Development of magnesium potassium phosphate cement pastes and mortars incorporating fly ash

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2018
Bilginer, Baki Aykut
Magnesium potassium phosphate cements (MKPCs) have some promising properties to be considered as an alternative to ordinary Portland cement binders. The favorable properties of these cements are high early and ultimate strength. On the other hand, they have some problems like rapid setting, high heat of reaction, high cost and poor water stability. In this study, the effect of several factors like magnesium-to-phosphate molar ratio (M/P), water-to-binder ratio (W/B) and retarder (borax) content on properties such as setting time, compressive strength and on the microstructural evolution of MKPC pastes is investigated. Also, the effect of sand-to-binder ratio (S/B) and fly ash content on properties of MKPC mortar is investigated. The setting times of the paste samples were found to be between 4 and 10 min. The compressive strengths of the pastes were about 50 MPa. The 28 d compressive strength of the highest-strength mortar, prepared with S/B = 1.25, was almost 80 MPa. This value decreased with increasing fly ash content. Also, the strength loss in water did not seem to change with fly ash replacement. TGA and SEM investigations were also performed on paste samples used to study the effects of M/P and fly ash content.

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Citation Formats
B. A. Bilginer, “Development of magnesium potassium phosphate cement pastes and mortars incorporating fly ash,” M.S. - Master of Science, Middle East Technical University, 2018.