Improving the Resilience of the Road Network in Algeria: A Comparative Analysis of Flexible, Geosynthetically Reinforced, and Rigid Pavements

Round 1

Reviewer 1 Report

Review Report

The authors presented an article titled “Improving the resilience of the road network in Algeria: a comparative analysis of flexible, geosynthetically reinforced and rigid pavements." The "Sustainability" journal covers this article. However, the article will be ready for publication after a major revision. Comments are listed below.

1.      A sentence about numerical results can be given in the abstract.

2.      What's the novelty of this article? How is it different from similar studies in the literature? It should be explained.

3.      The references given in the introduction seem insufficient. It can be increased.

4.      The phrase "Methodologie" given on page 5, line 144 should be corrected.

5.      All tables and figures given in the article should be cited in the text.

6.      All equations given in the article should be numbered.

7.      The discussion in the Results section seems insufficient. Similar studies in the literature should be compared and discussed.

8.      The article contains numerous typographic and language errors. It should be corrected.

9.      The article should be rearranged by taking into account the journal writing rules and citation rules.

 

 

Author Response

Reviewer # 1

• C1 (Comment1):   A sentence about numerical results can be given in the abstract.

R1 (Response 1): Done

• C2 (Comment2):   What's the novelty of this article? How is it different from similar studies in the literature? It should be explained.

R2 (Response 2): “What distinguishes our work is that it explores the idea of approximating the performance of a rigid pavement (more expensive) with a judiciously reinforced flexible pavement (more cost-effective).” : text inserted at end of introduction section. As far as we know, there is no mention of such an approach anywhere, the derivation of such a result using the polynomial curve fitting relationship of data points obtained from finite element analysis (FEM) calculations is nowhere mentioned.

• C3 :   The references given in the introduction seem insufficient. It can be increased.

R3 : Done “The reference section is expanded citing recent articles”

• C4 :   The phrase "Methodologie" given on page 5, line 144 should be corrected.

R4: Done

• C5 :   All tables and figures given in the article should be cited in the text.

R5 : Done

• C6 :   All equations given in the article should be numbered.

R6 : Done

• C7:  The discussion in the Results section seems insufficient. Similar studies in the literature should be compared and discussed.

R7 : Done

• C8 :   The article contains numerous typographic and language errors. It should be corrected.

R8 : Done

• C9 :   The article should be rearranged by taking into account the journal writing rules and citation rules.

R9 : Done

 

Author Response File: Author Response.pdf

Reviewer 2 Report

This manuscript provides a finite element analysis to study the effects of different rigidities of pavement structures on their performance during the service. The technical content is interesting and the results are presented in a clear way. However, some aspects of the paper are less secure.

Overall editorial: the English writing of this article needs improvement.

Equations 1~4: the variables referenced in the equations should be explained what they refer to.

Lines 135~136 and throughout the manuscript: variables should be formatted the same as in the equation.

Figure 3: Thicknesses of each layer need to be provided for the design.

Figure 4: Images of the finite element models has low resolution and are hard to recognize.

Section 4 (Numerical modeling): What are the sizes of the elements used for the study? Has a mesh sensitivity analysis been conducted, i.e. does a finer mesh leads to different FE analysis results?

Section 4 (Numerical modeling): How are the boundary conditions defined in the study? And How are the materials of the pavement structure modeled (what material model and their properties have been used)?

Section 5 (Results and analysis): There seems no validation of the numerical models, for example, against experimental results.

The English writing of this article needs improvement.

Author Response

Reviewer #2

• C1 (Comment1):   Overall editorial: the English writing of this article needs improvement.

R1 (Response 1): Done

• C2 (Comment2):   Equations 1~4: the variables referenced in the equations should be explained what they refer to.

R2 (Response 2): Done

• C3 :   Lines 135~136 and throughout the manuscript: variables should be formatted the same as in the equation.

R3 : Done

• C4 :   Figure 3: Thicknesses of each layer need to be provided for the design.

R4 : Done

• C5 :   Figure 4: Images of the finite element models has low resolution and are hard to recognize.

R5 : Done

• C6 :   Section 4 (Numerical modeling): What are the sizes of the elements used for the study? Has a mesh sensitivity analysis been conducted, i.e. does a finer mesh leads to different FE analysis results?

R6 :

The existing 2D finite element models found in the literature served as a reference point, and we conducted sensitivity analyses on the mesh. Subsequently, we selected the dimensions for the full-scale FE model, which measured 4 meters in the transverse direction (x-axis) and 2.75 meters in depth (y-axis).

Prior research has highlighted the importance of mesh size consistency in influencing the predictions of the FE model. Therefore, to enhance the model's accuracy, we opted for a relatively fine mesh size beneath the loading area and the superstructure of the pavement, where stresses and displacement are high. In contrast, a relatively coarse mesh size was employed for regions far from the loading area.

