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Article
Peer-Review Record

Effect of Elapsed Time after Mixing on the Strength Properties of Lime–Iron Ore Tailings Treated Black Cotton Soil as a Road Construction Material

Infrastructures 2020, 5(11), 89; https://doi.org/10.3390/infrastructures5110089
by Annafi Qaudri Babatunde 1, Eberemu Adrian Oshioname 2,*, Yohanna Paul 3 and Osinubi Kolawole Junwolo 1
Reviewer 1: Anonymous
Reviewer 2: Anonymous
Reviewer 3: Anonymous
Reviewer 4: Anonymous
Infrastructures 2020, 5(11), 89; https://doi.org/10.3390/infrastructures5110089
Submission received: 31 July 2020 / Revised: 24 September 2020 / Accepted: 24 September 2020 / Published: 25 October 2020
(This article belongs to the Special Issue Geomaterials for Transportation Infrastructures)

Round 1

Reviewer 1 Report

This paper discussed the performance of lime-iron ore tailings treated black cotton soil. The logic and structure are very good. There are still some issues needed to be improved.

  1. there are many strange statements. Please make the sentences more concise, such as “plastic limit (PL) of BCS decreased with increase lime and IOT content while plasticity index (PI) decreased from 27.7 to 22.9 % for 0 % lime/0 % IOT content and 30.6 to 26.6 % for 0 % lime/10 % IOT content.”, “Lime was used at stepped concentration of 0, 2, 4, 6, and 8 % for 0, 2, 4, 6, 8 and 10 % IOT, respectively”, etc.
  2. please provide much more information about the iron ore tailings, and according to Table 2, the chemical component of iron ore tailings was from some other publication. The iron ore tailings are solid wastes, the chemical component will not keep constant. Please detect the chemical component of used iron ore tailings. And why the unit is percentage for lime, while the chemical component of iron ore tailings was weighed by mass.
  3. All the figures in the paper are not well displayed, especially in section of 3.7, a picture is missing! Please number the figures in section of 3.7!
  4. Please concise the Conclusions, and list key results one by one.

Author Response

Comment: The authors may wish to explain more about why black cotton soils to be considered as the material to be used apart from mentioning the area it occupies in line 44.  

Response: Further explanation was added as presented in red print on line 44-46 in the manuscript.

Comment: In 2.2 methods, sample sizes need to be mentioned especially statistical analysis was performed as part of the methodology.  

Response: Sample size of 120 was used for the statistical analysis (i.e., regression) for varying proportion of additives and elapsed time considered.

Comment: A few formatting improvements, e.g., line 148, Table 1 seems to be off-alignment.  Various sections such as lines 152 and 153 need to be highlighted properly or to be given an index number to easily identify.  Similar cases can be found in lines 169, 181, 182, 194, ...etc.  

Response: The formatting error has been corrected in the manuscript.

Comment: Section 3.6 the Regression Analysis needs to be re-examined closely.  Sample size and crucial statistics, such as t values and correlation analysis, were not reported.  The large constant terms in the regression equations are cause of concern as they seem to have strong impacts to the UCS and CBR values forecasted.  There could be various factors leading to the large values.  The authors should examine closely to confirm whether the results are really as indicated.  The authors should also cross-examine with the experiment results to confirm the veracity.

Response: The regression results and the analysis were examined again as suggested. Minitab software and Microsoft (MS) Excel   used to develop the regression equations gave similar results. The t values and p values were also considered and are shown in the attached excel file.

Comment: The authors should use "figures" instead of "plates" in the paper.  Plate 2 in lines 421 to 422 seem off-position.  

Response: The ‘Plates’ have been renamed  “Figures” and numbered appropriately as suggested.

Reviewer 2 Report

The authors may wish to explain more about why black cotton soils to be considered as the material to be used apart from mentioning the area it occupies in line 44.  

In 2.2 methods, sample sizes need to be mentioned especially statistical analysis was performed as part of the methodology.  

A few formatting improvements, e.g., line 148, Table 1 seems to be off-alignment.  Various sections such as lines 152 and 153 need to be highlighted properly or to be given an index number to easily identify.  Similar cases can be found in lines 169, 181, 182, 194, ...etc.  

Section 3.6 the Regression Analysis needs to be re-examined closely.  Sample size and crucial statistics, such as t values and correlation analysis, were not reported.  The large constant terms in the regression equations are cause of concern as they seem to have strong impacts to the UCS and CBR values forecasted.  There could be various factors leading to the large values.  The authors should examine closely to confirm whether the results are really as indicated.  The authors should also cross-examine with the experiment results to confirm the veracity.  

The authors should use "figures" instead of "plates" in the paper.  Plate 2 in lines 421 to 422 seem off-position.  

Author Response

Comment: The authors may wish to explain more about why black cotton soils to be considered as the material to be used apart from mentioning the area it occupies in line 44.

Response: Further explanation was added as presented in red print on line 44-46 in the manuscript.

Comment: In 2.2 methods, sample sizes need to be mentioned especially statistical analysis was performed as part of the methodology.

Response: Sample size of 120 was used for the statistical analysis (i.e., regression) for varying proportion of additives and elapsed time considered.

Comment: A few formatting improvements, e.g., line 148, Table 1 seems to be off-alignment. Various sections such as lines 152 and 153 need to be highlighted properly or to be given an index number to easily identify. Similar cases can be found in lines 169, 181, 182, 194, ...etc.

Response: The formatting error has been corrected in the manuscript.

Comment: Section 3.6 the Regression Analysis needs to be re-examined closely. Sample size and crucial statistics, such as t values and correlation analysis, were not reported. The large constant terms in the regression equations are cause of concern as they seem to have strong impacts to the UCS and CBR values forecasted. There could be various factors leading to the large values. The authors should examine closely to confirm whether the results are really as indicated. The authors should also cross-examine with the experiment results to confirm the veracity.

Response: The regression results and the analysis were examined again as suggested. Minitab software and Microsoft (MS) Excel used to develop the regression equations gave similar results. The t values and p values were also considered and are shown in the attached excel file.

Comment: The authors should use "figures" instead of "plates" in the paper. Plate 2 in lines 421 to 422 seem off-position.

Response: The ‘Plates’ have been renamed “Figures” and numbered appropriately as suggested.

Reviewer 3 Report

Paper title: Effect of Elapsed Time After Mixing on the Strength 2 Properties of Lime – Iron Ore Tailings Treated Black 3 cotton Soil as a Road Construction Material

By Annafi et al

 

General comments are given as follows:

The paper content is interesting for the road engineers. It is a technical note reporting a full of experimental data. Authors give detailed results from treated and natural soils. They report a lot of data with different addition of mine tailing waste and lime. In this paper, authors consider different period of time for samples tested: early age after mixing: 0 to 3 hours; and 7 days and finally 28 days. And along the paper a large part is dedicated for early age and another part is related to aged samples (7 and 28 days). So, for readers it is difficult to understand the main objectives of this paper and some information is missing for a best understanding of all results. I recommend to limit the length of the paper and to propose as objectives: effect of elapsed time after mixing for an optimal formulation for road construction material (or equivalent). Section from 3.6 or 3.7 might be suppressed and the paper reorganized.

