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CITEEC is a leader in civil and building engineering research, focusing on innovative solutions for sustainable infrastructure and advanced materials.
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Pioneering research for sustainable development
CITEEC carries out pioneering research in civil engineering, materials, sustainability and infrastructure. Thanks to multidisciplinary projects and international collaborations, scientific papers are being published that address key challenges facing the sector. This section presents the main papers and results produced by our research groups.
You can access a wide range of scientific publications, which can be filtered by subject, author, year and more. Use the filters provided to find relevant literature and learn more about each of our contributions to the advancement of knowledge.
2022
Rojo-López, Gemma; González-Fonteboa, Belén; Martínez-Abella, Fernando; González-Taboada, Iris
Rheology, durability, and mechanical performance of sustainable self-compacting concrete with metakaolin and limestone filler Journal Article
In: Case Studies in Construction Materials, vol. 17, 2022, (Cited by: 40; All Open Access, Gold Open Access, Green Open Access).
Abstract | Links | BibTeX | Tags: Aggregates, Binders, Biocompatibility, Cements, Durability, Durability performance, Efficiency, Elasticity, Environmental impact, Fillers, Life cycle, Light velocity, Lime, Limestone, Limestone filler, Material efficiency, Mechanical performance, Metakaolins, Plastic viscosity, Resistivity, Self compacting concrete, Supplementary cementitious material, Ultrasonic pulse velocity, Viscosity, Yield stress
@article{Rojo-López2022,
title = {Rheology, durability, and mechanical performance of sustainable self-compacting concrete with metakaolin and limestone filler},
author = {Gemma Rojo-López and Belén González-Fonteboa and Fernando Martínez-Abella and Iris González-Taboada},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85134035376&doi=10.1016%2fj.cscm.2022.e01143&partnerID=40&md5=0f8f839bbe6aa5f1c5456f95d4cae965},
doi = {10.1016/j.cscm.2022.e01143},
year = {2022},
date = {2022-01-01},
urldate = {2022-01-01},
journal = {Case Studies in Construction Materials},
volume = {17},
publisher = {Elsevier Ltd},
abstract = {This study analyzed the performance of self-compacting concrete with a paste composition that includes limestone filler and metakaolin replacing cement to design binary (75% cement and 25% limestone filler) and ternary binders (60% cement, 25% limestone filler and 15% metakaolin). Furthermore, to analyze the effect of the solid volume fraction (volume of sand and coarse aggregate) on concrete rheology, the concretes were designed using four volumes of paste (350 l, 400 l, 450 l and 500 l). Rheological tests were performed at three resting times to measure the viscosity and yield stress over time. The results indicated that the viscosity decreased by 43.3% when the cement was replaced by limestone filler and increased by 73.1% when the cement was replaced by 15% metakaolin while maintaining the limestone filler. These values were obtained as 27.6% and 62.2%, respectively, when the yield stress was analyzed. In addition, the hardened properties (mechanical behavior and durability) were studied by measuring the strengths at 28 days, as well as the electrical resistivity and ultrasonic pulse velocity over time. In this case, at 28 days the use of binary binder reduces the strength and resistivity (about 20%) and the employment of ternary binder reduces strength (15%) while increases the resistivity up to the double (when compared to the 100 C concrete). Moreover, to measure the efficiency of the concrete, a material index was designed that considers the fresh behavior, mechanical performance, durability, cost, and environmental impact. Self-compacting concretes with ternary binders provided the highest indices. The use of alternative materials, particularly metakaolin has been proven to be a good option to enhance concrete sustainable performance. © 2022 The Authors},
note = {Cited by: 40; All Open Access, Gold Open Access, Green Open Access},
keywords = {Aggregates, Binders, Biocompatibility, Cements, Durability, Durability performance, Efficiency, Elasticity, Environmental impact, Fillers, Life cycle, Light velocity, Lime, Limestone, Limestone filler, Material efficiency, Mechanical performance, Metakaolins, Plastic viscosity, Resistivity, Self compacting concrete, Supplementary cementitious material, Ultrasonic pulse velocity, Viscosity, Yield stress},
pubstate = {published},
tppubtype = {article}
}
This study analyzed the performance of self-compacting concrete with a paste composition that includes limestone filler and metakaolin replacing cement to design binary (75% cement and 25% limestone filler) and ternary binders (60% cement, 25% limestone filler and 15% metakaolin). Furthermore, to analyze the effect of the solid volume fraction (volume of sand and coarse aggregate) on concrete rheology, the concretes were designed using four volumes of paste (350 l, 400 l, 450 l and 500 l). Rheological tests were performed at three resting times to measure the viscosity and yield stress over time. The results indicated that the viscosity decreased by 43.3% when the cement was replaced by limestone filler and increased by 73.1% when the cement was replaced by 15% metakaolin while maintaining the limestone filler. These values were obtained as 27.6% and 62.2%, respectively, when the yield stress was analyzed. In addition, the hardened properties (mechanical behavior and durability) were studied by measuring the strengths at 28 days, as well as the electrical resistivity and ultrasonic pulse velocity over time. In this case, at 28 days the use of binary binder reduces the strength and resistivity (about 20%) and the employment of ternary binder reduces strength (15%) while increases the resistivity up to the double (when compared to the 100 C concrete). Moreover, to measure the efficiency of the concrete, a material index was designed that considers the fresh behavior, mechanical performance, durability, cost, and environmental impact. Self-compacting concretes with ternary binders provided the highest indices. The use of alternative materials, particularly metakaolin has been proven to be a good option to enhance concrete sustainable performance. © 2022 The Authors
2020
González-Taboada, Iris; González-Fonteboa, Belén; Martínez-Abella, Fernando; Seara-Paz, Sindy
Self-consolidating recycled concrete: Rheological behavior over time Journal Article
In: ACI Materials Journal, vol. 117, no. 1, pp. 3-14, 2020, ISSN: 0889325X, (cited By 1).
