Review Reports - Interlayer Shear Response of Asphalt Bridge Deck Pavements Under Thermo-Mechanical Coupling and Moving Braking Loads

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In this manuscript, the authors developed a three-dimensional thermo-mechanical finite element framework to investigate the interlayer shear evolution of asphalt bridge deck pavements under temperature gradients, moving wheel loads, braking actions, slope conditions, axle-load levels, and pavement layer thickness variations. The topic is relevant to the durability and structural safety of bridge deck pavements and has practical engineering significance. The results may provide useful references for interlayer design and thickness optimization. However, the manuscript still requires improvement in terms of organization, writing, figure/table presentation, literature support, and the correspondence between conclusions and innovations. Therefore, I suggest that the manuscript be accepted after appropriate revisions. My comments are as follows.

1.The abstract should be further condensed and better organized.
The current abstract contains many modeling details, parameters, and numerical results. It is suggested that the authors reorganize it according to the logic of “background–method–main findings–engineering significance” and highlight the main innovation more clearly.

2.The connection between the literature review and research objectives should be strengthened.
Although many studies are cited, some references are not closely linked to the novelty of this work. The authors should better connect high-quality references with the key issues of this study, such as thermo-mechanical coupling, braking-induced shear stress, interlayer response, and thickness optimization.

3.The structure of the methodology section should be improved.
This section includes several technical aspects, such as thermal theory, boundary conditions, finite element modeling, interface treatment, material parameters, and loading parameters. Some long paragraphs should be divided, and the transition between the temperature-field model and the mechanical-response model should be clarified.

4.The model assumptions should be stated more concisely and linked to the scope of application.
The assumptions of homogeneous materials, continuous heat transfer, and fully bonded interfaces are acceptable for this numerical study. However, the authors should briefly explain how these assumptions affect the interpretation of the results and ensure that this limitation is reflected in the discussion and conclusions.

5.The presentation of results should better correspond to the research objectives.
The manuscript analyzes the effects of temperature, axle load, slope, braking coefficient, and layer thickness. Each results section should more clearly explain how the findings support the research objectives and claimed innovation.

6.The conclusions should be made more rigorous and should correspond more clearly to the innovation points of the study.
The current conclusions summarize the main numerical findings, but some statements are still relatively general. It is recommended that the authors reorganize the conclusions according to the main contributions of the paper, including temperature-field evolution, thermo-mechanical response under moving braking loads, effects of structural and traffic factors, and implications for thickness optimization. Each conclusion should be supported by specific results, and overgeneralization beyond the modeled conditions should be avoided.

7.The quality and relevance of the references should be further checked.
The authors should ensure that the key references are recent, high-quality, and directly related to the innovation of this study. Less relevant references may be reduced, while recent studies on bridge deck pavement interlayer behavior, moving-load modeling, braking-induced shear stress, and temperature-dependent asphalt response may be strengthened.

8.The readability and formatting of figures should be improved.
Some figures contain multiple curves or subfigures, which makes legends, axes, and annotations less clear. For example, the temperature-field model in Figure 2 should be presented with higher resolution, clearer labels, and consistent formatting. Units and captions should also be carefully checked.

The manuscript addresses an important engineering issue and provides meaningful numerical results. After improving the writing, structure, literature connection, conclusion rigor, and figure/table presentation, the manuscript would be suitable for publication.

Author Response

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

This study employs finite element analysis to investigate the interfacial stress between the asphalt overlay and concrete bridge deck, considering the combined effects of temperature and braking loads. The topic represents a relatively classical problem in pavement mechanics. However, the following issues require further revision and improvement:

The manuscript lists a relatively large number of affiliations. It should be clearly stated how each author and each institution contributed to this research work. The authors are advised to reconsider whether all these co-authors and affiliations are truly necessary, or whether some contributions could be appropriately acknowledged in the acknowledgments section.
This paper presents a typical case study. The authors should discuss the generalizability of the findings—whether the conclusions drawn from this specific case can be extended to other bridge deck pavement scenarios.
The introduction section is overly lengthy. It is recommended to condense it, focusing more sharply on the specific problem addressed in this study, clearly summarizing the limitations of existing research, and then leading to the research objectives.
Given that extensive research has already been published on the theoretical analysis and finite element modeling of this topic, the main contribution of this paper lies in its specific engineering case study background. Therefore, it is suggested to provide a more detailed introduction to the case, including relevant field data such as measured temperatures, stresses, and pavement distress conditions, to enhance the uniqueness and practical value of the paper.
Regarding Table 1, is it necessary to report temperature data to two decimal places? Furthermore, have the simulation results been validated against any field measurements?
How were the data in Table 3 obtained? Please clarify the source and method of data collection.
The most critical issue with this paper concerns whether the effects of the various factors discussed in the later sections are supported by actual field measurements, or at least partially validated by real data. If such validation is lacking, the conclusions may not be fully convincing, and the novelty of the work would be significantly compromised. If field data are available, the authors should place greater emphasis on comparative analysis between the simulations and measurements.

