Overlay Tester
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Overlay Tester
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Author : Fujie Zhou
language : en
Publisher:
Release Date : 2005
Overlay Tester written by Fujie Zhou and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with Pavements categories.
The focus of many asphalt mixture design procedures over the past 10 years has led to the development of stiffer, drier mixtures. However, these mixes are more difficult to construct and are potentially more prone to reflective cracking. In this research the upgraded overlay tester is introduced and proposed as a simple performance test on reflective cracking. The overlay tester can be run on standard size samples, typically 6 in (150 mm) long by 3 in (75 mm) wide by 1.5 in (38 mm) high. These specimens can be prepared from either field cores or from Superpave Gyratory Compactor (SGC) molded specimens. The test is rapid and repeatable, and poor samples fail in minutes. It characterizes both crack initiation and crack propagation properties of asphalt mixtures. Based on repeatability study results, three replicates are recommended for the overlay tester. Sensitivity studies indicate that the overlay tester provides reasonable test results. Increasing asphalt content will significantly improve the reflective cracking resistance of asphalt mixtures. In a series of tests on Texas mixtures, it was determined that aggregate absorption has a major impact on the performance of specimens in the overlay tester. This topic has not received much attention recently but it obviously needs to be investigated. In the lab these highly absorptive aggregates did not severely impact the rutting performance but they had a major impact on cracking life. The effectiveness of the overlay tester was validated by five case studies in Texas. The overlay tester results all correlated well with the field performance. Furthermore, the overlay tester results have good correlations with beam fatigue test results and low temperature performance of asphalt mixtures in the field. A preliminary framework of asphalt overlay mixture designs and associated criteria have been proposed. Based on the framework, two examples of asphalt overlay mixture designs are presented in this report. This framework and the associated criteria are preliminary and they will need further refinement. Finally, a brand new overlay tester has been manufactured and delivered to TxDOTs central lab at the edar Park office. In addition, training for the operation and analysis has been provided.
Upgraded Overlay Tester And Its Application To Characterize Reflection Cracking Resistance Of Asphalt Mixtures
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Author : Fujie Zhou
language : en
Publisher:
Release Date : 2003
Upgraded Overlay Tester And Its Application To Characterize Reflection Cracking Resistance Of Asphalt Mixtures written by Fujie Zhou and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003 with Pavements categories.
Reflection cracking is a major concern when placing an overlay on a cracked pavement. The opening and closing of joints and/or cracks induced by daily temperature cycles is a major contributor to reflection cracking. This mechanism is currently being simulated in the laboratory at the Texas Transportation Institute (TTI) using a specially modified overlay-tester device. To evaluate the overlay tester concept laboratory results are presented on cores from four Texas projects, three of which performed very poorly and one which performed excellently. The asphalt mixture on US 175 in Dallas was placed on a cracked stabilized base and did not have a single reflection crack after 10 years in service, whereas the mixtures on two projects were badly cracked after only few months. The results clearly show that the upgraded TTI overlay tester can effectively differentiate between the reflection cracking resistance of different asphalt mixtures. It is also found that the reflection cracking resistance of asphalt mixture has a good correlation with the asphalt binder properties. In this report the upgraded TTI overlay tester is also used to quantify the benefits of modified asphalt binders. This benefit is demonstrated with a single mix where specimens were prepared with a variety of asphalt binders. The mix prepared with PG 64-22 plus 3 percent SBR latex demonstrated superior reflection cracking resistance while still maintaining adequate rutting resistance. It is proposed that the overlay tester is a practical device which can be incorporated into mixture design systems, to complement the current systems, which often focus solely on minimizing rutting potential. In many instances it is necessary to optimize both crack resistance and rutting potential to obtain adequate long-term pavement performance.
The Overlay Tester Ot
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Author : Lubinda F. Walubita
language : en
Publisher:
Release Date : 2013
The Overlay Tester Ot written by Lubinda F. Walubita and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with Pavements categories.
The Overlay Tester
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Author : Lubinda F. Walubita
language : en
Publisher:
Release Date : 2012
The Overlay Tester written by Lubinda F. Walubita and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with Pavements categories.
Pilot Implementation Of The Overlay Tester And Double Blade Saw
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Author : Xiaodi Hu
language : en
Publisher:
Release Date : 2008
Pilot Implementation Of The Overlay Tester And Double Blade Saw written by Xiaodi Hu and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008 with Pavements categories.
Improved Overlay Tester For Fatigue Cracking Resistance Of Asphalt Mixtures
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Author : Victor M. Garcia
language : en
Publisher:
Release Date : 2017
Improved Overlay Tester For Fatigue Cracking Resistance Of Asphalt Mixtures written by Victor M. Garcia and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with Mechanical wear categories.
Developing Upgraded Overlay Tester System To Characterize The Reflection Cracking Resistance Of Asphalt Concrete
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Author : Fujie Zhou
language : en
Publisher:
Release Date : 2005
Developing Upgraded Overlay Tester System To Characterize The Reflection Cracking Resistance Of Asphalt Concrete written by Fujie Zhou and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with Pavements, Asphalt categories.
Numerical Simulation Of The Overlay Tester
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Author : Andrea Gutierrez
language : en
Publisher:
Release Date : 2016
Numerical Simulation Of The Overlay Tester written by Andrea Gutierrez and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with Asphalt concrete categories.
Preliminary Results Of Repeatability And Sensitivity Study On Overlay Tester For Crack Sealants
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Author : Fujie Zhou
language : en
Publisher:
Release Date : 2007
Preliminary Results Of Repeatability And Sensitivity Study On Overlay Tester For Crack Sealants written by Fujie Zhou and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with Pavements categories.
Using Rolling Dynamic Deflectometer And Overlay Tester To Determine The Reflective Cracking Potential
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Author : Dar-Hao Chen
language : en
Publisher:
Release Date : 2007
Using Rolling Dynamic Deflectometer And Overlay Tester To Determine The Reflective Cracking Potential written by Dar-Hao Chen and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with Building materials categories.
A forensic study was performed using a rolling dynamic deflectometer (RDD) and overlay tester (OT) to investigate the reflective cracks on SH87. Comparative tests were performed on the BU90 that has no cracks. The test results show that BU90 has lower density and lower asphalt content than SH87. This means the hot-mix asphalt (HMA) on BU90 has less resistance to reflective cracking than SH87. The OT confirmed that the cycles to failure are less for BU90 than for SH87. Thus, in terms of individual layer properties, the wearing surface and crack-retarding layer on SH87 has a greater crack resistance than that on BU90 and the asphalt mixes were not the principal reason for the cracking. The three main contributing factors for the reflective cracking on SH87 are: (1) thinner HMA, (2) higher joint movements, and (3) poor bonding between layers. Based on the reliability concept, at 90 % confidence level, the threshold W1-W3 deflection values were found to be 4.4 mils and it is much less than 6.5 mils developed from the IH20 project that has 100 mm of HMA as opposed to 64 mm for the SH87 project. It reaffirms that thicker HMA takes longer to have reflective cracking and it also needs a higher threshold W1-W3 deflection value. Thus, the thicker HMA overlay on BU90 (183 mm) would delay the reflective cracks. The methodology presented demonstrates RDD and OT's abilities to characterize the reflective cracking potential and the proposed threshold value provides a good foundation for further refinement when additional data are available.