Characterization of Microdamage Healing in Asphalt Concrete with a Smeared Continuum Damage Approach

2014 ◽  
Vol 2447 (1) ◽  
pp. 126-135 ◽  
Author(s):  
B. Shane Underwood ◽  
Waleed Abdelaziz Zeiada
Keyword(s):  
Asphalt Concrete ◽  
Continuum Damage ◽  
Microdamage Healing

scholarly journals Influence of the surroundings areas in the microclimates of Santo André City – Brazil and Indication of Bioclimatic Strategies for Buildings

2019 ◽  
Vol 111 ◽  
pp. 06005
Author(s):  
Helenice Maria Sacht ◽  
Andréa de Oliveira Cardoso ◽  
Victor Figueiredo Roriz
Keyword(s):  
Asphalt Concrete ◽  
Weather Data ◽  
Heat Island ◽  
Paulo State ◽  
Urban Heat ◽  
Air Circulation ◽  
The City ◽  
New Buildings ◽  
Great Absorption

The characterization of the climate of Santo André and its weather data are essential instruments for the study of implantation, both of new buildings and solutions of retrofit, as well as for the elaboration of projects of urban interventions or degraded areas occupation. In this study, meteorological weather data were obtained by meteorological stations in Santo André, a municipality located in the region of ABC Paulista (São Paulo State), for five different points of the city in order to evaluate the different micro climates and the influence of the surroundings in microclimates and an climate file in .epw format was developed for analysed bioclimatic strategies for buildings. Results show temperature and humidity variations among the five microclimates analyzed, as a consequence of the following actions: replacement of vegetation by constructions, asphalt, concrete and other impermeable surfaces, increased air pollution which cause a great absorption of solar radiation, forming a barrier for air circulation and of pollutant gases into the atmosphere creating urban heat island effects.

Mechanics of damage, healing, damageability, and integrity of materials: A conceptual framework

2016 ◽  
Vol 26 (1) ◽  
pp. 50-103 ◽  
Author(s):  
George Z Voyiadjis ◽  
Peter I Kattan
Keyword(s):  
Damage Mechanics ◽  
Healing Process ◽  
Continuum Damage Mechanics ◽  
Damage Variable ◽  
Continuum Damage ◽  
Variable Section ◽  
Damage Healing ◽  
Characterization Of Materials ◽  
New Formulation

In this work several new and fundamental concepts are proposed within the framework of continuum damage mechanics. These concepts deal primarily with the nature of the two processes of damage and healing along with introducing a consistent and systematic definition for the concepts of damageability and integrity of materials. Toward this end, seven sections are presented as follows: “The logarithmic damage variable” section introduces the logarithmic and exponential damage variables and makes comparisons with the classical damage variable. In “Integrity and damageability of materials” section a new formulation for damage mechanics is presented in which the two angles of damage–integrity and healing–damageability are introduced. It is shown that both the damage variable and the integrity variable can be derived from the damage–integrity angle while the healing variable and damageability variable are derived from the healing–damageability angle. “The integrity field” section introduces the new concept of the integrity field while “The healing field” section introduces the new concept of the healing field. These two fields are introduced as a generalization of the classical concepts of damage and integrity. “Unhealable damage and nondamageable integrity” section introduces the new and necessary concept of unrecoverable damage or unhealable damage. In this section the concept of permanent integrity or nondamageable integrity is also presented. In “Generalized nonlinear healing” section generalized healing is presented where a distinction is clearly made between linear healing and nonlinear healing. As an example of nonlinear healing the equations of quadratic healing are derived. Finally in “Dissection of the healing process” section a complete and logical/mathematical dissection is made of the healing process. It is hoped that these new and fundamental concepts will pave the way for new, consistent, and holistic avenues in research in damage mechanics and characterization of materials.

Effect of Loading Waveform Pattern and Rest Period on Fatigue Life of Asphalt Concrete Using Viscoelastic Continuum Damage Model

2018 ◽  
Vol 2672 (28) ◽  
pp. 451-461 ◽  
Author(s):  
Waleed Abdelaziz Zeiada ◽  
Padmini P. Gudipudi ◽  
B. Shane Underwood ◽  
Mena I. Souliman
Keyword(s):  
Fatigue Life ◽  
Fatigue Test ◽  
Asphalt Concrete ◽  
Rest Period ◽  
Test Method ◽  
Concrete Mixture ◽  
Continuum Damage ◽  
Viscoelastic Continuum Damage ◽  
Loading Waveform ◽  
Waveform Pattern

Fatigue cracking is one of the most critical types of distress in asphalt pavements and is due to actions of repetitive traffic loading over time. The fatigue life of asphalt concrete is often estimated from laboratory experiments where the performance depends directly on the test method, loading conditions, temperature, rest period, and aging in addition to the composition and properties of the mixture itself. The uniaxial fatigue test has become a popular method for developing constitutive models that describe the fatigue behavior of asphalt concrete mixture owing to the uniform states of stress across the specimen section. This study investigates the effect of the loading waveform (sinusoidal versus haversine) and rest period (continuous versus intermittent) on the laboratory fatigue life of asphalt concrete mixtures. The fatigue analysis was performed using the simplified viscoelastic continuum damage (S-VECD) approach where the damage characteristic (C-S) curves were established for all the cases, and then used to estimate the fatigue laws through simulated predictions. The proposed uniaxial fatigue test and analysis method were able to determine the fatigue life relationships of asphalt concrete mixture at different waveform and rest period conditions with a reduced testing time compared to other traditional testing and analysis methods. Overall, both rest period and waveform pattern were found to affect the laboratory fatigue life of asphalt concrete mixture. Model predictions show that pulse-rest loading yields an equivalent fatigue life to continuous loading at strain values that are approximately four times greater.

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