Alkali-Activation of Synthetic Aluminosilicate Glass With Basaltic Composition

Abstract

Alkali-activated materials (AAMs) are a potential alternative to Portland cement because they can have high strength, good durability and low environmental impact. This paper reports on the structural and mechanical characteristics of aluminosilicate glass with basalt-like compositions, as a feedstock for AAMs. The alkali-activation kinetics, microstructure, and mechanical performance of the alkali activated glass were investigated. The results show that AAMs prepared from basalt glass have high compressive strength (reaching up to 90 MPa after 7 days of hydration) compared to those made using granulated blast furnace slag (GBFS). In addition, calorimetry data show that the hydrolysis of the developed glass and subsequent polymerization of the reaction product occur at a faster rate compared to GBFS. Furthermore, the obtained results show that the alkali activation of the developed glass formed sodium aluminosilicate hydrate (N-A-S-H) intermixed with Ca aluminosilicate hydrate gel (C-A-S-H), while the alkali activation of GBFS resulted in predominantly C-A-S-H gel. The developed glass can be formed from carbonate-free and abundant natural resources such as basalt rocks or mixtures of silicate minerals. Therefore, the glass reported herein has high potential as a new feedstock of AAMs.

Impact of Na/Al Ratio on the Extent of Alkali-Activation Reaction: Non-linearity and Diminishing Returns

“…One of the most promising alternatives is alkali-activated materials (AAM) ( Rivera et al, 2021 ; van Deventer et al, 2021 ), also referred to as geopolymers. The terms geopolymers ( Davidovits, 1989 ), inorganic polymers ( Van Wazer, 1970 ), alkali-activated cement ( Palomo and López de la Fuente, 2003 ), and geocement ( Krivenko, 1994 ) are all used to describe these binding materials, which can provide comparable, or higher performance than the traditional cementitious binders ( Wang et al, 2019 ; Alzeer et al, 2021 ) with significantly lower greenhouse emissions ( Gartner, 2004 ; Palomo et al, 2021 ).…”

New synthetic glass-based supplementary cementitious materials derived from basalt composition

“…The glass could also be prepared from combinations of abundant silicate minerals such as anorthite, olivine and wollastonite [37] and therefore, it has potential for large-scale production and utilization with low raw-material related CO 2 emissions as compared to PC. The synthesis of the glass presented in this study and its performance as alkali activated materials (AAMs) has recently been reported [38]. In this work, we investigated the hydration kinetics, hydration phases, pozzolanic reactivity and mechanical properties of blended cements containing the developed glass and compared their SCM performance to commonly applied GBFS.…”