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Article ; Online: Raw-crushed wind-turbine blade: Waste characterization and suitability for use in concrete production

Revilla-Cuesta, Víctor / Skaf, Marta / Ortega-López, Vanesa / Manso, Juan M.

Resources, Conservation & Recycling. 2023 Nov., v. 198 p.107160-

2023

Abstract: Many of the first wind-turbine installations are reaching the end of their useful life, so their blades have to be replaced. Inexpensive, sustainable, and straightforward recycling solutions are therefore needed. The conversion of turbine blades into raw ...

Abstract	Many of the first wind-turbine installations are reaching the end of their useful life, so their blades have to be replaced. Inexpensive, sustainable, and straightforward recycling solutions are therefore needed. The conversion of turbine blades into raw materials for concrete solutions is proposed in this paper, through a novel recycling process entailing non-selective cutting, crushing, and sieving of the blade walls, without component separation. The material, Raw-Crushed Wind-Turbine Blade (RCWTB), consists of fiberglass-composite fibers, polyurethane, and balsa-wood particles. It serves as concrete fibers and aggregates, according to its physical and microscopic characterizations. A customized concrete mix design and a five-stage mixing procedure with up to 6% RCWTB achieved suitable workability levels. The compressive strength of the RCWTB concrete was 40 MPa, and it had a higher load-bearing capacity and a lower carbon footprint than ordinary concrete. The results encourage research on the overall performance of RCWTB concretes.
Keywords	carbon footprint ; compression strength ; concrete ; polyurethanes ; wind turbines ; Wind-turbine blade ; Recycling ; Waste characterization ; Concrete design ; Workability and mixing process ; Compressive behavior
Language	English
Dates of publication	2023-11
Publishing place	Elsevier B.V.
Document type	Article ; Online
ZDB-ID	1498716-8
ISSN	0921-3449
ISSN	0921-3449
DOI	10.1016/j.resconrec.2023.107160
Database	NAL-Catalogue (AGRICOLA)

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Article ; Online: Strength performance of low-bearing-capacity clayey soils stabilized with ladle furnace slag.

Espinosa, Ana B / Revilla-Cuesta, Víctor / Skaf, Marta / Serrano-López, Roberto / Ortega-López, Vanesa

Environmental science and pollution research international

2023 Volume 30, Issue 45, Page(s) 101317–101342

Abstract: In this paper, the performance of ladle furnace slag (LFS), a by-product of secondary steel refining, is evaluated as a binder to stabilize clayey soils of low bearing capacity. The aim is to define whether additions of this by-product to clayey soil can ...

Abstract	In this paper, the performance of ladle furnace slag (LFS), a by-product of secondary steel refining, is evaluated as a binder to stabilize clayey soils of low bearing capacity. The aim is to define whether additions of this by-product to clayey soil can stabilize the soil in accordance with the technical specifications of Spanish standards. To do so, three different soils stabilized with 5% LFS were compared with the same soils stabilized with 2% lime and with no stabilization, in order to investigate their different behaviors. The chemical and mineralogical characterizations of all the soil mixes were conducted using X-ray fluorescence, X-ray diffraction, and scanning electron microscopy. The Atterberg limit test was used to study the plastic behavior of the soils, and the results of compaction, bearing capacity, unconfined compressive strength, and direct shear strength (cohesion and friction angle) tests defined their strength characteristics. The analysis was completed with the pH monitoring of the mixes along the curing time in order to relate the pH changes with the strength evolution. The addition of LFS to the soils has resulted in an increase in the liquid limit and plastic limit, causing therefore a slight decrease in the plasticity index. All the soils showed increases between 30% and 70% in their California Bearing Ratios immediately after mixing with 5% LFS, and after 90 days of curing, improvements of 30-188% in their unconfined compressive strength were noted in comparison with untreated soil, which were higher than the lime-stabilized soils. The cohesion of soils stabilized with LFS at 28 days of curing obtained improvements ranging from 40 to 300% depending on the type of soil. However, the friction angle showed a slight increase of 10% in two of the soils and zero in another. The high initial pH in LFS-stabilized soils was maintained during the curing time, which favored the development of pozzolanic reactions that improve the soil strength. These results confirmed that the substitution of lime with LFS is a feasible option for soil stabilization.
Language	English
Publishing date	2023-08-30
Publishing country	Germany
Document type	Journal Article
ZDB-ID	1178791-0
ISSN	1614-7499 ; 0944-1344
ISSN (online)	1614-7499
ISSN	0944-1344
DOI	10.1007/s11356-023-29375-y
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article: Using recycled aggregate concrete at a precast-concrete plant: A multi-criteria company-oriented feasibility study

