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Publikasjoner (10 av 15) Visa alla publikasjoner
Sadagopan, M., Loubani, H., Kadawo, A. & Nagy, A. (2024). Optimized milling technique for glass recycling: Glass waste as cement replacement.
Åpne denne publikasjonen i ny fane eller vindu >>Optimized milling technique for glass recycling: Glass waste as cement replacement
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2024 (engelsk)Rapport (Annet vitenskapelig)
HSV kategori
Forskningsprogram
Resursåtervinning
Identifikatorer
urn:nbn:se:hb:diva-32577 (URN)
Prosjekter
Vinnova project- Circular and climate-reduced concrete
Tilgjengelig fra: 2024-09-20 Laget: 2024-09-20 Sist oppdatert: 2024-09-23bibliografisk kontrollert
Kadawo, A., Sadagopan, M., During, O., Bolton, K. & Nagy, A. (2023). Combination of LCA and circularity index for assessment of environmental impact of recycled aggregate concrete. Journal of Sustainable Cement-Based Materials, 12(1)
Åpne denne publikasjonen i ny fane eller vindu >>Combination of LCA and circularity index for assessment of environmental impact of recycled aggregate concrete
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2023 (engelsk)Inngår i: Journal of Sustainable Cement-Based Materials, ISSN 2165-0373, E-ISSN 2165-0381, Vol. 12, nr 1Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Multidisciplinary approach is used to evaluate concrete with recycled concrete aggregates (RCA) from technical, environmental impacts and product circularity perspectives. Two RCA replacements investigated, RAC50: fine aggregates; RAC100: both coarse, fine aggregates. Reference, recycled concretes have same cement content, similar workability and compressive strength requirement, proven experimentally. RCA is sourced from pre-fab element discards of a Swedish plant, the logistical alternatives requiring environmental impact analysis. Alternatives are RCA crushing at plant and crushing at a different location including transportation. LCA shows transportation is second largest contributor after cement in all impact categories. RAC alternatives show lower total impact than reference concrete due to RCA replacement. A circularity index for concrete based on economic value of recirculated aggregates; supplements LCA for sustainability reporting. Circularity index results: RAC100 > RAC50 > RC. Combining circularity index with LCA helps optimize recycling process with regard to amount of recycled material and logistics respectively.

Emneord
Concrete recycling, recycled aggregate, LCA, circular economy, sustainability, LIFE-CYCLE ASSESSMENT, HYDRATED CEMENT
HSV kategori
Identifikatorer
urn:nbn:se:hb:diva-27666 (URN)10.1080/21650373.2021.2004562 (DOI)000743439500001 ()2-s2.0-85122887571 (Scopus ID)
Merknad

Times Cited in Web of Science Core Collection: 0 Total Times Cited: 0 Cited Reference Count: 38

Tilgjengelig fra: 2022-03-21 Laget: 2022-03-21 Sist oppdatert: 2024-01-16bibliografisk kontrollert
Sadagopan, M., Oliva Rivera, A., Malaga, K. & Nagy, A. (2023). Recycled Fine and Coarse Aggregates’ Contributions to the Fracture Energy and Mechanical Properties of Concrete. Materials, 16(19), Article ID 6437.
Åpne denne publikasjonen i ny fane eller vindu >>Recycled Fine and Coarse Aggregates’ Contributions to the Fracture Energy and Mechanical Properties of Concrete
2023 (engelsk)Inngår i: Materials, E-ISSN 1996-1944, Vol. 16, nr 19, artikkel-id 6437Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

This paper investigates the fracture mechanical properties of concrete, using crushed concrete aggregates (CCA) and granulated blast furnace slag (GGBS) for partial cement replacement. CCAs made from prefabricated concrete replace 100% of the fine and coarse fractions in concrete recipes with w/c ratios of 0.42 and 0.48. Two pre-treatment methods, mechanical pre-processing (MPCCA) and accelerated carbonation (CO2CCA), are investigated for quality improvements in CCA. The resulting aggregates show an increased density, contributing to an increase in the concrete’s compressive strength. The novelty of this paper is the superposition of the effects of the composite parts of concrete, the aggregate and the cement mortar, and their contributions to concrete fracture. Investigations are directed toward the influence of fine aggregates on mortar samples and the influence of the combination of coarse and fine aggregates on concrete samples. The physical and mechanical properties of the aggregates are correlated with mortar and concrete fracture properties. The results show that CCA concrete achieves 70% of the fracture energy values of concrete containing natural aggregates, and this value increases to 80% for GGBS mixes. At lower w/c ratios, MPCCA and CO2CCA concretes show similar fracture energies. CO2CCA fine aggregates are the most effective at strengthening the mortar phase, showing ductile concrete behavior at a w/c ratio of 0.48. MPCCA aggregates contribute to higher compressive strengths for w/c ratios of 0.42 and 0.48. Thus, mechanical pre-processing can be improved to produce CCA, which contributes to more ductile concrete behavior.