Abstract | Links | BibTeX | Tags: Aggregates; Cements; Concrete aggregates; Recycling; Rheology; Water absorption; Yield stress, Recycled coarse aggregate; Rheographs; Thixotropy; Time-dependent evolutions; Workability loss, Self compacting concrete
@article{González-Taboada20203,
title = {Self-consolidating recycled concrete: Rheological behavior over time},
author = {Iris González-Taboada and Belén González-Fonteboa and Fernando Martínez-Abella and Sindy Seara-Paz},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85078988138&doi=10.14359%2f51720289&partnerID=40&md5=9ccd14497149ace1ab21ca43e83d15b3},
doi = {10.14359/51720289},
issn = {0889325X},
year = {2020},
date = {2020-01-01},
urldate = {2020-01-01},
journal = {ACI Materials Journal},
volume = {117},
number = {1},
pages = {3-14},
publisher = {American Concrete Institute},
abstract = {A rheograph is a plastic viscosity-yield stress diagram that systematically reveals the effects of diverse changes on the rheological behavior of the cement-based suspension. In this work, the time-dependent rheological behavior of self-consolidating recycled concrete (SCRC) and conventional self-consolidating concrete (SCC) was compared and the effect of changes in material quantities was assessed using different rheographs. The developed analysis leads to the conclusion that differences obtained depend on the quantity of water compensated in the mixing protocol to take into account the high absorption of recycled aggregates. This fact determines the region of the curves “rheological variations – effective water to cement ratio” where concretes are designed. The high slope region of these curves will be reached when high percentages of recycled aggregate are used, when SCRC is designed with a low water-cement ratio (w/c), and/or when long-term self-consolidating behavior is measured. In these cases, a different time-dependent rheological behavior is expected from an SCRC than from an SCC; otherwise, the rheological behavior over time of an SCRC will be similar to that of an SCC. Copyright © 2020, American Concrete Institute. All rights reserved,},
note = {cited By 1},
keywords = {Aggregates; Cements; Concrete aggregates; Recycling; Rheology; Water absorption; Yield stress, Recycled coarse aggregate; Rheographs; Thixotropy; Time-dependent evolutions; Workability loss, Self compacting concrete},
pubstate = {published},
tppubtype = {article}
}
A rheograph is a plastic viscosity-yield stress diagram that systematically reveals the effects of diverse changes on the rheological behavior of the cement-based suspension. In this work, the time-dependent rheological behavior of self-consolidating recycled concrete (SCRC) and conventional self-consolidating concrete (SCC) was compared and the effect of changes in material quantities was assessed using different rheographs. The developed analysis leads to the conclusion that differences obtained depend on the quantity of water compensated in the mixing protocol to take into account the high absorption of recycled aggregates. This fact determines the region of the curves “rheological variations – effective water to cement ratio” where concretes are designed. The high slope region of these curves will be reached when high percentages of recycled aggregate are used, when SCRC is designed with a low water-cement ratio (w/c), and/or when long-term self-consolidating behavior is measured. In these cases, a different time-dependent rheological behavior is expected from an SCRC than from an SCC; otherwise, the rheological behavior over time of an SCRC will be similar to that of an SCC. Copyright © 2020, American Concrete Institute. All rights reserved,
Rojo-López, Gemma; Nunes, Sandra; González-Fonteboa, Belén; Martínez-Abella, Fernando
Quaternary blends of portland cement, metakaolin, biomass ash and granite powder for production of self-compacting concrete Journal Article
In: Journal of Cleaner Production, vol. 266, 2020, (Cited by: 47; All Open Access, Green Open Access).
Abstract | Links | BibTeX | Tags: Binary mixtures, Carbon dioxide, Cement industry, Circular economy, Compressive strength, Concrete industry, Concrete mixtures, Concrete products, Cost engineering, Designed experiments, Efficiency, Engineering properties, Industrial emissions, Industrial sector, Material efficiency, Mortar, Portland cement, Resource efficiencies, Self compacting concrete, Supplementary cementitious material, Sustainable waste management, Waste management
@article{Rojo-López2020,
title = {Quaternary blends of portland cement, metakaolin, biomass ash and granite powder for production of self-compacting concrete},
author = {Gemma Rojo-López and Sandra Nunes and Belén González-Fonteboa and Fernando Martínez-Abella},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85084552139&doi=10.1016%2fj.jclepro.2020.121666&partnerID=40&md5=432f2c1cfd49358288f98b4f03788f9d},
doi = {10.1016/j.jclepro.2020.121666},
year = {2020},
date = {2020-01-01},
urldate = {2020-01-01},
journal = {Journal of Cleaner Production},
volume = {266},
publisher = {Elsevier Ltd},
abstract = {Given the rising societal pressure towards sustainable waste management and resource efficiency, in a more circular economy, an increased use and diversification of supplementary cementitious materials (SCM) will be necessary to achieve the CO2 mitigation goals. The current study addresses the development of self-compacting concrete, replacing part of the cement (the primary source of CO2 emissions) by metakaolin and wastes derived from two industrial sectors operating in the “Galicia–North of Portugal Euroregion”: wood manufacturing and natural stone quarrying. A study was carried out at the mortar level to investigate the effect of the mix design variables on several engineering properties of the self-compacting concrete. Statistically designed experiments reveal that an increase in water/powder volume ratio has a dominant effect on the fresh state properties, whereas the water/cement weight ratio has a dominant effect on the hardened state properties. A like-for-like comparison of the proposed quaternary blends and previously studied binary/ternary blends indicates that these mixtures exhibit improved self-compacting ability, greater compressive strength, and can offer interesting opportunities to reduce the unit cost and environmental impact of self-compacting concrete per m3. Four different mortar mixtures were optimised to achieve excellent self-compacting ability yet with distinct compressive strength levels at 28 days (65, 70, 75, and 80 MPa). A single measure of the material efficiency is proposed herein to reflect the engineering properties improvement (workability, compressive strength, and durability) over its economic (unit cost) and environmental impact. © 2020 Elsevier Ltd},
note = {Cited by: 47; All Open Access, Green Open Access},
keywords = {Binary mixtures, Carbon dioxide, Cement industry, Circular economy, Compressive strength, Concrete industry, Concrete mixtures, Concrete products, Cost engineering, Designed experiments, Efficiency, Engineering properties, Industrial emissions, Industrial sector, Material efficiency, Mortar, Portland cement, Resource efficiencies, Self compacting concrete, Supplementary cementitious material, Sustainable waste management, Waste management},