Comments are given versus the sections and the number of line considered is indicated:

Title:

Line 4: check the writing of each word in capital letter.

List of authors:

Line 6: check the position of affiliation in exponent before or after the author’s name. Only author must use one main affiliation, see line 6 and 7 for exponent 1, we have 2 affiliations.

Title, Abstract, Keywords:

Abstract content is adequate with the paper content.

Abstract:

Line 12: suppress the brackets.

Line 16: “microanalysis” of what? And what means this term?

Lines 18-21: unclear with too much numerical data.

Lines 21-22: totally unclear.

Lines 23-24: suppress the brackets.

Line 27: “parameters” in order to write “variables”.

Line 28: what means “low volume roads”?

Introduction:

Correct the number of the section and the following ones: 1. ; 2. ;…

Line 38: “vital” is not adequate term.

Line 46: “expand-contrast characteristics…” : unclear.

Line 57: small % of lime is generally used to treat clayey-silty soils: this % does not exceed 3-4% and depending on pH saturation point. Why here authors propose a higher % of lime (till 8%) without check the saturation point in BCS soil?

Line 59: use “addition” not “inclusion”.

Lines 71-72: “tonnes”.

Line 77: what “index”? (too general).

Line 85: why authors choose 3hours not more?

Lines 30, 39, 40, 46, 47: and others, references are written in exponent, not so readable but see instructions for authors of the journal.

Line 35: use “usually” not “generally”.

Materials and methods:

Materials:

Suppress all subsection titles from 2.1.1 to 2.1.3. Only one section for materials. Give the grain size distribution of soil and also for iron ore tailings and lime. Is lime commercial product and type of lime?

Methods

Subsection 2.2.1 and 2.2.2 must be written in only one subsection. Authors must clearly explain why they use such amount of lime till 8%; they must introduce the pH saturation point.

Line 98: what index properties?

Line 102: it is plasticity properties.

Line 105: subtitle: Compaction testing. “for the natural….”.

Line 106: value of energy per unit of volume? (for Proctor standard it is around 600 kN.m/m3).

Lines 114-115: give in all letters the acronyms MDD and OMC (first reading in the text).

Line 116: subtitle: Unconfined compressive strength.

Line 119: why authors choose the date of 7 days?

Line 124: in equation 1: usually stress is defined by σ not δ (for displacement); deformation is named ε expressed in %. E is deformation modulus. Give SI unit for all variables in lines 128-130.

Line 128: ν is the deformation of the sample.

Line 131: subtitle: California bearing ratio

Line 140: add “.” after penetration.

Results and discussion:

Index properties:

What are index properties?

Table1: give the size of N°200 sieve? Align the different column in table. Explain the specific gravity of 2.29? Mineralogical properties, grain size distribution and granulometric nature are missing.

Table 2: correct the legend because lime percentage of oxides is also in the table. Line 1: give only the names of materials and after put (%). For IOT material total exceeds 100% but for lime the total is around of 71% why? And for lime CaO is only of 53.4%: why?

Atterberg limits:

Liquid limit

It is plasticity and consistency properties. This section is very detailed: is it necessary? Because the paper length should be reduced or the last sections be suppressed on microanalysis (not so useful because only descriptive).

Line 158: reference “Obeahon, 1992” is dated from 1993 in the list (line 595).

Line 166: “Panikumar” is written as “Pani Kumar” in the reference list (line 637).

Figure 1: put a space in X-axis legend after “Iron ore tailings content” and “(%).

Line 172: “between 0 and 1 or 2 hours”?

Figure 2: put a space in X-axis legend after “Elapsed time” and “(hours). Why 8% lime-IOT sample has been chosen by authors? Or why in line 176: the authors write “the optimal BCS-8% lime”? idem in lines 196, 224, 286, 322, 325, 358.

Plastic limit

Lines 188-190: unclear.

Figure 3: put a space in X-axis legend after “Iron ore tailings content” and “(%).

Lines 197-198: unclear. “after 1 or 2 hours?

Line 201: “lime”.

Lines 202-203: not convincing.

Figure 4: put a space in X-axis legend after “Elapsed time” and “(hours).

Plasticity index

Lines 213-214: unclear.

Figure 5: put a space in X-axis legend after “Iron ore tailings content” and “(%).

Figure 6: put a space in X-axis legend after “Elapsed time” and “(hours).

Compaction parameters

Before discussing about MDD and OMC parameters (not characteristics), compaction curves must be presented and discussion on the displacement of these parameters towards “dry side” or wet side” must be given according IOT and lime addition.

Maximum dry density

Line 239: not for all %, MDD decrease beyond 8%.

Line 246: “mainly” not “principally”.

Figure 7: put a space in X-axis legend after “Iron ore tailings content” and “(%). In the figure legend correct “BCS-lime….”.

Figure 8: put a space in X-axis legend after “Elapsed time” and “(hours) and between Maximum dry density and Mg/m3 on Y-axis.

Optimum moisture content

Line 272: with 1 or 2 numbers for accuracy: 25.62 (line 289) or 25.6?

Figure 9: put a space between Optimum moisture content and (%) on Y-axis.

Line 278: adjust the line on left side.

Line 287: not “d”, fig. 10a-b.

Figure 10: put a space in X-axis legend after “Elapsed time” and “(hours) and between Optimum moisture content and (%) on Y-axis.

Unconfined compressive strength

Line 300: why UCS measurement for 7 and 28 days?

Lines 302-304: not only in this subsection, but for readers, it is difficult to check the numbers given and the values read on the graphs. A series of data in a same sentence lead to confuse understanding. And all data given are they useful?

Figure 11: put a space in X-axis legend after “Iron ore tailings” and “(%) and between UCS and (kN/mm2).  

Figure 12: put a space in X-axis legend after “Elapsed time” and “(hours) and between UCS and (kN/mm2).  

California bearing ratio

Line 348: “for base materials” according BS or NGS standard?

Figure 13: put a space in X-axis legend after “Iron ore tailings” and “(%) and between CBR and (%).

Lines 366-367: “for road base”? and “road sub-bases”?

Lines 370-371: “road sub-grade….base”.

Figure 14: put a space in X-axis legend after “Elapsed time” and “(hours) and between CBR and (%).

Regression analysis

What are the objectives of a such regression? A strong relationship exists between UCS and CBR results (plot a graph).

Line 376: equations 4 and 5, not 6.

Line 381: equation 4 and 5!

Line 387: “elapsed time”.

Line 391: but on site, compaction engines deliver a different energy as the laboratory energy used.

Line 397: “(unsoaked)”.

Line 401: “where” without W. “kN/m2”.

