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

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Durability of Alkali-Activated Calcined Clay: GGBFS Concrete Against Carbonation and Chloride Diffusion /Samuel de Carvalho Gomes.
作者:	de Carvalho Gomes, Samuel,
面頁冊數:	1 electronic resource (247 pages)
附註:	Source: Dissertations Abstracts International, Volume: 86-07, Section: B.
附註:	Advisors: Castel, Arnaud; Vessalas, Kirk; Li, Wengui.
Contained By:	Dissertations Abstracts International86-07B.
標題:	Concrete mixing.
電子資源:	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 /
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