pubstate = {published},
tppubtype = {article}
}
Given the rising societal pressure towards sustainable waste management and resource efficiency, in a more circular economy, an increased use and diversification of supplementary cementitious materials (SCM) will be necessary to achieve the CO2 mitigation goals. The current study addresses the development of self-compacting concrete, replacing part of the cement (the primary source of CO2 emissions) by metakaolin and wastes derived from two industrial sectors operating in the “Galicia–North of Portugal Euroregion”: wood manufacturing and natural stone quarrying. A study was carried out at the mortar level to investigate the effect of the mix design variables on several engineering properties of the self-compacting concrete. Statistically designed experiments reveal that an increase in water/powder volume ratio has a dominant effect on the fresh state properties, whereas the water/cement weight ratio has a dominant effect on the hardened state properties. A like-for-like comparison of the proposed quaternary blends and previously studied binary/ternary blends indicates that these mixtures exhibit improved self-compacting ability, greater compressive strength, and can offer interesting opportunities to reduce the unit cost and environmental impact of self-compacting concrete per m3. Four different mortar mixtures were optimised to achieve excellent self-compacting ability yet with distinct compressive strength levels at 28 days (65, 70, 75, and 80 MPa). A single measure of the material efficiency is proposed herein to reflect the engineering properties improvement (workability, compressive strength, and durability) over its economic (unit cost) and environmental impact. © 2020 Elsevier Ltd
2018
González-Taboada, Iris; González-Fonteboa, Belén; Martínez-Abella, Fernando; Seara-Paz, Sindy
Evaluation of self-compacting recycled concrete robustness by statistical approach Journal Article
In: Construction and Building Materials, vol. 176, pp. 720-736, 2018, ISSN: 09500618, (cited By 12).
Abstract | Links | BibTeX | Tags: Aggregates; Compressive strength; Concrete aggregates; Concrete mixing; Mixing; Recycling; Rheology; Robustness (control systems); Software testing, Characterization tests; Kendall's coefficient of concordance; Material characteristics; Recycled aggregates; Recycled concrete coarse aggregate; Spearman's rank correlation; Statistical approach; Sustainable construction, Self compacting concrete
@article{González-Taboada2018720,
title = {Evaluation of self-compacting recycled concrete robustness by statistical approach},
author = {Iris González-Taboada and Belén González-Fonteboa and Fernando Martínez-Abella and Sindy Seara-Paz},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85047093870&doi=10.1016%2fj.conbuildmat.2018.05.059&partnerID=40&md5=94bbc0175fab57967244b7931242f1e6},
doi = {10.1016/j.conbuildmat.2018.05.059},
issn = {09500618},
year = {2018},
date = {2018-01-01},
urldate = {2018-01-01},
journal = {Construction and Building Materials},
volume = {176},
pages = {720-736},
publisher = {Elsevier Ltd},
abstract = {The use of self-compacting recycled concrete appears as to be a very interesting technology for the sustainable construction future. However, one of the major obstacles to a more widespread use of self-compacting concrete is to obtain a robust material. Therefore, the emphasis of this work is placed on analysing both practice and theory to understand the properties that control and assess self-compacting recycled concrete robustness. Hence, forty-nine different mixes were produced with several replacement percentages of recycled concrete coarse aggregate (0, 20, 50 or 100%) and with two different mixing procedures (all aggregates in dry-state conditions or recycled aggregate with a 3% of natural moisture). The experimental program consisted of making, in the fresh state, rheological tests (a stress growth test and a flow curve test) and empirical characterization tests (slump flow, V-funnel, L-box, J-Ring and sieve segregation) at 15, 45 and 90 min from cement-water contact. In the hardened state, compressive strength was measured at 3, 7 and 28 days. All results were analysed using a statistical approach based on Kendall's coefficient of concordance and Spearman's rank correlation. This approach allowed us to successfully identify six key properties that can be measured to evaluate SCRC robustness (capacity of the material to tolerate certain variations in material characteristics and mixture parameters). For each mix, a ranking that defines its robustness category was obtained by considering all properties. Also, it showed that water control is the key factor that affects SCRC robustness. © 2018},
note = {cited By 12},
keywords = {Aggregates; Compressive strength; Concrete aggregates; Concrete mixing; Mixing; Recycling; Rheology; Robustness (control systems); Software testing, Characterization tests; Kendall's coefficient of concordance; Material characteristics; Recycled aggregates; Recycled concrete coarse aggregate; Spearman's rank correlation; Statistical approach; Sustainable construction, Self compacting concrete},
pubstate = {published},
tppubtype = {article}
}
The use of self-compacting recycled concrete appears as to be a very interesting technology for the sustainable construction future. However, one of the major obstacles to a more widespread use of self-compacting concrete is to obtain a robust material. Therefore, the emphasis of this work is placed on analysing both practice and theory to understand the properties that control and assess self-compacting recycled concrete robustness. Hence, forty-nine different mixes were produced with several replacement percentages of recycled concrete coarse aggregate (0, 20, 50 or 100%) and with two different mixing procedures (all aggregates in dry-state conditions or recycled aggregate with a 3% of natural moisture). The experimental program consisted of making, in the fresh state, rheological tests (a stress growth test and a flow curve test) and empirical characterization tests (slump flow, V-funnel, L-box, J-Ring and sieve segregation) at 15, 45 and 90 min from cement-water contact. In the hardened state, compressive strength was measured at 3, 7 and 28 days. All results were analysed using a statistical approach based on Kendall's coefficient of concordance and Spearman's rank correlation. This approach allowed us to successfully identify six key properties that can be measured to evaluate SCRC robustness (capacity of the material to tolerate certain variations in material characteristics and mixture parameters). For each mix, a ranking that defines its robustness category was obtained by considering all properties. Also, it showed that water control is the key factor that affects SCRC robustness. © 2018
González-Taboada, Iris; González-Fonteboa, Belén; Martínez-Abella, Fernando; Seara-Paz, Sindy
Thixotropy and interlayer bond strength of self-compacting recycled concrete Journal Article
In: Construction and Building Materials, vol. 161, pp. 479-488, 2018, ISSN: 09500618, (cited By 36).