Emneord
fracture mechanics, recycled fine aggregates, recycled coarse aggregates, climate-reduced concrete, eco-concrete, mechanical preprocessing, accelerated carbonation
HSV kategori
Identifikatorer
urn:nbn:se:hb:diva-30699 (URN)10.3390/ma16196437 (DOI)001083005400001 ()2-s2.0-85174006362 (Scopus ID)
Forskningsfinansiär
Swedish Research Council Formas, FR-2021/0004
Merknad

 This research was funded by the FORMAS-A Swedish research council for sustainabledevelopment. Project title: Construction waste as a carbon dioxide sink and raw material for newproduction. Decision number: FR-2021/0004.

Tilgjengelig fra: 2023-09-28 Laget: 2023-10-31 Sist oppdatert: 2024-07-04bibliografisk kontrollert
Sadagopan, M., Malaga, K., Lundin, M. & Nagy, A. (2021). Effects of Slag Addition and Mechanical Pre-Processing on the Properties of Recycled Concrete in Terms of Compressive Strength and Workability. Nordic Concrete Research, 64(1), 11-29
Åpne denne publikasjonen i ny fane eller vindu >>Effects of Slag Addition and Mechanical Pre-Processing on the Properties of Recycled Concrete in Terms of Compressive Strength and Workability
2021 (engelsk)Inngår i: Nordic Concrete Research, ISSN 0800-6377, Vol. 64, nr 1, s. 11-29Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Concrete waste as crushed concrete aggregates (CCA) in structural concrete prolongs the technical life of the reference concrete accomplishing closed loop recycling. CCA concrete reaches the reference concrete compressive strength and workability by the densification of CCA and cement paste. Our previous study demonstrates CCA densification by mechanical pre-processing, aggregate quality improvements discerned by increased packing density giving reference concrete strength and workability. This study addresses paste densification with blast furnace slag (GGBS) to replace 30 (wt.%) of Portland cement at reference concrete w/b ratio 0.5 and a lower w/b 0.42. Two CCA replacements are investigated: fine aggregates, CCA50; overall aggregate replacement, CCA100. Compressive strength results show that both CCA50, CCA100 mixes achieve reference values at w/b 0.42, only CCA100 achieves reference value at w/b 0.5 as a climate-optimized concrete. The CCA50 mix-w/b 0.5 reaches reference strength when paste densification by GGBS is combined with CCA densification from mechanical pre-processing of aggregates. The 7-day strength of CCA100 with GGBS increases by 11% by mixing with pre-soaked GGBS. Statistical analysis of CCA100 strength results shows significant improvements with GGBS compared to mechanical pre-processing. Significant improvements are possible in CCA50 mix for a combination of mechanical pre-processed aggregates and GGBS replacement.

