Multi-crack propagation in asphalt mixtures using pixel-based finite element method

Effect of wet-dry history on performances of dense asphalt mixture: Experimental investigation and predicting model

Focused on the fatigue performance of the asphalt mortar, this study proposed an assessment model for fatigue damage evolution based on the continuum mechanics. From the perspective of the material scale rather than the macrostructure, the proposed damage model was set by concentrating on the stress‐strain state of a tiny point which could characterize the material performance accurately. By the mechanical formula derivation and based on the four‐point bending fatigue tests, the damage evolution law was determined and then the proposed model was verified. Based on the finite element method (FEM), a commercial software named ABAQUS was utilized to develop the random mixtures consisting of coarse aggregates, mortar, and voids. Eventually, combined with the damage model and virtual simulation of bending tests, the factors influencing the fatigue resistance of the whole asphalt mixtures were analyzed further.

Study on affecting factors of interface crack for asphalt mixture based on microstructure

Asphalt-pavement rutting is one of the most commonly observed pavement distresses where crumb rubber could be used to decrease this distress. This research illustrates methods of improving the behavior of flexible pavements with a crumb-rubber modifier in asphalt mixtures and with geosynthetic reinforcement in pavements to protect against rutting. The scope of this research is to predict the rutting depth of pavements containing conventional asphalt with a geosynthetic layer using a 3D model an ABAQUS finite-element (FE) program, and compare that with the rutting depth of pavements containing rubberized asphalt. A dynamic creep test was performed on different specimens to obtain material parameters of low creep power. For each type, a model was developed and then the finite-element method was used to estimate the rut depth of a pavement structure by incorporating realistic material properties of a geosynthetic, asphalt mixture, and base, subbase, and subgrade layers. The results show that crumb rubber causes reduction in rut depth by 36 %. By conducting analytical finite-element modeling in ABAQUS, it found that using geosynthetic in the bottom of the first-, second-, third-, and fourth-quarter causes rut-depth reduction of 74 %, 68 %, 34 %, and 0.5 %, respectively. Therefore, using the geosynthetics on a pavement containing conventional asphalt mixtures is an effective way of decreasing the rut depth.

This study focused on the application of Rayleigh wave technology on a non-destructive determination of dynamic modulus of asphalt mixtures. A 3-D finite element numerical algorithm was developed to simulate Rayleigh wave propagation in a multi-layer half-space system. Numerical analysis verified the feasibility of Rayleigh wave technology to capture the mechanical property differences in shallow structures within asphalt pavements. Then, five asphalt mixtures were used in the experimental application of Rayleigh wave technology. A multichannel simulation with one receiver (MSOR) was adopted to generate Rayleigh waves in asphalt mixture samples. Changes in phase velocity-frequency energy spectra and wave velocity were used to evaluate effects of ambient air temperature and asphalt mixture type on wave propagation evolution in asphalt mixtures. Rayleigh wave technology was introduced to dynamic modulus analysis using various experimental temperatures and asphalt mixtures. Obtained modulus was compared with that using impact resonance method to evaluate the prediction precision for analysis dynamic modulus of asphalt mixtures.

Effects of different dosages of iron ore tailings on the fatigue performance of high-strength modified AC asphalt mixtures

The asphalt mixture can be reinforced by basalt fiber to improve its pavement performance. Firstly, the Marshall test was conducted on AC-13C asphalt mixture with 0.3% dosage of basalt fiber to determine the optimum asphalt-aggregate ratio. Comparisons between asphalt mixtures with and without basalt fiber were performed by means of immersion Marshall test, wheel tracking test and indirect tensile test. The results show that 0.3% dosage of basalt fiber can enhance asphalt mixture’s water stability, high temperature stability and low temperature cracking resistance. Secondly, based on asphalt mixture’s viscoelastic property, the deflection- time curves of basalt reinforced asphalt mixture were obtained through bending creep test. The general Maxwell model was utilized to fit viscoelastic parameters of asphalt mixture, then the wheel tracking test was simulated through finite element model to compare with laboratory test, and the results show that the simulation is very effective and the general Maxwell model can express asphalt mixture’s viscoelasticity satisfactorily.

Mechanism of fracture in a viscoelastic heterogeneous composite with thermo-rheological properties such as, asphalt mixture is quite involved and cannot be correctly simulated with simpler linear elastic fracture mechanics constitutive laws. Over the last decade and half, a number of researchers have adopted use of cohesive zone (CZ) fracture models for simulation of fracture in asphalt mixtures. CZ interface elements are utilised in finite element (FE) models for representation of crack path, these elements follow traction–displacement relationships that allow for gradually degrading traction capabilities along the crack path with increasing level of crack opening. This paper presents a review of CZ modelling approach for simulation of asphalt pavement and overlay cracking performances. Suitability of CZ modelling approach for capturing discrete fracture in asphalt mixtures at low temperatures is presented through simulation of lab scale test. An example is also presented to demonstrate applicability of CZ-based modelling effort in capturing the crack initiation and propagation in asphalt mixtures at low temperatures. Thereafter, an FE-based pavement simulation approach is discussed that can be utilised in design of asphalt overlays to lower the propensity of reflective cracking. A case study of designing asphalt overlay systems for four real-life pavements in Minnesota is presented to demonstrate the applicability of the CZ-based modelling approach in conducting mechanistic design of asphalt overlays.