Abstract | Links | BibTeX | Tags: Aggregates; Bond strength (materials); Colloids; Concretes; Mixing; Recycling; Testing; Water absorption; Yield stress, Interlayer; Interlayer bond strength; Recycled aggregates; Recycled coarse aggregate; Recycled concretes; Structural breakdown; Thixotropy; Water permeability, Self compacting concrete
@article{González-Taboada2018479,
title = {Thixotropy and interlayer bond strength of self-compacting recycled concrete},
author = {Iris González-Taboada and Belén González-Fonteboa and Fernando Martínez-Abella and Sindy Seara-Paz},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85036469517&doi=10.1016%2fj.conbuildmat.2017.11.157&partnerID=40&md5=d1bab093017d714b0c55e8191b499719},
doi = {10.1016/j.conbuildmat.2017.11.157},
issn = {09500618},
year = {2018},
date = {2018-01-01},
urldate = {2018-01-01},
journal = {Construction and Building Materials},
volume = {161},
pages = {479-488},
publisher = {Elsevier Ltd},
abstract = {This work is focused on assessing the thixotropy of self-compacting recycled concrete (SCRC) and on evaluating the interlayer bond strength. To do so, four SCRC mixes with 0%, 20%, 50%, and 100% of recycled coarse aggregate (by volume) were studied. This aggregate was used in dry-state conditions and an extra quantity of water was added during mixing in order to compensate its absorption. Three testing methods were used to assess the degree of thixotropy of SCRC: structural breakdown curves at various rotational speeds, hysteresis loop flow curves and yield stress at rest. To evaluate the effect of the structural build-up at rest on SCRC interlayer bond strength, two methods were used: flexural tests and water permeability tests. The results indicate that the increase of thixotropy and interlayer bond strength with the replacement percentage is due to the difference in the effective w/c ratio, result of the non–compensated water absorption, to the higher amount of fines in the recycled aggregates and generated from the old adhered mortar and also to the higher internal friction of recycled aggregates. Moreover, as water absorption is compensated in the mixing protocol, changes over time in the effective w/c ratio are negligible. Therefore, the thixotropic changing rate is similar in all studied mixes. © 2017 Elsevier Ltd},
note = {cited By 36},
keywords = {Aggregates; Bond strength (materials); Colloids; Concretes; Mixing; Recycling; Testing; Water absorption; Yield stress, Interlayer; Interlayer bond strength; Recycled aggregates; Recycled coarse aggregate; Recycled concretes; Structural breakdown; Thixotropy; Water permeability, Self compacting concrete},
pubstate = {published},
tppubtype = {article}
}
This work is focused on assessing the thixotropy of self-compacting recycled concrete (SCRC) and on evaluating the interlayer bond strength. To do so, four SCRC mixes with 0%, 20%, 50%, and 100% of recycled coarse aggregate (by volume) were studied. This aggregate was used in dry-state conditions and an extra quantity of water was added during mixing in order to compensate its absorption. Three testing methods were used to assess the degree of thixotropy of SCRC: structural breakdown curves at various rotational speeds, hysteresis loop flow curves and yield stress at rest. To evaluate the effect of the structural build-up at rest on SCRC interlayer bond strength, two methods were used: flexural tests and water permeability tests. The results indicate that the increase of thixotropy and interlayer bond strength with the replacement percentage is due to the difference in the effective w/c ratio, result of the non–compensated water absorption, to the higher amount of fines in the recycled aggregates and generated from the old adhered mortar and also to the higher internal friction of recycled aggregates. Moreover, as water absorption is compensated in the mixing protocol, changes over time in the effective w/c ratio are negligible. Therefore, the thixotropic changing rate is similar in all studied mixes. © 2017 Elsevier Ltd
González-Taboada, Iris; González-Fonteboa, Belén; Martínez-Abella, Fernando; Roussel, Nicolas
Robustness of self-compacting recycled concrete: analysis of sensitivity parameters Journal Article
In: Materials and Structures/Materiaux et Constructions, vol. 51, no. 1, 2018, ISSN: 13595997, (cited By 16).
