Dynamic modulus and phase angle prediction of laboratory aged asphalt mixtures

Nobakht, Mona; Sakhaeifar, Maryam S.

doi:10.1016/j.conbuildmat.2018.09.160

Cited by 49 publications

(24 citation statements)

References 14 publications

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“…In TTSP, the effects of temperature and loading time (or frequency) on the mechanical properties of viscoelastic materials are considered equivalent, i.e., the mechanical properties of viscoelastic materials at a low temperature are equivalent to that at a short loading time (or higher frequency) and vice versa [20]. Consequently, according to the TTSP, the master curves of the dynamic modulus and phase angle of asphalt mixture can be plotted based on shift factors and non-linear least squares regression analysis [21,22].…”

Section: Introductionmentioning

confidence: 99%

The Effects of Asphalt Migration on the Dynamic Modulus of Asphalt Mixture

2019

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Asphalt migration is one of the significant detrimental effects on asphalt pavement performance. In order to simulate the state after the occurrence of asphalt migration amid asphalt pavement layers and further investigate the effects of asphalt migration on the dynamic modulus of asphalt mixture, samples with different asphalt contents layers were firstly separated into the upper and lower half portions and then compacted together. By conducting the dynamic modulus test with the Superpave Simple Performance Tester (SPT), the variation laws of the dynamic modulus (|E*|) and the phase angle (δ) at different testing temperatures and loading frequencies were analyzed in this paper. Further, the dynamic modulus and the stiffness parameter (|E*|/sinδ) at the loading frequency of 10 Hz and testing temperature of 50 °C were illustrated. Simultaneously, the master curves of the dynamic modulus and phase angle of asphalt mixtures under different testing conditions were constructed to better investigate the effects of asphalt migration on the dynamic modulus by means of Williams–Landel–Ferry (WLF) equation and Sigmoidal function. Results show that, after the asphalt migration, the dynamic modulus of asphalt mixtures increase with the increasing loading frequency while they decrease with the increasing testing temperature; the dynamic modulus and the stiffness parameter are the highest when asphalt mixtures have the optimum asphalt content layers, and then decrease with the incremental difference of asphalt content in the upper and lower half portions. Besides this, different from the master curves of dynamic modulus, the master curves of phase angle firstly increase with the increase of loading frequency to the highest point and then decrease with the further increase of loading frequency and are not as smooth as that of dynamic modulus. It can be concluded that the asphalt migration has compromised the mixture’s mechanical structure, and the more asphalt migrates, the weaker the mechanical properties of asphalt mixture will be. Additionally, based on the shift factors and master curves in the time–temperature superposition principle (TTSP), the effects of asphalt migration on the dynamic modulus and the variation laws of the dynamic modulus of asphalt mixture after the occurrence of asphalt migration can be better construed at the quantitative level.

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Section: Introductionmentioning

confidence: 99%

The Effects of Asphalt Migration on the Dynamic Modulus of Asphalt Mixture

2019

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“…Nesse contexto, o módulo de rigidez dinâmico sob a ótica da análise mecanicista, apresenta-se como um parâmetro de importância fundamental na formulação de modelos constitutivos de misturas asfálticas, uma vez que busca introduzir princípios de mecânica no projeto de pavimentos, evidenciando sua conotação dúbia que retrata tanto a parcela do comportamento elástico, decorrente dos agregados, quanto o comportamento viscoso, oriundo do ligante asfáltico partícipe de tais composições [9][10][11]. Neste sentido, CENTOFANTE (2018) et al [12] assinalam que existe uma gama de estudos que abordam o comportamento viscoelástico linear de ligantes e misturas através de modelos desenvolvidos para capturar os efeitos das taxas de aplicação de carregamento, temperatura e, notadamente, do envelhecimento sobre a resposta mecânica do concreto asfáltico.…”

