Cyclic Triaxial Tests on Asphalt Concrete as a Water Barrier for Embankment Dams

Feizi-Khankandi, Siamak; Mirghasemi, Ali Asghar; Ghalandarzadeh, Abbas; Höeg, Kaare

doi:10.3208/sandf.48.319

Cited by 60 publications

(19 citation statements)

References 2 publications

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“…The most important aspect for hydraulic applications is that the barrier remain watertight even when subjected to severe static and earthquake loading (Feizi-Khankandi et al 2008;Wang 2008;Wang and Höeg 2011). Laboratory tests and field experience show that asphalt concrete with air-void content (porosity) < 3% is virtually impervious with a permeability coefficient in the range 10 −8 -10 −10 cm/s.…”

Section: Introductionmentioning

confidence: 99%

Watertightness, cracking resistance, and self-healing of asphalt concrete used as a water barrier in dams

et al. 2013

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The coefficient of permeability of hydraulic asphalt concrete is in the range 10 −8 -10 −10 cm/s. Laboratory test results show that triaxial specimens in axial compression can undergo axial strains up to 18% without any significant increase in permeability until approaching the compressive strength. For temperatures between 5 and 20°C and strain rates between 2 × 10 −3 %/s and 5 × 10 −3 %/s, conventional hydraulic asphalt concrete can tolerate 1%-3% tensile strains before cracking in direct tension tests and strains up to 3%-4% in bending. At 20°C the tensile and bending strains at cracking are 2-4 times higher than those at 0°C, and at −20°C they are approximately 0.2% and 0.8%, respectively. Asphalt concrete possesses pronounced crack self-healing properties. In the experiments, the crack leakage rate dropped 1-4 orders of magnitude within a few hours and the cracked specimens regained 55% of the intact tensile strength after only 1 day of self-healing. In summary, the comprehensive series of laboratory tests documents that asphalt concrete has characteristics that make the material extremely well suited for use in impervious barriers in dams, and the test results reported herein can be of great use in barrier design.Résumé : Le coefficient de perméabilité du béton bitumineux hydraulique utilisé comme barrière dans les barrages est entre 10 −8 à 10 −10 cm/s. Des essais triaxiaux en laboratoire démontrent que les éprouvettes sous compression axiale peuvent subir des déformations axiales de cisaillement jusqu'à 18 % sans augmentation significative de la perméabilité. Pour des températures entre 5 et 20°C et taux de déformation entre 2 × 10 −3 et 5 × 10 −3 %/s, le béton bitumineux hydraulique conventionnel peut tolérer des déformations entre 1 et 3 % avant de fissurer en tension et des déformations de 3 à 4 % en flexion. À 20°C, les déformations en tension et flexion au moment de la fissuration étaient de deux à quatre fois plus élevées que celles à 0°C. À −20°C, les déformations en tension et flexion au moment de la fissuration étaient de 0.2 et 0.8 % respectivement. Le béton bitumineux possède des caractéristiques auto-réparatrices des fissures, par exemple les fissures dues à un séisme sévère peuvent s'autoréparer rapidement. Dans les essais, le taux de fuite dans les fissures ont diminué d'un à quatre ordres de magnitude dans l'espace de quelques heures. Les spécimens fissurés cependant ont eu un regain de 55 % de leur résistance en tension intacte dans l'espace d'un jour d'auto-réparation. En conclusion, les essais de laboratoire démontrent que le béton bitumineux a des propriétés et caractéristiques qui le rendent très avantageux comme barrière imperméable pour barrages. Les résultats présentés peuvent être d'une grande utilité pour le dimensionnement de la barrière.Mots-clés : barrage, noyau interne, front en amont, béton bitumineux, imperméabilité, résistance à la fissuration, autoréparation.

