of recycled asphalt shingles (RAS) in hot mix asphalt (HMA) pavements provides many benefits as long as they are properly engineered into the various HMA mixes. Contractors, consultants, and Departments of Transportation have evaluated the performance of these various materials, although they are still only used in a limited number of areas. Alternatively, recycled asphalt pavement (RAP) is recognized as a high value recycled material and is actually the most recycled material in North America. In Ontario, RAP is successfully used in most HMA. Related studies on HMA containing RAS and RAP are limited in Canada although recently studies and field trials on effectively using RAS in HMA in Ontario have been completed by the Centre of Pavement and Transportation Technology (CPATT) at University of Waterloo in partnership with Miller Paving Ltd and the Ontario Centre of Excellence. This paper presents key findings from a comprehensive laboratory investigation and analysis of six asphalt mixes with RAS and RAP in Ontario through dynamic modulus, resilient modulus, thermal stress restrained specimen, and flexural fatigue testing. Using RAS alone or combining with RAP makes the asphalt stiffer at high and low temperatures respectively. Lowering the low temperature performance grade of the asphalt binder by 6 °C and incorporating 3% RAS or less with RAP in HMA mix design can result in meeting the appropriate specification. While field testing of RAS pavements demonstrated that surface friction properties are in good condition in various environmental and loading conditions, the laboratory test results and field performances indicate that RAS can be a useful additive to asphalt mixes in Ontario hot mix pavement through reasonable mix design.

scholarly journals Flexibility and fatigue evaluation of oblique as compared with anterior lumbar interbody cages with integrated endplate fixation

2016 ◽  
Vol 24 (1) ◽  
pp. 54-59 ◽  
Author(s):  
Andrew L. Freeman ◽  
William J. Camisa ◽  
Glenn R. Buttermann ◽  
James R. Malcolm
Keyword(s):  
Fatigue Testing ◽  
Plate Fixation ◽  
Pedicle Screws ◽  
Test Group ◽  
Pedicle Screw Fixation ◽  
Pullout Resistance ◽  
Pullout Tests ◽  
Cage Subsidence ◽  
Fatigue Evaluation

OBJECT This study was undertaken to quantify the in vitro range of motion (ROM) of oblique as compared with anterior lumbar interbody devices, pullout resistance, and subsidence in fatigue. METHODS Anterior and oblique cages with integrated plate fixation (IPF) were tested using lumbar motion segments. Flexibility tests were conducted on the intact segments, cage, cage + IPF, and cage + IPF + pedicle screws (6 anterior, 7 oblique). Pullout tests were then performed on the cage + IPF. Fatigue testing was conducted on the cage + IPF specimens for 30,000 cycles. RESULTS No ROM differences were observed in any test group between anterior and oblique cage constructs. The greatest reduction in ROM was with supplemental pedicle screw fixation. Peak pullout forces were 637 ± 192 N and 651 ± 127 N for the anterior and oblique implants, respectively. The median cage subsidence was 0.8 mm and 1.4 mm for the anterior and oblique cages, respectively. CONCLUSIONS Anterior and oblique cages similarly reduced ROM in flexibility testing, and the integrated fixation prevented device displacement. Subsidence was minimal during fatigue testing, most of which occurred in the first 2500 cycles.

scholarly journals EVALUATING FATIGUE BEHAVIOR OF ASPHALT BINDERS AND MIXES CONTAINING DATE SEED ASH

2017 ◽  
Vol 23 (8) ◽  
pp. 1164-1175 ◽  
Author(s):  
Ali FOROUTAN MIRHOSSEINI ◽  
Amir KAVUSSI ◽  
Mohammad Hossain JALAL KAMALI ◽  
Mohammad Mehdi KHABIRI ◽  
Abolfazl HASSANI
Keyword(s):  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Critical Role ◽  
Asphalt Binder ◽  
Asphalt Binders ◽  
Asphalt Pavements ◽  
Asphalt Mixes ◽  
Date Seed ◽  
Tensile Fatigue ◽  
Indirect Tensile

