This study presents a mechanics-based framework for evaluating the performance of asphalt pavements subjected to annual ground surface deformations induced by frost heave and thaw settlement. Within this framework, a novel thaw settlement model is developed and coupled with a thermomechanical frost heave model to represent the heaving and subsequent thawing behavior of the soil beneath pavements. In the proposed thaw settlement model, excess water generated during the melting of ice lenses is introduced as a damage parameter within a continuum mechanics formulation, resulting in a reduction of material stiffness. The frost heave–thaw settlement model is further coupled with a thermodynamics-based asphalt damage model to capture the progressive degradation of asphalt layers. The capabilities of the proposed framework are demonstrated through two study scenarios: (i) uniform frost heave and thaw settlement occurring across the entire subgrade layer. (ii) non-uniform frost heave and thaw settlement localized within a specific region of the subgrade. The results show that the proposed framework not only captures damage in the asphalt layer but also predicts temperature distributions, ice formation, and water content during freeze–thaw cycles. Furthermore, the analysis reveals that uniform heaving and settlement cause relatively minor asphalt damage but lead to surface unevenness, whereas non-uniform frost heave and settlement result in both surface irregularities and severe damage to the asphalt layer.

Transverse joints are introduced in jointed plain concrete pavement systems to mitigate the risk of cracks that can develop due to shrinkage and temperature variations. However, the structural behaviour of jointed plain concrete pavement (JPCP) is significantly affected by the transverse joint, as it creates a discontinuity between adjacent slabs. The performance of JPCP at the transverse joints is enhanced by providing steel dowel bars in the traffic direction. The dowel bar provides reliable transfer of traffic loads from the loaded side of the joint to the unloaded side, known as load transfer efficiency (LTE) or joint efficiency (JE). Furthermore, dowel bars contribute to the slab’s alignment in the JPCP. Joints are the critical component of concrete pavements that can lead to various distresses, necessitating rehabilitation. The Swedish Transport Administration (Trafikverket) is concerned with the repair of concrete pavement. Precast concrete slabs are efficient for repairing concrete pavement, but their performance relies on well-functioning dowel bars. In this study, a three-dimensional finite element model (3D-FEM) was developed using the ABAQUS software to evaluate the structural response of JPCP and analyse the flexural stress concentration in the concrete slab by considering the dowel bar at three different locations (i.e., at the concrete slabs’ top, bottom, and mid-height). Furthermore, the structural response of JPCP was also investigated for several important parameters, such as the joint opening between adjacent slabs, mispositioning of dowel bars (horizontal, vertical, and longitudinal translations), size (diameter) of the dowel bar, and bond between the slab and the dowel bar. The study found that the maximum LTE occurred when the dowel bar was positioned at the mid-depth of the concrete slab. An increase in the dowel bar diameter yielded a 3% increase in LTE. Conversely, the increase in the joint opening between slabs led to a 2.1% decrease in LTE. Additionally, the mispositioning of dowel bars in the horizontal and longitudinal directions showed a 2.1% difference in the LTE. However, a 0.5% reduction in the LTE was observed for a vertical translation. Moreover, an approximately 0.5% increase in LTE was observed when there was improved bonding between the concrete slab and dowel bar. These findings can be valuable in designing and evaluating dowel-jointed plain concrete pavements.

Asphalt materials deteriorate when used in pavements due to their continuous exposure to traffic loads and other degrading mechanisms. This paper presents an experimental investigation to capture the initiation and evolution of damage in asphalt mixtures under compressive loads, in which the material degradation is attributed to the viscoelastic energy. In order to study the influence of temperature on degradation of asphalt materials, the test is conducted at four distinct temperatures: 10C, 0C, 20C, and 40C. The obtained experimental data reveal that, at lower temperatures, the viscoelastic energy threshold required to initiate damage in the asphalt specimens considerably increases. Furthermore, the results highlight the significant impact of temperature on damage evolution in asphalt materials. This study also identifies a critical damage threshold, beyond which the rate of damage evolution experiences a substantial increase. Notably, the critical damage threshold is lower at colder temperatures.

