Resistance to Chemical Attack of Hybrid Fly Ash-Based Alkali-Activated Concretes
The environmental impacts related to Portland cement production in terms of energy consumption, the massive use of natural resources and CO<sub>2</sub> emissions have led to the search for alternative cementitious materials. Among these materials, alkali-activated cements based on fly as...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-07-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/25/15/3389 |
| _version_ | 1797561260969033728 |
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| author | William G. Valencia-Saavedra Ruby Mejía de Gutiérrez |
| author_facet | William G. Valencia-Saavedra Ruby Mejía de Gutiérrez |
| author_sort | William G. Valencia-Saavedra |
| collection | DOAJ |
| description | The environmental impacts related to Portland cement production in terms of energy consumption, the massive use of natural resources and CO<sub>2</sub> emissions have led to the search for alternative cementitious materials. Among these materials, alkali-activated cements based on fly ash (FA) have been considered for concrete production with greater sustainability. In the present article, the chemical durability properties (resistance to sulphates, chloride permeability, and resistance to carbonation) of a hybrid alkali-activated concrete based on fly ash–ordinary Portland cement (FA/OPC) with proportions of 80%/20% were evaluated. It is noted that the FA was a low-quality pozzolan with a high unburned carbon content (20.67%). The results indicated that FA/OPC concrete had good durability with respect to the OPC concrete, with 95% less expansion in the presence of sodium sulphate and a 2% strength loss at 1100 days, compared with the 56% strength loss of the OPC concrete. In addition, FA/OPC showed lower chloride permeability. On the contrary, the FA/OPC was more susceptible to carbonation. However, the residual compressive strength was 23 MPa at 360 days of CO<sub>2</sub> exposure. Based on the results, FA/OPC, using this type of FA, can be used as a replacement for OPC in the presence of these aggressive agents in the service environment. |
| first_indexed | 2024-03-10T18:11:31Z |
| format | Article |
| id | doaj.art-dd6ecdb93cc74a09bd89fcfa0c17b442 |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-10T18:11:31Z |
| publishDate | 2020-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-dd6ecdb93cc74a09bd89fcfa0c17b4422023-11-20T08:03:50ZengMDPI AGMolecules1420-30492020-07-012515338910.3390/molecules25153389Resistance to Chemical Attack of Hybrid Fly Ash-Based Alkali-Activated ConcretesWilliam G. Valencia-Saavedra0Ruby Mejía de Gutiérrez1Composites Materials Group (CENM), Universidad de Valle, Calle, Cali 13 #100-00, ColombiaComposites Materials Group (CENM), Universidad de Valle, Calle, Cali 13 #100-00, ColombiaThe environmental impacts related to Portland cement production in terms of energy consumption, the massive use of natural resources and CO<sub>2</sub> emissions have led to the search for alternative cementitious materials. Among these materials, alkali-activated cements based on fly ash (FA) have been considered for concrete production with greater sustainability. In the present article, the chemical durability properties (resistance to sulphates, chloride permeability, and resistance to carbonation) of a hybrid alkali-activated concrete based on fly ash–ordinary Portland cement (FA/OPC) with proportions of 80%/20% were evaluated. It is noted that the FA was a low-quality pozzolan with a high unburned carbon content (20.67%). The results indicated that FA/OPC concrete had good durability with respect to the OPC concrete, with 95% less expansion in the presence of sodium sulphate and a 2% strength loss at 1100 days, compared with the 56% strength loss of the OPC concrete. In addition, FA/OPC showed lower chloride permeability. On the contrary, the FA/OPC was more susceptible to carbonation. However, the residual compressive strength was 23 MPa at 360 days of CO<sub>2</sub> exposure. Based on the results, FA/OPC, using this type of FA, can be used as a replacement for OPC in the presence of these aggressive agents in the service environment.https://www.mdpi.com/1420-3049/25/15/3389fly ashhybrid concretealkali-activated cementsdurabilitysulphatescarbonation |
| spellingShingle | William G. Valencia-Saavedra Ruby Mejía de Gutiérrez Resistance to Chemical Attack of Hybrid Fly Ash-Based Alkali-Activated Concretes Molecules fly ash hybrid concrete alkali-activated cements durability sulphates carbonation |
| title | Resistance to Chemical Attack of Hybrid Fly Ash-Based Alkali-Activated Concretes |
| title_full | Resistance to Chemical Attack of Hybrid Fly Ash-Based Alkali-Activated Concretes |
| title_fullStr | Resistance to Chemical Attack of Hybrid Fly Ash-Based Alkali-Activated Concretes |
| title_full_unstemmed | Resistance to Chemical Attack of Hybrid Fly Ash-Based Alkali-Activated Concretes |
| title_short | Resistance to Chemical Attack of Hybrid Fly Ash-Based Alkali-Activated Concretes |
| title_sort | resistance to chemical attack of hybrid fly ash based alkali activated concretes |
| topic | fly ash hybrid concrete alkali-activated cements durability sulphates carbonation |
| url | https://www.mdpi.com/1420-3049/25/15/3389 |
| work_keys_str_mv | AT williamgvalenciasaavedra resistancetochemicalattackofhybridflyashbasedalkaliactivatedconcretes AT rubymejiadegutierrez resistancetochemicalattackofhybridflyashbasedalkaliactivatedconcretes |