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Microstructure Generation Of Asphalt Concrete And Lattice Modeling Of Its Cracking Behavior Under Low Temperature
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Book Synopsis Microstructure Generation of Asphalt Concrete and Lattice Modeling of Its Cracking Behavior Under Low Temperature by : Pu Zhang
Download or read book Microstructure Generation of Asphalt Concrete and Lattice Modeling of Its Cracking Behavior Under Low Temperature written by Pu Zhang and published by . This book was released on 2003 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: Keywords: virtual fabrication, asphalt concrete, lattice.
Book Synopsis Microstructure Generation of Asphalt Concrete and Lattice Modeling of Its Cracking Behavior Under Low Temperature by :
Download or read book Microstructure Generation of Asphalt Concrete and Lattice Modeling of Its Cracking Behavior Under Low Temperature written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue cracking has been pointed out as a major distress in asphalt concrete (AC) pavements. It is well known that cracking performance in AC mainly depends on the mechanical properties of its constituent materials, namely asphalt binder and aggregates. Study of such dependence is the key to effective characterization of the mechanical behavior of AC. Previous studies predicted AC behavior from the mixture properties using extensive physical experiments. As an alternative approach to physical experiments, micromechanical modeling, which is composed of microstructure generation and numerical modeling, is introduced in this study. Digital imaging processing (DIP) of physical specimens to generate microstructures is first investigated, followed by virtual fabrication, which makes use of the mix properties to virtually fabricate the specimen (or the cross section of specimen for 2D analysis), so that the appearance and mechanical behavior of the actual specimen can be simulated. The resulting microstructure is then processed to obtain a lattice network that is expected to mimic the mechanical behavior of the AC specimen. Lattice modeling approximates a continuum by using a lattice, with each link representing an intact bond that can be broken at any time to create a microcrack. The cracking process is simulated by successive removal of failed links. Due to the unrealistic computational cost of direct simulation, the multi-scale approach is adopted to perform microstructural analysis, which considers the effect of different-sized aggregates at different length scales. Such an approach reduces the computational cost significantly, while capturing the mechanical phenomena at various length scales. The effectiveness of the proposed multi-scale modeling approach is then illustrated by modeling the cracking behavior of the uniaxial tension tests under -10 & deg;C. In the end, the effects of surface energy are studied.
Book Synopsis Dissertation Abstracts International by :
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2004 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Fracture Modeling of Asphalt Concrete with Heterogeneous Microstructure by : Jian Wang
Download or read book Fracture Modeling of Asphalt Concrete with Heterogeneous Microstructure written by Jian Wang and published by . This book was released on 2015 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding fracture resistance of asphalt concrete is of great importance in designing pavements with long service life. This thesis focused on studying the micro and global fracture behavior of heterogeneous asphalt concrete with a numerical analysis approach. Finite element (FE) models were built with the capacity of taking heterogeneity into consideration. The asphalt concrete was modeled as a multi-phase material with coarse aggregates and fine aggregate matrix (FAM). Viscoelastic properties were assigned to the FAM. Different damage models were incorporated to study fracture at two length scales: micro-fracture within FAM and coarse aggregate-FAM interface under small displacement and global fracture resistance in the semi-circular bending (SCB) test. For micro-fracture simulation, asphalt mixture was modeled with both adhesive and cohesive failure potential. Two different fracture models, cohesive zone model (CZM) and extended finite element model (XFEM), were adopted to simulate fracture damage within the FAM (cohesive failure) and at the FAM-aggregate interface (adhesive failure), respectively. For global fracture properties, the SCB test was simulated to predict the crack propagation pattern and the load-crack mouth opening displacement (CMOD) curve of asphalt concrete. Parametric studies with different material properties of FAM and coarse aggregates-FAM interface, morphological characteristics of coarse aggregates, and testing conditions (loading rate and temperature) were carried out to study their effects on fracture behavior of asphalt concrete. The numerical models provide an effective method to study fracture mechanism of heterogeneous asphalt concrete and generates meaningful findings. The development of cracking shows that the damage in the FAM material would initiate first at a small displacement and then interconnect with the damage developed at the FAM-aggregate interface. The higher angularity and larger aggregate size induces the greater damage level; while the orientation angle along with aspect ratio has influence on the anisotropic behavior of asphalt concrete. On the other hand, the SCB test simulations show good agreements with experimental results in the literature. Increasing fracture strength and energy of FAM significantly improves fracture resistance of asphalt concrete. The spatial distribution and angularity of coarse aggregate affect crack path; while the gradation and size of coarse aggregate affect fracture strength of asphalt concrete.
