Modified Additive for Soil Stabilization by Deep Cementation

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The introduction does not adequately address the most recent advancements in soil stabilization methods. Please consider adding a discussion on approaches such as deep cementation.

The research gap requires clearer articulation to highlight the novelty of the study.

The selection of additive concentrations (0, 0.2, 0.4, 0.6, 0.8, and 1) should be justified.

Since all slump values are below 147 mm, please clarify whether the material remains practical for soil stabilization applications.

Statistical significance and variability should be analyzed and discussed to strengthen the reliability of the findings.

• Do you consider the topic original or relevant to the field? Does it
address a specific gap in the field? Please also explain why this is/ is not
the case.

The central inquiry of this research explores whether incorporating a paraffin-based additive can enhance the performance of cement-sand injection mixtures used in deep soil stabilization—specifically by improving flowability, minimizing water segregation, and sustaining or slightly boosting compressive strength.

• What does it add to the subject area compared with other published
material?

Although deep cementation techniques are well-established, the application of paraffin as a modifying agent remains relatively unexplored. This approach directly targets the persistent challenges of low mobility and inconsistent performance in conventional mixtures

• What specific improvements should the authors consider regarding the
methodology?

The methodology could benefit from greater rigor, specifically, clearer rationale for the selected additive concentrations, the inclusion of statistical tools such as ANOVA to substantiate observed trends, and evaluations of long-term durability under environmental stressors. Expanding the scope to include field-scale or pilot applications.

• Are the conclusions consistent with the evidence and arguments presented
and do they address the main question posed? Please also explain why this
is/is not the case.

The conclusions align reasonably well with the experimental findings, confirming that the additive improves mobility and reduces water separation while maintaining structural integrity. Nonetheless, the reported strength gains are modest and should be interpreted with caution.
• Are the references appropriate?

Checked some are ok

• Any additional comments on the tables and figures.

would further strengthen the study’s relevance.

Regarding presentation, the visual data are informative but could be optimized: Table 1 would be clearer if additive quantities were expressed as percentages relative to cement mass.

Author Response

Comments 1: 

The introduction does not adequately address the most recent advancements in soil stabilization methods. Please consider adding a discussion on approaches such as deep cementation.

The research gap requires clearer articulation to highlight the novelty of the study.

The selection of additive concentrations (0, 0.2, 0.4, 0.6, 0.8, and 1) should be justified.

Since all slump values are below 147 mm, please clarify whether the material remains practical for soil stabilization applications.

Statistical significance and variability should be analyzed and discussed to strengthen the reliability of the findings.

Response: 

In the revised manuscript, we expanded the Introduction (pp. 2–3) to include a more detailed discussion of recent advancements in soil stabilization methods, with particular emphasis on the deep cementation technique. We have incorporated recent references (Gupta & Kumar, 2023; Petchgate et al., 2025) to demonstrate current developments in deep mixing and cementation, highlighting their relevance to soil reinforcement in Kazakhstan.

 The research gap has been clarified in the Introduction (p. 4). Specifically, we emphasized that while numerous studies have explored polymeric and nano-modified additives, there is a lack of investigations into paraffin-based modifiers for cement-sand injection solutions under the geological conditions of Central Kazakhstan. We have explicitly highlighted how our study addresses this gap and contributes original findings to the field.

In the Methods section (p. 6), we added an explanation for the chosen additive concentrations. The stepwise increments of 0.2% were selected to allow sufficient resolution in identifying threshold effects of the additive on mobility, water separation, and strength. The upper limit of 1% was determined based on preliminary laboratory tests showing that higher concentrations led to mixture instability. This range ensured both practicality and scientific validity in capturing the trend of the additive’s influence.

In the Results and Discussion sections (pp. 17–18), we clarified that although the maximum measured slump value is 147 mm for the control mixture, the introduction of the additive increased slump flow by up to 23% (area increase by 62%). This significantly improves the injectability of the mixture. While slump values did not exceed 150 mm, the observed mobility was sufficient to achieve penetration into soil pores during pilot trials, confirming the practical applicability of the material for soil stabilization. This clarification has now been added to the manuscript.

