Download or read book Permanent Deformation Response of Asphalt Aggregate Mixes written by Christine W. Curtis and published by National Research Council. This book was released on 1994 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes the research conducted on permanent deformation of asphalt concrete mixes as part of the SHRP Asphalt Research Program. Divided into three sections the report addresses the following: the development of a series of accelerated performance tests to measure the permanent deformation response and a constitutive relationship to define it; validation of the binder properties included in the SHRP binder specification; and the use of the test methodology in an asphalt concrete mix design and analysis system.

Download or read book Permanent Deformation Response of Conventional and Modified Asphalt aggregate Mixtures Under Simple and Compound Shear Loading Conditions written by Alejandro José Tanco and published by . This book was released on 1992 with total page 546 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Permanent Deformation Properties of Asphalt Concrete Mixtures written by Rabbira Garba and published by . This book was released on 2002 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rutting is recognized to be the major distress mechanism in flexible pavements as a result of increase in tire pressures and axle loads. Rutting is caused by the accumulation of permanent deformation in all or some of the layers in the pavement structure. The accumulation of permanent deformation in the asphalt surfacing layer is now recognized to be the major component of rutting in flexible pavements. This is a consequence of increased tire pressures and axle loads, which subjects the asphalt surfacing layer nearest to the tire-pavement contact area to increased stresses. Thus the study of permanent deformation properties of asphalt mixtures has become the focus of research, which aim to mitigate or reduce rutting in flexible pavements. The research work reported in this thesis aims to contribute towards understanding of the material properties and factors affecting permanent deformation in asphalt mixtures, mechanisms of the permanent deformation, and methods of its prediction. The specific objectives of this research work include; review and evaluation of available models for permanent deformation of asphalt concrete mixtures, investigation of the effect of volumetric composition, loading and temperature conditions on the permanent deformation of asphalt concrete, and the identification and definition of simple measures of resistance to permanent deformation. To meet the objectives of the study a laboratory investigation is conducted on several asphalt concrete specimens with varying volumetric composition. Two testing procedures are adopted; the repeated load triaxial and triaxial creep and recovery tests. The tests were conducted at two temperature levels of 25 and 50oC under varying stress conditions. A review of literature on factors affecting permanent deformation and available models for prediction of the permanent deformation is also conducted. The literature review indicated that most of the research work done so far concentrated on evaluation of the effect on permanent deformation response of component material properties such as aggregate gradation, aggregate angularity and binder type (or grade). Most of the studies conducted on permanent deformation properties of asphalt mixtures were also found to be based on different testing procedures and methods of evaluation, which makes it difficult to compare them and draw firm conclusions. The literature also indicated that, as yet, there is no comprehensive model for deformation of asphalt concrete. Results of tests conducted in this study are analysed to investigate the effect of volumetric composition, particularly binder content and void content, and loading conditions on the permanent deformation response of the mixture. Both the binder content and void content are found to significantly influence the permanent deformation characteristics. The effect of loading conditions, i.e., the confining stress and the deviatoric stress, is also found to be significant. Throughout this study emphasis is placed on methods and parameters that are used to evaluate mixtures for their resistance to permanent deformation. The traditionally used parameters such as the slope and intercept of the power model are evaluated for their sensitivities to changes in volumetric composition. This evaluation is based on the premises that any measure of resistance to permanent deformation should be sensitive to changes in volumetric composition to be good enough. It is found that most of these parameters are not sensitive to changes in volumetric composition and therefore are not suitable for comparison of mixtures made from the same materials but with varying proportion of the components. Permanent deformation in asphalt concrete is caused by both densification and shear deformation. The mode of deformation in asphalt concrete pavements, for greater part of their service life, is considered to be the shear deformation. Therefore it is necessary to evaluate mixtures for their susceptibility to shear deformation. The shear deformation manifests itself in the form of large lateral deformation relative to axial deformation. It is found that one dimensional analysis, which does not take the lateral deformation into account may lead to misleading results regarding the resistance to permanent deformation of mixtures. Therefore parameters which include volumetric and lateral strain are proposed for use in evaluation of mixtures. Substantial effort is put into modelling the accumulation of permanent deformation under repeated loading. For this purpose two approaches were selected: the cyclic hardening model based on bounding surface plasticity concept and an elasto-viscoplastic model based on strain decomposition approach. The bounding surface plasticity approach is found to be a convenient method to model the accumulation of permanent deformation. It is demonstrated that deformations calculated using cyclic hardening model based on bounding surface plasticity fits the measured deformation quite well. The elasto-viscoplastic model, which is based on strain decomposition approach, provides a suitable method for analysis of creep and recovery test results. Deformations calculated using this model also fit the measured deformation quite well. Finally a new composite measure of resistance to permanent deformation is developed. The resistance index is based on strain decomposition approach and is simple to calculate. The index incorporates a parameter related to shear susceptibility of mixtures and is sensitive to changes in volumetric composition. It is believed that this index can be used to compare and select mixtures at mixture design stage. If its applicability to other materials is proved by further research, it can also be linked to performance related specifications, as a simple measure of performance with regard to rutting.

