Non-classical reaction pathways in alkali-activated systems

Author(s): L. Valentini
Paper category: Proceedings
Book title: Proceedings of the International Conference on Sustainable Materials, Systems and Structures (SMSS2019) New Generation of Construction Materials
Editor(s): Marijana Serdar, Nina Štirmer, John Provis
ISBN: 978-2-35158-217-6,
Vol 1. ISBN: 978-2-35158-223-7
e-ISBN: 978-2-35158-218-3
Publisher: RILEM Publications SARL
Publication year: 2019
Pages: 174-178
Total Pages: 5
Language : English

Abstract: With the beginning of the new millennium, society has (with some exception, sadly, especially in the last few years) embraced the idea of “sustainable development” as a key goal for the future generations to inherit a clean world. In the field of cement chemistry, this concept has boosted research oriented at designing a new generation of construction materials. Among low- CO2 alternatives to Portland cement, alkali-activated materials gained broad consensus in the scientific community and scientific literature on this topic is now consolidated.
Nonetheless, current research is still broadly oriented towards an approach dealing with the macroscopic properties of different mix designs, and the details of alkali activation, especially for what concerns the nano-structure of the reaction products, as well as the nature of the reaction pathways leading to the formation of such products is still puzzling. This fuzzy picture is accompanied by the broad use of descriptive terms inherited from the realm of organic polymer chemistry, which may not be appropriate for a rigorous description of the alkali activation of inorganic materials such as aluminium silicates.
In this contribution, I attempt to reconcile the processes associated with alkali activation with the current views on phase separation in saturated solutions. Recent research into non-classical pathways to nucleation and growth and formation of intermediate entities, namely prenucleation clusters, is reviewed, with focus on the implementation of these theories to those materials, such as zeolitic imidazolate frameworks, which share some common structural features with the products of alkali activation. The role of computer simulations in describing the details of the dissolution-precipitation processes in alkali-activated systems is addressed.

Online publication : 2019
Publication type : full_text
Public price (Euros) : 0.00