In the Results and Discussion sections (pp. 14–20), we now present statistical analysis using coefficients of variation to assess data reliability. We included threshold values (e.g., 4.95% for compressive strength, 6.77% for flexural strength) and explained that only changes exceeding these values can be attributed to the additive’s effect. This strengthens the interpretation of our results by differentiating real effects from statistical error. The discussion explicitly addresses the variability of results and their statistical significance.

Comments 2: 

Do you consider the topic original or relevant to the field? Does it address a specific gap in the field? Please also explain why this is/ is not the case.

The central inquiry of this research explores whether incorporating a paraffin-based additive can enhance the performance of cement-sand injection mixtures used in deep soil stabilization—specifically by improving flowability, minimizing water segregation, and sustaining or slightly boosting compressive strength.

Response: 

In the Results and Discussion sections (pp. 14–20), we now present statistical analysis using coefficients of variation to assess data reliability. We included threshold values (e.g., 4.95% for compressive strength, 6.77% for flexural strength) and explained that only changes exceeding these values can be attributed to the additive’s effect. This strengthens the interpretation of our results by differentiating real effects from statistical error. The discussion explicitly addresses the variability of results and their statistical significance.

Comments 3: 

What specific improvements should the authors consider regarding the methodology?

The methodology could benefit from greater rigor, specifically, clearer rationale for the selected additive concentrations, the inclusion of statistical tools such as ANOVA to substantiate observed trends, and evaluations of long-term durability under environmental stressors. Expanding the scope to include field-scale or pilot applications.

Response: 

In the revised manuscript, we have clarified the rationale for the selection of additive concentrations (Methods, p. 6), emphasizing that the range of 0.2–1.0% was based on preliminary laboratory trials and was sufficient to capture threshold effects while avoiding mixture instability.

Regarding statistical analysis, we acknowledge the importance of robust validation of experimental results. In this version, we have introduced discussion of coefficients of variation to identify statistically significant changes beyond experimental error (Results and Discussion, pp. 14–20). While full ANOVA testing was beyond the scope of this initial laboratory-scale study, we recognize its value and plan to incorporate it in future work to further substantiate observed trends.

We also agree with the reviewer that long-term durability under environmental stressors and field-scale verification are essential for practical application. Although these aspects could not be included in the present work due to time and resource limitations, we have added a note in the Conclusion (p. 30) highlighting the need for future research on durability testing under freeze–thaw, wet–dry, and saline conditions, as well as pilot-scale field trials.

Comments 4: 

Are the conclusions consistent with the evidence and arguments presented and do they address the main question posed? Please also explain why this is/is not the case.

The conclusions align reasonably well with the experimental findings, confirming that the additive improves mobility and reduces water separation while maintaining structural integrity. Nonetheless, the reported strength gains are modest and should be interpreted with caution.

Response: 

We acknowledge that the observed increases in compressive and flexural strength were relatively modest. To clarify this, we revised the Conclusions section (pp. 28–30) to explicitly state that strength gains should be interpreted with caution, as the main value of the additive lies in improving mobility and reducing segregation rather than significantly enhancing mechanical strength. This clarification ensures that the conclusions remain balanced and directly reflect the evidence presented.

Comments 5: 

Are the references appropriate?

Checked some are ok

Response: 

All of the references to sources are valid and relevant

Comments 6: 

Any additional comments on the tables and figures. Would further strengthen the study’s relevance.

Regarding presentation, the visual data are informative but could be optimized: Table 1 would be clearer if additive quantities were expressed as percentages relative to cement mass.

Response: 

In the current version of the manuscript, Table 1 presents additive values in grams to ensure full reproducibility of the laboratory procedure. However, to improve clarity, we have added explicit explanations in the text (Methods section, p. 7) indicating that these quantities correspond to 0.2–1.0% by cement mass. This avoids potential confusion while retaining the original presentation of the experimental formulations.