To improve convergence rate and computational efficiency, we utilized a CPE4R mesh model for mechanical analysis, characterized by a 4-node bilinear plane strain quadrilateral with reduced integration and hourglass control.

• C7 :   Section 5 (Results and analysis): There seems no validation of the numerical models, for example, against experimental results.

R7 : To validate our finite element model for reinforced flexible pavements, we also performed calculations using the layered elastic theory (LET), which has been successfully used in the structural analysis of flexible pavements for over 60 years. To ensure that our finite element calculation is viable, we have checked that it gives the same results using Burmister's multilayer elastic theory.

• C8:   Comments on the Quality of English Language, The English writing of this article needs improvement.

R8 : Done

 

 

 

 

 

 

Author Response File: Author Response.pdf

Reviewer 3 Report

1. The authors have modified the Abstract & Introduction by adding more details.

2. Design of pavement structures with and without geogrid, Explain the difference in practical example. 

3. Ground layer mechanical properties, show why these properties have been chosen. 

4. Numerical Model: Figures are not clear, so modify them. 

5. Numerical Model: Did you try using Abaqus? 

6. Stress Analysis: Explain the different colors in stress analysis of FEM 

7. Try To use a neural network to find the regression 

 

 

Author Response

Reviewer #3

• C1 (Comment1):    The authors have modified the Abstract & Introduction by adding more details.

R1 (Response 1): Done

• C2 (Comment2):    Design of pavement structures with and without geogrid, Explain the difference in practical example. 

R2 (Response 2):

• C3 :   Ground layer mechanical properties, show why these properties have been chosen. 

R3 : For this study, we selected a clayey soil with a low deformation modulus and moderate cohesion to effectively illustrate the deformations occurring within the pavement. If a more resistant soil had been chosen, it would have dampened the loads and reduced the strain on the pavement.

• C4 :   Numerical Model: Figures are not clear, so modify them. 

R4 : Done

• C5 :   Numerical Model: Did you try using Abaqus? 

R5 : This study is carried out with the Abaqus software version 2022, as mentioned in the manuscript.

• C6 :   Stress Analysis: Explain the different colors in stress analysis of FEM 

R6 : Done “Text mentioned in Figure 10.”

• C7:  Try To use a neural network to find the regression 

R7 : We have not used a neural network to find the regression because it is unnecessary in this case. Furthermore, the use of neural networks requires the availability of large databases to carry out the training, which in turn can be computationally intensive and may require specialized hardware such as GPUs or TPUs.  We have limited resources and it's a bit challenging for us at the moment.

 

Author Response File: Author Response.pdf

Reviewer 4 Report

Minor revision will be required. 

Comments for author File: Comments.pdf

Author Response

Reviewer # 4

• C1 (Comment1):   Abstract section is not clear. In fact, the whole abstract should be re-written again by mentioning aims and objectives of the study.

R1 (Response 1): Done

• C2 (Comment2):    The organization of the paper is missing. Define all acronyms for understating of the readers. List all in a tabular for after introduction section.

R2 (Response 2): Done

• C3 :  

 Kindly check equation (5). Does it converge? Please see the article “Second kind integral equations for the first kind Dirichlet problem of the biharmonic equation in three dimensions.”

R3 :

Thank you for raising this issue. Indeed, this is an improper integral that cannot be integrated analytically. This can only be done by slow convergence numerical integration near the surface of the top layer (z ~ 0). This is because the integrand in the Equation becomes strongly oscillatory near the surface. Since shallow-depth responses are essential, good accuracy and convergence near the surface are necessary. We therefore applied spline interpolation in an independent module to the point-load equations derived by Boussinesq (Timoshenko & Goodier, 1951) to calculate the structural responses of the equivalent two-layer structure to improve the near-surface responses with the half-space transformation proposed by Khazanovich (Khazanovich & Wang 2007). Programs such as UNLEA use this method.

• C4 :   What is the objective and motivation behind the study? Please mention it.

R4 : The aim was to achieve, through the study of the reinforcement effect of flexible pavements with geogrids, a behavior in flexible pavement similar to that of rigid pavement. This has been well mentioned in the abstract, conclusion, and a few places in the manuscript.

• C5 :   Figure 9 is not clear for readers, please modify it. Same for figure 11.

R5 : Tache effectuée Figure 9 est divisé en 2 figures 9 et 10 avec une qualité supérieure.

• C6 :   Reference section is too small. Cite recent articles and provide a separate section “Related Work”

R6 : Done

• C7 :   Validate your proposed method with existing literatures.

R7 : The reference section is expanded citing recent articles

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors completed the necessary revisions. This article may be published in its final version.

Reviewer 2 Report

The authors have addressed my comments in the revised manuscript.