國立高雄大學圖資館 |

Language: English

Back

Durability of Alkali-Activated Calcined Clay: GGBFS Concrete Against Carbonation and Chloride Diffusion /

Record Type:	Electronic resources : Monograph/item
Title/Author:	Durability of Alkali-Activated Calcined Clay: GGBFS Concrete Against Carbonation and Chloride Diffusion /Samuel de Carvalho Gomes.
Author:	de Carvalho Gomes, Samuel,
Description:	1 electronic resource (247 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 86-07, Section: B.
Notes:	Advisors: Castel, Arnaud; Vessalas, Kirk; Li, Wengui.
Contained By:	Dissertations Abstracts International86-07B.
Subject:	Concrete mixing.
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=31827510
ISBN:	9798302389848

Durability of Alkali-Activated Calcined Clay: GGBFS Concrete Against Carbonation and Chloride Diffusion /
de Carvalho Gomes, Samuel,

Durability of Alkali-Activated Calcined Clay: GGBFS Concrete Against Carbonation and Chloride Diffusion /Samuel de Carvalho Gomes. - 1 electronic resource (247 pages)

Source: Dissertations Abstracts International, Volume: 86-07, Section: B.

Several studies have emerged in recent years on the production of alternative cementitious materials with less environmental impact (zero clinker), focusing on fewer emissions of CO₂ in its production compared to Ordinary Portland Cement. One of these binders, called geopolymer, is obtained from the alkaline activation of raw materials rich in SiO₂ and Al₂O₃, which can be derived from by-products or industrial residues. Calcined clay has emerged as a potential candidate as a precursor for this type of material. Large amounts of suitable clays are available in Australia and around the world. However, there is not enough data allowing to assess their durability, which is much needed to evaluate the service life and potentialities of this material. The present research proposed to evaluate the durability of alkali-activated low-grade calcined clay blended with Ground Granulated Blast Furnace Slag (GGBFS) through tests assessing the performance in chloride and carbonation-rich environments. The results show that the inclusion of GGBFS as a rich calcium source, notably improves the mortar microstructure and increases the pH of the pore solution, enhancing the carbonation resistance. Concretes activated with NaOH showed better compressive strength than those activated with KOH. Adding MgO enhanced the concrete's water absorption capacity and resistance to carbonation. The results indicated that increasing Na₂O% from 8 to 10 led to enhanced the compressive strength, led to a more refined microstructure, and reduced carbonation (both accelerated and natural). The electrochemical measurements strongly indicate that the alkali activated concrete used in this study do not pose a risk of steel corrosion aside from the high carbonation's depth shown by the phenolphthalein test because the pH of carbonated alkali-activated concretes remains high compared to carbonated OPC systems. While a higher alkaline activator concentration resulted in an increase in shrinkage for mixes with high percentage of GGBFS, overall the total shrinkage of all alkali-activated concrete tested was similar or lower than typical values obtained for OPC concrete. Regarding their chloride penetration resistance, while alkali-activated concretes exhibited average compressive strengths, ranging from 31.5 to 63.5 MPa, their performed was not suitable for exposure to chloride-rich environments except for one concrete mix using high reactivity calcined clay. Indeed, a higher Na₂O concentrations and the use of high-grade calcined clay significantly reduced the chloride diffusion coefficient (Da) value, indicating improved chloride diffusion resistance equivalent to that of OPC concretes currently used in chloride environments in accordance with AS3600 specifications.