Roads are exposed to various degradation mechanisms during their lifetime. The pavement deterioration caused by the surrounding environment is particularly severe in winter when the humidity and subfreezing temperatures prevail. Frost heave-induced damage is one of the winter-related pavement deterioration. It occurs when the porewater in the soil is exposed to freezing temperatures. The study of frost heave requires conducting a multiphysics analysis, considering the thermal, mechanical, and hydraulic fields. This paper presents the use of a coupled thermo-mechanical approach to simulate frost heave in saturated soils. A function predicting porosity evolution is implemented to couple the thermal and mechanical field analyses. This function indirectly considers the effect of the water seepage inside the soil. Different frost heave scenarios with uniform and non-uniform boundary conditions are considered to demonstrate the capabilities of the method. The results of the simulations indicate that the thermo-mechanical model captures various processes involved in the frost heave phenomenon, such as water fusion, porosity variation, cryogenic suction force generation, and soil expansion. The characteristics and consequences of each process are determined and discussed separately. Furthermore, the results show that non-uniform thermal boundaries and presence of a culvert inside the soil result in uneven ground surface deformations.

To cope with the global climate crisis and assist in achieving the carbon neutrality, the use of biomass materials to fully or partially replace petroleum-based products and unrenewable resources is expected to become a widespread solution. Based on the analysis of the existing literature, this paper firstly classified biomass materials with potential application prospects in pavement engineering according to their application and summarized their respective preparation methods and characteristics. The pavement performance of asphalt mixtures with biomass materials was analyzed and summarized, and the economic and environmental benefits of bio-asphalt binder were evaluated. The analysis shows that pavement biomass materials with potential for practical appli-cation can be divided into three categories: bio-oil, bio-fiber, and bio-filler. Adding bio-oil to modify or extend the virgin asphalt binder can mostly improve the low temperature performance of asphalt binder. Adding styrene-butadienestyrene (SBS) or other preferable bio-components for composite modification will have a further improved effect. Most of the asphalt mixtures prepared by using bio-oil modified asphalt binders have improved the low temperature crack resistance and fatigue resistance of asphalt mixtures, but the high tem-perature stability and moisture resistance may decrease. As a rejuvenator, most bio-oils can restore the high and low temperature performance of aged asphalt and recycled asphalt mixture, and improve fatigue resistance. Adding bio-fiber could significantly improve the high temperature stability, low temperature crack resistance and moisture resistance of asphalt mixtures. Biochar as a bio-filler can slow down the asphalt aging process and some other bio-fillers can improve the high temperature stability and fatigue resistance of asphalt binders. Through calculation, it is found that the cost performance of bio-asphalt has the ability to surpass conventional asphalt and has economic benefits. The use of biomass materials for pavements not only reduces pollutants, but also reduces the dependence on petroleum-based products. It has significant environmental benefits and development potential.

To reveal the pore clogging law of porous asphalt mixture, the combination study of model experiment and simulation of porous asphalt mixture clogging was conducted. The pore characteristics of the porous asphalt mixture were analyzed based on the CT-scanning and discrete element software PFC3D V5. 0, and the pore data of the porous asphalt mixture were obtained. The aggregates of different particle sizes were put into PFC3D V5. 0, and the compacted virtual specimens were generated according to the pore characteristics. The accuracy of the model was verified by comparing the pore images of actual specimens with the MATLAB slices. In the self-weight condition, the simulation was set with the porous asphalt mixture specimen being intruded by clogging particles with specific gradation composition. The data of indoor experiments were compared and verified. The particle sizes of clogging particles were changed, and the pore decay rates of the specimen were analyzed. The clogging-sensitive particles were identified. In the self-weight condition, the fluid simulation experiment was introduced, and the change law of specimen clogging was analyzed by changing the seepage rate of fluid. Analysis results show that the virtual specimen generated by PFC3D V5. 0 has high accuracy, and the simulation reveals the clogging law of the specimen. The small particles not only accumulate at the throat position causing clogging, but also congregate and interlock with the particles of larger sizes resulting in clogging too. In the self-weight condition, the clogging is mainly concentrated at the upper 30 mm of the mixture specimen, and the size distribution of corresponding clogging-sensitive particles is 0. 150-0. 600 mm. The size distribution of clogging particles has a great impact on the clogging results. In the conditions of gravity and fluid, with the seepage rate increasing from 0. 005 m • s-1 to 0. 030 m • s-1, the changing rate of pore decay rate increases. In addition, the clogging particles remaining in the mixture decrease, accompanied by the reduction of the pore decay rate. Therefore, the local rainfall conditions should also be considered in the design and maintenance of drainage asphalt pavement. 2 tabs, 20 figs, 30 refs.