Download or read book Mechanistic Model to Predict the Impact of the Aggregate Matrix on the Permanent Deformation of Asphalt Mixtures written by Samer Hassan Dessouky and published by . This book was released on 2005 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hot mix asphalt (HMA) is a granular composite material stabilized by the presence of asphalt binder. The behavior of HMA is highly influenced by the microstructure distribution in terms of the different aggregate particles present in the mix, the directional distribution of aggregates, the distribution of voids, and the nucleation and propagation of cracks. Conventional continuum modeling of HMA lacks the ability to explicitly account for the effect of aggregate microstructure distribution features. This report presents the development of elastic and visco-plastic models that account for important aspects of the aggregate and microstructure distribution in modeling the macroscopic behavior of HMA. The objective of Project 0-1707 is to develop tools by which engineers can judge the impact of the aggregate on the performance of HMA based on simple and repeatable tests. Of greatest concern in Project 0-1707 is the ability of the HMA to resist permanent deformation or to rut, which leads to safety concerns, especially under wet surface conditions. In this report, the research team develops an approach is developed to introduce a length scale to the elasticity constitutive relationship in order to capture the influence of aggregate particle sizes on HMA response. A finite element (FE) analysis is used to analyze the microstructure response and predict the macroscopic properties of HMA. Each point in the microstructure is assigned effective local properties that are calculated using an analytical micromechanical model that captures the influence of the number of particles on the microscopic response of the HMA. The moving window technique and autocorrelation function are used to determine the microstructure characteristic length scales that are used in strain gradient elasticity. A number of asphalt mixes with different aggregate types and size distributions are analyzed . An elasto-visco-plastic continuum model is developed to predict HMA response and performance. The model incorporates a Drucker-Prager yield surface that is modified to capture the influence of stress path direction on the material response. Parameters that reflect the directional distribution of aggregates and damage density in the microstructure are included in the model. The elasto-visco-plastic model is converted into a numerical formulation and is implemented in FE analysis using a user-defined material subroutine (UMAT). A fully implicit algorithm in time-step control is used to enhance the efficiency of the FE analysis. The FE model used in this project simulates experimental data and pavement section.

Download or read book Viscoelastic and Permanent Deformation Characteristics of Asphalt Aggregate Mixes Tested as Hollow Cylinders and Subjected to Dynamic Axiel and Shear Loads written by Sirous Heydari Alavi and published by . This book was released on 1992 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling Permanent Deformation of Asphalt aggregate Mixes written by and published by . This book was released on 1994 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Engineering Properties of Asphalt Mixtures and the Relationship to Their Performance written by Gerald A. Huber and published by ASTM International. This book was released on 1995 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thirteen papers presented at the conference on [title], held in Phoenix, Arizona, December, 1994, discuss the products of the strategic highway research program, the Superpave method of mix design, and test methods for fatigue cracking and permanent deformation. Lacks an index. Annotation c. by Book

Download or read book Aggregate Contribution to Hot Mix Asphalt HMA Performance written by and published by ASTM International. This book was released on with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aggregate Contribution to Hot Mix Asphalt HMA Performance written by Thomas D. White and published by ASTM International. This book was released on 2001 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: Containing 13 papers from the December 2000 conference in Orlando, Florida, this book covers the use of the PURWheel laboratory tracking device, the Asphalt Pavement Analyzer, the identification of aggregate role, the evaluation of sensitivity, fine aggregate angularity, guidelines for the selection