Abstract | Links | BibTeX | Tags: Aggregates; Concretes; Recycling; Robustness (control systems); Sensitivity analysis; Waste management; Yield stress, Industrial tests; Plastic viscosity; Recycled coarse aggregate; Recycled concretes; Rheological change; Rheological parameter; Sensitivity parameters; Superplasticizers, Self compacting concrete
@article{González-Taboada2018,
title = {Robustness of self-compacting recycled concrete: analysis of sensitivity parameters},
author = {Iris González-Taboada and Belén González-Fonteboa and Fernando Martínez-Abella and Nicolas Roussel},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85040356995&doi=10.1617%2fs11527-017-1136-1&partnerID=40&md5=4fae90af74eb8245baecf35cf82021a2},
doi = {10.1617/s11527-017-1136-1},
issn = {13595997},
year = {2018},
date = {2018-01-01},
urldate = {2018-01-01},
journal = {Materials and Structures/Materiaux et Constructions},
volume = {51},
number = {1},
publisher = {Springer Netherlands},
abstract = {This work is focused on understanding the origin of the lower robustness detected in self-compacting recycled concretes and on identifying the parameters affecting this property to a greater extent. A reference concrete (0%) and three recycled concretes were studied. The replacement percentages of natural with recycled coarse aggregate were 20, 50 and 100% (by volume). Each baseline mix was modified using two levels of water (± W: − 3, + 3%), two levels of superplasticizer (± S: − 5, + 5%) and two levels of cement (± C: − 3, + 3%). The analysis is focused on the sensitivity parameters calculated with the variations of the results of different tests obtained with the modified mixes. Four industrial tests and two rheological tests were made at a mix age of 15 and 45 min. It could be concluded that self-compacting recycled concretes present the “Rheological parameter—∅/ ∅max” curves with higher slope than the ones of conventional self-compacting concrete. Then, when high percentages of recycled coarse aggregate are used, and when long term self-compacting behaviour is required, there is a greater possibility to reach the high slope region of high slope curves causing high rheological changes and low robustness. © 2018, RILEM.},
note = {cited By 16},
keywords = {Aggregates; Concretes; Recycling; Robustness (control systems); Sensitivity analysis; Waste management; Yield stress, Industrial tests; Plastic viscosity; Recycled coarse aggregate; Recycled concretes; Rheological change; Rheological parameter; Sensitivity parameters; Superplasticizers, Self compacting concrete},
pubstate = {published},
tppubtype = {article}
}
This work is focused on understanding the origin of the lower robustness detected in self-compacting recycled concretes and on identifying the parameters affecting this property to a greater extent. A reference concrete (0%) and three recycled concretes were studied. The replacement percentages of natural with recycled coarse aggregate were 20, 50 and 100% (by volume). Each baseline mix was modified using two levels of water (± W: − 3, + 3%), two levels of superplasticizer (± S: − 5, + 5%) and two levels of cement (± C: − 3, + 3%). The analysis is focused on the sensitivity parameters calculated with the variations of the results of different tests obtained with the modified mixes. Four industrial tests and two rheological tests were made at a mix age of 15 and 45 min. It could be concluded that self-compacting recycled concretes present the “Rheological parameter—∅/ ∅max” curves with higher slope than the ones of conventional self-compacting concrete. Then, when high percentages of recycled coarse aggregate are used, and when long term self-compacting behaviour is required, there is a greater possibility to reach the high slope region of high slope curves causing high rheological changes and low robustness. © 2018, RILEM.
2017
González-Taboada, Iris; González-Fonteboa, Belén; Martínez-Abella, Fernando; Seara-Paz, Sindy
Analysis of rheological behaviour of self-compacting concrete made with recycled aggregates Journal Article
In: Construction and Building Materials, vol. 157, pp. 18-25, 2017, ISSN: 09500618, (cited By 50).
Abstract | Links | BibTeX | Tags: Aggregate morphology; Intrinsic characteristics; Maximum packing; Recycled aggregates; Recycled coarse aggregate; Rheological behaviour; Rheological curves; Water to cement (binder) ratios, Aggregates; Cements; Concrete aggregates; Concretes; Elasticity; Mixing; Mortar; Recycling; Rheology; Viscosity; Water absorption, Self compacting concrete
@article{González-Taboada201718,
title = {Analysis of rheological behaviour of self-compacting concrete made with recycled aggregates},
author = {Iris González-Taboada and Belén González-Fonteboa and Fernando Martínez-Abella and Sindy Seara-Paz},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85029679984&doi=10.1016%2fj.conbuildmat.2017.09.076&partnerID=40&md5=752fcb73111e896433ef54171298dc84},
doi = {10.1016/j.conbuildmat.2017.09.076},
issn = {09500618},
year = {2017},
date = {2017-01-01},
urldate = {2017-01-01},
journal = {Construction and Building Materials},
volume = {157},
pages = {18-25},
publisher = {Elsevier Ltd},
abstract = {This research focuses on studying the fresh state behaviour of self-compacting recycled concrete (SCRC) using rheology as a fundamental tool. For said purpose, a reference self-compacting concrete (SCC) was designed and it was modified to obtain other two SCCs with different water to cement ratios. Lastly, the natural coarse aggregate of each SCC was replaced with recycled aggregate using three different replacement percentages, 20%, 50% and 100% (by volume). At 15 min from the contact time of water with cement (reference time), two different tests were carried out with a rheometer: a stress growth test and a flow curve test. The results show that the specificity of SCRC design lies in the quantity of extra water necessary to compensate the recycled aggregate absorption during the mixing protocol and in the intrinsic characteristics of this particular aggregate. Mainly the rough texture when both natural and recycled coarse aggregates are crushed-shaped and the fines content in the recycled aggregate and generated during mixing by the wear of old adhered mortar change the baseline mortar. All these singularities lead to different “rheological variations – (w/c)ef” curves in a SCRC compared to a SCC. The SCRC curves present higher slope than the SCC ones, so they predict higher rheological variations, especially when the w/c ratio is low. © 2017 Elsevier Ltd},