Microanalysis of specimens

Specimens cured for 7 days

Authors try to link the microstructure analysis to support a part of their results. It is a rough microstructure analysis. But in my opinion from subsection 3.7, it is not very useful for readers.

Do not use “plate”, as usually use “figure”. Gather plates 1 and 2 in one figure, the same for: plates 3 and 4; plates 5 and 6; plates 7 and 8, plates 9 and 10; plates 11 and 12.

Line 411: “From the SEM images….”.

Plates 1 and 2: improve the quality of figure and simplify the legend.

Specimens cured for 28 days

Why use SEM images of 28days samples?

Line 429: “the SEM image….”.

Lines 432-434: not convincing.

Plates 3 and 4: improve the quality of figure and simplify the legend.

Fibremetric analysis

Fibre histograms

Subsection title is not representative of the subsection content. What is really the objective of this poor and reduced subsection, what is really the usefulness for the readers? This subsection concerns 7 and 28 days samples.

Plates 5 and 6: improve the quality of figure and simplify the legend.

Plates 7 and 8: improve the quality of figure and simplify the legend.

Pore histograms

Subsection title is not representative of the subsection content. What is really the objective of this poor and reduced subsection, what is really the usefulness for the readers? This subsection concerns 7 and 28 days samples and comments are not convincing.

Plates 9 and 10: improve the quality of figure and simplify the legend.

Plates 11 and 12: improve the quality of figure and simplify the legend.

Conclusions:

Line 498: “low volume roads” : what is the meaning?

References

Use and respect the alphabetic order, see instructions for authors.

An important part of references are local references.

 

Author Response

General comments are given as follows:

Comment: The paper content is interesting for the road engineers. It is a technical note reporting a full of experimental data. Authors give detailed results from treated and natural soils. They report a lot of data with different addition of mine tailing waste and lime. In this paper, authors consider different period of time for samples tested: early age after mixing: 0 to 3 hours; and 7 days and finally 28 days. And along the paper a large part is dedicated for early age and another part is related to aged samples (7 and 28 days). So, for readers it is difficult to understand the main objectives of this paper and some information is missing for a best understanding of all results. I recommend to limit the length of the paper and to propose as objectives: effect of elapsed time after mixing for an optimal formulation for road construction material (or equivalent). Section from 3.6 or 3.7 might be suppressed and the paper reorganized.

Response: The objective of the study has been revised and is highlighted in the manuscript as suggested. The 28 days component of the paper has been removed as suggested. Sections 3.6 and 3.7 were suppressed and the paper reorganized as suggested. The paper length has significantly reduced with the changes made.

Comments are given versus the sections and the number of line considered is indicated:

Title:

Comment: Line 4: check the writing of each word in capital letter.

Response: The error has been corrected in the manuscript as suggested

List of authors:

Comment: Line 6: check the position of affiliation in exponent before or after the author’s name. Only author must use one main affiliation, see line 6 and 7 for exponent 1, we have 2 affiliations.

Response: The affiliation error has been corrected in the manuscript as suggested

Title, Abstract, Keywords:

Abstract content is adequate with the paper content.

Abstract:

Comment: Line 12: suppress the brackets.

Response: The brackets have been reduced as suggested.

Comment: Line 16: “microanalysis” of what? And what means this term?

Response: Microanalysis referred to scanning electrons microscope (SEM) analysis of specimens.

Comment: Lines 18-21: unclear with too much numerical data.

Response: The numerical data was used to explain the changes in the specimens with respect to varying additive contents and elapsed time after mixing..

Comment: Lines 21-22: totally unclear.

Response: The error has been corrected as highlighted in the manuscript.

Comment: Lines 23-24: suppress the brackets.

Response: The brackets have been reduced as suggested.

Comment: Line 27: “parameters” in order to write “variables”.

Response: variables has been changed to ‘Parameters’ has been used to replace “Variables” in the manuscript as suggested.

Comment: Line 28: what means “low volume roads”?

Response: Low-volume roads means road of low traffic volume.

Introduction:

Comment: Correct the number of the section and the following ones: 1. ; 2. ;…

Response: The numbering has been corrected as suggested for all the sections.

Comment: Line 38: “vital” is not adequate term.

Response: The word ‘vital’ has been replaced with “essential” in the manuscript.

Comment: Line 46: “expand-contrast characteristics…” : unclear.

Response: The sentence has been revised in the manuscript with more clear terms as suggested.

Comment: Line 57: small % of lime is generally used to treat clayey-silty soils: this % does not exceed 3-4% and depending on pH saturation point. Why here authors propose a higher % of lime (till 8%) without check the saturation point in BCS soil?

Response: We exceeded the 4% because the optimal strength gain was achieved beyond the 4% lime. Furthermore, the unique expansive nature of black cotton soil soil with montmorrilonite as the dominant clay mineral requires higher dosage of lime to achieve good results.

Comment: Line 59: use “addition” not “inclusion”.

Response: The word ‘inclusion’ has been replaced with “addition” as suggested.

Comment: Lines 71-72: “tonnes”.

Response: The word ‘tonnes’ can be replaced with “Ton” (or “tonne”) in the manuscript.

Comment: Line 77: what “index”? (too general).

Response: Index (i.e., Index properties) means the basic properties of the natural soil.

Comment: Line 85: why authors choose 3 hours not more?

Response: Previous studies on elapsed time after mixing show that beyond 3 hours delay the properties of the treated specimens become very poor and the material not usable..

Comment: Lines 30, 39, 40, 46, 47: and others, references are written in exponent, not so readable but see instructions for authors of the journal.

Response:

Comment: Line 35: use “usually” not “generally”.

Response: The word was not found

Materials and methods:

Materials:

Comment: Suppress all subsection titles from 2.1.1 to 2.1.3. Only one section for materials. Give the grain size distribution of soil and also for iron ore tailings and lime. Is lime commercial product and type of lime?

Response: The sections have been merged as suggested and providing the grain sizes will increase the volume of the paper.

Methods

Comment: Subsection 2.2.1 and 2.2.2 must be written in only one subsection. Authors must clearly explain why they use such amount of lime till 8%; they must introduce the pH saturation point.

Response: The subsections have been merged together as suggested. We exceeded the 4% lime because the optimal strength gain was achieved beyond the 4% lime.

Comment: Line 105: subtitle: Compaction testing. “for the natural….”.

Response: The errors with subsections have been corrected as suggested.

Comment: Line 106: value of energy per unit of volume? (for Proctor standard it is 605.9 kJ/m3).

Response: Noted

Comment: Lines 114-115: give in all letters the acronyms MDD and OMC (first reading in the text).

Response: The error has been corrected as suggested by writing MDD and OMC In full (i.e., Maximum dry density (MDD) and optimum moisture content (OMC)) when first mentioned.

Comment: Line 116: subtitle: Unconfined compressive strength.

Response: The sub tittle for Unconfined compressive strength has been removed as suggested.

Comment: Line 119: why authors choose the date of 7 days?

