Journal ArticleDOI
Alkaline Activation of Metakaolin: Effect of Calcium Hydroxide in the Products of Reaction
TLDR
In this article, metakaolin (MK) and (MK + Ca(OH) 2 ) mixes were activated with 5M and 12M NaOH solutions and cured at 45°C.Abstract:
The alkali activation of metakaolin (MK) leads to the production of high-mechanical-performance network-structure materials. Adding calcium hydroxide (Ca(OH) 2 ) to the raw MK produces a somewhat different reaction: a network structure and C-S-H gel form. In the present study, MK and (MK + Ca(OH) 2 ) mixes were activated with 5M and 12M NaOH solutions and cured at 45°C. A 5M concentration, in the absence of Ca(OH) 2 , did not produce MK activation within the test time. An activator concentration of 12M resulted in complete activation and the formation of a network structure. When Ca(OH) 2 was present in the raw mix, a small amount of C-S-H gel formed.read more
Citations
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Journal ArticleDOI
Geopolymer technology: the current state of the art
Peter Duxson,Ana Fernández-Jiménez,John L. Provis,Grant C. Lukey,Ángel Palomo,J.S.J. van Deventer +5 more
TL;DR: A brief history and review of geopolymer technology is presented with the aim of introducing the technology and the vast categories of materials that may be synthesized by alkali activation of aluminosilicates as mentioned in this paper.
Journal ArticleDOI
Geopolymers and Related Alkali-Activated Materials
John L. Provis,Susan A. Bernal +1 more
TL;DR: In this paper, the synthesis of alkali-activated binders from blast furnace slag, calcined clay (metakaolin), and fly ash is discussed, including analysis of the chemical reaction mechanisms and binder phase assemblages that control the early-age and hardened properties of these materials.
Journal ArticleDOI
Effect of GGBFS on setting, workability and early strength properties of fly ash geopolymer concrete cured in ambient condition
Pradip Nath,Prabir Kumar Sarker +1 more
TL;DR: In this paper, a fly ash-based geopolymer concrete for curing in ambient condition can be proportioned for desirable workability, setting time, and compressive strength using ground granulated blast-furnace slag (GGBFS) as a small part of the binder.
Journal ArticleDOI
A review: The comparison between alkali-activated slag (Si + Ca) and metakaolin (Si + Al) cements
TL;DR: In this article, the authors compare the properties of slag and metakaolin cements, including the general properties of metakaol and slag, hydration products reaction mechanisms, and the role of Ca and Al.
Journal ArticleDOI
Microstructure Development of Alkali-Activated Fly Ash Cement: A Descriptive Model
TL;DR: In this paper, the microscopic study of a set of alkali-activated and thermally cured fly ash samples enabled the authors to establish a descriptive model for the microstructural development of fly ash-based cementitious geopolymers.
References
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Journal ArticleDOI
Geopolymers : inorganic polymeric new materials
TL;DR: In the last few years, technological progress has been made in the development of new materials such as "geopolymers" and new techniques, such as ''sol-gel'' as mentioned in this paper, opening up new applications and procedures and transforming ideas that have been taken for granted in inorganic chemistry.
Journal ArticleDOI
29Si MAS NMR study of the structure of calcium silicate hydrate
TL;DR: In this article, a defect-tobermorite structural model is proposed for single-phase calcium silicate hydrate with known compositions using the combined capabilities of 29Si magic angle spinning (MAS) NMR, powder X-ray diffraction (XRD), and chemical analysis of the solution and solid.
Journal ArticleDOI
High-resolution aluminum-27 NMR of aluminosilicates
E. Lippmaa,Ago Samoson,M. Magi +2 more
TL;DR: In this paper, the first and second coordination spheres and the Al-O-Si bond angles were used to determine isotropic chemical shifts of quadrupolar nuclei in solids.
Journal ArticleDOI
The potential use of geopolymeric materials to immobilise toxic metals: Part II. Material and leaching characteristics
TL;DR: In this paper, the physical and chemical properties of geopolymers manufactured from fly ash originating from two different regions were investigated using compressive strength testing, specific surface area determinations, Transmission Electron Microscopy (TEM), Nuclear Magnetic Resonance (NMR) and leaching tests.
Journal ArticleDOI
Silicon‐29 Magic Angle Spinning Nuclear Magnetic Resonance Study of Calcium Silicate Hydrates
TL;DR: The reaction products formed in a series of fully-equilibrated, room-temperature-hydrated, fumed colloidal silica plus lime water mixtures were examined using 29Si magic angle spinning nuclear magnetic resonance as discussed by the authors.