Author Response

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript develops a three-dimensional ABAQUS model to investigate the thermal and mechanical response of asphalt bridge deck pavement in Zhongshan, China. Field meteorological records are used to simulate transient pavement temperatures, after which moving vertical and braking loads are applied to examine the effects of axle load, road gradient, braking coefficient, and asphalt-layer thickness on interlayer stresses. The results suggest that braking produces the largest longitudinal shear concentration, while upper- and lower-layer thicknesses affect stress redistribution differently. The subject is relevant, and the numerical findings may support bridge pavement design. I consider that the manuscript requires minor revisions before publication, particularly regarding model reproducibility, validation, interpretation, and reference accuracy. Below are my specific comments.

The meteorological observations are used as boundary inputs, but they do not validate the finite element model. The authors should compare the predicted surface temperature and at least one internal temperature history with measurements from the monitored bridge. Quantitative indicators such as RMSE, maximum error, and peak-time difference would help establish whether the reported values of 58.95 °C and the four-hour thermal lag are reliable.
The thermal analysis cannot currently be reproduced because the initial temperature field, bottom thermal boundary condition, and simulation warm-up procedure are not reported. A single 24-hour cycle can produce results that depend strongly on the assumed initial temperature, especially within the concrete slab. The authors should state whether several daily cycles were simulated until a periodic temperature response was obtained. The stress-free reference temperature used to calculate thermal strain should also be specified.
Section 2.4 states that the temperature field at 14:00 represents the peak surface-temperature condition. However, the abstract, Section 3.1, and Conclusion 1 identify the surface peak at 13:00. Moreover, the bottom of the asphalt overlay reaches its maximum at 17:00. The authors should correct this inconsistency and demonstrate which temperature field actually produces the highest interlayer shear response, possibly by comparing the results at 13:00, 14:00, and 17:00.
The asphalt layers are represented using temperature-dependent linear elasticity at only 20, 35, and 50 °C, although the simulated surface temperature reaches 58.95 °C. The interpolation or extrapolation procedure above 50 °C must therefore be explained. The source or experimental determination of the elastic moduli should also be provided. Because asphalt response at high temperature is strongly dependent on loading rate, the limitations of neglecting viscoelasticity should be discussed, particularly for a moving load applied at 120 km/h.
Both interfaces are defined using tie constraints, which prohibit the slip and separation associated with the distress mechanisms discussed throughout the paper. The authors should clarify how S13 and S23 were extracted, including the layer side, integration point, and averaging method used at each interface. These stresses represent demand within a perfectly bonded system and should not be interpreted directly as interface resistance or failure. Any recommendations concerning slippage should either be supported by temperature-dependent bond-strength data or explicitly limited to intact interfaces.
The moving-load and slope implementations need more detail. Table 4 is cited, but no contact-pressure values are presented in the supplied manuscript. The distribution of each axle load between the two rectangular contact areas, the analysis step, time increment, mesh size, and load-passage duration should be reported. It is also unclear whether slope was represented by inclined geometry, self-weight, or an additional longitudinal force such as Psinθ. This point is important because the explanation in Section 4.2 attributes the response directly to gravity.
The term “shear evolution” is not fully supported by the presented results. Figures 6–10 mainly compare peak responses for different input values, without showing how shear stress changes as the wheel approaches, passes, and leaves a selected point. A longitudinal shear-stress history and several contour plots during load passage would substantiate the title. Otherwise, the manuscript should describe the analysis as a parametric evaluation of peak interlayer response.
The statement that braking is the “dominant factor” is based on percentage changes over very different parameter intervals: axle load increases from 100 to 200 kN, slope from 1% to 5%, and braking coefficient from 0 to 0.7. These percentages are not directly comparable. The authors should calculate normalized sensitivity coefficients or restrict the conclusion to “the parameter producing the largest change within the ranges examined.” Possible interactions between braking, slope, axle load, and temperature should also be acknowledged.
For the thickness analysis, the authors should confirm that the thermal field was recalculated for every geometry and then transferred to its corresponding mechanical model. A comparison at constant total asphalt thickness would help distinguish the effect of layer distribution from the effect of increasing the complete overlay depth. The descriptions “excessive thickening” and “reasonable range” are also unsupported because no performance threshold or optimum thickness is established. These expressions should be replaced by conclusions limited to the investigated ranges.
Several in-text citations do not correspond to the reference list. For example, Yang et al. are cited as [14], although [14] is Wang’s thesis; Jaskuła and Ryś are cited as [11], but appear as [13]; Jia et al. are cited as [20], but appear as [21]; and Chen et al. are cited as [19], but appear as [20].
The duplicate numbering of Figures 6 and 7 should be corrected.