Revilla-Cuesta, Víctor / Fiol, Francisco / Perumal, Priyadharshini / Ortega-López, Vanesa / Manso, Juan M.

Journal of cleaner production. 2022 Nov. 01, v. 373

2022

Abstract: Numerous test results at laboratory scale confirm the utility of Recycled Aggregate (RA) for the development of concrete that demonstrates durability and adequate in-fresh and mechanical behavior. However, feasibility evaluations of the use of RA in real ...

Abstract	Numerous test results at laboratory scale confirm the utility of Recycled Aggregate (RA) for the development of concrete that demonstrates durability and adequate in-fresh and mechanical behavior. However, feasibility evaluations of the use of RA in real industrial applications are necessary, before any large-scale industrial application of these products can begin. In this research, the feasibility of producing precast-concrete components containing large amounts of coarse RA at a precast-concrete plant is analyzed. Two Self-Compacting Concretes (SCC) were produced incorporating 0% and 100% coarse RA, respectively, at both laboratory scale (0.08 m³) and industrial scale (2 m³). Work took place at the industrial-scale facilities of a precast-concrete company that was collaborating in this study. Flowability and mechanical behavior were maintained as concrete production volumes increased, and concrete strength even increased after adding coarse RA, due to a careful mix design. However, the durability performance worsened by around 20% when produced at industrial scale, being this worsening higher whether coarse RA was used. A Multi-Criteria Decision-Making (MCDM) analysis, in which the criteria of the precast-concrete company defined the relative importance of each concrete property, showed the feasibility of manufacturing precast-SCC components containing coarse RA for interior usage, whose fundamental requirement is adequate mechanical strength. The results of the MCDM analysis also underlined the lower cost of coarse RA, making its use in SCC components cast with large concrete volumes advisable. Overall, the addition of coarse RA in the precast-concrete industry is recommended in the interests of a greener construction sector.
Keywords	concrete ; durability ; feasibility studies ; industrial applications ; multi-criteria decision making ; strength (mechanics)
Language	English
Dates of publication	2022-1101
Publishing place	Elsevier Ltd
Document type	Article
ISSN	0959-6526
DOI	10.1016/j.jclepro.2022.133873
Database	NAL-Catalogue (AGRICOLA)

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Article: Multi-criteria feasibility of real use of self-compacting concrete with sustainable aggregate, binder and powder

Revilla-Cuesta, Víctor / Skaf, Marta / Espinosa, Ana B. / Ortega-López, Vanesa

Journal of cleaner production. 2021 Nov. 20, v. 325

2021

Abstract: Replacing natural raw materials with industrial by-products can increase the sustainability of Self-Compacting Concrete (SCC), although its fresh and hardened behavior will usually worsen. The benefits of increased sustainability must therefore outweigh ... ...