Emneord
Recycled concrete, 100% recycled aggregates, Supplementary cementitious materials, Blast furnace slag, Sustainability, Green concrete, climate-optimized concrete, SELF-COMPACTING CONCRETE, CEMENT REPLACEMENT, FLY-ASH, PHYSICAL-PROPERTIES, AGGREGATE CONCRETE, DURABILITY, BEHAVIOR, GLASS, PERFORMANCE, COARSE
HSV kategori
Forskningsprogram
Resursåtervinning
Identifikatorer
urn:nbn:se:hb:diva-27085 (URN)10.2478/ncr-2020-0018 (DOI)000727315800003 ()
Tilgjengelig fra: 2021-12-16 Laget: 2021-12-16 Sist oppdatert: 2024-02-01bibliografisk kontrollert
Nagy, A., Ringsberg, H. & Sadagopan, M. (2021). Regional recycling of concrete: prestudy. Borås
Åpne denne publikasjonen i ny fane eller vindu >>Regional recycling of concrete: prestudy
2021 (engelsk)Rapport (Annet vitenskapelig)
sted, utgiver, år, opplag, sider
Borås: , 2021
Emneord
concrete recycling, survey study, sustainability, logistics, betong återvinning
HSV kategori
Forskningsprogram
Resursåtervinning
Identifikatorer
urn:nbn:se:hb:diva-25634 (URN)
Prosjekter
RE:Concrete
Tilgjengelig fra: 2021-06-24 Laget: 2021-06-24 Sist oppdatert: 2021-08-16bibliografisk kontrollert
Sadagopan, M., Malaga, K. & Nagy, A. (2020). Improving Recycled Aggregate Quality by Mechanical Pre-Processing. Materials, 13(19)
Åpne denne publikasjonen i ny fane eller vindu >>Improving Recycled Aggregate Quality by Mechanical Pre-Processing
2020 (engelsk)Inngår i: Materials, Vol. 13, nr 19Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Concrete with crushed concrete aggregates (CCA) shows lesser compressive strength than reference concrete with natural aggregates. The goal of this study is to improve the strength of structural concrete with 53% and 100% CCA replacements without increasing the cement content. Thus, improvements in CCA quality are induced by combining mechanical and pre-soaking pre-processing techniques. Mechanical pre-processing by rotating drum is separately pursued on fine and coarse CCA for 10 and 15 min respectively. Results show, adhered mortar content and CCA water absorption reduces as pre-processing duration increases. Pre-processing influences CCA particle grading, flakiness index, shape index, void-content, unit-weight and density, jointly seen as packing density, which increases with pre-processing duration. Water amount to pre-soak CCA before concrete mixing is stable despite grading modifications, due to reduced water absorption resulting from mechanical pre-processing. Compressive strength and workability for pre-processed CCA50 and CCA100 concrete are comparable to reference concrete and show similar trends of improvement with packing density. Packing density markedly shows the quality improvements induced by pre-processing on CCA, maybe considered as one of the quality assessment indexes for CCA. Packing density should be investigated for other recipes to see the stability of the trend with workability and compressive strength.

sted, utgiver, år, opplag, sider
MDPI, 2020
Emneord
concrete recycling; sustainability; recycled aggregates; mechanical pre-processing; aggregate quality; packing density; aggregate shape; compressive strength; workability
HSV kategori
Identifikatorer
urn:nbn:se:hb:diva-24811 (URN)10.3390/ma13194342 (DOI)000586581500001 ()2-s2.0-85093938328 (Scopus ID)
Tilgjengelig fra: 2021-01-25 Laget: 2021-01-25 Sist oppdatert: 2022-01-20bibliografisk kontrollert
Sadagopan, M., Malaga, K. & Nagy, A. (2020). Modified pycnometer method to measure the water absorption of crushed concrete aggregates. Journal of Sustainable Cement-Based Materials
Åpne denne publikasjonen i ny fane eller vindu >>Modified pycnometer method to measure the water absorption of crushed concrete aggregates
2020 (engelsk)Inngår i: Journal of Sustainable Cement-Based Materials, ISSN 2165-0373, E-ISSN 2165-0381Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The water absorption of crushed concrete aggregates (CCA) has a major influence on concrete workability. In order to determine the water absorption of CCA, a more porous material than natural aggregates, modifications to the standard pycnometer method are proposed as: (1) Water absorption is measured on a combined fraction CCA consisting of fine and coarse aggregates proportioned according to concrete recipe. (2) The CCA is pre-processed to mitigate sedimentation. (3) Saturated surface dry condition of aggregate is assessed by vacuum filtration and ocular technique. Water absorption development is measured at 0 min, 15 min, and 24 h. About 90% of the 24-h water absorption occurs in 15 min, value which is introduced in the concrete recipe; slump flow and compressive strength are determined. The modified pycnometer method shortens test duration, is operator insensitive and gives reliable water absorption result for CCA leading to concrete workability fitting industrial application.