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript “Modified additive for soil stabilization by deep cementation” presents relevant and practical research on improving cement–sand injection solutions using a paraffin-based additive. The experimental program is systematic, the data are clearly presented, and the topic is important for soil stabilization applications. The paper is suitable for publication after completing the following revisions:

1. While the use of paraffin as an additive is practical, the discussion could better situate this work within the context of recent advancements (e.g., polymer additives, nanomaterials, geopolymers). A clearer comparison with state-of-the-art additives would strengthen the manuscript.
2. The mechanisms of improvement are mentioned but only briefly explained. Expanding the discussion with references to relevant literature (e.g., studies on microstructural changes or chemical interactions) would make the conclusions more convincing.
3. The results are limited to laboratory conditions. A short statement in the discussion or conclusion acknowledging this limitation, and noting that field validation or long-term durability tests remain future work, would make the scope of the study clearer.
4. Some figures (e.g., Figures 5–7) contain many sub-parts. Adding clearer captions that highlight the main findings of each figure would improve readability.
5. When presenting statistical results (coefficients of variation, etc.), it would help to briefly explain their significance for the reader. This will strengthen the interpretation without requiring new analyses.
6. Minor English editing is needed for fluency and to reduce repetition (for example, simplifying long sentences in the introduction and discussion).

Author Response

Comments 1:

While the use of paraffin as an additive is practical, the discussion could better situate this work within the context of recent advancements (e.g., polymer additives, nanomaterials, geopolymers). A clearer comparison with state-of-the-art additives would strengthen the manuscript.

Response 1:

We appreciate the reviewer’s comment. They are often costly and less accessible in Central Kazakhstan due to practical conditions. Geopolymers, on the other hand, offer significant environmental advantages [Musa et al., 2025], but they require specialised production processes and raw materials that are not widely available in the region. In contrast, the paraffin-based additive tested in this study strikes a balance between improved mobility, reduced water separation and preserved strength, while using materials that are both locally available and economically feasible. This establishes paraffin as a practical alternative that fills a niche not fully covered by existing state-of-the-art additives.

Comments 2:

The mechanisms of improvement are mentioned but only briefly explained. Expanding the discussion with references to relevant literature (e.g., studies on microstructural changes or chemical interactions) would make the conclusions more convincing.

Response 2:

We would like to emphasise that introducing paraffin increases the carbon content, which promotes the formation of calcium carbonate by interacting with calcium hydroxide. This densifies the cement matrix. We also emphasise that reduced levels of mobile alkaline ions (Na, K and Mg) mitigate the risk of secondary crystallisation and structural disruption. These effects are consistent with the findings of previous studies on microstructural densification and chemical stabilisation in cement-based systems.

Comments 3:

The results are limited to laboratory conditions. A short statement in the discussion or conclusion acknowledging this limitation, and noting that field validation or long-term durability tests remain future work, would make the scope of the study clearer.

Response 3:

We agree. While the present study focused on laboratory-scale experiments, future research will expand the methodological framework by using statistical tools such as ANOVA to validate observed differences between sample groups more thoroughly. Furthermore, testing the material's long-term durability under environmental stressors (e.g. freeze–thaw cycles, wet–dry alternation and exposure to saline solutions) will be necessary to assess its performance under realistic field conditions. Additionally, pilot-scale field trials will be conducted to confirm the practical applicability of the proposed additive in geotechnical engineering projects.

Comments 4:

Some figures (e.g., Figures 5–7) contain many sub-parts. Adding clearer captions that highlight the main findings of each figure would improve readability.

Response 4:

We thank the reviewer for highlighting the need for clearer figure captions. We have revised the captions for Figures 5–7, making them more concise and emphasising the main findings of each sub-part. The updated captions highlight that each panel addresses a distinct yet related parameter, thereby improving readability while retaining the informative multi-part structure.

Comments 5:

When presenting statistical results (coefficients of variation, etc.), it would help to briefly explain their significance for the reader. This will strengthen the interpretation without requiring new analyses.