Abstract	Replacing natural raw materials with industrial by-products can increase the sustainability of Self-Compacting Concrete (SCC), although its fresh and hardened behavior will usually worsen. The benefits of increased sustainability must therefore outweigh any reduction in concrete flowability and strength. These aspects can be analyzed through Multi-Criteria Decision-Making (MCDM) algorithms. In all, 19 SCC mixes were studied. One reproduced commercial SCC (limestone filler and conventional cement), the others were produced with more sustainable materials: 100% coarse Recycled Concrete Aggregate (RCA); 0%, 50% or 100% fine RCA; 45% Ground Granulated Blast-furnace Slag (GGBS); and sustainable aggregate powders such as limestone fines 0/0.5 mm and RCA powder 0/0.5 mm. Decreased flowability at 15 and at 60 min, compressive strength, modulus of elasticity, carbon footprint, and cost of mix were all studied. Both the carbon footprint and the cost were calculated considering only the composition of the SCC, without including aspects that depend on each particular case study, such as transport distances. These aspects constituted the decision-making criteria of the MCDM analysis, under which 14 scenarios were evaluated with different requirements for SCC, using 3 different algorithms (TOPSIS, AHP, and PROMETHEE). The results suggested that the ideal choice for fast concreting is a combination of GGBS, 100% coarse RCA and limestone fines, although if SCC has to be transported to the concreting point, then conventional cement should be used. Strength and stiffness can be maximized by limiting the fine RCA content to 50%. Finally, considering a versatile choice, only SCC with coarse RCA, limestone fines, GGBS and 0% fine RCA could compete with conventional SCC. Adapting the design to minimize the detrimental effects of by-products is therefore essential to promote sustainable SCC that is also commercially competitive.
Keywords	carbon footprint ; case studies ; cement ; compression strength ; concrete ; limestone ; modulus of elasticity ; multi-criteria decision making ; slags
Language	English
Dates of publication	2021-1120
Publishing place	Elsevier Ltd
Document type	Article
ISSN	0959-6526
DOI	10.1016/j.jclepro.2021.129327
Database	NAL-Catalogue (AGRICOLA)

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Article ; Online: The Outbreak of the COVID-19 Pandemic and its Social Impact on Education: Were Engineering Teachers Ready to Teach Online?

Revilla-Cuesta, Víctor / Skaf, Marta / Varona, Juan Manuel / Ortega-López, Vanesa

International journal of environmental research and public health

2021 Volume 18, Issue 4

Abstract: The major impacts of the COVID-19 pandemic are still affecting all social dimensions. Its specific impact on education is extensive and quite evident in the adaptation from Face-to-Face (F2F) teaching to online methodologies throughout the first wave of ... ...

Abstract	The major impacts of the COVID-19 pandemic are still affecting all social dimensions. Its specific impact on education is extensive and quite evident in the adaptation from Face-to-Face (F2F) teaching to online methodologies throughout the first wave of the pandemic and the strict rules on lockdown. As lesson formats changed radically, the relevance of evaluating student on-line learning processes in university degrees throughout this period became clear. For this purpose, the perceptions of engineering students towards five specific course units forming part of engineering degree courses at the University of Burgos, Spain, were evaluated to assess the quality of the online teaching they received. Comparisons were also drawn with their perceptions of the F2F teaching of the course units prior to the outbreak of the pandemic. According to the students' perceptions, the teachers possessed the technical knowledge, the social skills, and the personal capabilities (empathy and understanding of the at times troubled situation of each student) for a very abrupt adaptation of their courses to an online methodology. The shortcomings of the online teaching were related to its particularities and each teacher's personality traits. Overall, engineering teachers appeared well prepared for a situation of these characteristics and, if similar online teaching scenarios were ever repeated, the quality of engineering teaching appears to be guaranteed.
MeSH term(s)	COVID-19 ; Communicable Disease Control ; Education, Distance/trends ; Engineering/trends ; Humans ; Pandemics ; Social Change ; Spain/epidemiology ; Teaching/organization & administration ; Universities
Language	English
Publishing date	2021-02-22
Publishing country	Switzerland
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ISSN	1660-4601
ISSN (online)	1660-4601
DOI	10.3390/ijerph18042127
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Reflections throughout the COVID-19 Lockdown: What Do I Need for Successful Learning of Engineering?

Revilla-Cuesta, Víctor / Skaf, Marta / Navarro-González, Milagros / Ortega-López, Vanesa

International journal of environmental research and public health

2021 Volume 18, Issue 21

Abstract: The intention of this study was to identify the elements that engineering students consider fundamental for successful learning on engineering courses. The aim was to provide generic guidelines suitable for any engineering course with which the teaching ... ...