Book Synopsis Modelling of Low-temperature Behaviour of Cracks in Asphalt Pavement Structures by :
Download or read book Modelling of Low-temperature Behaviour of Cracks in Asphalt Pavement Structures written by and published by . This book was released on 1990 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper examines the transient stress analysis of a multilayer pavement structure subjected to heat conduction and associated thermoelastic effects by the cooling of its surface. In particular, the layered structure contains a transverse crack which can be created either during the construction of the pavement or during its service life. The numerical treatment of the transient stress analysis is achieved using a finite element scheme, which models the heat conduction and thermoelasticity of each component in the layered system and the singular stress field at the extremities of a crack. The numerical scheme is applied to examine the manner in which the propagation of an existing crack is influenced by the thermoelastic mismatch between the layers adjacent to the crack location. The analysis alos illustrates the influence of the thermoelastic mismatch between a cracked pavement and an overlay, in the suppression of crack propagation.
Book Synopsis Micromechanics-based Multiscale Lattice Modeling of Fatigue Cracking in Hot Mixed Asphalt by :
Download or read book Micromechanics-based Multiscale Lattice Modeling of Fatigue Cracking in Hot Mixed Asphalt written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents a novel micromechanics-based lattice procedure designed to characterize the cracking performance of hot mix asphalt (HMA) from its constituent material properties. The approach essentially consists of a series of direct-lattice models integrated with multiscale technique. A typical direct-lattice modeling starts with a preprocessor that discretizes the microstructure of a specimen, which is either physically or virtually fabricated, into a random truss lattice. The mixture performance can be predicted by analyzing such lattice network using a general-purpose finite element program FEP++. The cracking process in HMA is simulated by successive removal of failed links representing microcracks. In this study, a surface energy based failure criterion is developed to trigger the creation and subsequent extension of microcracks. Due to the disparate length scales associated with microcracking and specimen size, the direct-lattice modeling described above would demand unrealistic computational cost for modeling even a laboratory scale HMA specimens. In order to make the procedure more practical, the multiscale approach is implemented. Essentially, multi-scale model considers the effect of different-sized aggregates at different length scales. Such an approach reduces the computational cost significantly, while capturing the mechanical phenomenon at various length scales. Finally, the effectiveness of the proposed multiscale lattice procedure is illustrated by modeling an actual indirect tensile (IDT) test on a thin cylindrical HMA specimen and making quantitative comparisons with experimental measurements, including full-strain fields measured by the digital image correlations (DIC) technique.
Book Synopsis Prediction of Low Temperature Cracking of Asphalt Concrete Mixtures with Thermal Stress Restrained Specimen Test Results by : Hannele K. Kanerva
Download or read book Prediction of Low Temperature Cracking of Asphalt Concrete Mixtures with Thermal Stress Restrained Specimen Test Results written by Hannele K. Kanerva and published by . This book was released on 1993 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Low temperature cracking is attributed to tensile stresses induced in an asphalt concrete pavement that develop when the pavement is subjected to a cold temperature. Cracking results in poor ride quality and a reduction in service life of the pavement. Low temperature cracking has been predicted by regression equations, mechanistic approaches and by simulation measurements. The purpose of the study reported herein is to (1) evaluate the Thermal Stress Restrained Specimen Test (TSRST) as an accelerated performance test to simulate low temperature cracking of asphalt concrete mixtures and (2) develop a deterministic and probabilistic model to predict low temperature cracking with TSRST results. Construction histories, cracking observations and temperature data were collected for five test roads in Alaska, Pennsylvania and Finland. A full scale and fully controlled low temperature cracking test program was conducted at the U.S. Army Cold Regions Research and Engineering Laboratory (USACRREL). Specimens were fabricated in the laboratory with original asphalt cements and aggregates from the test roads. In addition, asphalt concrete pavement specimens were cut from the test sections. The TSRST results obtained for these samples were correlated with the field observations. Based on a statistical analysis of the data, the TSRST fracture temperature is associated with the field cracking temperature and crack frequency for the test roads where mixture properties dominated low temperature cracking. It was concluded that the TSRST can be used to simulate low temperature cracking of asphalt concrete mixtures. A deterministic and a probabilistic model were developed to predict crack spacing as a function of time using the TSRST results, pavement thickness and bulk density, pavement restraint conditions and air temperature. The affect of aging on pavement properties was incorporated in the models by predicting the field aging with Long Term Oven Aging (LTOA) treatment in the laboratory. The calculation of the crack spacing is based on the theory that the pavement slab cracks when the pavement temperature reaches the cracking temperature of the mixture and the slab is fully restrained. The deterministic model predicts crack spacing with time whereas the probabilistic model predicts crack spacing and its variation with time and yields the reliability of the design with regard to a minimum acceptable crack spacing criterion defined by road authorities. The models were verified by comparing the predicted crack spacings for the five test roads to the observed crack spacings. The probabilistic model is recommended for use in predicting the low temperature cracking of asphalt concrete mixtures.
