Performance of Superpave Mixtures Under Accelerated Load Testing

2000 ◽  
Vol 1716 (1) ◽  
pp. 126-134 ◽  
Author(s):  
Zhong Wu ◽  
Mustaque Hossain ◽  
Andrew J. Gisi
Keyword(s):  
Fatigue Damage ◽  
Maximum Size ◽  
Fatigue Tests ◽  
Transverse Strain ◽  
Load Testing ◽  
Soil Pressure ◽  
Tire Pressure ◽  
River Sand ◽  
Equivalency Factors ◽  
Pavement Damage

The performances of two Superpave® test sections, constructed with 12.5 mm (0.5 in.) nominal maximum size Superpave mixture (SM-2A) with varying percentages of river sand at the Kansas Accelerated Testing Laboratory (K-ATL), are described. A 150-kN (34-kip) tandem axle with dual wheels and 620-kPa (90-psi) tire pressure was used for loading. After 10,000 repetitions, the sections were loaded by 160-kN (36-kip), 150-kN (34-kip), and 144-kN (32.5-kip) tandem axles and 98-kN (22-kip), 90-kN (20-kip), and 80-kN (18-kip) single axles, for estimating relative pavement damage due to different axle loads and configurations. Critical pavement responses were measured on each test section with the transverse strain gauges and soil pressure cells under both K-ATL tandem axle and falling weight deflectomter (FWD) loads. The pavement responses were also estimated from a multilayer elastic analysis program, ELSYM5. Laboratory fatigue tests were conducted on the SM-2A beams. Fatigue and rutting damage analyses were then conducted. The results indicated very little fatigue damage on these sections. The Superpave mixtures appeared to be less susceptible to fatigue damage, presumably due to better aggregate structure and higher binder content than the traditional asphalt mixtures. Rutting on the section with 15 percent river sand was mainly due to consolidation of the SM-2A and/or other layers since no significant flow of the Superpave mixture was evident. The AASHTO load equivalency factors were found to be much higher than those calculated in this study.

scholarly journals Fatigue Damage of Al/SiC Composites - Macroscopic and Microscopic Analysis

2015 ◽  
Vol 60 (1) ◽  
pp. 101-105 ◽  
Author(s):  
A. Rutecka ◽  
Z.L. Kowalewski ◽  
K. Makowska ◽  
K. Pietrzak ◽  
L. Dietrich
Keyword(s):  
Fatigue Damage ◽  
Microscopic Analysis ◽  
Inelastic Strain ◽  
Damage Parameter ◽  
Fatigue Tests ◽  
Cyclic Plasticity ◽  
Damage Mechanisms ◽  
Before And After ◽  
Fatigue Damage Parameter ◽  
Sic Composites

Abstract The results of comparative examinations of mechanical behaviour during fatigue loads and microstructure assessment before and after fatigue tests were presented. Composites of aluminium matrix and SiC reinforcement manufactured using the KoBo method were investigated. The combinations of two kinds of fatigue damage mechanisms were observed. The first one governed by cyclic plasticity and related to inelastic strain amplitude changes and the second one expressed in a form of ratcheting based on changes in mean inelastic strain. The higher SiC content the less influence of the fatigue damage mechanisms on material behaviour was observed. Attempts have been made to evaluate an appropriate fatigue damage parameter. However, it still needs further improvements.

Analysis of Fatigue Mechanical Behaviors of Welding Conformations in Orthotropic Steel Bridge Deck

2015 ◽  
Vol 1096 ◽  
pp. 562-566 ◽  
Author(s):  
Bo Yu ◽  
Tao Hong ◽  
Jian Zhang ◽  
Qing Yu Liang
Keyword(s):  
Fatigue Damage ◽  
Bridge Deck ◽  
Fatigue Tests ◽  
Steel Bridge ◽  
Test Results ◽  
Practical Application ◽  
Mechanical Behaviors ◽  
Homogeneous Test ◽  
Orthotropic Steel Bridge Deck ◽  
Damage Theory

Due to the superior structure style, orthotropic steel bridge deck has been getting more and more widely practical application. The static and fatigue tests of the orthotropic steel bridge deck models were carried out in this research paper, which presented the fatigue damage developing laws, compared the test results with homogeneous test results in existing documents, and according to the relative fatigue accumulative damage theory, the fatigue accumulative damage equations of the sectional specimen and the whole specimen are respectively studied.

Effect of flotation tires used for agricultural field equipment on flexible pavement damage

2019 ◽  
Vol 46 (6) ◽  
pp. 501-510 ◽  
Author(s):  
Jean-Pascal Bilodeau ◽  
Damien Grellet ◽  
Guy Doré ◽  
Maurice Phénix
Keyword(s):  
Experimental Research ◽  
Damage Mechanism ◽  
Flexible Pavement ◽  
Pavement Performance ◽  
Agricultural Field ◽  
Tire Pressure ◽  
Field Equipment ◽  
Truck Tires ◽  
Pavement Response ◽  
Pavement Damage

Agricultural field equipment are typically equipped with wide single tires with particular tire tread and low inflation working pressures. Because of the significant differences with standard truck tires, the effect of flotation implement tire on pavement performance and load associated damage is likely to differ. This paper presents the results of an experimental research project where flotation tires were used to test the response of an instrumented flexible pavement built in an indoor test pit. The effect of load, tire pressure, and tire type was investigated as part of the study. Based on the collected results, the tire type and design greatly influence the pavement response. The critical and governing pavement damage mechanism was found to be subgrade structural rutting. Wide specialty tires were found to generally induce less damage than standard truck tires. A method for axle weight adjustment for wide farm tires was proposed as part of the project.