Abstract	The intention of this study was to identify the elements that engineering students consider fundamental for successful learning on engineering courses. The aim was to provide generic guidelines suitable for any engineering course with which the teaching may be adapted in the light of comments from students, while student learning improves. The abrupt transition from face-to-face to asynchronous online teaching due to the COVID-19 pandemic prompted reflection among students on both teaching methods. Students were invited to evaluate each method through a survey of open-ended questions, identifying useful elements for their learning. The survey was repeated over nine weeks, to obtain the views of students after they had accepted the change and had critically analyzed how to improve online teaching. A cross-coded qualitative and mixed (word counting) analysis showed that the explanation of engineering concepts should be organized, hierarchical, repetitive, and exemplified. Furthermore, the teacher should link all the activities and projects to the concepts explained and quickly solve any doubts that they raised. As a consequence of the online teaching resulting from COVID-19, the need of independent student learning and peer support was also very evident. Teaching functions are essential on engineering courses, as teachers have to explain the overall concepts carefully, identify the key concepts, and demonstrate their industrial and professional applications. Furthermore, teaching methodologies that balance these aspects with autonomy and peer support for learning on engineering courses should be promoted.
MeSH term(s)	COVID-19 ; Communicable Disease Control ; Engineering ; Humans ; Pandemics ; SARS-CoV-2
Language	English
Publishing date	2021-11-02
Publishing country	Switzerland
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2175195-X
ISSN	1660-4601 ; 1661-7827
ISSN (online)	1660-4601
ISSN	1661-7827
DOI	10.3390/ijerph182111527
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article: Performance and Durability of Porous Asphalt Mixtures Manufactured Exclusively with Electric Steel Slags.

Skaf, Marta / Pasquini, Emiliano / Revilla-Cuesta, Víctor / Ortega-López, Vanesa

Materials (Basel, Switzerland)

2019 Volume 12, Issue 20

Abstract: Electric arc furnace slag (EAFS) and ladle furnace slag (LFS) are by-products of the electric steelmaking sector with suitable properties for use in bituminous mixtures as both coarse and fine aggregates, respectively. In this research, the production of ...

Abstract	Electric arc furnace slag (EAFS) and ladle furnace slag (LFS) are by-products of the electric steelmaking sector with suitable properties for use in bituminous mixtures as both coarse and fine aggregates, respectively. In this research, the production of a porous asphalt mixture with an aggregate skeleton consisting exclusively of electric steelmaking slags (using neither natural aggregates nor fillers) is explored. The test program examines the asphalt mixtures in terms of their mechanical performance (abrasion loss and indirect tensile strength), durability (cold abrasion loss, aging, and long-term behavior), water sensitivity, skid and rutting resistance, and permeability. The results of the slag-mixes are compared with a standard mix, manufactured with siliceous aggregates and cement as filler. The porous mixes manufactured with the slags provided similar results to the conventional standard mixtures. Some issues were noted in relation to compaction difficulties and the higher void contents of the slag mixtures, which reduced their resistance to raveling. Other features linked to permeability and skid resistance were largely improved, suggesting that these mixtures are especially suitable for permeable pavements in rainy regions. In conclusion, a porous asphalt mixture was produced with 100% slag aggregates that met current standards for long-lasting and environmentally friendly mixtures.
Language	English
Publishing date	2019-10-11
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2487261-1
ISSN	1996-1944
ISSN	1996-1944
DOI	10.3390/ma12203306
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: The Outbreak of the COVID-19 Pandemic and its Social Impact on Education

Víctor Revilla-Cuesta / Marta Skaf / Juan Manuel Varona / Vanesa Ortega-López

International Journal of Environmental Research and Public Health, Vol 18, Iss 2127, p

Were Engineering Teachers Ready to Teach Online?

2021 Volume 2127

Abstract	The major impacts of the COVID-19 pandemic are still affecting all social dimensions. Its specific impact on education is extensive and quite evident in the adaptation from Face-to-Face (F2F) teaching to online methodologies throughout the first wave of the pandemic and the strict rules on lockdown. As lesson formats changed radically, the relevance of evaluating student on-line learning processes in university degrees throughout this period became clear. For this purpose, the perceptions of engineering students towards five specific course units forming part of engineering degree courses at the University of Burgos, Spain, were evaluated to assess the quality of the online teaching they received. Comparisons were also drawn with their perceptions of the F2F teaching of the course units prior to the outbreak of the pandemic. According to the students’ perceptions, the teachers possessed the technical knowledge, the social skills, and the personal capabilities (empathy and understanding of the at times troubled situation of each student) for a very abrupt adaptation of their courses to an online methodology. The shortcomings of the online teaching were related to its particularities and each teacher’s personality traits. Overall, engineering teachers appeared well prepared for a situation of these characteristics and, if similar online teaching scenarios were ever repeated, the quality of engineering teaching appears to be guaranteed.
Keywords	COVID-19 pandemic ; social science ; social activities ; human behaviors ; empathy ; face-to-face teaching ; Medicine ; R
Subject code	370
Language	English
Publishing date	2021-02-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Reflections throughout the COVID-19 Lockdown