Development of finite element model based on indirect tensile test for various asphalt mixtures

Modified two-phase micromechanical model and generalized self-consistent model for predicting dynamic modulus of asphalt concrete

The properties of a piezoelectric generator-embedded asphalt mixture are investigated by means of parameters including size, effectiveness, and production of energy. The optimum size and the composition of the piezoelectric materials are first studied using a finite element method, scanning electron microscopy, transmission electron microscopy, energy dispersive spectrometer, and mechanical testing. The piezoelectric elements were embedded in the asphalt mixture with different mix proportions. The compatibility and piezoelectric properties of such a piezoelectric generator-embedded mixture are investigated and discussed. The results show that PMnS–PZN–PZT ceramic rings doped with 0.45 wt. % Fe2O3 (OD = 18 mm, ID = 10 mm, 4 mm by 8 pieces) are better suited than others. The AC-10 asphalt mixture containing piezoelectric generator maintain both good pavement properties and remarkable micropower electrical energy.

The method of testing asphalt mixtures, including initial cracks appearing in pavements, is presented in this paper. The main aim of the study was a determination of the durability of asphalt mixtures, in regard to crack sizes. For this purpose, the four-point bending test was performed according to the technical standard PN-EN 12697-24. The test was conducted with selected asphalt mixtures under the controlled strain, and with the application of different crack sizes. Specimens with cracks were analyzed. Moreover, a model based on finite-element method (FEM) calculations was worked out, which allowed for the verification of conditions of the asphalt mixtures’ response to strains and the assessment of the state of stresses and strains at the crack tip. The wide range of studied conditions helped to determine the fatigue criterion for the “cracked” beam in the fatigue tests. The presented fatigue condition is very useful in the estimation of fatigue durability of asphalt mixtures. The results of analyses clearly showed the influence of cracks on the decrease in stiffness modulus. This effect has a nonlinear behaviour in the case of larger cracks. The proposed FEM model of beam, including cracks, is very useful in studies of stresses and tensile strains concentrated at the crack tip.

Two asphalt cements (PG76-22 and PMB PG76-22) and two aggregate gradations used in the construction of surface and base courses were selected to study their effect on the mixtures’ rutting behavior. A dynamic modulus and wheel tracking tests were performed to determine the rutting potential of asphalt mixtures at different temperature levels. The study revealed that modified asphalt cement (PMB PG76-22) with coarse aggregate gradation (base course) may offer more resistance to rutting than unmodified asphalt with coarse and/or fine aggregate gradation. ABAQUS version 6.14 software was used to estimate the rutting of modified and unmodified asphalt mixtures under various values of CBR for subgrade, complex modulus of asphalt mixtures, temperatures and repeated tire pressures. The goodness between rut depth obtained from wheel track and ABAQUS software were observed. The rut depth model has been developed by analyses of 336 ABAQUS software runs by using SPSS STATISTICS version 23 software.

The incorporation of basalt fiber into asphalt mixtures offers potential improvements in their viscoelastic properties. This study explores the addition of basalt fiber to Styrene Butadiene Styrene (SBS)-modified asphalt mixtures with varying SBS contents. Specifically, 0.3% basalt fiber was added to an asphalt mixture containing 3% SBS, and its performance, measured in terms of dynamic stability and flexural strength, was compared with a mixture with 7% SBS content. Additionally, finite element analysis using the Modified Burger’s Logit model was conducted to assess rutting and fatigue behavior. Given the high cost associated with increasing the SBS content, basalt fiber presents a cost-effective alternative without sacrificing performance. Laboratory tests, including the Marshall stability test, dynamic stability, flexural strength, and fatigue tests, were conducted to evaluate both mixtures. Results indicate that the mixture with 0.3% basalt fiber and 3% SBS outperforms the 7% SBS mixture, showing a 47% improvement in dynamic stability and rutting resistance and a 16% increase in flexural strength.

Accurate prediction of fracture energy (Gf) in asphalt mixtures is important for durable asphalt pavements designing. Traditional experimental approaches are reliable but need resources, whereas numerical simulations, such as finite element models (FEM), offer flexibility but needs accurate input parameters and calibration. Recent advances in machine learning offer rapid prediction capabilities; however, interpretability and physical relevance remain challenging in this regard. This study presents a hybrid framework that integrates experimental Single Edge Notch Beam (SENB) tests, finite element simulations, and machine learning models to predict fracture parameters for asphalt mixtures. Experimental testing quantified fracture energy, while FEM simulations replicated the fracture response numerically. Machine learning models, including Linear Regression, Gradient Boosting, and AdaBoost, were trained on mixture properties such as stability, flow, air voids, and Stiffness Modulus at 20 °C (ITSM20) to predict surrogate fracture energy. A novel, dimensionally consistent surrogate equation was proposed to link key mixture properties to fracture energy, validated against both experimental and numerical results. The surrogate model demonstrated best accuracy with a mean relative error compared to experimental data. This novel integrated approach, adopted in this study, provides a practical and physics-guided methodology for rapid and reliable prediction of fracture behavior in asphalt mixtures, bridging experimental observations, numerical simulations, and data-driven machine learning modeling, and offering insights for mixture optimization and pavement design.