Compressive Strength, Permeability, and Abrasion Resistance of Pervious Concrete Incorporating Recycled Aggregate

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This is a study of the mechanical properties, i.e. compressive strength, permeability and abrasion resistance, of pervious concrete incorporating recycled aggregates. The manuscript is well-written but needs a few revisions.

1. The abstract is well-written and contains a brief overview of the article's content and main results.

2. The introduction and material sections are clear, but I have some doubts about the loss on ignition of the SF and cement samples (table 3), because with such a high CaO content we'll get a higher LOI at 950°C, so we need to specify whether it's LOI 550°C or 950°C.

3. I think you can also use the chemical composition results that you have with the physico-chemical properties through triangular diagrams, to determine for example the effect of CaO or Silica content on the mixing properties.

In general, the manuscript is well written and the results obtained are very encouraging.

Comments on the Quality of English Language

the english of the paper is fine.

Author Response

Response 1:

Thank you very much for the strong support to our work.

Response 2:

Thank you for your guidance. We made some errors in the process of organizing the components of the material. The Table 3 in the revised version of the manuscript has been corrected.

Response 3:

Thank you for your suggestions, and we apologize for your questions about the material components in Table 3 because we made an error in organizing the material components. However, it is exciting to study the effect of CaO or silica content on the mixing properties, which we will carry out in our subsequent work.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The paper discusses the compressive strength, permeability, and abrasion resistance of pervious concrete incorporating recycled aggregate. The central argument of the paper is sound and in line with current thinking and well-focused on the topics established in the Sustainability journal. Nevertheless, it is the opinion of this reviewer that the research presented in the study is of a good international caliber that is relevant to the engineering community, however, it needs major revision. Authors are encouraged to consider the following comments and include them in their paper:

1.     The paper requires minor English Language editing and some proofreading.

2.     The authors should identify the core and highlights of the study and point out the innovations concerning other studies.

3.     Some references in the text are not given correctly. For example, on page 2, line 52: Viera [24], correctly Viera et al. [24]; on page 2, line 64: Akkaya [28], correctly Akkaya and Çağatay [28].

4.     The authors must explain why the recycled aggregate replacement rate was 50%.

5.     The meaning of “Δh” in Equation 2 is not explained (Page 6, line 144).

6.     It would be important to give the number of tested specimens for each test.

7.     The authors should cite relevant literature to compare and explain the test results.

8.  Some references in the reference list are incomplete (e.g. [28], [32], [38]). I recommend that authors check the correctness of the authors' names.

Author Response

Response 1:

The overall language of the manuscript has been improved a lot from an invited experienced English speaker who studies in our research area.

Response 2:

Thanks to your valuable suggestions, we have reworked and labeled the abstract and introduction in the revised version of the manuscript. The adjusted portion of the introduction is as follows:

(1) Third paragraph: With the continuous progress of urbanization and rapid development of infrastructure construction, a large amount of construction and demolition wastes (C&DW) has been generated, which inevitably causes environmental pollution [1-4]. The primary method for treating solid construction waste such as abandoned concrete is direct landfilling in the field, which restricts the utilization of renewable resources. Recycled coarse aggregate (RCA) is obtained by crushing and sorting abandoned concrete particles after screening and washing [5-8]. Using RCA in concrete will promote sustainable development in the construction industry and is an economical and environmentally friendly option. However, concrete prepared with RCA exhibits lower mechanical and durability properties due to the presence of microcracks within RCA [9,10]. Therefore, RCA is only suitable for non-structural or pavement projects.

 

(2) Fourth paragraph: Pervious concrete is a crucial material for sponge city construction, and its internal pores are interconnected, which can effectively reduce stormwater runoff and purify sewage. In addition, pervious concrete can reduce noise and mitigate the heat island effect. These advantages make pervious concrete widely used in constructing ecological parks, parking lots, and sidewalks [11-13]. Given the tremendous sustainability of C&DW as an alternative to natural aggregates and the multiple environmental benefits of PC, the production of PC using RCA not only highlights ecological friendliness but also contributes to the sustainability of the construction industry [14].