Book Synopsis Investigation of Low Temperature Cracking in Asphalt Pavements by : Mihai O. Marasteanu
Download or read book Investigation of Low Temperature Cracking in Asphalt Pavements written by Mihai O. Marasteanu and published by . This book was released on 2012 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work detailed in this report represents a continuation of the research performed in phase one of this national pooled fund study. A number of significant contributions were made in phase two of this comprehensive research effort. Two fracture testing methods are proposed and specifications are developed for selecting mixtures based on fracture energy criteria. A draft SCB specification, that received approval by the ETG and has been taken to AASHTO committee of materials, is included in the report. In addition, alternative methods are proposed to obtain mixture creep compliance needed to calculate thermal stresses. Dilatometric measurements performed on asphalt mixtures are used to more accurately predict thermal stresses, and physical hardening effects are evaluated and an improved model is proposed to take these effects into account. In addition, two methods for obtaining asphalt binder fracture properties are summarized and discussed. A new thermal cracking model, called "ILLI-TC," is developed and validated. This model represents a significant step forward in accurately quantifying the cracking mechanism in pavements, compared to the existing TCMODEL. A comprehensive evaluation of the cyclic behavior of asphalt mixtures is presented, that may hold the key to developing cracking resistant mixtures under multiple cycles of temperature.
Book Synopsis A Simple Test Procedure for Evaluating Low Temperature Crack Resistance of Asphalt Concrete by : Sang Soo Kim
Download or read book A Simple Test Procedure for Evaluating Low Temperature Crack Resistance of Asphalt Concrete written by Sang Soo Kim and published by . This book was released on 2009 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: The current means of evaluating the low temperature cracking resistance of HMA relies on extensive test methods that require assumptions about material behaviors and the use of complicated loading equipment. The purpose of this study was to develop and validate a simple test method to directly measure the cracking resistance of hot mix asphalt under field-like conditions. A ring shape asphalt concrete cracking device (ACCD) was developed. ACCD utilizes the low thermal expansion coefficient of Invar steel to induce tensile stresses in a HMA sample as temperature is lowered. The results of the tests of the notched ring shaped specimens compacted around an ACCD Invar ring showed good repeatability with less than 1.0°C (1.8°F) standard deviation in cracking temperature. A laboratory validation indicated that ACCD results of five mixes correlate well with thermal stress restrained specimen test (TSRST) results with the coefficient of determination , r2 = 0.86. To prepare a sample and complete TSRST measurement, it takes minimum 2-3 days. For ACCD, two samples can be easily prepared and tested in a single day with a small test set-up. The capacity of ACCD can be increased easily with minimal cost to accommodate a larger number of samples. Among factors affecting the low temperature performance of HMA, the coefficient of thermal expansion (CTE) of aggregate has been overlooked for years. A composite model of HMA is proposed to describe the low temperature cracking phenomenon. Due to the orthotropic and composite nature of asphalt pavement contraction during cooling, the effects of aggregate CTE is amplified up to 18 times for a typical HMA. Of 14 Ohio aggregates studied, the maximum and the minimum CTEs are 11.4 and 4.0 x 10-6/°C, respectively. During cooling, the contraction of Ohio aggregate with high CTE can double the thermal strain of asphalt binders in the asphalt mix and may cause asphalt pavement thermal cracking at warmer temperature.
Book Synopsis Validation of Thermally Induced Internal Cracking in Asphalt Mixtures Using Indirect Tensile Test by : Joshua Oklu
Download or read book Validation of Thermally Induced Internal Cracking in Asphalt Mixtures Using Indirect Tensile Test written by Joshua Oklu and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: s stated in the House Bill 62 Transportation Budget in Brief, roughly 5 billion dollars is spent yearly on road pavement construction in the state of Ohio, with a significant chunk for maintenance. Moreover, maintenance activities and their associated costs are increased in the colder regions of the US where damages and distress on roadways are associated to the Low Temperature Cracking (LTC) phenomena or at least in combination with other distress like rutting and fatigue cracking. Thermally induced internal cracking is a mechanism that occurs under low temperature conditions. Akentuna et al. (2017) postulated that the differential in Coefficient of Thermal Contraction (CTC) values in asphalt binder and aggregate gives rise to thermally induced internal cracking at low temperatures. Owing to its potential significance and effect on LTC modeling, this study investigated the thermally induced thermal cracking phenomena using the Indirect Tensile (IDT) test. The IDT test was selected since it is the test procedure used in fracture property investigation in the AASHTOWare Pavement Mechanistic Empirical (ME) Design program for low temperature cracking modeling. In addition, a study on the effect of loading rate and temperature on asphalt mixtures during the ITS test was also investigated. Although thermally induced internal cracking was observed by Li et al. (2007) using the acoustic emissions test and Behnia et al. (2014) using the Disc-shaped Compact Test (DCT), its quantified effect has not been studied. The results garnered from this study validated the occurrence of thermally induced internal cracking, evidenced by significant reduction in IDT peak strengths and energy at peak stress to averaged magnitudes of 4% and 12% respectively. The second objective of this study on varying loading rate and temperature during the IDT strength tests proved that the standard test loading rate of 12.5mm/min rate was too fast and not representative of field loading rate. In addition, knowing that LTC could occur even at lower stress compared to the IDT strengths, ‘Creep to fail’ tests were performed to analyze the behavior of mixtures in such circumstances. Results showed that creep loads at extremely lower percentages of IDT strengths still fractured asphalt samples with output parameters offering valuable information on crack behavior under low temperature conditions. Time to fracture and crack speed parameters were shown to decrease 62% and increase 46% in thermally induced internal cracking samples.
