Blending Plastics Waste with Highly Available Jordanian Kaolin for Preparation of Alkali-Activated Mortars

Round 1

Reviewer 1 Report (Previous Reviewer 2)

The comments were taken into consideration and the paper was improved.

Reviewer 2 Report (Previous Reviewer 3)

The paper can be accepted

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 authors have done lots of interesting experiments for a long period, but  unfortunately the experiment and the paper is not well organized and written.  Firstly, the title must be improved to attract readers attention. When I first read the title, I couldn't understand why authors use both kaolin and metakaolin and what the application would be for this material. If they use coal-fired fly ash, which is quite nice feedstock for geopolymers, their products will be more sustainable. The structure of geopolymers and nomenclature was proposed by Dadivodits that was not quoated in the text at all. The authors omitted references that have to be quoated  in many parts of the text. For mix design, too much Na was mixed in the experiments, which can be improved by looking at Prof. Kriven's paper.  XRD patterns have to be matched with the library such as JCPDF, not one of the previous studies. Line 187, dihydroxylation -> dehydroxylation. Line 188, double-layer structure of kaolin, it should be changed to 1:1 layer sturcutre (1 silica sheet + 1 alumina sheet = 1:1 layer). In fiture 1, all peaks should be assigned.  Line 220, a bracket must be removed (]). In figure 2, the letters are too small to read. The authors should agonize how effectively they can present their data. It should be better to draw one graph so that the readers can easily see the changes between patterns. Line 254-255, geopolymer is X-ray amorphous. You can see amorphous hump in X-ray patterns of geopolymers.  I don't understand why authors involve figure 3 if they think that geopolymerization result does not show in Fig. 3.  Then what figure 3 tells to readers ? Fig. 4 is not well presented with too small letters and no exis titles. Line 176, does AXS mean Bruker AXS ? You also should present the model name of your EDS detertor. Fig. 6, too samll letters and numbers. Figure and table legends are not just titles of them. They must be self-explanatory.  In Conclusions, the authors insisted that the application of their alkali-activated materials is  solified matrix for reducing the plastic waste. Then the plastic-containing materials are stored somewhere ? The key point should be put on improving the weakness of geopolymers by adding plastic wastes for some specific application.  Lastly, I recommend that the authors put a piece of their alkali-activated materials in water. If it is not geopolymer, it will crumble.

Reviewer 2 Report

The paper presents the use of kaolin and metakaolin for the preparation of alkali activated mortars containing silica sand, recyclable and non-recyclable plastics as fillers. The study includes interesting idea of reusing plastic waste to decrease the negative impact of plastics on the environment. In my opinion, the paper includes noteworthy results, but the discussion should be improved. Here are my comments:

- English should be corrected - there are a lot of grammar mistakes.

- Table 1: What kind of a polymer is Astra polymer?

- Table 2: Specify, what does it mean - mix design for 3 cubes. What are 3 cubes?

- Section 2.3: How many measurements (repetitions) were conducted? On how many samples? If the presented values are the average values, add error bars. 

- Lines 210: the lowest value in the Table 5 is 1.75 MPa, not 9 MPa. Explain.

- Table 5: Explain the difference between the results for KS and MKS based samples.

- Table 5: Explain the reduction of compressive strength with time (between 7 and 28 days).

- Use the same abbreviations for the samples over the entire paper - sometimes there is KST, sometimes KAS, MKST - MKAS, KPV - MKPV or MKPVC.

- Line 264: "... containing plastic fillers did not exhibit specific adhesion of plastic samples to geopolymer matrix." Which results support this? Where could this be observed?

- Figure 4 and Table 7: what do the numbers 1, 2,3 and 4 represent?

- Section 4.3.: What is the importance of the study of the effect of alkaline activator on the plastic samples? How was this expressed in the studied GP samples?

- Table 9: explain the negative mass change. Why were such results obtained?

 

Reviewer 3 Report

I have the following comments on this paper:

1. Abstract: It contains general information about the current paper, so I encourage the authors to add some numerical results (the main findings in this paper)

2. Keywords: it is better to replace (kaolin) by (Jordanian kaolin)

3. Introduction: I think it is unsuitable to add figure in this section, so you can remove Fig.1

4. Introduction: the authors must explain the difference between the current study and other similar studies 

5. section 2.2: In Table 3: what are the codes (KAS, KPS, KPP,....etc), I mean can you explain these abbreviations?

6. section 3.1: I think this is Fig,.2 (XRD), since you already added Fig.1 in the introduction, if you remove Fig.1 from the introduction, then you can consider the XRD as Fig.1

7. line 196: please check The values of compressive strengths of for.....

8. Please check the subscription such as the unit of the density in Tables 4 and 5

9.  Can you please improve the resolution of FTIR figure

10. Some important findings must be added in the conclusion 

11. Some of the References are old, so I encourage the authors to update the Refs and add some recent Refs (2020, 2021 and 2022)