Author Response

Author Response File: Author Response.docx

Reviewer 4 Report

Comments and Suggestions for Authors

The paper titled "Evolution of Interlayer Shear Stress in Asphalt Bridge Deck Pavement under Thermo-Mechanical Coupling and Moving Braking Loads" falls within the scope of the journal *Infrastructures*. The study establishes a 3D thermo-mechanical coupled finite element model to investigate the effects of axle load, pavement slope, braking coefficient, and pavement layer thickness on the interlayer response of asphalt bridge deck pavement.
The paper is well-structured, and the research findings offer valuable engineering insights. However, please address the following issues before publication:
1. Please verify and clarify the element types used for the thermal and mechanical analyses. Section 2.3.1 states that the temperature field model employs C3D8R elements; however, C3D8R elements are typically used for stress-displacement analysis, whereas heat transfer analysis generally utilizes elements specifically designed for thermal analysis (such as DC3D8). The authors should specify the actual element types used in both analyses.
2. The pavement surface temperature reaches its maximum (58.95 °C) at 13:00, yet the study selects the temperature field at 14:00 as the critical high-temperature scenario. Please justify the choice of 14:00 as the analysis time point.
3. Please explain the definition and extraction method for interlayer shear stress. The authors should clarify whether the S13 and S23 components are derived from elements above or below the "tied" interface and specify whether the reported values represent integration point values, nodal averages, or peak values within the region.
4. Please include a table summarizing the baseline conditions for the parametric analysis, including vehicle speed, axle load, slope, braking coefficient, thickness of each layer, season, and the selected time point for the temperature field.
5. Table 3 lists temperature-dependent material parameters only for 20 °C, 35 °C, and 50 °C, whereas the maximum pavement temperature reaches 58.95 °C. Please describe the interpolation or extrapolation methods used to determine the material parameters.
6. Regarding the conclusions concerning the beneficial effects of increasing the upper layer thickness and the adverse effects of excessive lower layer thickness, please ensure these conclusions are qualified by the specific thickness ranges and modeling conditions addressed in the study. Please avoid qualitative descriptions such as "excessive thickening" and use quantitative descriptions instead.
7. The introduction is not sufficient, some recent studies should be considered in the introduction like "Performance of rubber modified asphalt mixture with tire-derived aggregate subgrade"
8. Please verify figure numbering and cross-references, as Figures 6 and 7 appear repeatedly across different sections. Additionally, proofread the manuscript for issues such as run-on words, missing spaces, and inconsistent formatting. The title of Section 2 should be revised to more accurately reflect the content of the finite element modeling work.

Author Response

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

My comments have been addressed. The paper is now acceptable.

Author Response

We sincerely thank the reviewer for the positive evaluation and for confirming that the previous comments have been satisfactorily addressed. We greatly appreciate the reviewer’s constructive suggestions, which have helped us improve the clarity, rigor, and overall quality of the manuscript.

Reviewer 2 Report

Comments and Suggestions for Authors

The references cited in the paper are relatively outdated. It is recommended that the authors update and improve the literature review.

Author Response

Thank you for this valuable comment. We carefully re-examined the Introduction and the complete reference list and made a targeted update to improve the timeliness and relevance of the literature review. Five recent studies published between 2024 and 2026 were added, covering temperature–load coupled dynamic response of asphalt pavements on concrete bridge decks, realistic thermal-field and thermo-mechanical modeling, multiscale finite element analysis, layer-thickness effects, and waterproof adhesive performance on concrete bridge decks. Several earlier references that were only indirectly related to the present study or had been superseded by more recent research were removed or replaced. Earlier publications were retained only when they provide foundational theory, original calculation formulations, full-scale experimental evidence, or bridge-deck-specific findings that could not be adequately replaced by newer studies.

The corresponding discussion in the Introduction was also revised rather than simply supplemented with additional citations. In particular, recent advances in viscoelastic bridge deck pavement modeling, interlayer contact representation, realistic environmental loading, multiscale structural analysis, and thickness-dependent response were synthesized. The research gap was then refined to emphasize the aspects that remain insufficiently addressed: the sequential transfer of a transient temperature field into a moving-load model incorporating braking-induced longitudinal traction, and the consistent comparison of axle load, roadway slope, braking action, and upper- and lower-layer thicknesses under the same thermal, material, and interface conditions. Related citations in the methodology and discussion sections were also updated. All changes have been highlighted in the revised manuscript.

Reviewer 4 Report

Comments and Suggestions for Authors

The author has been revised based on my comments.

Author Response

We sincerely thank the reviewer for confirming that the manuscript has been revised in accordance with the comments. We greatly appreciate the reviewer’s constructive suggestions, which have helped improve the quality and clarity of the manuscript.