Modelling the performance of asphalt concrete using continuum damage theories is an approach that has gained international attention in recent years. These types of models are advantageous because they ignore many of the complicated physical interactions at the microscale level and instead characterise a material using macroscale observations. One such model, the viscoelastic continuum damage model, is used in this study to examine the fatigue performance of asphalt concrete mixtures. A mathematically rigorous exploration is undertaken to specialise the model for easy prediction and characterisation using cyclic fatigue tests on cylindrical specimens. This process reveals that certain theoretical shortcomings are evident in other similar models and corrects them with a newly developed model. The resulting model is capable of capturing the underlying material property, i.e. the damage characteristic curve, which is responsible for the performance of controlled stress, controlled crosshead strain and consta...

Improved calculation method of damage parameter in viscoelastic continuum damage model

Cracking in asphalt concrete pavements is a major form of pavement distress in the United States. Because the cracking phenomenon is complex and cracking is often affected by both material and structural factors, field engineers have no quick and effective test and analysis protocols. A suite of fatigue analysis tools—as well as applications built around the simplified viscoelastic continuum damage (S-VECD) model—is presented. The S-VECD formulation is presented in a summarized form. Next, the characterization protocols, which are consistent with the capabilities of the asphalt mixture performance tester, are shown. Considerable attention is then given to S-VECD-based analysis tools for assessment of material- and pavement-level fatigue performance. Results show that the S-VECD model can be used to predict the number of cycles until fatigue failure for both constant stress and constant strain loading. The S-VECD model's sensitivity to mixture composition and external factors is shown through predictions o...

Simplified Viscoelastic Continuum Damage Model as Platform for Asphalt Concrete Fatigue Analysis

A review on solutions for improving rutting resistance of asphalt pavement and test methods

FOUR volumes of the Bulletin of this society were completed with the last year. They contain many papers of interest and value, most of which have been noticed in these columns, and several -evidently the work of novices-which the Publication Committee might with advantage have suppressed. The first part of the fifth volume, which has been issued recently, contains six papers, three of which are of general interest. Of the others, one on the seasonal periodicity of earthquakes is inconclusive. Mr. Carl H. Beal describes an earthquake which originated near the town of Los Alamos, in southwestern California, on January 11 last. This is probably the first earthquake in which the long-distance telephone has been used in the collection of records. Prof. J. C. Branner insists on the untrustworthiness of personal impressions on the direction of an earthquake-shock, and he urges that, in investigations of an earthquake, the question dealing with such impressions should be omitted. It has long been known that single observations on the apparent direction of the shock or on the fall of a column, etc., are valueless, the apparent direction being almost invariably perpendicular to the principal walls of the house in which it is observed. But the average of a large number of personal observations within a limited area has been found in several cases to coincide with the direction of the area from the epicentre. Moreover, after the Tokyo earthquake of June 20, 1894, Prof. Omori measured the direction of fall of 140 stone lanterns with circular bases in Tokyo, and the average of these measurements coincides exactly with the direction of the single great oscillation registered in that city.

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The Seismological Society of America

As shown by strains measured on full scale experimental aircraft structures, traffic of slow-moving multiple loads leads to asymmetric transverse strains that can be higher than longitudinal strains at the bottom of asphalt pavement layers. To analyze this effect, a model and a software called ViscoRoute have been developed. In these tools, the structure is represented by a multilayered half-space, the thermo-viscoelastic behaviour of asphalt layers is accounted by the Huet-Sayegh rheological law and loads are assumed to move at constant speed. First, the paper presents a comparison of results obtained with ViscoRoute to results stemming from the specialized literature. For thick asphalt pavement and several configurations of moving loads, other ViscoRoute simulations confirm that it is necessary to incorporate viscoelastic effects in the modelling to well predict the pavement behaviour and to anticipate possible damages in the structure.

https://hal.archives-ouvertes.fr/hal-00421048/document

ViscoRoute 2.0 A Tool for the Simulation of Moving Load Effects on Asphalt Pavement