Response 5:

We appreciate the reviewer’s comment. In the revised manuscript, we have provided brief explanations of the meaning of statistical parameters (e.g. the coefficient of variation). Specifically, we have noted that the coefficient of variation reflects the degree of scatter in the data relative to the mean value and enables us to distinguish between the real effects of additive factors and random fluctuations within statistical error. This clarification enhances the interpretation of the results, eliminating the need for further analysis.

Comments 6:

Minor English editing is needed for fluency and to reduce repetition (for example, simplifying long sentences in the introduction and discussion).

Response 6:

We agree. We have corrected.

Reviewer 3 Report

Comments and Suggestions for Authors

In this paper, the research results of a modified additive designed for the cement-sand injection solution (used for soil reinforcement) are presented. The proposed additive contains paraffin, with the aim of enhancing the mobility of the mixture and retaining the active cement ions within the mixture by increasing its density. This paper developed a formulation and production technology for a universal cement injection solution additive used in deep soil consolidation methods. It presents the results of these scientific studies, particularly regarding the transformation process of the solution in terms of strength and the mobility.

This research has certain engineering applicability. However, there are many flaws in the manuscript, and it still needs to be further revised and improved.

1. Clearly defining the research objectives is essential. The abstract of the manuscript should include a clear description of the research goals.
2. In the abstract, the description of the research results is not detailed enough. It is suggested that this be improved.
3. The introduction falls short in terms of the level of discussion of the existing research. It is suggested to enrich the review of the existing relate.
4. On page 2, line 67 of the manuscript, the superscript of the unit of measurement is incorrect. “…… to 5000 cm2/g”
5. In Section 2 of the manuscript, After multiple iterations of preparing the mixture, the optimal composition of components was obtained, taking into account water evaporation: 1000 g of cement, 200 g of paraffin, 100 g of sulfuric acid, water 1000 g. The basis for choosing this proportion should be elaborated in detail.
6. On page 4 of the manuscript, there is an error in the sequence number in "Figure 2. Laboratory testing complex".
7. On page 5, "(Figure 1A)", "(Figure 1B)", and "(Figure 1C, 1D)" are inconsistent with Figure 1.
8. On page 5, line 168 of the manuscript, "Generative Artificial Intelligence (GenAI) tools were not used in this study" should be deleted.
9. On page 5, lines 172 and 173 of the manuscript, the statements "Figure 1 shows microscopic illustrations of the samples, and Figure 2 shows the results of the elemental composition" do not match Figure 1 and Figure 2.
10. On page 10, line 227 of the manuscript, "WCR = 0.30%" is incorrect.
11. On page 10, line 237 of the manuscript, "samples with WCR = 0.50%".
12. On page 12, lines 262-263 of the manuscript, "According to diagram 1A, there is a tendency for strength to increase with increasing additive concentration" should have "diagram 1A" adjusted.
13. On page 13, line 309 of the manuscript, "diagram 2G" also needs to be corrected.
14. The conclusion is overly lengthy and not concise. It is recommended to summarize the research content of the manuscript concisely and clearly, and the expression should be further refined.

Comments on the Quality of English Language

 The English could be improved to more clearly express the research.

Author Response

Comments 1:

In the abstract, the description of the research results is not detailed enough. It is suggested that this be improved.

Response 1:

Abstract has been expanded to provide a more detailed description of the key research results.

Comments 2:

The introduction falls short in terms of the level of discussion of the existing research. It is suggested to enrich the review of the existing relate.

Response 2:

In the revised manuscript, the Introduction has been significantly expanded to provide a broader discussion of existing research on soil stabilization methods. In particular, we incorporated recent studies on deep cementation, polymer- and nano-modified additives, and alternative binders, highlighting both international developments and their relevance to the conditions of Central Kazakhstan. These additions strengthen the contextual background, clarify the existing knowledge base, and more clearly define the specific research gap that our work addresses.

Comments 3:

On page 2, line 67 of the manuscript, the superscript of the unit of measurement is incorrect. “…… to 5000 cm2/g”

Response 3:

We have corrected the unit to cm²/g and harmonized superscript formatting for all occurrences of specific surface area units in the Introduction.