Response: The choice of 7 days is based on standard practice.

Comment: Line 124: in equation 1: usually stress is defined by σ not δ (for displacement); deformation is named ε expressed in %. E is deformation modulus. Give SI unit for all variables in lines 128-130.

Response: All references to equation (1) have been edited and SI units provided as suggested.

Comment: Line 128: ν is the deformation of the sample.

Response: The error has been corrected as suggested. v is the amount of deformation of the sample.

Comment: Line 131: subtitle: California bearing ratio.

Response: The sub tittle for California bearing ratio has been deleted as suggested.

Comment: Line 140: add “.” after penetration.

Response: The after has been added to penetration in the manuscript as suggested.

Results and discussion:

Comment: Table1: give the size of N°200 sieve? Align the different column in table. Explain the specific gravity of 2.29? Mineralogical properties, grain size distribution and granulometric nature are missing.

Response: No 200 sieve is 0.075 mm sieve size. The specific gravity of the natural soil is 2.29. The mineralogical properties were determined using x-ray diffraction (XRD) analysis, while oxide composition of Lime and Iron ore tailings (IOT) was determined using x-ray fluorescence (XRF).

Comment: Table 2: correct the legend because lime percentage of oxides is also in the table. Line 1: gives only the names of materials and after put (%). For IOT material total exceeds 100% but for lime the total is around of 71% why? And for lime CaO is only of 53.4%: why?

Response:

Atterberg limits:

Liquid limit

Comment: It is plasticity and consistency properties. This section is very detailed: is it necessary? Because the paper length should be reduced or the last sections be suppressed on microanalysis (not so useful because only descriptive).

Response: The paper length has been reduced. 28 days curing under the micro analysis has been removed as suggested.

Comment: Line 158: reference “Obeahon, 1992” is dated from 1993 in the list (line 595).

Response: The error has been corrected in the manuscript.to Obeahon 1993

Comment: Line 166: “Panikumar” is written as “Pani Kumar” in the reference list (line 637).

Response: The error has been corrected in both manuscript and reference list . Is now Phani Kumar not Panikumar

Comment: Figure 1: put a space in X-axis legend after “Iron ore tailings content” and “(%).

Response: A space was provided as suggested and similar corrections were made to the entire figures in the manuscript.

Comment: Line 172: “between 0 and 1 or 2 hours”?

Response: not clear please

Comment: Figure 2: put a space in X-axis legend after “Elapsed time” and “(hours). Why 8% lime-IOT sample has been chosen by authors? Or why in line 176: the authors write “the optimal BCS-8% lime”? item in lines 196, 224, 286, 322, 325, 358.

Response: The error has been corrected as suggested. 8 % lime-IOT sample was chosen because it is the optimal or best result obtained. Putting all the results will make the paper too bulky. Therefore we considered the 0 % lime – IOT and 8 % lime – IOT to reduce the paper length.

Plastic limit

Comment: Figure 3: put a space in X-axis legend after “Iron ore tailings content” and “(%).

Response: The error has been corrected as suggested.

Comment: Lines 197-198: unclear. “after 1 or 2 hours?

Response: For varying time interval of 0,1, 2 and 3 hours denoted with a, b, c and d respectively.

Comment: Line 201: “lime”.

Response: The error has been corrected as suggested.

Comment: Lines 202-203: not convincing.

Response: The sentence has been revised in the manuscript as suggested.

Comment: Figure 4: put a space in X-axis legend after “Elapsed time” and “(hours).

Response: The error has been corrected as suggested.

Plasticity index

Comment: Lines 213-214: unclear.

Response: The sentence has been improved in the manuscript.

Comment: Figure 5: put a space in X-axis legend after “Iron ore tailings content” and “(%).

Response: The error has been corrected as suggested.

Comment: Figure 6: put a space in X-axis legend after “Elapsed time” and “(hours).

Response: The error has been corrected as suggested.

Compaction parameters

Comment: Before discussing about MDD and OMC parameters (not characteristics), compaction curves must be presented and discussion on the displacement of these parameters towards “dry side” or wet side” must be given according IOT and lime addition.

Response: We did not make such provision because the paper length will be too much.

Maximum dry density

Comment: Line 239: not for all %, MDD decrease beyond 8%.

Response: The error has been corrected. y.

Comment: Line 246: “mainly” not “principally”.

Response: ‘principally’ has been replaced with “mainly”.

Comment: Figure 7: put a space in X-axis legend after “Iron ore tailings content” and “(%). In the figure legend correct “BCS-lime….”.

Response: The error has been corrected as suggested.

Comment: Figure 8: put a space in X-axis legend after “Elapsed time” and “(hours) and between Maximum dry density and Mg/m3 on Y-axis.

Response: The error has been corrected as suggested.

Optimum moisture content

Comment: Line 272: with 1 or 2 numbers for accuracy: 25.62 (line 289) or 25.6?

Response: The error has been corrected by changing all the numbers to 2 decimal places as suggested.

Comment: Figure 9: put a space between Optimum moisture content and (%) on Y-axis.

Response: The error has been corrected as suggested.

Comment: Line 278: adjust the line on left side.

Response: The error has been corrected as suggested.

Comment: Line 287: not “d”, fig. 10a-b.

Response: The comment is not clear.

Comment: Figure 10: put a space in X-axis legend after “Elapsed time” and “(hours) and between Optimum moisture content and (%) on Y-axis.

Response: The error has been corrected as suggested.

Unconfined compressive strength

Comment: Line 300: why UCS measurement for 7 and 28 days?

Response: UCS for 7 days was considered based on standard practice.

Comment: Lines 302-304: not only in this subsection, but for readers, it is difficult to check the numbers given and the values read on the graphs. A series of data in a same sentence lead to confuse understanding. And all data given are they useful?

Response: All data provided are relevant to the subject matter.

Comment: Figure 11: put a space in X-axis legend after “Iron ore tailings” and “(%) and between UCS and (kN/mm2).

Response: The error has been corrected as suggested.

Comment: Figure 12: put a space in X-axis legend after “Elapsed time” and “(hours) and between UCS and (kN/mm2).

Response: The error has been corrected as suggested.

California bearing ratio

Comment: Figure 13: put a space in X-axis legend after “Iron ore tailings” and “(%) and between CBR and (%).

Response: The error has been corrected as suggested.

Comment: Lines 366-367: “for road base”? and “road sub-bases”?

Response: The comment is not clear

Comment: Figure 14: put a space in X-axis legend after “Elapsed time” and “(hours) and between CBR and (%).

Response: The error has been corrected as suggested.

Regression analysis

Comment: What are the objectives of a such regression? A strong relationship exists between UCS and CBR results (plot a graph).

Response: The objective is to show relationship between strength properties (i.e., UCS and CBR) as dependent soils variables with Lime content (L), Iron ore tailing content (IOT), Elapsed time (ET), Liquid limit (LL), Plasticity index (PI),Maximum dry density (MDD) and Optimum moisture content (OMC) as independent variables.