note = {cited By 50},
keywords = {Aggregate morphology; Intrinsic characteristics; Maximum packing; Recycled aggregates; Recycled coarse aggregate; Rheological behaviour; Rheological curves; Water to cement (binder) ratios, Aggregates; Cements; Concrete aggregates; Concretes; Elasticity; Mixing; Mortar; Recycling; Rheology; Viscosity; Water absorption, Self compacting concrete},
pubstate = {published},
tppubtype = {article}
}
This research focuses on studying the fresh state behaviour of self-compacting recycled concrete (SCRC) using rheology as a fundamental tool. For said purpose, a reference self-compacting concrete (SCC) was designed and it was modified to obtain other two SCCs with different water to cement ratios. Lastly, the natural coarse aggregate of each SCC was replaced with recycled aggregate using three different replacement percentages, 20%, 50% and 100% (by volume). At 15 min from the contact time of water with cement (reference time), two different tests were carried out with a rheometer: a stress growth test and a flow curve test. The results show that the specificity of SCRC design lies in the quantity of extra water necessary to compensate the recycled aggregate absorption during the mixing protocol and in the intrinsic characteristics of this particular aggregate. Mainly the rough texture when both natural and recycled coarse aggregates are crushed-shaped and the fines content in the recycled aggregate and generated during mixing by the wear of old adhered mortar change the baseline mortar. All these singularities lead to different “rheological variations – (w/c)ef” curves in a SCRC compared to a SCC. The SCRC curves present higher slope than the SCC ones, so they predict higher rheological variations, especially when the w/c ratio is low. © 2017 Elsevier Ltd
González-Taboada, Iris; González-Fonteboa, Belén; Martínez-Abella, Fernando; Carro-López, Diego
Self-compacting recycled concrete: Relationships between empirical and rheological parameters and proposal of a workability box Journal Article
In: Construction and Building Materials, vol. 143, pp. 537-546, 2017, ISSN: 09500618, (cited By 29).
Abstract | Links | BibTeX | Tags: Aggregates; Concretes; Mechanical properties; Recycling; Yield stress, Empirical parameters; Experimental program; Recycled coarse aggregate; Recycled concrete coarse aggregate; Rheological parameter; Rheological response; Time-dependent evolutions; Workability box, Self compacting concrete
@article{González-Taboada2017537,
title = {Self-compacting recycled concrete: Relationships between empirical and rheological parameters and proposal of a workability box},
author = {Iris González-Taboada and Belén González-Fonteboa and Fernando Martínez-Abella and Diego Carro-López},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85016136209&doi=10.1016%2fj.conbuildmat.2017.03.156&partnerID=40&md5=7e732bb6e374b2a917a4e93ce10b72aa},
doi = {10.1016/j.conbuildmat.2017.03.156},
issn = {09500618},
year = {2017},
date = {2017-01-01},
urldate = {2017-01-01},
journal = {Construction and Building Materials},
volume = {143},
pages = {537-546},
publisher = {Elsevier Ltd},
abstract = {An only suitable type of self-compacting recycled concrete (SCRC) for all applications does not exist, as happens with conventional self-compacting concrete (SCC). An experimental program was carried out to evaluate workability and rheology of 49 mixes of self-compacting concrete made replacing the natural coarse aggregate by recycled concrete coarse aggregate. Workability responses included the slump flow, L-box, J-Ring and sieve segregation tests. The suitability of the limits fixed with these tests for the usual applications in SCC was discussed for SCRC. Rheological responses included the stress growth and flow curve tests. Both workability and rheological responses were compared to indicate relationships between them and in order to observe if they follow the same trend in SCRC as in conventional SCC. Finally, a workability box was proposed to describe recommended combinations of both static yield stress and plastic viscosity for SCRC at 15 min from the cement-water contact, taking into account the fulfilment of several workability limits. Also, a second box was defined at 45 min to describe the time-dependent evolution of the first one. © 2017 Elsevier Ltd},
note = {cited By 29},
keywords = {Aggregates; Concretes; Mechanical properties; Recycling; Yield stress, Empirical parameters; Experimental program; Recycled coarse aggregate; Recycled concrete coarse aggregate; Rheological parameter; Rheological response; Time-dependent evolutions; Workability box, Self compacting concrete},
pubstate = {published},
tppubtype = {article}
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An only suitable type of self-compacting recycled concrete (SCRC) for all applications does not exist, as happens with conventional self-compacting concrete (SCC). An experimental program was carried out to evaluate workability and rheology of 49 mixes of self-compacting concrete made replacing the natural coarse aggregate by recycled concrete coarse aggregate. Workability responses included the slump flow, L-box, J-Ring and sieve segregation tests. The suitability of the limits fixed with these tests for the usual applications in SCC was discussed for SCRC. Rheological responses included the stress growth and flow curve tests. Both workability and rheological responses were compared to indicate relationships between them and in order to observe if they follow the same trend in SCRC as in conventional SCC. Finally, a workability box was proposed to describe recommended combinations of both static yield stress and plastic viscosity for SCRC at 15 min from the cement-water contact, taking into account the fulfilment of several workability limits. Also, a second box was defined at 45 min to describe the time-dependent evolution of the first one. © 2017 Elsevier Ltd
Carro-López, Diego; González-Fonteboa, Belén; Martínez-Abella, Fernando; González-Taboada, Iris; Brito, Jorge De; Varela-Puga, Fernando
Proportioning, Microstructure and Fresh Properties of Self-compacting Concrete with Recycled Sand Conference
vol. 171, Elsevier Ltd, 2017, ISSN: 18777058, (cited By 21).
