Shear Strength Improvement of Clay Soil Stabilized by Coffee Husk Ash

Round 1

Reviewer 1 Report

I can confirm that the subject matter of this study (Shear Strength Improvement of Clay Soil Stabilized by Coffee Husk Ash) is of interest and relevance for publication in Applied Sciences.

Dear Authors, I read with your interesting manuscript. Here are some revisions to improve it.

• ln 90-91 change sentence, “Previously…” – when? at the end of the 20th century? make it clear
• ln 110, 141: chemical composition (%) is in % of dry matter?
• ln 182: ‘2.4.2. UCS’ change to: 2.4.2. Unconfined Compression Test

Author Response

1. ln 90-91 change sentence, “Previously…” – when? at the end of the 20th century? make it clear (Answer: Thank you for suggestion. Has been clarified in line 90-91, section 1, page 2)

2. ln 110, 141: chemical composition (%) is in % of dry matter? (Answer: Has been corrected accordingly in line 113, section 2.1, page 3)

3. ln 182: ‘2.4.2. UCS’ change to: 2.4.2. Unconfined Compression Test (Answer: Has been corrected accordingly in line 183, section 2.4.2, page 5)

Reviewer 2 Report

Reviewer

MDPI - Applied Sciences

Manuscript Number: applsci- 1740107

Title: «Shear Strength Improvement of Clay Soil Stabilized by Coffee Husk Ash».

The study of these substances, like coffee husk ash for improving the condition of soils, is important for increasing soil fertility.

line 99 The purpose of the study must be specified.

line 101. 2.1. Clay Soil. Please, to write soil type according to WRB (2015)

line 141. What is LOI? How is it decrypted?

Figure 2 needs to change the title. It is not clear what these a) and b) mean without a common name for the figure.

Author Response

1. line 99 The purpose of the study must be specified. (Answer: Thank you for suggestion. The explanation has been clarified in line 93-95, section 1, page 2)

2. line 101. 2.1. Clay Soil. Please, to write soil type according to WRB (2015) (Answer: Already clarified as suggestion in line 129-131, section 2.1, page 4)

3. line 141. What is LOI? How is it decrypted? (Answer: LOI is employed in analytical chemistry, especially for mineral analysis. It involves heating a sample of the material at a given temperature until its mass stops changing.)
4. Figure 2 needs to change the title. It is not clear what these a) and b) mean without a common name for the figure. (Answer: Has been fixed accordingly in line 156, section 2.2, page 5)

Reviewer 3 Report

Comments for Autors  

1) Page 3, insert image - map Paya Kameng, Aceh Besar District, Aceh Province-Indonesia, where soil samples were taken.

2) The article does not state the estimated lifespan and stability of the soil - areas treated using coffee husk ash.

3) It was appropriate to insert a chapter comparing and analyzing (advantages, disadvantages) the presented soil treatments versus conventional cement stabilizers.

4) Briefly add to the conclusion the scientific knowledge of your research, benefits, advantages -disadvantages, practical application. Perspectives in continuing research and testing.

5) The higher value of the article would be if the area thus prepared were analyzed in detail after a certain period of operation, load and the impact of weather conditions. The article presented in this way remains only on a theoretical level without real application and testing in practice.

Comments for author File: Comments.pdf

Author Response

1. Page 3, insert image - map Paya Kameng, Aceh Besar District, Aceh Province-Indonesia, where soil samples were taken. (Answer: Thank you for the suggestion, the map has been added in line 111, section 2.1, page 3)
2. The article does not state the estimated lifespan and stability of the soil - areas treated using coffee husk ash. (Answer: We appreciate your suggestions. The reviewer's comments will be considered for further research)
3. It was appropriate to insert a chapter comparing and analyzing (advantages, disadvantages) the presented soil treatments versus conventional cement stabilizers. (Answer: We appreciate your concerns. The remarks of the reviewer will be proposed for future research. However, the insight related to current versus conventional stabilizer has been clarified in line 55-79, section 1, page 2)
4. Briefly add to the conclusion the scientific knowledge of your research, benefits, advantages -disadvantages, practical application. Perspectives in continuing research and testing. (Answer: Already provided as a recommendation from a reviewer in Line 330-333, section 4, page 11)
5. The higher value of the article would be if the area thus prepared were analyzed in detail after a certain period of operation, load and the impact of weather conditions. The article presented in this way remains only on a theoretical level without real application and testing in practice. (Answer: Thank you for the suggestions. The suggestions from the reviewer will be recommended for further study.)

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The Article aims to investigate the influence of coffee husk ash(CHA) on the strength behavior of local clayey soil. Researchers across the globe have been using different type of ash, coal, and other such materials for soil stabilisations. The  basic characterisation of soil and CHA has been done seperately. The inference on soil behavior are made by conducting elementary test, such as shear, atterberg limits etc. It is prudent to understand the microstrucutre composition and behavior after the blending and thereby  also characterize the blended soil-CHA matrix ( say before and after experimentl test). The article is simply written and easy to understand. The quality of figures can be improved. Overall the article is presented more as Consulting or Observation report.  The results are as expected abnd widely reported in exisiting literature. It is not clear that except using CHA and local soil, what is the novelty value especially in terms of new findings / methodolgy / technique in the study,? if any, it should be elaborated.  

The referencing style should be consistent and anolmalies should be addresed. The volume numbers must be presented uniformly for eg., see ref 29. Also Unwanted references/  self citation should be avoided.

 

Reviewer 2 Report

Authors tested mixture of soil and coffee husk ash in terms of various mechanical property. They could suggest that the increasing amount of coffee husk ash could increase shear strength of soils. Although the result is clear, he following points are not sufficiently addressed as a research paper.

Major points

1) Clay is a part of soil but not all the soil can be referred to as clay.

2) There was no explanation what kind of clays were included in the tested soil. It is recommended to carry out X-ray diffraction to characterize clays.

3) It was not clearly demonstrated how the tested sample for mechanical test was prepared. Eg. Powder as it is, ground powder, pressed pellet and etc.

4) There is little scientific discussion on why the strength of soil-CHA composite increased compared with soil itself. What component of soil and which part of CHA interact in macro-, micro-, nano- and molecular level should be suggested for scientific discussion.

 

Minor points

1) Too many abbreviations appeared without proper definition.

2) It is not clearly demonstrated how chemical compositions (Table 1) and grain size (Fig. 1) were measured utilizing what kinds of instruments.

3) Is there any organic contents or carbon species in the CHA (Table 3)?

Reviewer 3 Report

I can confirm that the subject matter of this study (Shear strength improvement of clay soil stabilized by coffee husk ash) is of interest and relevance for publication in Applied Sciences. The novelty of manuscript is very high and made focus in a very serious problem. The paper presents original research. Congratulations on a very interesting article. The manuscript is well written, and I have only minor comments to the Authors:

-The authors did not present any hypothesis at the beginning

-References Double check name spelling, year, page, etc. I will not check them; it is your responsibility (according to Instructions for Authors).