Corrosion of steel rebars embedded in One-part Alkali activated concrete mixes
To reduce CO2 emissions and turn a variety of industrial/agricultural wastes into valuable cementitious products, alkali-activated materials (AAM) are recognized as suitable substitutes for regular Portland cement (OPC). However, the concentrated aqueous alkali solutions used in conventional two-par...
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| Format: | Article |
| Language: | English |
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EDP Sciences
2023-01-01
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| Series: | E3S Web of Conferences |
| Subjects: | |
| Online Access: | https://www.e3s-conferences.org/articles/e3sconf/pdf/2023/42/e3sconf_icstce2023_03024.pdf |
| _version_ | 1797756213473050624 |
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| author | Reddy Bijivemula Kiran Kumar Narasimhan Mattur C. |
| author_facet | Reddy Bijivemula Kiran Kumar Narasimhan Mattur C. |
| author_sort | Reddy Bijivemula Kiran Kumar |
| collection | DOAJ |
| description | To reduce CO2 emissions and turn a variety of industrial/agricultural wastes into valuable cementitious products, alkali-activated materials (AAM) are recognized as suitable substitutes for regular Portland cement (OPC). However, the concentrated aqueous alkali solutions used in conventional two-part alkali activated materials are highly corrosive, viscous, and are difficult to handle in direct field applications. As a result, the potential for developing so-called "just add water" type one-part AAMs, as compared to traditional two-part AAM, is being explored, particularly in cast-in-situ applications. In the present study on corrosion of reinforcing steel bars in fly ash-slag (FA-GGBS) based one-part AAC mixtures, three parameters—the total binder content, the relative proportions of GGBS and Fly-ash and the percentage of sodium oxide (Na2O) - are recognized as the key factors in determining the strength and durability performance (including corrosion of rebars embedded in it) of a given AAC mix. Accordingly, experiments were conducted on AAC mixes with three binder contents (440, 460, and 480 kg/m3), three Slag/FA ratios (80/20, 70/30 and 60/40, by volume) and three alternate Na2O percentages (5, 6, and 7%, by weight of total binder content). Prismatic cylindrical test specimens of reinforced geopolymer concrete were prepared and half-cell potential and corrosion rate measurements were made after 28-, 56-, and 90 days of continuous exposure to 3% of NaCl solution, to accelerate the corrosion process. Measured corrosion current density and corrosion rates using a Electro-chemical Corrosion Analyser have indicated that the AAC mixture having a total binder content 440 kg/m3, GGBS/FS ratio of 70/30 and 6% Na2O content, exhibits best corrosion resistance amongst the various mixes tested herein, as measured up to the end of 90-days. |
| first_indexed | 2024-03-12T17:58:13Z |
| format | Article |
| id | doaj.art-31215144cda640de88864252abde8885 |
| institution | Directory Open Access Journal |
| issn | 2267-1242 |
| language | English |
| last_indexed | 2024-03-12T17:58:13Z |
| publishDate | 2023-01-01 |
| publisher | EDP Sciences |
| record_format | Article |
| series | E3S Web of Conferences |
| spelling | doaj.art-31215144cda640de88864252abde88852023-08-02T13:18:12ZengEDP SciencesE3S Web of Conferences2267-12422023-01-014050302410.1051/e3sconf/202340503024e3sconf_icstce2023_03024Corrosion of steel rebars embedded in One-part Alkali activated concrete mixesReddy Bijivemula Kiran Kumar0Narasimhan Mattur C.1Department of Civil Engineering, NITKDepartment of Civil Engineering, NITKTo reduce CO2 emissions and turn a variety of industrial/agricultural wastes into valuable cementitious products, alkali-activated materials (AAM) are recognized as suitable substitutes for regular Portland cement (OPC). However, the concentrated aqueous alkali solutions used in conventional two-part alkali activated materials are highly corrosive, viscous, and are difficult to handle in direct field applications. As a result, the potential for developing so-called "just add water" type one-part AAMs, as compared to traditional two-part AAM, is being explored, particularly in cast-in-situ applications. In the present study on corrosion of reinforcing steel bars in fly ash-slag (FA-GGBS) based one-part AAC mixtures, three parameters—the total binder content, the relative proportions of GGBS and Fly-ash and the percentage of sodium oxide (Na2O) - are recognized as the key factors in determining the strength and durability performance (including corrosion of rebars embedded in it) of a given AAC mix. Accordingly, experiments were conducted on AAC mixes with three binder contents (440, 460, and 480 kg/m3), three Slag/FA ratios (80/20, 70/30 and 60/40, by volume) and three alternate Na2O percentages (5, 6, and 7%, by weight of total binder content). Prismatic cylindrical test specimens of reinforced geopolymer concrete were prepared and half-cell potential and corrosion rate measurements were made after 28-, 56-, and 90 days of continuous exposure to 3% of NaCl solution, to accelerate the corrosion process. Measured corrosion current density and corrosion rates using a Electro-chemical Corrosion Analyser have indicated that the AAC mixture having a total binder content 440 kg/m3, GGBS/FS ratio of 70/30 and 6% Na2O content, exhibits best corrosion resistance amongst the various mixes tested herein, as measured up to the end of 90-days.https://www.e3s-conferences.org/articles/e3sconf/pdf/2023/42/e3sconf_icstce2023_03024.pdfalkali activated materialsrebar corrosioncarbon emissionselectrochemical methodsgeopolymer concretes |
| spellingShingle | Reddy Bijivemula Kiran Kumar Narasimhan Mattur C. Corrosion of steel rebars embedded in One-part Alkali activated concrete mixes E3S Web of Conferences alkali activated materials rebar corrosion carbon emissions electrochemical methods geopolymer concretes |
| title | Corrosion of steel rebars embedded in One-part Alkali activated concrete mixes |
| title_full | Corrosion of steel rebars embedded in One-part Alkali activated concrete mixes |
| title_fullStr | Corrosion of steel rebars embedded in One-part Alkali activated concrete mixes |
| title_full_unstemmed | Corrosion of steel rebars embedded in One-part Alkali activated concrete mixes |
| title_short | Corrosion of steel rebars embedded in One-part Alkali activated concrete mixes |
| title_sort | corrosion of steel rebars embedded in one part alkali activated concrete mixes |
| topic | alkali activated materials rebar corrosion carbon emissions electrochemical methods geopolymer concretes |
| url | https://www.e3s-conferences.org/articles/e3sconf/pdf/2023/42/e3sconf_icstce2023_03024.pdf |
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