Coefficients of determination of for UCS and for CBR was used to measure the strength of the relationship. The significance of the regression shows that strength of the treated soil depends strongly on the independent variables.

Comment: Line 376: equations 4 and 5, not 6.

Response: The error has been corrected as suggested.

Comment: Line 381: equation 4 and 5!

Response: The error has been corrected as suggested.

Comment: Line 387: “elapsed time”.

Response: The error has been corrected as suggested. Changed to elapsed time

Comment: Line 391: but on site, compaction engines deliver a different energy as the laboratory energy used.

Response: Yes, but the desired field density is measured relative to the laboratory density obtained via compaction test. This is achieved through in situ density test in the field.

Comment: Line 397: “(unsoaked)”.

Response: The error has been corrected as suggested.

Comment: Line 401: “where” without W. “kN/m2”.

Response: The error has been corrected as suggested.

Microanalysis of specimens

Specimens cured for 7 days

Comment: Authors try to link the microstructure analysis to support a part of their results. It is a rough microstructure analysis. But in my opinion from subsection 3.7, it is not very useful for readers.

Response: Micro-analysis is used to show the improvement recorded at the micro level. It is key in understanding the morphological changes that occur within the modified soil when compared with the natural soil.

Comment: Do not use “plate”, as usually use “figure”. Gather plates 1 and 2 in one figure, the same for: plates 3 and 4; plates 5 and 6; plates 7 and 8, plates 9 and 10; plates 11 and 12.

Response: All ‘plates’ have been changed to “figures” as suggested in the entire manuscript.

Comment: Line 411: “From the SEM images….”.

Response: The error has been corrected as suggested.

Comment: Specimens cured for 28 days

Comment: Why use SEM images of 28days samples?

Response: 28days samples has been removed as suggested since 28 days UCS was not considered in this study.

Comment: Line 429: “the SEM image….”.

Response: This section of the paper has been deleted (i.e.,the section on 28 days curing period)

Comment: Lines 432-434: not convincing.

Response: This section of the paper has been deleted (i.e., the section on 28 days curing period)

Comment: Plates 3 and 4: improve the quality of figure and simplify the legend.

Response: This section of the paper has been deleted (i.e., the section on 28 days curing period).

Fibremetric analysis

Fibre histograms

Comment: Subsection title is not representative of the subsection content. What is really the objective of this poor and reduced subsection, what is really the usefulness for the readers? This subsection concerns 7 and 28 days samples.

Response: This section explains the changes in the soil fabrics and areas of pores within the natural and optimally modified soil. The variation defines the level of improvement at the micro level. The section on 28 days curing period has been deleted.

Comment: Plates 5 and 6: improve the quality of figure and simplify the legend.

Response: The quality of figures has been improved as suggested.

Comment: Plates 7 and 8: improve the quality of figure and simplify the legend.

Response: This section of the paper has been deleted (i.e., the section on 28 days curing period).

Pore histograms

Comment: Subsection title is not representative of the subsection content. What is really the objective of this poor and reduced subsection, what is really the usefulness for the readers? This subsection concerns 7 and 28 days samples and comments are not convincing.

Response: The section explains the changes in the soil fabrics and areas of pores within the natural and optimally modified soil. The variation defines the level of improvement at micro level. The section 28 days curing period has been deleted.

Comment: Plates 9 and 10: improve the quality of figure and simplify the legend.

Response: The quality of figures has been improved as suggested.

Comment: Plates 11 and 12: improve the quality of figure and simplify the legend.

Response: This section of the paper has been deleted (i.e., the section on 28 days curing period).

Conclusions:

Comment: Line 498: “low volume roads” : what is the meaning?

Response: They Are roads with low traffic volume

References

Comment: Use and respect the alphabetic order, see instructions for authors.

An important part of references are local references.

Response:

Reviewer 4 Report

The article covers the topic of the Effect of Elapsed Time After Mixing on the Strength Properties of Lime – Iron Ore Tailings Treated Black cotton Soil as a Road Construction Material. In my opinion, article presents valuable content. The subject and the supporting experiments are informative and present added value to the body of knowledge on the subject area. The manuscript has good cohesion.
However, some modification should be considered:
1. Please change the numeration of major points from 1.0./2.0. form to 1/2 formula.
2. I suggest to add separated point 2 - Research significance - Please descibe here the main essence of the research. (Why presented
paper is so important? What is major innovation accent in presented studies?).
3. Please add the keyword: Road Construction Material at the first position.
4. Pleas add more details of the materials (current point 2.1) ex. size of particles, content of organic pollution.
5. Tables 1 and 2 should be presented in point 2.1. - Materials.
6. It is strongly recommended to show the content of mixtures in the table.
7. The style in lines 393-404 should be improved.
8. Plates 1-4 (I suggest to rename to figures) - please use different color when describing the photos. The current color is illegible.
9. I suppose that the number of self-citations it seems to be high. I suggest to slightly reduce the amount of self-citations by one position.
10. I suggest that major conclusions should be presented point by point.

Author Response

Comment: The article covers the topic of the Effect of Elapsed Time After Mixing on the Strength Properties of Lime – Iron Ore Tailings Treated Black cotton Soil as a Road Construction Material. In my opinion, article presents valuable content. The subject and the supporting experiments are informative and present added value to the body of knowledge on the subject area. The manuscript has good cohesion.

However, some modification should be considered:


Comment: 1. Please change the numeration of major points from 1.0./2.0. form to 1/2 formula.

Response: The numbering of major points in the paper has been changed as suggested.


Comment: 2. I suggest to add separated point 2 - Research significance - Please descibe here the main essence of the research. (Why presented
paper is so important? What is major innovation accent in presented studies?).

Response: A summary of the research significance has been provided and modified in the concluding part of the paper as : This study was focused on the improvement of BCS with lime using IOT as admixture for elapsed time after mixing up to 3 hours. The objectives were to determine the effect of elapsed time after mixing for an optimal formulation for road construction material (or equivalent.)


Comment: 3. Please add the keyword: Road Construction Material at the first position.

Response: Road Construction Material has been added to the keywords as suggested.

Comment: 4. Please add more details of the materials (current point 2.1) ex. size of particles, content of organic pollution.

Response: Additional information has been provided in the section of the manuscript as suggested.


Comment: 5. Tables 1 and 2 should be presented in point 2.1. - Materials.

Response: It is better that the tables remain in Results and Discussion. because they are results and not materials.


Comment: 6. It is strongly recommended to show the content of mixtures in the table.

Response: Inclusion of the mix ratios in the table will increase the paper length which may not be acceptable for publication.


Comment: 8. Plates 1-4 (I suggest to rename to figures) - please use different color when describing the photos. The current color is illegible.

Response: The use of other colours will not be clear as expected. Red is the only colour that can be seen on the images.


Comment: 9. I suppose that the number of self-citations it seems to be high. I suggest to slightly reduce the amount of self-citations by one position.