 

(3) Fifth paragraph: Recently, several studies have been conducted on using RCA for PC production. As the amount of RCA increases, the mechanical properties, including compressive strength and flexural strength of recycled aggregate pervious concrete (RAPC), gradually decrease, and the permeability coefficient gradually increases [15-17]. However, Guneyisi et al. [18] and Lund et al. [19] have shown that a smaller aggregate size and a lower water-cement ratio will lead to higher strength of RAPC. Lima et al. [20] found that Hydroxypropyl methylcellulose (HPMC) incorporated with 50% RCA improved the mechanical properties of RAPC without affecting its permeability when used with superplasticizer (SP). Tamimi et al. [21] found that adding date leaf fibers had a negligible effect on the compressive strength of RAPC, but its effect on the tensile strength was significant. Aliabdo et al. [22] studied the effects of various fibers and styrene-butadiene latex on the properties of RAPC. The results showed that polypropylene fiber and styrene-butadiene latex positively impact the strength index of RAPC, while rubber fibers reduce their compressive strength and tensile strength. Based on the above literature, it can be found that factors such as RCA replacement rate and particle size play a significant role in the mechanical properties and permeability of RAPC. Meanwhile, the comprehensive performance of RAPC is better when the RCA particle size is controlled in the range of 5mm-20mm, the RCA replacement rate is controlled within 50%, the water-cement ratio is controlled around 0.30, and the target porosity is controlled between 15%-25%.

 

(4) Fourth paragraph: Long-term mass loss under moving traffic loads is one of the environments in which RAPC pavements are applied. Compared with ordinary concrete, RAPC has poor abrasion resistance due to its particular pore structure and is more susceptible to external wear damage [23,24]. However, these drawbacks can be mitigated by incorporating supplementary cementitious materials (SCMs), which can enhance concrete's mechanical properties and abrasion resistance due to microfilming and pozzolanic reactivity [25]. At the same time, if SCMs can be used to produce concrete by replacing cement, greenhouse gas emissions can be reduced, and the environment can be protected [26]. Debbarma et al. [27] found that the incorporation of silica fume (SF) and bagasse ash (BA) significantly improved the abrasion resistance and resistance of concrete to chloride and sulfate ions. Ganesh and Murthy [28] investigated the effect of ground granulated blast-furnace slag (GGBS) on Ultra high-performance concrete (UHPC). The results showed that the compressive strength and split tensile strength of UHPC increased significantly with the increase in GGBS content. In addition, controlling the amount of RCA and adding fiber are also good options. Zaetanga et al. [29] studied the effect of aggregate type and substitution rate on the abrasion resistance of pervious concrete. The results showed that when the amount of RCA reached 20%, the compressive strength and abrasion resistance of pervious concrete were improved. Ipek et al. [30] found that replacing NCAs with low-density polyethylene particles can enhance the abrasion resistance of pervious concrete. Furkan Ozel et al. [31] studied the effects of different aggregates and fibers on pervious concrete. The findings indicate that incorporating steel fibers significantly enhances abrasion resistance while adding polypropylene fibers remarkably improves permeability. Although many studies have been conducted on RAPC, little attention has been paid to its long-term abrasion resistance under moving traffic loads. Furthermore, the synergistic effect of SF and GGBS on enhancing RAPC abrasion resistance has yet to be explored in detail. Given this, there is an urgent need to understand in detail the effects of SF and GGBS on the long-term performance of RAPC.

Response 3:

Thanks to your reminder, we have recorrected the author citations in the references in the revised version of the manuscript.

Response 4:

Thank you for your advice. Yes, the replacement rate of recycled aggregate has a significant impact on the strength and permeability of pervious concrete. For this reason, in our preliminary work, we used orthogonal tests to investigate the effects of recycled aggregate replacement rate, particle size, water-binder ratio, and target porosity on pervious concrete. Please refer to the annex for the specific test results.

Response 5:

Thank you for the reminder, and we apologize for our carelessness. We have recorrected the meaning of "Δh" in the revised version of the manuscript, and "H" has been replaced by "Δh".

Response 6:

Thank you for your reminder and we totally agree with your comments. We have re-given and labeled the number of specimens for the compressive strength test, the coefficient of permeability test, and the Cantabro abrasion test in the revised version of the manuscript.

Response 7:

Thanks for the reminder that explanations and literature comparisons have been given in the discussion in Section 3.6.

Response 8:

Thanks to your reminder, we have recorrected the authors' names in the revised manuscript's reference list.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript presents an experimental investigation of the engineering properties of porous concrete incorporating SCMs and RCA. Overall, my impression is that the novelty of the study is not demonstrated. Numerous studies are focusing on examining the effect of SF, GGBS, and RCA on the engineering properties of porous concrete. This paper could not sufficiently bring new knowledge into the community. The specific comments are attached below:

1. Why the particle sizes of NCA and RCA are different? How does this difference affect the following test results?

2. In Fig. 9, it is well known that permeability is a crucial parameter in evaluating the performance of porous concrete. Although the sample S7G20 shows good strength performance, compared to OPC, S7G20 has a significantly lower permeability, which is undesirable in pavement constructions using porous concrete. A sufficient justification or discussion is needed. 

