| 1. |
- Chen, Feng, 1987-, et al.
(author)
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Vibration-induced aggregate segregation in asphalt mixtures
- 2020
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In: Materials and Structures. - : SPRINGER. - 1359-5997 .- 1871-6873. ; 53:2
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Journal article (peer-reviewed)abstract
- Aggregate segregation in asphalt mixture is a bothersome engineering issue during pavement construction. The practitioners have some measures to mitigate the segregation potential based on experiences which, however, can only reduce the risk to a certain extent. In this research, the authors aim to contribute to the discussion in a rational non-empirical way, by using novel experimental and numerical techniques. A case study is carried out to investigate the vibration-induced segregation in asphalt mixtures, corresponding to the circumstance arising during material transportation to the construction site. A novel experimental test is conducted for evaluating the segregation characteristics of asphalt mixtures under vertical vibration in laboratory conditions. A numerical investigation based on discrete element method is further performed to study the phenomenon from a micromechanical point of view. The obtained experimental and numerical results indicate that vibratory loading induces aggregate size segregation in asphalt mixtures, and the degree of segregation is influenced profoundly by the adhesive properties of bituminous binders and the aggregate gradation.
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| 2. |
- Fadil, Hassan, et al.
(author)
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A New Viscoelastic Micromechanical Model for Bitumen-Filler Mastic
- 2020
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In: Construction and Building Materials. - : Elsevier BV. - 0950-0618 .- 1879-0526. ; 253
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Journal article (peer-reviewed)abstract
- A new micromechanical model for predicting viscoelastic properties of mastic is proposed and validated with experiments. The developed model is based on the finite element method and allows predicting the viscoelastic properties of mastic by means of the fundamental mechanical and geometrical properties of its constituents. The influence of modelling parameters on the model’s accuracy is evaluated and optimal parameter combinations are identified. It is shown that the proposed model can capture the measured viscoelastic behaviour of mastics for the range of loading, temperature and material parameters examined. Accordingly, it may be a useful tool for optimizing mastics material design meeting the target viscoelastic properties.
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| 3. |
- Jelagin, Denis, et al.
(author)
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Experimental and numerical modelling of shear bonding between asphalt layers
- 2023
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In: International Journal on Road Materials and Pavement Design. - : Taylor & Francis. - 1468-0629 .- 2164-7402. ; 24:S1, s. 176-191
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Journal article (peer-reviewed)abstract
- Interlayers in asphalt pavements are potential structural damage initiators. In order to better understand the quantitative role of interlayer parameters, such as surface roughness, binder type, binder content and loading type on interlayer shear strength, this paper focuses on the effects of particle interlock and contact conditions on interlayer strength through experimental and numerical modelling. Experimentally, interlayer shear box strength tests on a model material consisting of stiff binder blended with steel balls are performed with and without normal force confinement. A Discrete Element method model of the test is developed using measurements of the model material for calibrating the contact law and for validating the model. It is shown that this model captures adequately the measured force-displacement response of the specimens. It is thus a feasible starting point for numerically and experimentally studying the role of binder and tack coat regarding interlayer shear strength of real asphalt layers.
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| 4. |
- Jiang, Shunji, et al.
(author)
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Modelling structural response of flexible plug expansion joints under thermal movements
- 2020
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In: International Journal on Road Materials and Pavement Design. - : TAYLOR & FRANCIS LTD. - 1468-0629 .- 2164-7402. ; 21:4, s. 1027-1044
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Journal article (peer-reviewed)abstract
- This paper focuses on experiments and finite element modelling of flexible plug expansion joints (Asphaltic Plug Joints, APJ) subject to thermally induced horizontal movements. Five geometric and structural key parameters that influence (APJs) responses under thermal movements are studied: (1) joint length; (2) joint thickness; (3) joint width; (4) anti-bonding mat; (5) movement-aid spring. The viscoelastic computational finite element models are based on properties determined with a special cyclic coaxial shear test (CAST) and validated by an integrated approach incorporating cold temperature repeated movement capacity tests with a special Joint Movement Simulator (JMS) and a 3-Dimensional Digital Image Correlation system (3D DIC). It was found that the increase of joint width significantly reduces the stress at the interface between the mastic asphalt and APJ. The results also showed, that thin joints generate lower stress levels in APJ under thermal condition. Moreover, peak stresses in APJ appeared controlled mainly by the total size of the debonded region and the horizontal movement applied. The main findings are considered valuable for superior structural design, geometry selection and construction guidelines for APJ.
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| 5. |
- Ling, Senlin, et al.
(author)
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Predicting the mechanical properties of semi-flexible pavement material with micromechanical modeling
- 2024
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In: Materials & design. - : Elsevier BV. - 0264-1275 .- 1873-4197. ; 239
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Journal article (peer-reviewed)abstract
- Semi-flexible pavement (SFP) material is a composite comprising cement, coarse aggregates and asphalt mortar, which has complex mechanical properties. Traditional experimental methods struggle to accurately quantify the effect of each phase and their interfaces on the SFP's mechanical properties. Micromechanical modelling based on finite element method offers a promising solution. In this study, a new micromechanical model for SFP is proposed, idealizing the material by representative volume elements. SFP mesostructure is represented as a simplified five element composite consisting of cement, asphalt mortar, aggregate, pore and cement-asphalt mortar interface. Periodic boundary conditions are used to simulate an infinite repetitive structure within a finite computational domain. The resulting model allows evaluating the stiffness and damage resistance of SFP in a computationally efficient manner. This model is utilized to explore the mechanical properties of SFPs and the results are compared with the experimental findings. The results show that the model captures the uniaxial compressive strength and stiffness for all materials examined. The model is further used to evaluate the effect of properties of individual elements of SFP on its stiffness and strength. The feasibility of using the proposed modelling approach to optimize the material design of SFP is discussed.
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