Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.764853
Title: Alkali activated binders valorised from tungsten mining waste : materials design, preparation, properties and applications
Author: Kastiukas, Gediminas
ISNI:       0000 0004 7658 2289
Awarding Body: Brunel University London
Current Institution: Brunel University
Date of Award: 2017
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Abstract:
Alkali-activated binders (AABs) are the third-generation class of binders after lime and Portland cement. These binders have the potential to be made from a variety of industrial waste sources, many of which have remained largely unexplored. Significant drawbacks of AABs are the requirement of highly alkaline solutions for its production and the lack of available data regarding its implementation in the field. To bridge this gap, this study aimed to research the recycling and valorization of tungsten mining waste (TMW) to produce AABs, using waste glass (WG) as a supplementary material for reducing the alkali activator demand. Finally, a connection was made between the fundamental research on AABs and a practical engineering application. A detailed approach was undertaken to determine the most appropriate TMW-WG AAB preparation methods and curing conditions, an understudied area, with a strong emphasis on the microstructural development during hardening. The alkali activator appeared to be sensitive to prolonged stirring, which appeared to induce a stripping effect of the water molecules from the alkali metal ions, leading to a less intense attack on the silicon-oxygen bonds in precursor material. The effects of WG (dissolution and chemical reaction) were investigated to understand its contribution to the AAB system. WG was observed to provide an additional source reactive silica, contributing to the formation of a calcium-containing N-A-S-H gel, and significantly improve the mechanical strength. PCM macro-encapsulated aggregates (ME-LWAs) were also researched and incorporated into the TMW-WG AAB for the development of an energy-saving building material. The ME-LWAs stood out to be leak proof, with excellent thermal stability and thermal conductivity, latent heat capacity and abrasion resistance. It was also found out it is feasible to produce foamed lightweight alkali-activated materials using tungsten mining waste (TMW-WG FAAB) and other precursor materials. FAAB can be used in several applications where low density and fire resistance is required. The TMW-WG FAAB was also designed to suit a wide range of densities and compressive strengths using chemical foaming, achieving very low thermal conductivity. Finally, the TMW-WG AAB proved itself to be convenient to prepare on-site, demonstrating in service its ease of preparation, rapid hardening and durability as a novel road repair mortar.
Supervisor: Zhou, X. ; Huang, Z. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.764853  DOI: Not available
Keywords: Geopolymer ; Inorganic binder ; Sustainability ; Alumionosilicates ; Microstructure
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