3. Some mineralogical and microstructural analyses are suggested to incorporate into this study. 

 

Author Response

Response 1:

Thank you for your advice. Yes, the particle sizes of NCA and RA have a great influence on the strength and permeability of pervious concrete. For this reason, in our preliminary work, we used orthogonal tests to investigate the effects of recycled aggregate replacement rate, particle size, water-binder ratio, and target porosity on pervious concrete. Please refer to the annex for the specific test results.

Response 2:

Thank you for your feedback. The relationship between compressive strength and permeability of the RAPC is negatively correlated, and the increase in compressive strength will lead to a decrease in permeability performance. In contrast, the increase in permeability performance is unfavorable to compressive strength development. According to the essential requirement that the permeability coefficient of the material meets 0.5mm/s, greater compressive strength is more favorable to the durability of pervious concrete pavement. Compared with the OPC, the S7G20 specimen showed good strength and abrasion resistance, and its permeability coefficient also reached 1.2 mm/s, which is by CJJ/T 135-2009.

Response 3:

Thank you for this valuable comment. Yes, it is true that we did not consider the effect of the microstructure of SF and GGBS on recycled aggregate pervious concrete (RAPC). For this paper, our research centers on the effects of SF and GGBS on the compressive strength, permeability coefficient, porosity, and abrasion resistance of RAPC, with the aim of mitigating the negative environmental impacts of excess cement waste and improving the engineering properties of RAPC. In the future study, we will perform related studies for deeply and thoroughly understand this problem. Thank you very much for this creative idea.

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

 

Sunday, April 7, 2024

 

Ref.:  Manuscript titled: "Compressive strength, permeability, and abrasion resistance of pervious concrete incorporating recycled aggregate" Sustainability-2958016

 

Dear Authors,

 

I read with interest your manuscript titled:  "Compressive strength, permeability, and abrasion resistance of pervious concrete incorporating recycled aggregate" submitted for possible publication in Sustainability.

 

The manuscript introduces the performance parameters of recycled aggregate pervious concrete (RAPC) and strives to explore the optimum parameters of admixtures. The research explores the optimum mixtures of silica fume (SF) and ground granulated blast-furnace slag (GGBS) for the performance of RAPC.

The topic of recycled aggregate pervious concrete (RAPC) is widely discussed in the state-of-the-art literature(Xu, Kong et al. 2022; Xu, Li et al. 2022; Tran et al. 2024; Lima et al. 2022; Wang, X. et al. 2023; Li et al. 2023; Tamimi et al. 2023; Machado Da França and Bianchi Pereira Da Costa 2022; Wang, Z. et al. 2023; El-Hassan et al. 2023), please provide a research framework related to the state-of-the-art and stating the novelty and contribution of the present research to pervious concrete domain. The methodology includes compressive strength tests, permeability coefficient tests, porosity, and abrasion resistance tests. The findings reveal that the incorporation of GGBS and SF effectively improves the compressive strength of RAPC though reduces the permeability coefficient and porosity.

 

 

The manuscript contributes to state-of-the-art. Following are minor revisions proposed to strengthen the research novelty and contribution,

 

1.      Please elaborate the literature review with reference to the literature, please make clear statement of the research gap this manuscript is aimed at.

2.      Please add a research framework with clear presentation of the novelty and contribution of the present research to state-of-the-art research.

3.      In expression [2] line 144: please correct VL to V (L), please provide explanation how  is calculated.

4.      Please discuss the implications of the findings (RAPC) to the LCC and CO2 foot-print of roads, this can be significant contribution and highly relevant to the journal readership.

5.      Please provide a thought-provoking discussion with reference to the above revisions.

6.      Please discuss the research limitations.

7.      Please update the abstract with reference to the revisions.

 

Good luck!

 

Ref.

El-Hassan, H., Kianmehr, P., Tavakoli, D., El-Mir, A., and Dehkordi, R. S. (2023). "Synergic effect of recycled aggregates, waste glass, and slag on the properties of pervious concrete." Developments in the Built Environment, 15.

Li, F., Cai, X., Zhang, Y., Guo, X., and Jiang, M. (2023). "Mechanical and Permeability Analysis and Optimization of Recycled Aggregate Pervious Concrete Based on Response Surface Method." Journal of Renewable Materials, 11(4), 1745.

Lima, G. T. D. S., Rocha, J. C., and Cheriaf, M. (2022). "Investigation of the properties of pervious concrete with a recycled aggregate designed with a new combination of admixture." Construction and Building Materials, 340.

