Influence of Fly Ash on Compressive Strength and Micro-Characteristics of Magnesium Potassium Phosphate Cement Mortars

Abstract

Although the reactivity of fly ash (FA) in magnesium potassium phosphate cement (MKPC) systems is still unclear, it has been generally treated as an inert filler in the mix designs of FA/MKPC-based materials. In this study, FA was incorporated in MKPC mortars through two different design methods, where FA was either treated as inert or reactive. Fresh performance, compressive strength and micro-characteristics of the FA/MKPC mortars were systematically evaluated. The experimental results show that the design method where FA was treated as reactive can lead to better fresh performance, better optimized microstructure and higher mechanical strengths. The SEM analysis indicates some reaction of the FA particles within the MKPC mortars; howAlthough the reactivity of fly ash (FA) in magnesium potassium phosphate cement (MKPC) systems is still unclear, it has been generally treated as an inert filler in the mix designs of FA/MKPC-based materials. In this study, FA was incorporated in MKPC mortars through two different design methods, where FA was either treated as inert or reactive. Fresh performance, compressive strength and micro-characteristics of the FA/MKPC mortars were systematically evaluated. The experimental results show that the design method where FA was treated as reactive can lead to better fresh performance, better optimized microstructure and higher mechanical strengths. The SEM analysis indicates some reaction of the FA particles within the MKPC mortars; however, the detailed compositions of the formed secondary reaction products could not be directly determined by either XRD or TGA analysis. Furthermore, this study underlines the importance of two ratios, RMagnesia : FA and RKDP : (Magnesia + FA), in optimum designs of FA/MKPC-based materials.ever, the detailed compositions of the formed secondary reaction products could not be directly determined by either XRD or TGA analysis. Furthermore, this study underlines the importance of two ratios, RMagnesia: FA and RKDP: (Magnesia + FA), in optimum designs of FA/MKPC-based materials.

Department(s)

Civil, Architectural and Environmental Engineering

Keywords and Phrases

Cements; Design; Fly Ash; Magnesium; Mortar; Phosphates; Potassium; Reactivity (Nuclear); Strength of Materials; Design Method; Fresh Performance; Inert Filler; Magnesium Potassium Phosphate Cements; Micro Characteristics; Optimum Designs; Secondary Reactions; SEM Analysis; Compressive Strength

International Standard Serial Number (ISSN)

0008-8846

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2017 Elsevier Ltd, All rights reserved.

Publication Date

01 Sep 2017

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