Emneord
Crushed concrete aggregates, recycled aggregates, water absorption, pycnometer, saturated surface dry condition, sustainability
HSV kategori
Forskningsprogram
Resursåtervinning
Identifikatorer
urn:nbn:se:hb:diva-23137 (URN)10.1080/21650373.2020.1715902 (DOI)000512023500001 ()2-s2.0-85078489111 (Scopus ID)
Prosjekter
RE:Concrete
Tilgjengelig fra: 2020-04-06 Laget: 2020-04-06 Sist oppdatert: 2024-02-01bibliografisk kontrollert
Nagy, A., Ringsberg, H. & Sadagopan, M. (2020). Regional recycling of concrete: survey study. In: Agnes Nagy (Ed.), Webbinarium: Regional återvinning av betong: . Paper presented at Regional återvinning av betong, Borås (Digitalt), 9 december, 2020. Borås
Åpne denne publikasjonen i ny fane eller vindu >>Regional recycling of concrete: survey study
2020 (engelsk)Inngår i: Webbinarium: Regional återvinning av betong / [ed] Agnes Nagy, Borås, 2020Konferansepaper, Oral presentation with published abstract (Annet vitenskapelig)
sted, utgiver, år, opplag, sider
Borås: , 2020
Emneord
Concrete recycling, survey, regional level, sustainability
HSV kategori
Forskningsprogram
Resursåtervinning
Identifikatorer
urn:nbn:se:hb:diva-25635 (URN)
Konferanse
Regional återvinning av betong, Borås (Digitalt), 9 december, 2020
Prosjekter
RE:Concrete
Tilgjengelig fra: 2021-06-24 Laget: 2021-06-24 Sist oppdatert: 2021-08-16bibliografisk kontrollert
Sadagopan, M., Malaga, K. & Nagy, A. (2019). A modified pycnometer method to determine the water absorption of combined crushed concrete aggregate fractions. In: Gabrijel I, Grosse C, Skazlić M (Ed.), International Conference on Sustainable Materials, Systems and Structures (SMSS2019): Novel Methods for Characterization of Materials and Structures. Paper presented at International Conference on Sustainable Materials, Systems and Structures (SMSS2019), Rovin, March 20-22, 2019. (pp. 286-292).
Åpne denne publikasjonen i ny fane eller vindu >>A modified pycnometer method to determine the water absorption of combined crushed concrete aggregate fractions
2019 (engelsk)Inngår i: International Conference on Sustainable Materials, Systems and Structures (SMSS2019): Novel Methods for Characterization of Materials and Structures / [ed] Gabrijel I, Grosse C, Skazlić M, 2019, s. 286-292Konferansepaper, Publicerat paper (Fagfellevurdert)
Abstract [en]

Crushed Concrete Aggregates (CCA) as fine and coarse aggregates in new concrete helps achieve closed-loop recycling. Assessment of workability, mechanical properties and durability of concrete demands knowledge of the water absorbed by the CCA. The EN 1097-6standard method is difficult to execute due to the presence of entrapped air and CCAsedimentation while performing water absorption experiment for fine CCA. Additionally, the assessment of Saturated Surface Dry (SSD) state seems operator specific and nonreproducible;moreover, giving water absorption measurement only at 24 hours. However, findings from this paper show measurements at 15 minutes is influential for concrete workability. The modified pycnometer method analyses the water absorption of a combined fraction consisting of coarse and fine CCA as proportioned in a given concrete recipe. Furthermore, sedimentation and entrapped air are prevented by pre-soaking the CCA in a solution of distilled water and poly-carboxylate based superplasticizer before commencing the experiment. Ultimately, the combined fraction is drained to SSD condition by vacuum filtration, which is easy to handle by professional operators. In this way, the water absorption development is measured from starting point to 24 hours for the combined fraction to determine the appropriate water amount to saturate CCA during concrete mixing.

Emneord
crushed concrete aggregate, water absorption, pcynometer, SSD, sustainability
HSV kategori
Forskningsprogram
Resursåtervinning
Identifikatorer
urn:nbn:se:hb:diva-15948 (URN)978-2-35158-217-6 (ISBN)
Konferanse
International Conference on Sustainable Materials, Systems and Structures (SMSS2019), Rovin, March 20-22, 2019.
Prosjekter
RE:Concrete
Tilgjengelig fra: 2019-04-05 Laget: 2019-04-05 Sist oppdatert: 2019-04-12bibliografisk kontrollert
Richards, T., Erikson, M. G., Eriksson, A., Nagy, A. & Johnson, E. (2017). A conceptual model of how research can influence student development. In: : . Paper presented at Connecting Higher Education: International perspectives on research-based education, London, 26-28 June, 2017.
Åpne denne publikasjonen i ny fane eller vindu >>A conceptual model of how research can influence student development
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2017 (engelsk)Konferansepaper, Oral presentation only (Fagfellevurdert)
HSV kategori
Identifikatorer
urn:nbn:se:hb:diva-12581 (URN)
Konferanse
Connecting Higher Education: International perspectives on research-based education, London, 26-28 June, 2017
Tilgjengelig fra: 2017-09-18 Laget: 2017-09-18 Sist oppdatert: 2017-09-19bibliografisk kontrollert
Organisasjoner
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0003-2194-9277