Author :S. K. Chen, Altair Engineering Inc., California, USA Publisher :DEStech Publications, Inc ISBN 13 :1605951501 Total Pages :665 pages Book Rating :4.6/5 (59 download)
Book Synopsis 2014 International Conference on Artificial Intelligence and Software Engineering(AISE2014) by : S. K. Chen, Altair Engineering Inc., California, USA
Download or read book 2014 International Conference on Artificial Intelligence and Software Engineering(AISE2014) written by S. K. Chen, Altair Engineering Inc., California, USA and published by DEStech Publications, Inc. This book was released on 2014-02-06 with total page 665 pages. Available in PDF, EPUB and Kindle. Book excerpt: 2014 International Conference on Artificial Intelligence and Software Engineering(AISE2014) aims to provide a forum for accessing to the most up-to-date and authoritative knowledge from both Artificial Intelligence and Software Engineering. AISE2014 features unique mixed topics of AI Algorithms, Data Mining, Knowledge-based Systems, Software Process and so on. The goal of this conference is to bring researchers, engineers, and students to the areas of Artificial Intelligence and Software Engineering to share experiences and original research contributions on those topics. Researchers and practitioners are invited to submit their contributions to AISE2014.
Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2566 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Metallography and Microstructure in Ancient and Historic Metals by : David A. Scott
Download or read book Metallography and Microstructure in Ancient and Historic Metals written by David A. Scott and published by Getty Publications. This book was released on 1992-01-02 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: David A. Scott provides a detailed introduction to the structure and morphology of ancient and historic metallic materials. Much of the scientific research on this important topic has been inaccessible, scattered throughout the international literature, or unpublished; this volume, although not exhaustive in its coverage, fills an important need by assembling much of this information in a single source. Jointly published by the GCI and the J. Paul Getty Museum, the book deals with many practical matters relating to the mounting, preparation, etching, polishing, and microscopy of metallic samples and includes an account of the way in which phase diagrams can be used to assist in structural interpretation. The text is supplemented by an extensive number of microstructural studies carried out in the laboratory on ancient and historic metals. The student beginning the study of metallic materials and the conservation scientist who wishes to carry out structural studies of metallic objects of art will find this publication quite useful.
Book Synopsis Engineering Heat Transfer by : Donatello Annaratone
Download or read book Engineering Heat Transfer written by Donatello Annaratone and published by Springer Science & Business Media. This book was released on 2010-03-14 with total page 333 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a generalist textbook; it is designed for anybody interested in heat transmission, including scholars, designers and students. Two criteria constitute the foundation of Annaratone’s books, including the present one. The first one consists of indispensable scientific rigor without theoretical exasperation. The inclusion in the book of some theoretical studies, even if admirable for their scientific rigor, would have strengthened the scientific foundation of this publication, yet without providing the reader with further applicable know-how. The second criterion is to deliver practical solution to operational problems. This criterion is fulfilled through equations based on scientific rigor, as well as a series of approximated equations, leading to convenient and practically acceptable solutions, and through diagrams and tables. When a practical case is close to a well defined theoretical solution, corrective factors are shown to offer simple and correct solutions to the problem.
Download or read book Warts and All written by Pat Cook and published by Baker's Plays. This book was released on 1991 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Concrete : Microstructure, Properties, and Materials by : P. Mehta
Download or read book Concrete : Microstructure, Properties, and Materials written by P. Mehta and published by McGraw Hill Professional. This book was released on 2005-09-26 with total page 684 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook presents the art and science of concrete in a simple, clear, hands-on manner, focusing on the following: Cement and concrete are predicted to be the premier building material of the 21st Century; Includes unique diagrams, photographs, and summary tables; Updated to include new chapters on non-destructive methods for concrete; future challenges in concrete technology; an increased number of examples of concrete applications; and new developments in durability.