Machado Da França, A. P., and Bianchi Pereira Da Costa, F. (2022). "Evaluating the effect of recycled concrete aggregate and sand in pervious concrete paving blocks." Road Materials and Pavement Design, 24(2), 560.

Tamimi, A., Tabsh, S. W., and El-Emam, M. (2023). "Pervious Concrete Made with Recycled Coarse Aggregate and Reinforced with Date Palm Leaves Fibers." Materials, 16(23),.

Tran, T. N. H., Kaur, H., Sukcharoen, T., Pulngern, T., Sata, V., Jaturapitakkul, C., Ban, C. C., and Tangchirapat, W. (2024). "Application of ultra high-performance mortar for producing high-performance pervious concrete with low carbon emissions and cost." Journal of Building Engineering, 86.

Wang, X., Liu, X., Wu, Y., Zhu, P., Liu, H., Chen, C., and Wang, F. (2023). "Road use and electrothermal performance of graphene-conductive asphalt-recycled pervious concrete under severe cold environment." Construction and Building Materials, 400.

Wang, Z., Chen, L., Zhang, W., and Zhang, K. (2023). "Environmental compatibility of pervious concrete with recycled coarse aggregate applying in riparian buffer area." Construction and Building Materials, 411.

Xu, F., Kong, F., Xiong, Q., Li, Y., Zhu, J., Sun, T., Peng, C., and Lin, J. (2022). "Internal interfacial interaction analysis of geopolymer-recycled aggregate pervious concrete based on a infiltration model." Construction and Building Materials, 333.

Xu, F., Li, X., Xiong, Q., Li, Y., Zhu, J., Yang, F., Sun, T., Peng, C., and Lin, J. (2022). "Influence of aggregate reinforcement treatment on the performance of geopolymer recycled aggregate permeable concrete: From experimental studies to PFC 3D simulations." Construction and Building Materials, 354.

 

 

Author Response

Response 1:

Thank you for your suggestions, we have reviewed the literature you provided and made modifications and updates to our literature section. At the same time, we have reworked the abstract and introduction. The adjusted portion of the introduction is as follows:

(1) Third paragraph: With the continuous progress of urbanization and rapid development of infrastructure construction, a large amount of construction and demolition wastes (C&DW) has been generated, which inevitably causes environmental pollution [1-4]. The primary method for treating solid construction waste such as abandoned concrete is direct landfilling in the field, which restricts the utilization of renewable resources. Recycled coarse aggregate (RCA) is obtained by crushing and sorting abandoned concrete particles after screening and washing [5-8]. Using RCA in concrete will promote sustainable development in the construction industry and is an economical and environmentally friendly option. However, concrete prepared with RCA exhibits lower mechanical and durability properties due to the presence of microcracks within RCA [9,10]. Therefore, RCA is only suitable for non-structural or pavement projects.

 

(2) Fourth paragraph: Pervious concrete is a crucial material for sponge city construction, and its internal pores are interconnected, which can effectively reduce stormwater runoff and purify sewage. In addition, pervious concrete can reduce noise and mitigate the heat island effect. These advantages make pervious concrete widely used in constructing ecological parks, parking lots, and sidewalks [11-13]. Given the tremendous sustainability of C&DW as an alternative to natural aggregates and the multiple environmental benefits of PC, the production of PC using RCA not only highlights ecological friendliness but also contributes to the sustainability of the construction industry [14].

 

(3) Fifth paragraph: Recently, several studies have been conducted on using RCA for PC production. As the amount of RCA increases, the mechanical properties, including compressive strength and flexural strength of recycled aggregate pervious concrete (RAPC), gradually decrease, and the permeability coefficient gradually increases [15-17]. However, Guneyisi et al. [18] and Lund et al. [19] have shown that a smaller aggregate size and a lower water-cement ratio will lead to higher strength of RAPC. Lima et al. [20] found that Hydroxypropyl methylcellulose (HPMC) incorporated with 50% RCA improved the mechanical properties of RAPC without affecting its permeability when used with superplasticizer (SP). Tamimi et al. [21] found that adding date leaf fibers had a negligible effect on the compressive strength of RAPC, but its effect on the tensile strength was significant. Aliabdo et al. [22] studied the effects of various fibers and styrene-butadiene latex on the properties of RAPC. The results showed that polypropylene fiber and styrene-butadiene latex positively impact the strength index of RAPC, while rubber fibers reduce their compressive strength and tensile strength. Based on the above literature, it can be found that factors such as RCA replacement rate and particle size play a significant role in the mechanical properties and permeability of RAPC. Meanwhile, the comprehensive performance of RAPC is better when the RCA particle size is controlled in the range of 5mm-20mm, the RCA replacement rate is controlled within 50%, the water-cement ratio is controlled around 0.30, and the target porosity is controlled between 15%-25%.