The longevity of asphalt pavements is a key focus of road engineering, which closely relates to the self-healing ability of bitumen. Our work aims to establish a CGMD model and matched force field for bitumen and break through the limitations of the research scale to further explore the microscopic mechanism of bitumen self-healing. In this study, a CGMD mapping scheme containing 16 kinds of beads is proposed, and the non-bond potential energy function and bond potential energy function are calculated based on all-atom simulation to construct and validate a coarse-grained model for bitumen. On this basis, a micro-crack model with a width of 36.6nm is simulated, and the variation laws of potential energy, density, diffusion coefficient, relative concentration and temperature in the process of bitumen self-healing are analyzed with the cracking rate parameter proposed to characterize the degree of bitumen crack healing. The results show that the computational size of the coarse-grained simulation is much larger than that of the all-atom, which can explain the self-healing mechanism at the molecular level. In the self-healing process, non-bonded interactions dominate the molecular movement, and differences in the decreased rate of diffusion among the components indicate that saturates and aromatics play a major role in self-healing. Meanwhile, the variations in crack rates reveal that healing time is inversely proportional to temperature. The impact of increasing temperature on reducing healing time is most obvious when the temperature approaches the glass transition temperature (300 K).

De-icing fluids are known to have a potential to negatively affect infrastructure materials such as asphalt. In order to evaluate the resistance of asphalt materials to de-icing fluids, the European standard method EN 12697-41 is commonly used. There are however a number of issues related to the method, such as a high variability of the results and poor correlation between test results and behavior in the field, which may be caused by some of the parameters of the test. This paper aims to identify and investigate some parameters that are of importance to the relevancy of the test. To do this, experimental tests of asphalt mastic and mixture are performed with two concentrations of a deicer and water. Additionally, to gain a better understanding of what occurs in the tested samples during the conditioning and loading, finite element simulations using a microscale model with a mesh based on an X-ray CT scan of a real sample, are performed. The results show that both the geometry and the set-up of the conditioning and mechanical testing can cause misleading results. Based on this, recommendations are made for areas for future studies to improve the test method.

During continuous and repeated loading, bituminous materials undergo damage. These materials also exhibit healing when enough rest periods are given between loadings. In this study, a new method is proposed to quantify the healing of bituminous materials based on the recovery of viscoplastic deformation. The method considers the damage in the material as a part of the viscoplastic deformation. Later, the method is applied to the data from the creep and recovery test to capture healing on both bitumen and bituminous mastic. Experiments are conducted at three stress levels using a dynamic shear rheometer (DSR). The strains accumulated during the creep and recovery period are segregated into the viscoelastic and viscoplastic strains. It is hypothesized that the recovery of viscoplastic strain in the material when subjected to prolonged rest period can be used to relate to healing.

Based on the publications from two databases during 1998–2020, this paper presents a systematic literature review on pavement maintenance effectiveness evaluation to summarize the current trend and identify the research gap that must be addressed for a sustainable maintenance management. This review has analyzed and synthesized maintenance thresholds and their mechanisms, the measurement methods of effectiveness in terms of performance, cost and environmental impacts. In particular, this paper has critically examined the state-of-art maintenance effectiveness optimization strategy that has included environmental concerns and sustainable goals, in comparison with the traditional cost-effectiveness evaluation method. The study has revealed the ambiguous definition of pavement maintenance effectiveness and data availability have caused inconsistencies in the evaluation process; moreover, the embryonic pavement life cycle assessment studies and limited study on pavement use phase have set obstacles in the expanding system boundary of sustainable maintenance effectiveness evaluation.