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Estudo viscoelástico de misturas asfálticas frescas e envelhecidas com agregado sinterizado de argila calcinada

et al. 2020

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RESUMO Os revestimentos asfálticos dos pavimentos flexíveis, em função do ligante betuminoso presente em sua composição, possuem comportamento mecânico dependente de vários fatores, dentre eles: processo de compactação, temperatura e taxa de aplicação de carregamento. Várias são as reações passíveis de ocorrerem nos principais constituintes dessas formulações asfálticas, dentre estas, pode-se citar a oxidação, endurecimento físico e perda de voláteis. No caso do ligante asfáltico, o envelhecimento aumenta a viscosidade, associada a uma diminuição da penetração e alguma perda de suas características aglutinantes. Em particular, o aumento de consistência confere maior dureza com o tempo. No trabalho em pauta, estudou-se o comportamento mecânico de misturas asfálticas confeccionadas com Agregado Sinterizado de Argila Calcinada (ASAC), por meio de ensaios dinâmicos de flexão a quatro pontos. Determinou-se experimentalmente o efeito do processo de compactação dos corpos de prova prismáticos, bem como a influência do envelhecimento do ligante asfáltico no módulo dinâmico |E*| da mistura. Constatou-se queda de até 81,1% no valor do módulo complexo, frente às solicitações de temperatura e frequência selecionadas. Os resultados experimentais foram analisados à luz do modelo de Euler-Bernoulli generalizado para materiais viscoelásticos com carregamento dinâmico representativo do ensaio de flexão a quatro pontos. Salienta-se a compatibilidade do modelo teórico para as duas composições estudadas (fresca e envelhecida), face ao ajuste alcançado, representado pelos coeficientes de determinação (R²) resultantes.

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“…Different objective functions were used to fit the master curves, but the master curves of the asphalt mixture were not predicted. Nobakht [24] proposed a kinetic-based aging model to predict the dynamic modulus master curve of asphalt mixtures. The influence of aging on the dynamic modulus and phase angle master curves was analyzed.…”

Section: Introductionmentioning

confidence: 99%

Mesostructural Modeling of Dynamic Modulus and Phase Angle Master Curves of Rubber Modified Asphalt Mixture

Chen

Zhang

et al. 2019

Materials

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The main objective of this paper was to develop a mesostructure-based finite element model of rubber modified asphalt mixture to predict both the dynamic modulus master curve and phase angle master curve under a large frequency range. The asphalt mixture is considered as a three-phase material consisting of aggregate, asphalt mortar, and air void. The mesostructure of the asphalt mixture was digitized by a computed tomography (CT) scan and implemented into finite element software. The 2S2P1D model was used to obtain the viscoelastic information of an asphalt mortar under a large range of frequencies and temperatures. The continuous spectrum of the 2S2P1D model was converted to a discrete spectrum and characterized by the generalized Maxwell model for numerical simulation. The Prony series parameters of the generalized Maxwell model and the elastic modulus of the aggregates were inputted into the finite element analysis as material properties. The dynamic modulus tests of a rubber modified asphalt mortar and asphalt mixture were conducted under different temperatures and loading frequencies. The dynamic modulus master curve and phase angle master curve of both asphalt mortar and asphalt mixture were constructed. The frequency of the finite element simulations of the dynamic modulus tests ranged from 10−6 to 104. The dynamic modulus and phase angle of the asphalt mixture was calculated and the master curves were compared with the master curves obtained from the experimental data. Furthermore, the effect of the elastic modulus of aggregates on the master curves was analyzed. Acceptable agreement between dynamic modulus master curves obtained from experimental data and simulation results was achieved. However, large errors between phase angle master curves appeared at low frequencies. A method was proposed to improve the prediction of the phase angle master curve by adjusting the equilibrium modulus of the asphalt mortar.

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Dynamic modulus and phase angle prediction of laboratory aged asphalt mixtures

Cited by 49 publications

References 14 publications

The Effects of Asphalt Migration on the Dynamic Modulus of Asphalt Mixture

The Effects of Asphalt Migration on the Dynamic Modulus of Asphalt Mixture

Estudo viscoelástico de misturas asfálticas frescas e envelhecidas com agregado sinterizado de argila calcinada

Mesostructural Modeling of Dynamic Modulus and Phase Angle Master Curves of Rubber Modified Asphalt Mixture

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