 

(4) Fourth paragraph: Long-term mass loss under moving traffic loads is one of the environments in which RAPC pavements are applied. Compared with ordinary concrete, RAPC has poor abrasion resistance due to its particular pore structure and is more susceptible to external wear damage [23,24]. However, these drawbacks can be mitigated by incorporating supplementary cementitious materials (SCMs), which can enhance concrete's mechanical properties and abrasion resistance due to microfilming and pozzolanic reactivity [25]. At the same time, if SCMs can be used to produce concrete by replacing cement, greenhouse gas emissions can be reduced, and the environment can be protected [26]. Debbarma et al. [27] found that the incorporation of silica fume (SF) and bagasse ash (BA) significantly improved the abrasion resistance and resistance of concrete to chloride and sulfate ions. Ganesh and Murthy [28] investigated the effect of ground granulated blast-furnace slag (GGBS) on Ultra high-performance concrete (UHPC). The results showed that the compressive strength and split tensile strength of UHPC increased significantly with the increase in GGBS content. In addition, controlling the amount of RCA and adding fiber are also good options. Zaetanga et al. [29] studied the effect of aggregate type and substitution rate on the abrasion resistance of pervious concrete. The results showed that when the amount of RCA reached 20%, the compressive strength and abrasion resistance of pervious concrete were improved. Ipek et al. [30] found that replacing NCAs with low-density polyethylene particles can enhance the abrasion resistance of pervious concrete. Furkan Ozel et al. [31] studied the effects of different aggregates and fibers on pervious concrete. The findings indicate that incorporating steel fibers significantly enhances abrasion resistance while adding polypropylene fibers remarkably improves permeability. Although many studies have been conducted on RAPC, little attention has been paid to its long-term abrasion resistance under moving traffic loads. Furthermore, the synergistic effect of SF and GGBS on enhancing RAPC abrasion resistance has yet to be explored in detail. Given this, there is an urgent need to understand in detail the effects of SF and GGBS on the long-term performance of RAPC.

Response 3:

Thank you for your careful review, but here, "V" and "L" are two separate parameters, "V" stands for the amount of water flowing through the sample in a certain period of time, and "L" stands for the height of the sample. V" is the amount of water that flows through the specimen in a certain period of time, and "L" is the height of the specimen.

Response 4:

Thanks to your suggestion, we have added some implications for CO₂ in the discussion section. Yes, it would be significant to study the effect of RPAC on LCC and CO₂ foot-print. We are working on this and thank you so much for this great idea.

Response 5:

Thanks to your advice, we have revised the discussion section in the revised version of the manuscript.

Response 6:

Thank you for your comments. For this paper, our research centers on the effects of SF and GGBS on the compressive strength, permeability coefficient, porosity, and abrasion resistance of RAPC, with the aim of mitigating the negative environmental impacts of excess cement waste and improving the engineering properties of RAPC. However, the intrinsic mechanism of RAPC enhancement by SF and GGBS needed to be better-reflected. In future studies, we will carry out relevant microstructural analyses to gain a deep and thorough understanding of these issues.

Response 7:

Thank you for your suggestion, we have reworked the abstract, and the specific changes are listed below:

Abstract: Extensive use of cement in the construction industry increases CO₂ emissions and has a negative impact on the environment. In this work, recycled coarse aggregate (RCA) from construction and demolition wastes (C&DW) was used to fabricate sustainable pervious concrete (PC). In order to mitigate the environmental hazards of excess cement waste and to improve the engineering properties of PC, silica fume (SF) and ground granulated blast-furnace slag (GGBS) were added. The effects of SF and GGBS on the compressive strength, permeability coefficient, porosity, and abrasion resistance of recycled aggregate pervious concrete (RAPC) were investigated. Results show that the incorporation of GGBS and SF effectively improves the compressive strength of RAPC but reduces the permeability coefficient and porosity. Moreover, due to the filling effect and pozzolanic activity, the incorporation of GGBS and SF significantly enhances the abrasion resistance of RAPC. Furthermore, the relationships between compressive strength, permeability coefficient, porosity, and abrasion resistance of RAPC are clarified. The optimum replacement is achieved when the SF content is 7%, and the GGBS content is 20%, respectively, which results in the highest compressive strength (28.9 MPa) and the lowest permeability coefficient (1.2mm/s) at 28 days, and the lowest mass loss rate (12.1%) after Cantabro abrasion test.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

I accept corrections and revisions by the authors. I recommend the manuscript for publication.