Early-age Reactivity and Strength Development in High Volume Mine Tailings-Based Alkali Activated Binders and their Application Potential

Abstract

Mine tailings (MT) present environmental and health risks, necessitating suitable waste management strategies to safely dispose them. One of the most effective methods to immobilize detrimental ingredients present in tailings, yet at the same time synthesize value-added materials in large volumes, is through the development of cementitious binders containing tailings. In this work, copper mine tailings are used to develop alkali-activated binders for several construction-related applications. The binders are designed with ≥70 % by mass of MT, along with minor additions of reactive materials such as cement (C) or slag (S), to obtain 28-day compressive strengths of up to 40 MPa when cured under ambient conditions, contrary to low strength MT-based binders that are generally reported. Setting time is used as a simple criterion to screen the mixtures. The influence of varying Na2O-to source material (MT + cement/slag) ratio (n) and SiO2-to-Na2O ratio (Ms) of the activator on the calorimetric response, flow, and compressive strength development are studied in detail. MT-S blends demonstrate higher strengths (up to 40 MPa) as compared to MT-C blends (up to 12 MPa). Lower Ms and higher n values lead to higher strengths for MT-S blends, while a higher Ms yields better strength for MT-C blends. Based on the binder strength, application avenues such as structural/non-structural masonry, pre-cast non-structural/structural panels, and grouts are identified.

Department(s)

Materials Science and Engineering

Second Department

Civil, Architectural and Environmental Engineering

Comments

National Science Foundation, Grant None

Keywords and Phrases

Alkali activation; Calorimetry; Cement; Mine tailings; Slag; Strength development

International Standard Serial Number (ISSN)

0892-6875

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2024 Elsevier, All rights reserved.

Publication Date

01 Aug 2024

Link to Full Text

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