Comments 4:

In Section 2 of the manuscript, after multiple iterations of preparing the mixture, the optimal composition of components was obtained, taking into account water evaporation: 1000 g of cement, 200 g of paraffin, 100 g of sulfuric acid, water 1000 g. The basis for choosing this proportion should be elaborated in detail.

Response 4:

The proportion 1000 g cement: 200 g paraffin: 100 g sulfuric acid: 1000 g water - was established following a series of preliminary iterations aimed at (i) forming a stable, pumpable additive concentrate without phase separation for at least 60 min; (ii) enhancing mobility and limiting water separation in the final mortar; and (iii) preserving cement hydration kinetics within the ranges prescribed by GOST 310.3 and GOST 310.6. A paraffin content of 20% by cement mass was adopted as the lowest dosage that consistently produced a measurable increase in slump flow (and reduction in water separation) while avoiding mixture instability observed at higher paraffin fractions. The sulfuric acid dosage of 10% by cement mass represents the minimum quantity required to promote dispersion of paraffin in the alkaline cementitious medium and to prevent agglomeration, without reducing the pore-solution alkalinity below the level needed for normal hydration. Because neutralisation is exothermic and causes partial water loss, the water-to-cement ratio of 1.0 was fixed for the concentrate to compensate evaporation and to maintain a workable viscosity for dosing into the base mix. With this concentrate, the target WCR of the final injection mortar was kept at 0.50, and the additive was dosed at 0.2–1.0% of cement mass (Mix(0.2)…Mix(1.0)), which is the range found to balance mobility gains with strength retention in subsequent tests.

Comments 5:

On page 4 of the manuscript, there is an error in the sequence number in "Figure 2. Laboratory testing complex".

Response 5:

We agree. We have corrected.

Comments 6:

On page 5, "(Figure 1A)", "(Figure 1B)", and "(Figure 1C, 1D)" are inconsistent with Figure 1.

Response 6:

We agree. We have corrected.

Comments 7:

On page 5, line 168 of the manuscript, "Generative Artificial Intelligence (GenAI) tools were not used in this study" should be deleted.

Response 7:

We agree. We have corrected.

Comments 8: 

On page 5, lines 172 and 173 of the manuscript, the statements "Figure 1 shows microscopic illustrations of the samples, and Figure 2 shows the results of the elemental composition" do not match Figure 1 and Figure 2.

Response 8:

We agree. We have corrected.

Comments 9:

On page 10, line 227 of the manuscript, "WCR = 0.30%" is incorrect.

Response 9:

We agree. We have corrected.

Comments 10:

On page 10, line 237 of the manuscript, "samples with WCR = 0.50%".

Response 10:

We agree. We have corrected.

Comments 11:

On page 12, lines 262-263 of the manuscript, "According to diagram 1A, there is a tendency for strength to increase with increasing additive concentration" should have "diagram 1A" adjusted.

Response 11:

We agree. We have corrected.

Comments 12:

On page 13, line 309 of the manuscript, "diagram 2G" also needs to be corrected.

Response 12:

We agree. We have corrected.

Comments 13:

The conclusion is overly lengthy and not concise. It is recommended to summarize the research content of the manuscript concisely and clearly, and the expression should be further refined.

Response 13:

We agree. We have corrected.

Comments 14:

When presenting statistical results (coefficients of variation, etc.), it would help to briefly explain their significance for the reader. This will strengthen the interpretation without requiring new analyses.

Response 14:

We appreciate the reviewer’s comment. In the revised manuscript, we have provided brief explanations of the meaning of statistical parameters (e.g. the coefficient of variation). Specifically, we have noted that the coefficient of variation reflects the degree of scatter in the data relative to the mean value and enables us to distinguish between the real effects of additive factors and random fluctuations within statistical error. This clarification enhances the interpretation of the results, eliminating the need for further analysis.