Response: The number of self citations has been reduced as suggested.


Comment: 10. I suggest that major conclusions should be presented point by point.

Response: The major conclusions are presented point by point in the revised manuscript as suggested.

Round 2

Reviewer 3 Report

Paper title: Effect of Elapsed Time After Mixing on the Strength 2 Properties of Lime – Iron Ore Tailings Treated Black 3 cotton Soil as a Road Construction Material- version 2

By Annafi et al

 

General comments

For readers it is difficult to understand the main objectives of some subsections in this paper (the last part).

Some information is missing for a best understanding of the choice of some suggestions and some results.

It is recommended to limit the length of the paper and to propose as objectives: effect of elapsed time after mixing for an optimal formulation for road construction material (or equivalent). Section from 3.7 or 3.8 might be suppressed.

Many comments need in the text some answers.

Comments on improvements and corrections of the revised version

List of authors:

Affiliation 1 even added with “*” must be unique. Use 2 for another one affiliation.

Abstract:

Line 12: put the brackets for (BCS) and suppress them after.

Line 16: “microstructure” will be more precise term.

Lines 20-21: are the all values useful in an abstract? No, percentages are better for readers.

Line 23: suppress the brackets after i.e.

Line 28: what means “low volume roads”? No adequate term.

Introduction

Line 48: suppress “-“ between expansion and contraction.

Line 57: As written from literature, small % of lime is generally used to treat clayey-silty soils: this % does not exceed 3-4% and depending on pH saturation point. Authors must explain why they suggest using lime up to 5%, (see line 99).

Lines 72-74: correct “tonnes”.

Line 78: what “index”? (too general).

Line 86: why authors choose 3hours not more?

Materials and methods

Write correctly 2., for the number of section

Materials:

Line 90: make an introductive sentence for soil. Do not begin by writing “Soil:”. Do the same lines 92 and 94.

Give the grain size distribution of soil and also for iron ore tailings and lime.

Methods

Line 97: make an introductive sentence for index properties. Do not begin by writing “Index properties: ”. Do the same lines 102, 105, 116 and 131.

Line 97: what index properties?

 

Line 99: Authors must clearly explain why they use such amount of lime till 8%.

Line 100: “sample size of 120”, unclear.

Line 102: it is plasticity properties.

Line 106: indicate if the energy used differs from Proctor standard? If yes, give the energy (it is around 600 kN.m/m3 , for normal Proctor). Write British Standard Light (BSL).

Line 119: why authors choose the date of 7 days?

Results and discussion:

Write correctly 3., for the number of section

Index properties:

What are index properties?

Table1: Align the different column in table. Explain the specific gravity of 2.29? Mineralogical properties, grain size distribution and granulometric nature are missing.

Table 2: correct the legend because lime percentage of oxides is also in the table. Line 1: give only the names of materials and after put (%). For IOT material total exceeds 100% why? And for lime CaO is only of 54.92%: why? Use the same font for Bernard (2011).

Atterberg limits:

Liquid limit

It is plasticity and consistency properties. This section is very detailed if it is necessary, the paper length should be reduced and the last sections be suppressed on microanalysis (not so useful because only descriptive).

Figure 2: use the same symbols a and b in legend as in the text and on figure. Why 8% lime-IOT sample has been chosen by authors? Or why in line 176: the authors write “the optimal BCS-8% lime”? idem in lines 196, 224, 285, 321, 324, 357.

Plastic limit

Lines 188-190: unclear.

Figure 3: use the same symbols a b, c, and d in legend as in the text and on figure. Do not superpose the figures.

Line 201: “lime”.

Figure 4: use the same symbols a and b in legend as in the text and on figure.

Plasticity index

Figure 5: use the same symbols a b, c, and d in legend as in the text and on figure. Do not superpose the figures.

Figure 6: use the same symbols a and b in legend as in the text and on figure.

Compaction parameters

Before discussing about MDD and OMC parameters (not characteristics), compaction curves must be presented and discussion on the displacement of these parameters towards “dry side” or wet side” must be given according IOT and lime addition.

Maximum dry density

Line 238: suppress “.’ After Fig. 7a-d”.

Figure 7: use the same symbols a b, c, and d in legend as in the text and on figure. Do not superpose the figures. In the figure legend correct “BCS-lime….” (avoid space).

Figure 8: use the same symbols a and b in legend as in the text and on figure.

Optimum moisture content

Line 271: 23.60 not 25.62 (line 288).

Figure 9: use the same symbols a b, c, and d in legend as in the text and on figure. Do not superpose the figures.

Line 286: not “d”, fig. 10a-b.

Figure 10: use the same symbols a and b in legend as in the text and on figure.

Unconfined compressive strength

Line 299: why UCS measurement for 7 and 28 days?

Lines 302-304: even with supplementary tables (too long paper) it will not easy to read the series of data. So rounded values are sufficient for readers.

Figure 11: use the same symbols a b, c, and d in legend as in the text and on figure. Do not superpose the figures. It is possible to use in Y-axis legend “UCS”.

 Figure 12: use the same symbols a and b in legend as in the text and on figure. It is possible to use in Y-axis legend “UCS”.

California bearing ratio

Line 347: “for road base materials” according BS or NGS standard?

Figure 13: use the same symbols a b, c, and d in legend as in the text and on figure. Do not superpose the figures

Lines 365-366: “for road base” and “road sub-bases”.

Lines 370-371: “road sub-grade….base”.

Figure 14: use the same symbols a and b in legend as in the text and on figure.

Regression analysis

What are the objectives of a such regression? A strong relationship exists between UCS and CBR results (plot a graph).

Line 391: but on site, compaction engines deliver a different energy as the laboratory energy used: How do authors integrate this?.

Microanalysis of specimens

Specimens cured for 7 days

Authors must justify this subsection? What is the usefulness of it? It is a rough microstructure analysis. But in my opinion from subsection 3.7, it is not very useful for readers without any justification.

Line 406: correct 3.7.1; it is “SEM image not micrograph? Write with the same font size the figures 15 and 16. For these figures write correctly the legends (optimal, blend or blended…); only one figure, for figures 15 and 16 is sufficient. Do the same for figures 17-18 and 19-20.

Improve the quality of figures 15 and 16. Do not use indications in red and correct “coarser”.

Fibremetric analysis

Fibre histograms

Authors must really justify this subsection? What is the usefulness of it?

Figures 17 and 18: Improve the quality of figure and simplify the legend. Write correctly the legend. See above, only one figure is sufficient grouping theses 2 figures.

Pore histograms

Authors must really justify this subsection? What is the usefulness of it?

Figures 19 and 20: Improve the quality of figure and simplify the legend. Write correctly the legend. See above, only one figure is sufficient grouping theses 2 figures.

Conclusions:

Line 477: “low volume roads” : what is the meaning?

References

Use and respect the alphabetic order, see instructions for authors.