English

ISBN: 9798302389848Subjects--Topical Terms:

990259
Concrete mixing.

Durability of Alkali-Activated Calcined Clay: GGBFS Concrete Against Carbonation and Chloride Diffusion /
LDR:04273nmm a22004213i 4500 001 676418
005 20250420214402.5
006 m o d
007 cr|nu||||||||
008 250901s2024 miu||||||m |||||||eng d
020 $a 9798302389848
035 $a (MiAaPQD)AAI31827510
035 $a (MiAaPQD)TechSydney182358
035 $a AAI31827510
040 $a MiAaPQD $b eng $c MiAaPQD $e rda
100 1 $a de Carvalho Gomes, Samuel, $e author. $3 990258
245 1 0 $a Durability of Alkali-Activated Calcined Clay: GGBFS Concrete Against Carbonation and Chloride Diffusion / $c Samuel de Carvalho Gomes.
264 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2024
300 $a 1 electronic resource (247 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertations Abstracts International, Volume: 86-07, Section: B.
500 $a Advisors: Castel, Arnaud; Vessalas, Kirk; Li, Wengui.
502 $b Ph.D. $c University of Technology Sydney (Australia) $d 2024.
520 $a Several studies have emerged in recent years on the production of alternative cementitious materials with less environmental impact (zero clinker), focusing on fewer emissions of CO₂ in its production compared to Ordinary Portland Cement. One of these binders, called geopolymer, is obtained from the alkaline activation of raw materials rich in SiO₂ and Al₂O₃, which can be derived from by-products or industrial residues. Calcined clay has emerged as a potential candidate as a precursor for this type of material. Large amounts of suitable clays are available in Australia and around the world. However, there is not enough data allowing to assess their durability, which is much needed to evaluate the service life and potentialities of this material. The present research proposed to evaluate the durability of alkali-activated low-grade calcined clay blended with Ground Granulated Blast Furnace Slag (GGBFS) through tests assessing the performance in chloride and carbonation-rich environments. The results show that the inclusion of GGBFS as a rich calcium source, notably improves the mortar microstructure and increases the pH of the pore solution, enhancing the carbonation resistance. Concretes activated with NaOH showed better compressive strength than those activated with KOH. Adding MgO enhanced the concrete's water absorption capacity and resistance to carbonation. The results indicated that increasing Na₂O% from 8 to 10 led to enhanced the compressive strength, led to a more refined microstructure, and reduced carbonation (both accelerated and natural). The electrochemical measurements strongly indicate that the alkali activated concrete used in this study do not pose a risk of steel corrosion aside from the high carbonation's depth shown by the phenolphthalein test because the pH of carbonated alkali-activated concretes remains high compared to carbonated OPC systems. While a higher alkaline activator concentration resulted in an increase in shrinkage for mixes with high percentage of GGBFS, overall the total shrinkage of all alkali-activated concrete tested was similar or lower than typical values obtained for OPC concrete. Regarding their chloride penetration resistance, while alkali-activated concretes exhibited average compressive strengths, ranging from 31.5 to 63.5 MPa, their performed was not suitable for exposure to chloride-rich environments except for one concrete mix using high reactivity calcined clay. Indeed, a higher Na₂O concentrations and the use of high-grade calcined clay significantly reduced the chloride diffusion coefficient (Da) value, indicating improved chloride diffusion resistance equivalent to that of OPC concretes currently used in chloride environments in accordance with AS3600 specifications.
546 $a English
590 $a School code: 1295
650 4 $a Concrete mixing. $3 990259
650 4 $a Greenhouse gases. $3 202257
650 4 $a Clay. $3 282859
650 4 $a Spectrum analysis. $3 188665
650 4 $a Emissions. $3 915579
650 4 $a Analytical chemistry. $3 708695
650 4 $a Climate change. $2 bicssc $3 689368
650 4 $a Optics. $3 204142
690 $a 0486
690 $a 0543
690 $a 0404
690 $a 0752
710 2 $a University of Technology Sydney (Australia). $3 967055
720 1 $a Castel, Arnaud $e degree supervisor.
720 1 $a Vessalas, Kirk $e degree supervisor.
720 1 $a Li, Wengui $e degree supervisor.
773 0 $t Dissertations Abstracts International $g 86-07B.
790 $a 1295
791 $a Ph.D.
792 $a 2024
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=31827510