Influence of Forced Carbonisation on the Binding Properties of Sludge with a High β-Belite Content

Alternative binders activated by forced carbonisation are regarded as one of the potential solutions to reducing greenhouse gas emissions, water, and energy consumption. Such binders, in particular those based on nepheline sludge (a by-product of alumina production), cured in carbon dioxide with sub...

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Main Authors: Aleksandr Bakhtin, Nikolay Lyubomirskiy, Stanisław Fic, Tamara Bakhtina
Format: Article
Language:English
Published: MDPI AG 2021-12-01
Series:Materials
Subjects:
Online Access:https://www.mdpi.com/1996-1944/14/24/7899
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author Aleksandr Bakhtin
Nikolay Lyubomirskiy
Stanisław Fic
Tamara Bakhtina
author_facet Aleksandr Bakhtin
Nikolay Lyubomirskiy
Stanisław Fic
Tamara Bakhtina
author_sort Aleksandr Bakhtin
collection DOAJ
description Alternative binders activated by forced carbonisation are regarded as one of the potential solutions to reducing greenhouse gas emissions, water, and energy consumption. Such binders, in particular those based on nepheline sludge (a by-product of alumina production), cured in carbon dioxide with subsequent hydration, are clinkerless building materials. The development of such binders contributes to the involvement of multi-tonnage solid industrial waste in the production cycle. This type of waste is capable of binding man-made CO<sub>2</sub> and transforming it into stable insoluble compounds, having binder properties. The optimum technological parameters of the forced carbonisation of the nepheline slime binder was determined by the mathematical planning of the experiment. The novelty of the research is the expansion of the secondary raw material base that can bind the man-made CO<sub>2</sub> with obtaining the construction products of appropriate quality. It was revealed that the process of active CO<sub>2</sub> absorption by the minerals of nepheline slime is observed in the first 120 min of the forced carbonization. Immediately after carbonisation, the resulting material develops compressive strength up to 57.64 MPa, and at the subsequent hydration within 28 days this figure increases to 68.71 MPa. Calcium carbonate is the main binder that determines the high mechanical properties of the samples. During the subsequent hydration of the uncoated belite, gel-like products are formed, which additionally harden the carbonised matrix. Thus, after the forced carbonisation and the following 28 days of hardening, the material with compressive strength in the range 4.38–68.71 MPa and flexural strength of 3.1–8.9 MPa was obtained. This material was characterised by water absorption by mass in the range of 13.9–23.3% and the average density of 1640–1886 kg/m<sup>3</sup>. The softening coefficient of the material was 0.51–0.99. The results obtained enables one to consider further prospects for research in this area, in terms of the introduction of additional technological parameters to study the process of forced carbonisation of nepheline slime.
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spelling doaj.art-90066f8e92af4cd58aee43b9354aa4152023-11-23T09:24:42ZengMDPI AGMaterials1996-19442021-12-011424789910.3390/ma14247899Influence of Forced Carbonisation on the Binding Properties of Sludge with a High β-Belite ContentAleksandr Bakhtin0Nikolay Lyubomirskiy1Stanisław Fic2Tamara Bakhtina3Department of Civil Engineering and Materials Science, Faculty of Architecture and Civil Engineering, Academy of Civil Engineering and Architecture, V.I. Vernadsky Crimean Federal University, Prospekt Vernadskogo 4, 295007 Simferopol, Republic of CrimeaDepartment of Civil Engineering and Materials Science, Faculty of Architecture and Civil Engineering, Academy of Civil Engineering and Architecture, V.I. Vernadsky Crimean Federal University, Prospekt Vernadskogo 4, 295007 Simferopol, Republic of CrimeaFaculty of Civil Engineering and Architecture, Lublin University of Technology, Nadbystrzycka 40, 20-619 Lublin, PolandDepartment of Civil Engineering and Materials Science, Faculty of Architecture and Civil Engineering, Academy of Civil Engineering and Architecture, V.I. Vernadsky Crimean Federal University, Prospekt Vernadskogo 4, 295007 Simferopol, Republic of CrimeaAlternative binders activated by forced carbonisation are regarded as one of the potential solutions to reducing greenhouse gas emissions, water, and energy consumption. Such binders, in particular those based on nepheline sludge (a by-product of alumina production), cured in carbon dioxide with subsequent hydration, are clinkerless building materials. The development of such binders contributes to the involvement of multi-tonnage solid industrial waste in the production cycle. This type of waste is capable of binding man-made CO<sub>2</sub> and transforming it into stable insoluble compounds, having binder properties. The optimum technological parameters of the forced carbonisation of the nepheline slime binder was determined by the mathematical planning of the experiment. The novelty of the research is the expansion of the secondary raw material base that can bind the man-made CO<sub>2</sub> with obtaining the construction products of appropriate quality. It was revealed that the process of active CO<sub>2</sub> absorption by the minerals of nepheline slime is observed in the first 120 min of the forced carbonization. Immediately after carbonisation, the resulting material develops compressive strength up to 57.64 MPa, and at the subsequent hydration within 28 days this figure increases to 68.71 MPa. Calcium carbonate is the main binder that determines the high mechanical properties of the samples. During the subsequent hydration of the uncoated belite, gel-like products are formed, which additionally harden the carbonised matrix. Thus, after the forced carbonisation and the following 28 days of hardening, the material with compressive strength in the range 4.38–68.71 MPa and flexural strength of 3.1–8.9 MPa was obtained. This material was characterised by water absorption by mass in the range of 13.9–23.3% and the average density of 1640–1886 kg/m<sup>3</sup>. The softening coefficient of the material was 0.51–0.99. The results obtained enables one to consider further prospects for research in this area, in terms of the introduction of additional technological parameters to study the process of forced carbonisation of nepheline slime.https://www.mdpi.com/1996-1944/14/24/7899carbonate hardeninghydrationnepheline sludgemicrostructuremechanical performancerecycling
spellingShingle Aleksandr Bakhtin
Nikolay Lyubomirskiy
Stanisław Fic
Tamara Bakhtina
Influence of Forced Carbonisation on the Binding Properties of Sludge with a High β-Belite Content
Materials
carbonate hardening
hydration
nepheline sludge
microstructure
mechanical performance
recycling
title Influence of Forced Carbonisation on the Binding Properties of Sludge with a High β-Belite Content
title_full Influence of Forced Carbonisation on the Binding Properties of Sludge with a High β-Belite Content
title_fullStr Influence of Forced Carbonisation on the Binding Properties of Sludge with a High β-Belite Content
title_full_unstemmed Influence of Forced Carbonisation on the Binding Properties of Sludge with a High β-Belite Content
title_short Influence of Forced Carbonisation on the Binding Properties of Sludge with a High β-Belite Content
title_sort influence of forced carbonisation on the binding properties of sludge with a high β belite content
topic carbonate hardening
hydration
nepheline sludge
microstructure
mechanical performance
recycling
url https://www.mdpi.com/1996-1944/14/24/7899
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