Comments 15:

Minor English editing is needed for fluency and to reduce repetition (for example, simplifying long sentences in the introduction and discussion).

Response 15:

We agree. We have corrected.

Reviewer 4 Report

Comments and Suggestions for Authors

The manuscript presents a study on a modified additive designed for cement-13 sand injection solutions for soil stabilization.  The authors need to address the following issues to improve the quality of the manuscript for publication:

1. Abstract: The authors should include the implications of the study as the last sentence of the abstract.

2. Lumped-up references: The authors should avoid the use of lumped-up references. They should rather provide brief findings of each study.

3. Inconsistency in the use of upper case and lower case in figure numbering. The authors need to stick to either 1a, 2a, 2b .... or 1A, 2A, 2B, ...

4.  Figure 3: The authors need to provide a "key" or "legend" for the labelling of the peaks.

5. Table 1- The authors should indicate the name of the additive used.

6. Table 2: There is no defined pattern in the content of calcium as the percentage of the additive is increased. This raises concerns about the validity of the results.

7.  Figure 4 conveys the same information already presented in Table 2. The authors need to remove Figure 4.

8. Figure 5: What do the authors mean by "Type of sample" in the x-axis? This labelling appears to be incorrect. The authors need to provide a correct x-axis labelling.

9.  Figure 7b: The y-axis labelling is incorrect. The key is also not clear

10. Graph clarity: The authors need to increase the clarity of all the graphs. Too many sketches in the graph limit the understanding of the plots.

11. Conclusion: The conclusion is too long. The authors need to summarize it.

Author Response

Comments 1:

Abstract: The authors should include the implications of the study as the last sentence of the abstract.

Response 1:

Corrections have been made

Comments 2:

Lumped-up references: The authors should avoid the use of lumped-up references. They should rather provide brief findings of each study.

Response 2:

We thank the reviewer for this valuable comment. In the revised version, we have summarised the main findings of the cited studies to avoid lumping them together.

Comments 3:

Inconsistency in the use of upper case and lower case in figure numbering. The authors need to stick to either 1a, 2a, 2b .... or 1A, 2A, 2B, ...

Response 3:

Corrections have been made

Comments 4:

Figure 3: The authors need to provide a "key" or "legend" for the labelling of the peaks.

Response 4:

Corrections have been made

Comments 5:

Table 1- The authors should indicate the name of the additive used.

Response 5:

Corrections have been made

Comments 6:

Table 2: There is no defined pattern in the content of calcium as the percentage of the additive is increased. This raises concerns about the validity of the results.

Response 6:

Calcium content does not show a linear dependence on additive concentration, this reflects the redistribution of Ca between portlandite and carbonate phases during hydration. Similar non-monotonic trends have been reported in studies of modified cementitious systems [Karlina et al., 2023; Davoodi et al., 2024], and the overall stabilization of Ca within a narrow range indicates the preservation of the cement matrix rather than experimental inconsistency.

Comments 7:

Figure 4 conveys the same information already presented in Table 2. The authors need to remove Figure 4.

Response 7:

While it is true that both Table 2 and Figure 4 present the elemental composition data, we respectfully consider that the two formats serve complementary purposes. Table 2 provides the exact numerical values, which are important for precision and reproducibility, whereas Figure 4 offers a graphical visualization of the same data, allowing readers to more easily identify relative trends, fluctuations, and comparisons between elements across additive concentrations.

Comments 8:

Figure 5: What do the authors mean by "Type of sample" in the x-axis? This labelling appears to be incorrect. The authors need to provide a correct x-axis labelling.

Response 8:

We agree. Corrections have been made

Comments 9:

Figure 7b: The y-axis labelling is incorrect. The key is also not clear

Response 9:

We agree. Corrections have been made

Comments 10:

Graph clarity: The authors need to increase the clarity of all the graphs. Too many sketches in the graph limit the understanding of the plots.

Response 10:

We agree. Corrections have been made

Comments 11:

Conclusion: The conclusion is too long. The authors need to summarize it.

Response 11:

We agree. We have corrected.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

all comments were addressed