Fatigue is one of the most occurring distresses in asphalt pavements. Asphalt binder plays a critical role in fa­tigue behavior of asphalt mixes. Modelling and predicting fatigue behavior of binders will result in more fatigue resistant mixes. In this research, possibility of using Date Seed Ash alongside two commonly used additives (namely, a siliceous and a limestone) as bitumen modifier were investigated. Then, the influence of these additives on fatigue behavior of asphalt binders and mixes was investigated. Linear Amplitude Sweep (LAS) test was carried out and Viscoelastic Con­tinuum Damage (VECD) parameter was determined. In addition, Indirect Tensile Fatigue Test (ITFT) was performed on mixes containing these additives. Correlation equations were developed to link fatigue behavior of binders to those of mixes. The results showed acceptable agreement between binders and mixes fatigue testing results. In addition, with predicted models it was able to obtain the asphalt binders contribution to mixes fatigue resistance. However, in the case of ash modified samples, no good correlation was observed between fatigue behavior of binders and that of mixes.

Symptom Validity Testing

2018 ◽  
Vol 23 (6) ◽  
pp. 14-15
Author(s):  
Lee H. Ensalada
Keyword(s):  
Memory Deficits ◽  
Symptom Validity ◽  
Sensory Cues ◽  
Validity Testing ◽  
Symptom Validity Testing ◽  
Tunnel Vision ◽  
Blurry Vision ◽  
The Common ◽  
Fatigue Evaluation ◽  
Choice Testing

Abstract Symptom validity testing (SVT), also known as forced-choice testing, is a means of assessing the validity of sensory and memory deficits, including tactile anesthesias, paresthesias, blindness, color blindness, tunnel vision, blurry vision, and deafness. The common feature among these symptoms is a claimed inability to perceive or remember a sensory signal. SVT comprises two elements: a specific ability is assessed by presenting a large number of items in a multiple-choice format, and then the examinee's performance is compared to the statistical likelihood of success based on chance alone. These tests usually present two alternatives; thus the probability of simply guessing the correct response (equivalent to having no ability at all) is 50%. Thus, scores significantly below chance performance indicate that the sensory cues must have been perceived, but the examinee chose not to report the correct answer—alternative explanations are not apparent. SVT also has the capacity to demonstrate that the examinee performed below the probabilities of chance. Scoring below a norm can be explained by fatigue, evaluation anxiety, inattention, or limited intelligence. Scoring below the probabilities of chance alone most likely indicates deliberate deceptions and is evidence of malingering because it provides strong evidence that the examinee received the sensory cues and denied the perception. Even so, malingering must be evaluated from the total clinical context.

Impairment Questions and Answers

1999 ◽  
Vol 4 (4) ◽  
pp. 4-4
Keyword(s):  
Symptom Validity ◽  
Validity Testing ◽  
Symptom Validity Testing ◽  
Negative Results ◽  
Tunnel Vision ◽  
Questions And Answers ◽  
Blurry Vision ◽  
Fatigue Evaluation ◽  
Choice Testing ◽  
Rule Out

Abstract Symptom validity testing, also known as forced-choice testing, is a way to assess the validity of sensory and memory deficits, including tactile anesthesias, paresthesias, blindness, color blindness, tunnel vision, blurry vision, and deafness—the common feature of which is a claimed inability to perceive or remember a sensory signal. Symptom validity testing comprises two elements: A specific ability is assessed by presenting a large number of items in a multiple-choice format, and then the examinee's performance is compared with the statistical likelihood of success based on chance alone. Scoring below a norm can be explained in many different ways (eg, fatigue, evaluation anxiety, limited intelligence, and so on), but scoring below the probabilities of chance alone most likely indicates deliberate deception. The positive predictive value of the symptom validity technique likely is quite high because there is no alternative explanation to deliberate distortion when performance is below the probability of chance. The sensitivity of this technique is not likely to be good because, as with a thermometer, positive findings indicate that a problem is present, but negative results do not rule out a problem. Although a compelling conclusion is that the examinee who scores below probabilities is deliberately motivated to perform poorly, malingering must be concluded from the total clinical context.

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