 

 

Author Response

H

Author Response File: Author Response.docx

Reviewer 4 Report

All remarks have been considered by authors. Errors have been eliminated. The authors responded to all comments of the reviewer.
The current version is satisfactory for reviewer. In my opinion, article could be published.

Author Response

General comments

For readers it is difficult to understand the main objectives of some subsections in this paper (the last part).

Some information is missing for a best understanding of the choice of some suggestions and some results.

It is recommended to limit the length of the paper and to propose as objectives: effect of elapsed time after mixing for an optimal formulation for road construction material (or equivalent). Section from 3.7 or 3.8 might be suppressed.

Many comments need in the text some answers.

Comments on improvements and corrections of the revised version

List of authors:

Comment: Affiliation 1 even added with “*” must be unique. Use 2 for another one affiliation.

Response: The numbering of authors affiliation has been changed to 1,2, and 3 as suggested.

Abstract:

Comment: Line 12: put the brackets for (BCS) and suppress them after.

Response: Bracket has been provided as suggested in the article.

Comment: Line 16: “microstructure” will be more precise term.

Response: micro analysis has been changed to microstructure as suggested.

Comment: Lines 20-21: are the all values useful in an abstract? No, percentages are better for readers.

Response: The way is written is ok. The results are for two different mixes which will be confusing if changed.

Comment: Line 23: suppress the brackets after i.e.

Response: A bracket has been provided after 1.e as suggested.

Comment: Line 28: what means “low volume roads”? No adequate term.

Response:The words have been changed from low volume roads to low trafficked roads in the article

Introduction

Comment: Line 48: suppress “-“ between expansion and contraction.

Response: Not clear please

Comment: Line 57: As written from literature, small % of lime is generally used to treat clayey-silty soils: this % does not exceed 3-4% and depending on pH saturation point. Authors must explain why they suggest using lime up to 5%, (see line 99).

Response: The choice of upto 8% Lime beyond the value recommended in literatures is based on the fact that at lower lime content the desired consistency and strength properties was not achieved. Thus increase in lime concentration. From the result the strength increased with lime concentration beyond 4% lime.

Comment: Lines 72-74: correct “tonnes”.

Response: The error has been corrected.  tonnes has been changed  to tons as suggested.

Comment: Line 78: what “index”? (too general).

Response: Index properties are the basic or fundamental tests are carried out on soils prior detail test such strength or permeability etc. The basic test include atterberg limit, sieve analysis, specific gravity among others.

Comment: Line 86: why authors choose 3hours not more?

Response: Based on literatures, Maximum of 3hours delay time was used. Delay due to failure of equipment or environmental factors normally do not exceed 3 hours.

 Also, based on the result of UCS and CBR, Maximum strength was achieved at 2hours delay time. A decrease in both UCS and CBR was recorded at 3 hours.

Materials and methods

Comment: Write correctly 2., for the number of section

Response: The error has been corrected suggested.

Materials:

Comment: Line 90: make an introductive sentence for soil. Do not begin by writing “Soil:”. Do the same lines 92 and 94.

Response:  I suggest   the paper remain in its present form. Adding introductive sentence will make it look ambiguous

Methods

Comment: Line 97: make an introductive sentence for index properties. Do not begin by writing “Index properties: ”. Do the same lines 102, 105, 116 and 131.

Response: I suggest   the paper remain in its present form. Adding introductive sentence will make it look ambiguous

Comment: Line 97: what index properties?

Response:  Index properties are the basic or fundamental tests are carried out on soils prior detail test such strength or permeability etc. The basic test include atterberg limit, sieve analysis, specific gravity among others.

Comment: Line 99: Authors must clearly explain why they use such amount of lime till 8%.

Response: The choice of upto 8% Lime beyond the value recommended in literatures is based on the fact that at lower lime content the desired consistency and strength properties was not achieved. Thus increase in lime concentration. From the result the strength increased with lime concentration beyond 4% lime

Comment: Line 100: “sample size of 120”, unclear.

Response: We use 120 sample variations. The IOT, Lime and elapsed time were varied to 120 different variations. Please see the attached excel file of row results for details.

Comment: Line 102: it is plasticity properties.

Response: It has  been changed from atterberg limits to plasticity properties as suggested.

Comment: Line 106: indicate if the energy used differs from Proctor standard? If yes, give the energy (it is around 600 kN.m/m, for normal Proctor). Write British Standard Light (BSL).

Response: British Standard Light  i.e standard proctor was used with 596 kN/menergy. The information has been provided  in the paper as suggested.

Comment: Line 119: why authors choose the date of 7 days?

Response: The choice of seven days was based on past literatures of related works. 7, 14 and 28 days are commonly used as reported in several literatures.

Results and discussion:

Comment: Write correctly 3., for the number of section

Response: The error has been corrected as suggested.

Index properties:

Comment: What are index properties?

Response: :  Index properties are the basic or fundamental tests are carried out on soils prior detail test such strength or permeability etc. The basic test include atterberg limit, sieve analysis, specific gravity among others.

Comment: Table1: Align the different column in table. Explain the specific gravity of 2.29? Mineralogical properties, grain size distribution and granulometric nature are missing.

Response: An information was added to buttress more on that in the article and now reads; Previous reports by similar authors i.e (Osinubi et al.,2015 and Etim et al.,2017) showed that Montmorillonite  is the dominant clay mineral in the soil while specific gravity of 2.29 falls close to the previously reported values.

Comment: Table 2: correct the legend because lime percentage of oxides is also in the table. Line 1: give only the names of materials and after put (%). For IOT material total exceeds 100% why? And for lime CaO is only of 54.92%: why? Use the same font for Bernard (2011).

Response: The error with oxide composition has been corrected. see attached the raw laboratory result.

Atterberg limits:

Liquid limit

Comment: It is plasticity and consistency properties. This section is very detailed if it is necessary, the paper length should be reduced and the last sections be suppressed on microanalysis (not so useful because only descriptive).

Response: Reducing the paper length will reduce the paper quality

Comment: Figure 2: use the same symbols a and b in legend as in the text and on figure. Why 8% lime-IOT sample has been chosen by authors? Or why in line 176: the authors write “the optimal BCS-8% lime”? idem in lines 196, 224, 285, 321, 324, 357.

Response: All figures are numbered a and b as suggested. Optimal means the best overall results based on the different variations of lime, IOT and Elapsed time that were considered. BCS – 8 % lime - 10 % IOT mixtures. I suggest is ok as expressed in the manuscript.

Plastic limit

Comment: Figure 3: use the same symbols a b, c, and d in legend as in the text and on figure. Do not superpose the figures.

Response: The errors has been addressed as suggested. The text on the figure legend has been change to small letters  as suggested

Comment: Line 201: “lime”.

Response: Not clear please

Comment: Figure 4: use the same symbols a and b in legend as in the text and on figure.

Response: The errors  has been addressed as suggested. The text on the figure legend has been change to small letters  as suggested

Plasticity index

Comment: Figure 5: use the same symbols a b, c, and d in legend as in the text and on figure. Do not superpose the figures.

