Eco-Efficient Hybrid Cements: Pozzolanic, Mechanical and Abrasion Properties

Round 1

Reviewer 1 Report

The manuscript applsci-1034344, is focus on the elaboration of cementitious material from alternative waste material with pouzzolanic properties.

The paper is in general well written and the objective of the work are clearly stated. The overall presentation and discussion of the work is of good scientific level. The paper is publishable after minor revisions state below:

The title of the paper well correlated to the work and should be revised. for instance "Eco-efficient Hybrid cementitious materials from some wastes materials: Abrasion, Pouzzolanic and mechanical properties"

Introduction Line 67: "By way of example...." please revise the sentence

results and discussion: Figure 1a, the authors are ask to indicate the bands value on the graph and insert them in the text along with the structural element related.

How does the error bars on figures 3 to 6 are evaluated? On figure 6, the error on the volume lost is relatively high, in particular for HS 3 % how does the authors justified it?

Conclusion Line 384: "The main purpose of this work has been..." replace "has been" by "was"

Author Response

The manuscript applsci-1034344, is focus on the elaboration of cementitious material from alternative waste material with pouzzolanic properties.

The paper is in general well written and the objective of the work are clearly stated. The overall presentation and discussion of the work is of good scientific level. The paper is publishable after minor revisions state below:

• The title of the paper well correlated to the work and should be revised. for instance "Eco-efficient Hybrid cementitious materials from some wastes materials: Abrasion, Pouzzolanic and mechanical properties"

Thank you for this comment. We agree with reviewer and we have changed the manuscript title: Eco-efficient hybrid cements: pozzolanic, mechanical and abrasion properties.

• Introduction Line 67: "By way of example...." please revise the sentence

Thank you for this comment. We have revised the sentence.

• Results and discussion: Figure 1a, the authors are ask to indicate the bands value on the graph and insert them in the text along with the structural element related.

Thank you for this comment. However, we consider not necessary to add the bands value on the graph due to all bands are explained in the text. We think that adding more information to the graph can be confusing for the reader.

• How does the error bars on figures 3 to 6 are evaluated? On figure 6, the error on the volume lost is relatively high, in particular for HS 3 % how does the authors justified it?

Thank you for this comment. Mechanical properties were determined in mortars with a MICROTEST universal testing machine (Microtest, Madrid, Spain). Three samples of each mortar were measured at different ages of curing. This information is included in the manuscript (experimental part, line 183) (Figure 3, 4 and 6).

Figure 5 and 6: Böhme results (height loss and volume loss). In the experimental part we have the following information: “Böhme machine (Ibertest, Madrid, Spain) test was used to carry out the abrasive test on mortars in accordance with UNE-EN 13892-3 standard. The tests were carried out at room temperature. Brown fused alumina (Al2O3) was used as abrasive material, and the applied load was 294 N. Three samples of each mortar were tested. As the standard suggests, thickness reduction was measured. Moreover, mass loss in each sample was measured, and hence volume loss was determined according to Eq. 1”.

The system HS-3% presented a high error on the volume loss. However, we do not consider this to be critical since it may be that one of the tested specimens has lost a greater volume due to the greater loss of aggregate. A specific evet.

• Conclusion Line 384: "The main purpose of this work has been..." replace "has been" by "was"

Thank you for this comment. We have modified the conclusion.

Reviewer 2 Report

The paper investigates the possibility of using alternative materials to Portland cement to obtain more sustainable and durable cementitious materials. The manuscript is well written, and the topic is timely and of interest to the academic and professional communities. The paper in this form can be published in Applied Science, but before publishing I would like the authors to address the following comments:

1. Page:8; Section: 3.3

Can you explain why after using NaOH to activate the slag the compression strength is also lower compared to the reference system (CEM I)?

2. Line: 292-293;  Page: 9; Section: 3.3 and Figure 4

According to the Figure 4 presented in the paper the AAS-N system has higher total porosity compared to CEM I system although you mentioned that both alkaline activated cements have lower porosity compared to CEM I system.

Author Response

The paper investigates the possibility of using alternative materials to Portland cement to obtain more sustainable and durable cementitious materials. The manuscript is well written, and the topic is timely and of interest to the academic and professional communities. The paper in this form can be published in Applied Science, but before publishing I would like the authors to address the following comments:

1. Page:8; Section: 3.3

• Can you explain why after using NaOH to activate the slag the compression strength is also lower compared to the reference system (CEM I)?

Thank you for this comment. We agree with reviewer in this comment due to usually, when NaOH solution is used to prepare alkali-activated slag, the compressive strengths are higher compared to the reference system, in this case, CEM I. Maybe the NaOH solution used in this work could be carbonated or in bad condition, and that may be one of the reasons.

2. Line: 292-293;  Page: 9; Section: 3.3 and Figure 4

• According to the Figure 4 presented in the paper the AAS-N system has higher total porosity compared to CEM I system although you mentioned that both alkaline activated cements have lower porosity compared to CEM I system.

Thank you for this comment. We have modified in the manuscript this sentence.

Reviewer 3 Report

The present paper shows a very well-conducted study about substitution of cement components with wastes from ceramic industry. In my opinion, the topic is very interesting and very well explained by the authors, thereafter, I suggest to publish this paper with minor revisions:

• Line 205-208 and Figure 1b please indicate also the ICDD number of the mineralogical phases founded. 
• Table 4 please indicate also the standard deviation for each measured density value. 

Author Response

The present paper shows a very well-conducted study about substitution of cement components with wastes from ceramic industry. In my opinion, the topic is very interesting and very well explained by the authors, thereafter, I suggest to publish this paper with minor revisions:

• Line 205-208 and Figure 1b please indicate also the ICDD number of the mineralogical phases founded. 

Thank you for this comment. We have added the number of the ICDD number for the mineralogical phases indicated in the manuscript (number or PDF card).

• Table 4 please indicate also the standard deviation for each measured density value. 

Thank you for this comment. We have added the standard deviation in Table 4.