A nonlocal damage model is proposed to predict the behavior of pavement fatigue cracking. This constitutive relation has been implemented in a finite-element code, along with a self-adaptive jump-in-cycle procedure for high cycle fatigue computations. Strain localization analysis shows that during uniaxial fatigue tests, bifurcation due to strain softening occurs much later than in monotonic tests. The incorporation of an internal length into the constitutive model is advocated since the model should encompass loading histories with very different amplitudes of cycles, in which localization may still occur. The influence of the internal length on the fatigue life of bending beams is also investigated. Calibration of the damage model is performed after thermal effects have been evaluated and accounted for in a simplified way, uncoupled to damage. Parameter identification is performed in bending and uniaxial tests. The resulting calibrated constitutive relation is found to yield a good description of several different uniaxial tests.

https://hal.archives-ouvertes.fr/hal-01004693/document

Continuum damage approach to asphalt concrete fatigue modeling

Multi-particle modelling for the prediction of delamination in multi-layered materials

La these a pour but de concevoir un outil simple d'utilisation, pour l'ingenieur, capable d'analyser les champs de contraintes tridimensionnels responsables de delaminage au bord ou de fissuration transverse dans les materiaux multicouches. Dans la premiere partie du memoire, nous construisons des modelisations multiparticulaires (M4) a partir de champs de contraintes tridimensionnels approches ecrits sous forme de polynomes de Legendre en z par couche. Les coefficients de ces polynomes sont des champs en (x,y) relies aux efforts generalises. Nous utilisons la formulation d'Hellinger-Reissner pour en deduire les deplacements et les deformations generalisees associees. Par stationnarite de la fonctionnelle, nous donnons les equations d'equilibre, les conditions aux limites et le comportement ecrit en souplesse. La richesse plus ou moins grande des champs de contraintes approches ainsi construit mene a 7n, 5n, 3n et (2n+1) (n: nombre de couches) equations d'equilibre dans le plan. Dans la seconde partie de la these, nous testons quatre modeles sur le probleme de la traction simple pour des stratifies non troues d'empilement quelconque et troues d'empilement (0°, 90°)s. Nous posons analytiquement les systemes d'equations qui par combinaison se condensent en un systeme d'equations differentielles de degre 2 en y et dont la resolution se fait par le logiciel de calcul formel MATHEMATICA. Sur le cas du stratifie (0°, 90°)s non troue, nous montrons que l'energie due aux efforts manquants dans les modeles reduits ne disparait pas completement mais est transferee sur celles des efforts restants. Dans le cas du modele multiparticulaire M4_(2n+1)M (M: pour membrane) le plus simple, pour assurer l'equilibre global de la plaque, nous proposons un concept, generalisable, d'effort lineique de type Dirac dont l'intensite est relie au maximum des cisaillements au bord. Nous pensons que l'intensite du Dirac peut servir de base a un critere sur le delaminage.

https://pastel.archives-ouvertes.fr/tel-00197853/document

Analyse des efforts à l'interface entre les couches des matériaux composites à l'aide de modèles multiparticulaires de matériaux multicouches (M4)

This article addresses the question of whether the viscoelastic behavior of asphalt pavements, as part of the factors that impact the rolling resistance, might lead to substantially higher energy consumption of road traffic, as compared to non-dissipative pavements. In the context of sustainable development (fuel consumption, gas emission), this is a current issue for the pavement design community. This problem is tackled by a theoretical approach which consists in computing the structure-induced rolling resistance (SRR) for a vehicle by using the mechanical response of a layered viscoelastic medium excited by moving loads (i.e. tires of the vehicle). The structure-induced power dissipation is shown to be proportional to the integral over contours of the applied loads of the pavement deflection, times the outward normal to these contours. Following the developed approach, the determination of the SRR force engendered by the structure-induced dissipation is obtained from the computation of the deflection of the viscoelastic pavement to an assumed pressure distribution. Such an approach applied to a thick asphalt pavement allows the SRR for a typical road structure to be evaluated as a function of temperature and speed. A non-dimensional analysis is also presented to extend the results to some other contexts. Under the assumptions made for the derivation of the SRR, the main conclusion of the case study is that the extra fuel consumption for a vehicle resulting from the viscoelastic behavior of asphalt pavements is small.

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Armelle Chabot

Papers

ViscoRoute 2.0 A Tool for the Simulation of Moving Load Effects on Asphalt Pavement

Continuum damage approach to asphalt concrete fatigue modeling

Multi-particle modelling for the prediction of delamination in multi-layered materials

Analyse des efforts à l'interface entre les couches des matériaux composites à l'aide de modèles multiparticulaires de matériaux multicouches (M4)

Evaluation of the structure-induced rolling resistance (SRR) for pavements including viscoelastic material layers