Download or read book PRO 28 6th International RILEM Symposium on Performance Testing and Evaluation of Bituminous Materials PTEBM 03 written by Manfred N. Partl and published by RILEM Publications. This book was released on 2003 with total page 658 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Permanent Deformation in Bituminous Mixes Effects of Consistency of Bitumen Type of Aggregate and Mix Composition written by and published by . This book was released on 1988 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Prediction of Permanent Deformation in Asphalt Mixtures written by Hasan Al-Mosawe and published by . This book was released on 2017-11-04 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Viscoelastic and Permanent Deformation Characteristics of Asphalt aggregate Mixes Tested as Hollow Cylinders and Subjected to Dynamic Axial and Shear Loads written by Sirous Heydari Alavi and published by . This book was released on 1992 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Quality Management of Hot Mix Asphalt written by ASTM Committee D-4 on Road and Paving Materials and published by ASTM International. This book was released on 1996 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Relationships Between Modified Asphalt Binders Rheology and Binder Aggregate Mixture Permanent Deformation Response written by and published by . This book was released on 1991 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Stage 1 Validation of the Relationship Between Asphalt Properties and Asphalt aggregate Mix Performance written by and published by Strategic Highway Research Program (Shrp). This book was released on 1994 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: A primary objective for the Strategic Highway Research Program (SHRP) A-003A contract was to extend and verify the results obtained by other SHRP contractors on the performance-related characteristics of asphalt binders in paving mixes. This report specifically addresses validation of the following: 1) binder properties proposed by the A-002A contractor to predict asphalt-aggregate mix performance in terms of fatigue, permanent deformation, and thermal cracking; and 2) conditioning procedures that produce binder properties representative of those in a pavement immediately after construction and after several years of service. While water sensitivity requirements are not included in the binder specification, validation efforts in the water-sensitivity area are also described. Materials used in the investigation included 8 to 16 asphalt binders and 2 to 4 aggregates obtained from the SHRP Materials Reference Library.

Download or read book Permanent Deformation Characteristics of Dense graded Mixes Using Asphalt Pavement Analyzer written by Jesús A. Sandoval-Gil and published by . This book was released on 2004 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Asphalt Pavement Analyzer (APA) device was used to characterize the impact of various mix factors on the development of permanent deformation in dense-graded mixes given a standard compactive effort. Factors included two aggregate sizes, three VMA levels, two fines contents, three binder contents and four binder types. All specimens received the same compactive effort (100 gyrations) using the Superpave Gyratory Compactor (SGC). For some tests, testing temperatures followed the standard APA test protocol (64C) and for some others, the test temperature was set at the high temperature of standard performance asphalt binder grade (e.g. 70C for a PG 70-22 asphalt binder). Statistical results showed that increased binder content increased permanent deformation in the 19.0 mm dense graded mixes prepared with the PG 64-22 binder irrespective of the other mix parameters. These effects were not noted in the mixes prepared with PG 70-22 and PG 76-22 binders, when tested at 64C. However, the same effect was noted when mixes prepared with PG 70-22, PG 70-22 Modified and PG 76-22 binders were tested at the high temperature of standard performance asphalt binder grade. All mixes prepared with the stiffer binders showed very low permanent deformation when tested at the standard 64C regardless of the value of the other mix parameters. The statistical analysis of permanent deformation provides evidence that the mixes prepared with the PG 76-22 and PG 70-22 Modified binders perform better than mixes prepared with the PG 70-22 and the PG 64-22 binders. The effect of VMA on permanent deformation depends on the maximum aggregate size used, test temperature, binder type and the fines content. It was not possible to separate these interaction effects. The results of this study suggest that the APA is relatively insensitive to changes in mix properties within the range of variables studied, when using the standard APA test temperature (64C). However, the APA device is sensitive when the test temperature matches the high temperature of the standard performance binder grade (e.g. 70C for a PG 70-22 binder). Based on the results of this study, it appears that the APA can be used to indicate the rut resistance of a mixture. Although some of the mix factors have an interactive effect in the mixes, the APA has a potential to predict the relative rutting of the hot mix asphalt mixes even when polymer modified mixes are used, provided that testing is conducted at the appropriate test temperature.