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Section: Introductionmentioning

confidence: 99%

Watertightness, cracking resistance, and self-healing of asphalt concrete used as a water barrier in dams

et al. 2013

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“…To obtain the material parameters for asphalt concrete, a series of monotonic and cyclic triaxial tests were performed (Feizi-Khankandi et al, 2008).…”

Section: Experimental Work On Asphalt Concretementioning

confidence: 99%

“…Twenty-four cyclic triaxial tests were carried out in this research (Feizi-Khankandi et al, 2008). Specimens with rubber membranes were placed in the triaxial cell and then subjected to a conˆning pressure.…”

Section: Cyclic Triaxial Testsmentioning

confidence: 99%

Seismic Analysis of the Garmrood Embankment Dam with Asphaltic Concrete Core

Feizi-Khankandi

Ghalandarzadeh

Mirghasemi

et al. 2009

Soils and Foundations

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The seismic behaviour of asphaltic concrete core dam under earthquake loads has been studied. The study consists of three parts; element tests on asphalt concrete, numerical analysis and some model tests. In theˆrst part, a series of triaxial monotonic and cyclic tests were performed at the Norwegian Geotechnical Institute (NGI)'s laboratory to determine the geotechnical parameters of asphalt concrete. Then, numerical analyses were carried out for Garmrood dam in Iran with a height of 110 m. The diŠerent stages of construction and impounding were analyzed using a hyperbolic stress-strain model. The dynamic analysis was then performed using two diŠerent models; nonlinear elasto-plastic material model and an equivalent linear method followed by the Newmark approach to estimate the permanent displacements. Finally, some 1-g model shaking table tests were performed on a typical rockˆll dam to have a qualitative picture of the modes of seismic behaviour of an asphaltic concrete core rockˆll dam. Element tests result shows that the asphaltic concrete is resistant to earthquake excitations and the earthquake has to be very strong to cause any detrimental cracking or material degradation of the properties of a ductile asphaltic concrete. In addition, the obtained results from numerical analysis and model tests show the appropriate response of the dam during and after earthquake caused shaking.

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“…Results of numerical analysis show that the greater part of earthquake energy is in the frequency range of 1 to 5 Hz [16]. However, all the cyclic deviator stresses using triaxial tests, in earlier studies, were applied in uniform sinusoidal cycles at frequencies of up to 0.2 Hz [17].…”

Section: Introductionmentioning

confidence: 99%

Loading Frequency Effect on Dynamic Properties of Mixed Sandy Soils

Araei¹,

Ghodrati²

2017

Scientia Iranica

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Most of the previous studies focused on pure (clean) sands, silts and clays and less effort has been dedicated toward understanding the dynamic behaviors of natural sandy soils. The purpose of this paper is to evaluate the effect of loading frequency as one of the most important factors affects the dynamic properties especially stiffness and damping characteristics of natural sandy soils mixed with silt and gravel. For this purpose, 40 dynamic triaxial tests were carried out on the cylindrical samples prepared from three mixed sandy materials. Cyclic tests were performed using large triaxial apparatus under different confinement, waveforms and loading frequencies. Results showed that, shear modulus and damping ratio were dependent on confining pressure and loading frequency. Shear modulus and damping ratio increase as loading frequency increases. Moreover, the shear modulus increases as confining pressure increases but damping ratio decreases. However, the effect of triangle, sinusoidal and rectangle waveforms on the dynamic behavior was negligible. At the ranges of strains studied, the effects of number of cyclic loading and excess pore water pressure over max / G G and D were negligible. There are considerable differences between obtained results for the tested soils and literature results, even for the almost same loading frequency.

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Cyclic Triaxial Tests on Asphalt Concrete as a Water Barrier for Embankment Dams

Cited by 60 publications

References 2 publications

Watertightness, cracking resistance, and self-healing of asphalt concrete used as a water barrier in dams

Watertightness, cracking resistance, and self-healing of asphalt concrete used as a water barrier in dams

Seismic Analysis of the Garmrood Embankment Dam with Asphaltic Concrete Core

Loading Frequency Effect on Dynamic Properties of Mixed Sandy Soils

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