Reducing Damage to Low-Volume Roads by Using Trucks with Reduced Tire Pressures

1997 ◽  
Vol 1589 (1) ◽  
pp. 9-18 ◽  
Author(s):  
Maureen A. Kestler ◽  
Richard L. Berg ◽  
Thomas L. Moore
Keyword(s):  
Cross Sections ◽  
Design Procedure ◽  
Army Corps ◽  
Army Corps Of Engineers ◽  
Tire Pressure ◽  
Low Volume Roads ◽  
Minimal Damage ◽  
Allowable Load ◽  
Low Volume ◽  
Pavement Damage

Heavy-volume highways in seasonal frost areas are designed to resist the effects of spring thaw. However, timber access roads, county roads, and other low-volume roads with thin bituminous surfaces can be quite susceptible to pavement damage during midwinter- and spring-thaw periods. To reduce damage to low-volume roads, towns, cities, and states typically either post reductions in allowable load or completely prohibit hauling during damage-susceptible periods. Associated economic impact can be significant. To evaluate the effects of tire pressure on cumulative road damage, a mechanistic pavement design procedure developed by the U.S. Army Corps of Engineers for use in seasonal frost areas was used on a matrix of tire pressures, low-volume pavement cross sections, and environmental conditions. A series of computer simulations showed ( a) trucks operating with conventional tire pressures can cause excessive damage, particularly in the form of cracking, to low-volume roads with thin bituminous surfaces during relatively short thaw periods; ( b) pavement damage could be reduced substantially by restricting hauling to trucks operating with reduced tire pressures; and ( c) there are “threshold” tire pressures under which only minimal damage occurs, even during critical spring thaw. These results could influence guidelines for hauling restrictions and, in turn, associated economics.

Using the Three-Stage Weibull Equation and Tree-Based Model to Characterize the Mix Fatigue Damage Process

2005 ◽  
Vol 1929 (1) ◽  
pp. 227-237 ◽  
Author(s):  
Bor-Wen Tsai ◽  
John T. Harvey ◽  
Carl L. Monismith
Keyword(s):  
Crack Initiation ◽  
Fatigue Damage ◽  
Fatigue Tests ◽  
Fatigue Performance ◽  
Data Set ◽  
Warm Up ◽  
Weibull Parameters ◽  
Damage Process ◽  
Initiation Stage ◽  
Weibull Equation

The primary purpose of this paper is to demonstrate the applicability of the three-stage Weibull equation to describe the fatigue damage process using flexural controlled deformation fatigue tests. A data set of 179 beam fatigue tests originally designed for exploring the fatigue performance of conventional dense graded asphalt concrete (DGAC) and asphalt–rubber hot-mix gap-graded (ARHM-GG) mixes was used to inspect the three-stage Weibull parameters that were estimated using a genetic algorithm. The tree-based regression–category models were then used to uncover the data structure of the estimated parameters as a function of material properties, conditioning methods, temperatures, compaction methods, and strain levels. In general, the three-stage Weibull equation provides satisfactory fitting results for the three-stage fatigue damage process occurring in a beam test. It was found that the tree-based models of three-stage Weibull parameters associated with the crack initiation stage were statistically adequate and reliable compared with the models of parameters related to the warm-up stage and the crack propagation stage. It might suggest that these crack initiation parameters are better indexes to assess the fatigue performance.

A comparison of plastic and tile drain pipes with differing cover materials

1970 ◽  
Vol 10 (46) ◽  
pp. 614
Author(s):  
JG Obbink
Keyword(s):  
Water Table ◽  
Plastic Material ◽  
Practical Significance ◽  
Soil Pressure ◽  
River Sand ◽  
Soil Material ◽  
Tile Drains ◽  
Plastic Pipe ◽  
Cover Material

A comparison was made between three types of plastic drain pipes and conventional earthen tile drains combined with cover materials of washed river sand, fibreglass, and tar paper. Rate of drawdown of a water table was measured for each combination of pipe and cover material over a period of 220 hours. Soil material that accumulated over three years in the observation pits and over four years in the pipes was measured. All combinations of pipes and cover materials provided satisfactory drainage and there were no differences of practical significance between them in terms of rate of drawdown. The river sand used in the experiment caused blockage of slot openings in corrugated plastic pipe, and one type of smooth walled plastic pipe was badly distorted by soil pressure leading to a widening of the slots, entry of soil material and breaking the fibreglass covering. Another type of plastic pipe was unsatisfactory because the perforation method left plastic material as hairs within the pipe. The fibreglass, 0.2 mm thick, was too thin to be entirely satisfactory, but was, under favourable conditions, a most effective cover material. Tar paper was quite unsatisfactory as material to prevent soil entry to pipes.