Response: The errors  has been addressed as suggested. The text on the figure legend has been change to small letters as suggested

Comment: Figure 6: use the same symbols a and b in legend as in the text and on figure.

Response: The errors  has been addressed as suggested. The text on the figure legend has been change to small letters  as suggested

Compaction parameters

Comment: Before discussing about MDD and OMC parameters (not characteristics), compaction curves must be presented and discussion on the displacement of these parameters towards “dry side” or wet side” must be given according IOT and lime addition.

Response: Providing additional discussion and compaction curves as suggested will increased the paper size beyong limit. I suggest the paper is ok in its present form.

Maximum dry density

Comment: Line 238: suppress “.’ After Fig. 7a-d”.

Response: Figure  error has been corrected as suggested.

Comment: Figure 7: use the same symbols a b, c, and d in legend as in the text and on figure. Do not superpose the figures. In the figure legend correct “BCS-lime….” (avoid space).

Response: The errors  has been addressed as suggested. The text on the figure legend has been change to small letters  as suggested

Comment: Figure 8: use the same symbols a and b in legend as in the text and on figure.

Response: The errors  has been addressed as suggested. The text on the figure legend has been change to small letters  as suggested

Optimum moisture content

Comment: Line 271: 23.60 not 25.62 (line 288).

Response: The error has been corrected is 25.62%

Comment: Figure 9: use the same symbols a b, c, and d in legend as in the text and on figure. Do not superpose the figures.

Response: The errors  has been addressed as suggested. The text on the figure legend has been change to small letters  as suggested

Comment: Line 286: not “d”, fig. 10a-b.

Response: The error has been corrected.

Comment: Figure 10: use the same symbols a and b in legend as in the text and on figure.

Response: The errors  has been addressed as suggested. The text on the figure legend has been change to small letters  as suggested

Unconfined compressive strength

Comment: Line 299: why UCS measurement for 7 and 28 days?

Response: The choice of seven days was based on past literatures of related works. 7, 14 and 28 days are commonly used as reported in several literatures. 28 days  UCS was not consider.

Comment: Lines 302-304: even with supplementary tables (too long paper) it will not easy to read the series of data. So rounded values are sufficient for readers.

Response: The decimal places has been reduced as suggested to 1 decimal place.

Comment: Figure 11: use the same symbols a b, c, and d in legend as in the text and on figure. Do not superpose the figures. It is possible to use in Y-axis legend “UCS”.

Response: The errors has been addressed as suggested. The text on the figure legend has been change to small letters  as suggested

Comment: Figure 12: use the same symbols a and b in legend as in the text and on figure. It is possible to use in Y-axis legend “UCS”.

Response: The errors  has been addressed as suggested. The text on the figure legend has been change to small letters  as suggested. Using UCS may not be good for legend. I suggest the paper is ok in its present form.

California bearing ratio

Comment: Line 347: “for road base materials” according BS or NGS standard?

Response: The error has been corrected is NGS standard

Comment: Figure 13: use the same symbols a b, c, and d in legend as in the text and on figure. Do not superpose the figures

Response: The errors has been addressed as suggested. The text on the figure legend has been change to small letters as suggested

Comment: Lines 365-366: “for road base” and “road sub-bases”.

Response: The error has been corrected and reads; base  course and sub-base  course 

Comment: Lines 370-371: “road sub-grade….base”.

Response: The error has been corrected and reads;  sub base  course and base  course 

Comment: Figure 14: use the same symbols a and b in legend as in the text and on figure.

Response: The errors  has been addressed as suggested. The text on the figure legend has been change to small letters  as suggested

Regression analysis

Comment: What are the objectives of a such regression? A strong relationship exists between UCS and CBR results (plot a graph).

Response: The regression shows relationship or effect of independent parameters i.e (Lime, IOT, Liquid limit, plasticity index, elapsed time, MDD and OMC) on UCS

Also  a relationship or effect of independent parameters i.e (Lime, IOT, Liquid limit, plasticity index, elapsed time, MDD and OMC) on CBR separately.

UCS and CBR are dependent variables and were each tested against the independent variables.

Comment: Line 391: but on site, compaction engines deliver a different energy as the laboratory energy used: How do authors integrate this?.

Response: Yes, but the desired field density is measured relative to the laboratory density obtained via compaction test. This is achieved through insitu density test in the field.

 

 

 

 

Microanalysis of specimens

Specimens cured for 7 days

Comment: Authors must justify this subsection? What is the usefulness of it? It is a rough microstructure analysis. But in my opinion from subsection 3.7, it is not very useful for readers without any justification.

Response: Microanalysis of specimens shows the soil improvement at micro level. The recorded improvement based on the laboratory results can be seen pictorially using the micro structure. This approached has been use in many published articles.

Comment: Line 406: correct 3.7.1; it is “SEM image not micrograph? Write with the same font size the figures 15 and 16. For these figures write correctly the legends (optimal, blend or blended…); only one figure, for figures 15 and 16 is sufficient. Do the same for figures 17-18 and 19-20.

Response: The  corrections suggested have been made on figures 15 to the end. Font size changed as suggested

Comment: Improve the quality of figures 15 and 16. Do not use indications in red and correct “coarser”.

Response: The picture quality has been improved as suggested. Red indications removed as suggested.

Fibremetric analysis

Fibre histograms

Comment: Authors must really justify this subsection? What is the usefulness of it?

Response: An introduction has been added to buttress more light on it in the manuscript and reads; The Fibre metric  analysis  is a SEM  integrated statistical application package that analysis data point on the sample. It automatically analyses hundreds of data points that provide solid statistical analysis. Fibremetric analysis gives results in the form of  interactive fibre and pore size distribution histograms called  Fibre histogram and pore histogram.

Comment: Figures 17 and 18: Improve the quality of figure and simplify the legend. Write correctly the legend. See above, only one figure is sufficient grouping theses 2 figures.

Response: The picture quality has been improved and figure legend simplify as suggested

Pore histograms

Comment: Comment: Authors must really justify this subsection? What is the usefulness of it?

Response: An introduction has been added to buttress more light on it in the manuscript and reads; The Fibre metric  analysis  is a SEM  integrated statistical application package that analysis data point on the sample. It automatically analyses hundreds of data points that provide solid statistical analysis. Fibremetric analysis gives results in the form of  interactive fibre and pore size distribution histograms called  Fibre histogram and pore histogram.

Figures 19 and 20: Improve the quality of figure and simplify the legend. Write correctly the legend. See above, only one figure is sufficient grouping theses 2 figures.

Response: The picture quality has been improved and figure legend simplify as suggested.

Conclusions:

Comment: Line 477: “low volume roads” : what is the meaning?

Response: It has been changed to low trafficked road.

References

Comment: Use and respect the alphabetic order, see instructions for authors.

Response: The references have been rearranged alphabetically as suggested.

 

 

 

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