Víctor Revilla-Cuesta / Marta Skaf / Milagros Navarro-González / Vanesa Ortega-López

International Journal of Environmental Research and Public Health, Vol 18, Iss 11527, p

What Do I Need for Successful Learning of Engineering?

2021 Volume 11527

Abstract	The intention of this study was to identify the elements that engineering students consider fundamental for successful learning on engineering courses. The aim was to provide generic guidelines suitable for any engineering course with which the teaching may be adapted in the light of comments from students, while student learning improves. The abrupt transition from face-to-face to asynchronous online teaching due to the COVID-19 pandemic prompted reflection among students on both teaching methods. Students were invited to evaluate each method through a survey of open-ended questions, identifying useful elements for their learning. The survey was repeated over nine weeks, to obtain the views of students after they had accepted the change and had critically analyzed how to improve online teaching. A cross-coded qualitative and mixed (word counting) analysis showed that the explanation of engineering concepts should be organized, hierarchical, repetitive, and exemplified. Furthermore, the teacher should link all the activities and projects to the concepts explained and quickly solve any doubts that they raised. As a consequence of the online teaching resulting from COVID-19, the need of independent student learning and peer support was also very evident. Teaching functions are essential on engineering courses, as teachers have to explain the overall concepts carefully, identify the key concepts, and demonstrate their industrial and professional applications. Furthermore, teaching methodologies that balance these aspects with autonomy and peer support for learning on engineering courses should be promoted.
Keywords	COVID-19 pandemic ; lockdown ; engineering course ; higher education ; online teaching ; face-to-face teaching ; Medicine ; R
Subject code	370
Language	English
Publishing date	2021-11-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Student Perceptions of Formative Assessment and Cooperative Work on a Technical Engineering Course

Víctor Revilla-Cuesta / Marta Skaf / Juan Manuel Manso / Vanesa Ortega-López

Sustainability, Vol 12, Iss 4569, p

2020 Volume 4569

Abstract: Formative Assessment and Cooperative Work (FACW) is a teaching methodology that promotes student learning based on peer support, both in solving problems and identifying the mistakes made through feedback. The perceptions of 49 mechanical engineering ... ...

Abstract	Formative Assessment and Cooperative Work (FACW) is a teaching methodology that promotes student learning based on peer support, both in solving problems and identifying the mistakes made through feedback. The perceptions of 49 mechanical engineering students at the University of Burgos are analyzed in this article with regard to their first practical experience of FACW methodology in a technical subject, characterized by a highly complex content and a strong link between theoretical and practical concepts. The responses of the students to two blocks of open questions were evaluated in a qualitative, mixed, and statistical analysis. Various aspects that the students raised in relation to FACW could therefore be studied, such as their points of view towards: (1) The usefulness of FACW teaching modality; and (2) their preferences regarding the optimum teaching modality. The results showed that, although the students expressed favorable opinions towards FACW, they did not consider, in general, that teamwork was necessary for optimal learning, revealing a clear dependence on formal classroom presentations for the explanation of theoretical concepts. Students considered that theoretical concepts could not be autonomously acquired. Therefore, the application of the FACW teaching methodology to these courses could be especially beneficial to favor autonomous learning and to develop teamwork skills, training engineers with the right knowledge and skills today for tomorrow’s world.
Keywords	formative assessment and cooperative work ; active and collaborative learning ; student-centered learning environments ; technical engineering subject ; mixed analysis ; autonomy ; Environmental effects of industries and plants ; TD194-195 ; Renewable energy sources ; TJ807-830 ; Environmental sciences ; GE1-350
Subject code	370
Language	English
Publishing date	2020-06-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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