Thermomechanical Model and Experimental Analysis of Progressive Fatigue Damage in Steel Specimens

2006 ◽  
Author(s):  
Francesca Cura` ◽  
Graziano Curti ◽  
Raffaella Sesana
Keyword(s):  
Differential Equation ◽  
Fatigue Damage ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Steel Specimen ◽  
Damage Parameter ◽  
Fatigue Tests ◽  
Temperature Evolution ◽  
Thermomechanical Model ◽  
Temperature Growth

This paper presents a thermomechanical model to predict the surface temperature evolution of a specimen during a fatigue test. In particular, the aim of this theoretical approach is to evaluate the amount of accumulated fatigue damage in the material, on the basis of its temperature growth indicated as damage parameter. To do that, a thermomechanical model has been developed and applied to a unidimensional steel specimen, with rectangular cross-section, fatigued by alternate axial stresses. Temperature variation along the thickness of the specimen has been disregarded. Thermomechanical differential equation has been integrated by applying both initial and boundary conditions. Temperature evolution of steel specimens measured during fatigue tests by means of thermographic techniques has been compared to the corresponding predicted by the theoretical model.

X-Ray Diffraction Study of Microstructural Changes During Fatigue Damage in Steel Pipelines

2012 ◽  
Author(s):  
Bianca Pinheiro ◽  
Jacky Lesage ◽  
Ilson Pasqualino ◽  
Noureddine Benseddiq ◽  
Edoardo Bemporad
Keyword(s):  
Fatigue Damage ◽  
Fatigue Behavior ◽  
Ion Beam ◽  
Fatigue Tests ◽  
X Ray Diffraction ◽  
Microstructural Changes ◽  
X Ray ◽  
Steel Pipes ◽  
Damage Initiation ◽  
Three Stages

Steel pipes used for oil and gas exploitation undergo the action of cyclic loads that can cause their failure by fatigue. A consistent evaluation of the fatigue behavior should take into account the micromechanisms of fatigue damage initiation, which precede macroscopic cracking and macrocrack propagation. In this work, microstructural changes in terms of variations in microdeformations and residual stresses (macrostresses) are evaluated by X-ray diffraction in real time during alternating bending fatigue tests performed on samples taken from an API 5L X60 grade steel pipe. Three stages of microstructural changes are detected. It is found that their amplitudes and durations are proportional to the level of alternating stress applied. Changes in density and distribution of dislocations are observed by transmission electron microscopy combined with the technique of focused ion beam. To understand the role of the initial dislocation structure, fatigue tests on annealed samples are performed under the same test conditions. Again, three stages of changes are observed, but with an increase in microdeformations during the first stage instead of a decrease as found for as-machined samples, suggesting the influence of the initial state of the dislocation network. The results obtained are very encouraging for the consideration of microstructural evolutions in the development of an indicator of fatigue damage initiation in steel pipes.

Fatigue Damage Evaluation in CFRP Woven Fabric Composites Through Dynamic Modulus Measurements

2004 ◽  
Author(s):  
Hideaki Kasano ◽  
Osamu Hasegawa ◽  
Chiaki Miyasaka
Keyword(s):  
Fatigue Damage ◽  
Material Properties ◽  
Elastic Moduli ◽  
Fatigue Loading ◽  
Damage Function ◽  
Fatigue Tests ◽  
Woven Fabric ◽  
Damage Development ◽  
Dynamic Elastic Moduli ◽  
Number Of Cycles

Advanced fiber reinforced composite materials offer substantial advantages over metallic materials for the structural applications subjected to fatigue loading. With the increasing use of these composites, it is required to understand their mechanical response to cyclic loading [1–4]. Our major concern in this work is to macroscopically evaluate the damage development in composites during fatigue loading. For this purpose, we examine what effect the fatigue damage may have on the material properties and how they can be related mathematically to each other. In general, as the damage initiates in composite materials and grows during cyclic loading, material properties such as modulus, residual strength and strain would vary and, in many cases, they may be significantly reduced because of the progressive accumulation of cracks. Therefore, the damage can be characterized by the change in material properties, which is expected to be available for non-destructive evaluation of the fatigue damage development in composites. Here, the tensiontension fatigue tests are firstly conducted on the plain woven fabric carbon fiber composites for different loading levels. In the fatigue tests, the dynamic elastic moduli are measured on real-time, which will decrease with an increasing number of cycles due to the degradation of stiffness. Then, the damage fimction presenting the damage development during fatigue loading is determined from the dynamic elastic moduli thus obtained, from which the damage function is formulated in terms of a number of cycles and an applied loading level. Finally, the damage function is shown to be applied for predicting the remaining fifetime of the CFRP composites subjected to two-stress level fatigue loading.

Sign in / Sign up

Export Citation Format

Share Document