Abstract | Links | BibTeX | Tags: Aggregates; Compressive strength; Concrete aggregates; Concretes; Mechanical properties; Microstructure; Mortar; Recycling; Sand; Structures (built objects), Fine recycled aggregate; Mechanical performance; Porosity distributions; proportioning; Real-life applications; Recycled aggregates; Recycled sands; Subsequent reduction, Self compacting concrete
@conference{Carro-López2017645,
title = {Proportioning, Microstructure and Fresh Properties of Self-compacting Concrete with Recycled Sand},
author = {Diego Carro-López and Belén González-Fonteboa and Fernando Martínez-Abella and Iris González-Taboada and Jorge De Brito and Fernando Varela-Puga},
editor = {Ueda T. Muller H. S. Tim T.C.},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85014541005&doi=10.1016%2fj.proeng.2017.01.401&partnerID=40&md5=7de5e53af9c47cfc49f52378170a6094},
doi = {10.1016/j.proeng.2017.01.401},
issn = {18777058},
year = {2017},
date = {2017-01-01},
urldate = {2017-01-01},
journal = {Procedia Engineering},
volume = {171},
pages = {645-657},
publisher = {Elsevier Ltd},
abstract = {The use of fine recycled aggregates from recycled concrete is limited due to the high absorption of the material and the subsequent reduction in mechanical performance. At the same time, Self-Compacting Concrete (SCC) uses large amounts of fines to ensure its flowability. Therefore, this type of concrete could allow the use of fine recycled aggregates. Hence, the aim of this work is to study the proportioning and the effects in the microstructure and the fresh basic properties of the use of recycled sand to produce SCC. The concrete mixes analyzed incorporate recycled sand (in percentages of 0%, 20%, 50% and 100%) and natural coarse aggregates. The mix design used an equivalent mortar, which allowed obtaining a suitable concrete that could be at the same time comparable between different replacement ratios and usable in real-life applications. During the design of the mixes with the mortars, the workability was measured from 10 min to 90 min using mini-cone and mini-funnel tests and the suitable ones were chosen to perform self-compacting concrete. Once this was done, these mixes were produced at concrete scale, and with these, basic properties were measured. The fine recycled aggregate changes the workability and the rheology of the mortar and concrete. These differences also affect the microstructure in terms of bonding and porosity distribution. There is a severe reduction of compressive and splitting strength as a result of the use of recycled sand, and this could be linked directly to these changes of the microstructure. The recommended substitution ratio with small decrease of mechanical performance is up to 20%. © 2017 The Authors.},
note = {cited By 21},
keywords = {Aggregates; Compressive strength; Concrete aggregates; Concretes; Mechanical properties; Microstructure; Mortar; Recycling; Sand; Structures (built objects), Fine recycled aggregate; Mechanical performance; Porosity distributions; proportioning; Real-life applications; Recycled aggregates; Recycled sands; Subsequent reduction, Self compacting concrete},
pubstate = {published},
tppubtype = {conference}
}
The use of fine recycled aggregates from recycled concrete is limited due to the high absorption of the material and the subsequent reduction in mechanical performance. At the same time, Self-Compacting Concrete (SCC) uses large amounts of fines to ensure its flowability. Therefore, this type of concrete could allow the use of fine recycled aggregates. Hence, the aim of this work is to study the proportioning and the effects in the microstructure and the fresh basic properties of the use of recycled sand to produce SCC. The concrete mixes analyzed incorporate recycled sand (in percentages of 0%, 20%, 50% and 100%) and natural coarse aggregates. The mix design used an equivalent mortar, which allowed obtaining a suitable concrete that could be at the same time comparable between different replacement ratios and usable in real-life applications. During the design of the mixes with the mortars, the workability was measured from 10 min to 90 min using mini-cone and mini-funnel tests and the suitable ones were chosen to perform self-compacting concrete. Once this was done, these mixes were produced at concrete scale, and with these, basic properties were measured. The fine recycled aggregate changes the workability and the rheology of the mortar and concrete. These differences also affect the microstructure in terms of bonding and porosity distribution. There is a severe reduction of compressive and splitting strength as a result of the use of recycled sand, and this could be linked directly to these changes of the microstructure. The recommended substitution ratio with small decrease of mechanical performance is up to 20%. © 2017 The Authors.
González-Taboada, Iris; González-Fonteboa, Belén; Eiras-López, Javier; Rojo-López, Gemma
Tools for the study of self-compacting recycled concrete fresh behaviour: Workability and rheology Journal Article
In: Journal of Cleaner Production, vol. 156, pp. 1 – 18, 2017, (Cited by: 88).
