Gel deterioration in alkali-activated slag and fly ash pastes under natural carbonation

Conference paper (2018)

Authors

Marija Nedeljković Materials and Environment - CEG
Corrie van Hoek Tata Steel
Enno Zinngrebe Tata Steel
Sieger van der Laan Tata Steel
G. Ye Materials and Environment - CEG
Research Group
Materials and Environment (CEG) (TU Delft)
Gel Carbonation PARC Alkali-activated GBFS and FA
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Published Date

2018

Language

English

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Faculty

Civil Engineering & Geosciences

Department

Materials- Mechanics- Management & Design

Research Group

Materials and Environment

Abstract

Carbonation of alkali-activated fly ash (FA) and ground granulated blast furnace slag (GBFS) pastes has been investigated after one year of exposure to 0.038 % (v/v) CO2 at 20°C, 55% RH. In particular, the aim was to study the gel deterioration in the samples and changes of the compositions and proportions of the individual chemical domains after carbonation. For that purpose, a new method called PhAse Recognition and Characterization (PARC) [1] based on SEM-EDS elemental mapping was used. The paste bulk chemical composition was evaluated with PARC and XRF. The crystalline products of carbonation were determined and quantified with X-ray diffraction (XRD). Local microanalysis shows that carbonation of the pastes was occurring predominantly around GBFS particles (carbonation of Ca-(Na-)Al-Si-H+Mg gel) and throughout the gel (carbonation of Ca-(Na-)Al-Si-H and Ca-(Na-)Si-H).