Abstract | Links | BibTeX | Tags: Aggregates, Concrete mixing, Concretes, Elasticity, Fresh behaviour, Mechanical properties, Mixing, Moisture, Recycled aggregates, Recycled coarse aggregate, Recycled concrete coarse aggregate, Recycled concretes, Recycling, Replacement ratio, Rheological behaviour, Rheology, Self compacting concrete, Water absorption, Workability
@article{González-Taboada20171,
title = {Tools for the study of self-compacting recycled concrete fresh behaviour: Workability and rheology},
author = {Iris González-Taboada and Belén González-Fonteboa and Javier Eiras-López and Gemma Rojo-López},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85019157098&doi=10.1016%2fj.jclepro.2017.04.045&partnerID=40&md5=dc483461bc80b8981beee59d6b2ab36b},
doi = {10.1016/j.jclepro.2017.04.045},
year = {2017},
date = {2017-01-01},
urldate = {2017-01-01},
journal = {Journal of Cleaner Production},
volume = {156},
pages = {1 – 18},
abstract = {This work studies the fresh behaviour of self-compacting recycled concrete (SCRC) with different replacement percentages of recycled concrete coarse aggregate (20, 50 and 100%). To control the high absorption of recycled aggregate, three different mixing methods are also used in each studied concrete: M1 (dry aggregate and extra water), M2 (pre-soaked aggregate) and M3 (aggregate with a 3% of natural moisture and extra water). The fresh-state properties are measured with empirical and rheological tests, both carried out at 15, 45 and 90 min from the water-cement contact. Results obtained lead to conclude that rheology is the best tool to control fresh state behaviour of SCRC mixes and that Bingham 5-lowest is the suitable model to describe their rheological behaviour. Additionally, it has been concluded that the best method to produce SCRC is to compensate the recycled aggregate absorption during mixing using an extra quantity of water. With this method, self-compacting behaviour can be maintained with all replacement percentages until 45 min, and even until 90 min when the replacement ratio does not exceed 50%. Moreover, the use of the recycled coarse aggregate with a previous moisture content involves a greater difficulty to control workability and rheology than its use in dry-state condition. © 2017 Elsevier Ltd},
note = {Cited by: 88},
keywords = {Aggregates, Concrete mixing, Concretes, Elasticity, Fresh behaviour, Mechanical properties, Mixing, Moisture, Recycled aggregates, Recycled coarse aggregate, Recycled concrete coarse aggregate, Recycled concretes, Recycling, Replacement ratio, Rheological behaviour, Rheology, Self compacting concrete, Water absorption, Workability},
pubstate = {published},
tppubtype = {article}
}
This work studies the fresh behaviour of self-compacting recycled concrete (SCRC) with different replacement percentages of recycled concrete coarse aggregate (20, 50 and 100%). To control the high absorption of recycled aggregate, three different mixing methods are also used in each studied concrete: M1 (dry aggregate and extra water), M2 (pre-soaked aggregate) and M3 (aggregate with a 3% of natural moisture and extra water). The fresh-state properties are measured with empirical and rheological tests, both carried out at 15, 45 and 90 min from the water-cement contact. Results obtained lead to conclude that rheology is the best tool to control fresh state behaviour of SCRC mixes and that Bingham 5-lowest is the suitable model to describe their rheological behaviour. Additionally, it has been concluded that the best method to produce SCRC is to compensate the recycled aggregate absorption during mixing using an extra quantity of water. With this method, self-compacting behaviour can be maintained with all replacement percentages until 45 min, and even until 90 min when the replacement ratio does not exceed 50%. Moreover, the use of the recycled coarse aggregate with a previous moisture content involves a greater difficulty to control workability and rheology than its use in dry-state condition. © 2017 Elsevier Ltd
2015
Carro-López, Diego; González-Fonteboa, Belén; Brito, Jorge De; Martínez-Abella, Fernando; González-Taboada, Iris; Silva, Pedro
Study of the rheology of self-compacting concrete with fine recycled concrete aggregates Journal Article
In: Construction and Building Materials, vol. 96, pp. 491-501, 2015, ISSN: 09500618, (cited By 140).
Abstract | Links | BibTeX | Tags: Absorption; Compressive strength; Concrete aggregates; Concretes; Elasticity; Mortar; Recycling; Rheology; Rheometers; Yield stress, Empirical test; Filling abilities; Fine recycled aggregate; Natural aggregate; Passing ability; Plastic viscosity; Recycled concrete aggregates; Recycled sands, Self compacting concrete
@article{Carro-López2015491,
title = {Study of the rheology of self-compacting concrete with fine recycled concrete aggregates},
author = {Diego Carro-López and Belén González-Fonteboa and Jorge De Brito and Fernando Martínez-Abella and Iris González-Taboada and Pedro Silva},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84939511043&doi=10.1016%2fj.conbuildmat.2015.08.091&partnerID=40&md5=c15a3d8587928d4893760dc9b0edd069},
doi = {10.1016/j.conbuildmat.2015.08.091},
issn = {09500618},
year = {2015},
date = {2015-01-01},
urldate = {2015-01-01},
journal = {Construction and Building Materials},
volume = {96},
pages = {491-501},
publisher = {Elsevier Ltd},
abstract = {Abstract This work studies the effect of incorporating fine recycled aggregates on the rheology of self-compacting concrete over time (at 15, 45 and 90 min). The fine fraction of the natural aggregates was replaced at 0%, 20%, 50% and 100% with recycled sand. The fresh-state properties were studied by empirical tests (slump-flow, J-Ring, L-Box) and fundamental ones in an ICAR rheometer. The mixes with 50% and 100% recycled sand lost their SCC characteristics at 90 min. Contrarily the mix with 20% replacement maintained suitable passing and filling ability. The causes of this trend were an initial increase of plastic viscosity and afterwards an increase of yield stress. The compressive strength of the 50% and 100% replacement mixes decreased significantly and that of the 20% replacement mix less than 10%. © 2015 Elsevier Ltd.},
note = {cited By 140},
keywords = {Absorption; Compressive strength; Concrete aggregates; Concretes; Elasticity; Mortar; Recycling; Rheology; Rheometers; Yield stress, Empirical test; Filling abilities; Fine recycled aggregate; Natural aggregate; Passing ability; Plastic viscosity; Recycled concrete aggregates; Recycled sands, Self compacting concrete},
pubstate = {published},
tppubtype = {article}
}
Abstract This work studies the effect of incorporating fine recycled aggregates on the rheology of self-compacting concrete over time (at 15, 45 and 90 min). The fine fraction of the natural aggregates was replaced at 0%, 20%, 50% and 100% with recycled sand. The fresh-state properties were studied by empirical tests (slump-flow, J-Ring, L-Box) and fundamental ones in an ICAR rheometer. The mixes with 50% and 100% recycled sand lost their SCC characteristics at 90 min. Contrarily the mix with 20% replacement maintained suitable passing and filling ability. The causes of this trend were an initial increase of plastic viscosity and afterwards an increase of yield stress. The compressive strength of the 50% and 100% replacement mixes decreased significantly and that of the 20% replacement mix less than 10%. © 2015 Elsevier Ltd.
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