Effect of mixture proportioning on the strength and mineralogy of magnesium phosphate cements

Magnesium potassium phosphate cement (MKPC) has properties advantageous over ordinary portland cement such as quick setting and rapid strength gain. Although the effect of mixture proportioning on MKPC pastes has been studied, there are conflicting reports on how calcination of magnesia, parameters like magnesium-to-phosphate ratio (M/P) and water-to-binder ratio (W/B), added materials like borax and fly ash, or the addition of sand influence mineralogy and properties like setting and strength. These factors are evaluated over a practical range of values for each using X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy on paste samples. Strength development is evaluated using both pastes and mortars. Calcination of magnesia forms some forsterite with impurity SiO2 which may be linked to the reduction of reactivity. Increasing W/B increases setting time more significantly at lower M/P. Increasing M/P increases early strength but not so much ultimate strength. The main final phases in the pastes are K-struvite and unreacted MgO. Addition of borax or low-lime fly ash does not alter the mineralogy of hydrated pastes. Varying M/P simply changes the relative amounts of these solid phases. Unlike in Portland systems, adding up to ~60 vol% sand to pastes does not decrease strength considerably.
Construction and Building Materials


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Replacement of the Basic and Acidic Components of Magnesium Potassium Phosphate Cement with Calcium Sulphoaluminate Cement and Fly Ash Phosphate Salts
Mazaheri Shadbad, Hossein; Erdoğan, Sinan Turhan; Akgül, Çağla; Department of Civil Engineering (2022-12-02)
Magnesium phosphate cement (MPC) is an acid-base cement with applications as a construction material. This cement has properties superior to portland cement like high early strength. However, MPC has a short setting time, high heat of hydration, and poor water resistance. In addition, this cement uses dead-burned magnesium oxide, prepared at around 1500 ˚C, which consumes much energy, releases CO2, and increases cost. In this study, the two main components of magnesium potassium phosphate cement, dead-burne...
Development of magnesium potassium phosphate cement pastes and mortars incorporating fly ash
Bilginer, Baki Aykut; Erdoğan, Sinan Turhan; Department of Civil Engineering (2018)
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 propertie...
Effects of separate and intergrinding on some properties of portland composite cements
Soyluoğlu, Serdar; Tokyay, Mustafa; Department of Cement Engineering (2009)
In the production of cement, to increase the cement/clinker ratio and decrease CO2 emission, the most important alternative is to produce mineral admixture incorporated cements (CEM II-III-IV-V) instead of portland cement (CEM I). These cements are usually produced by intergrinding the portland cement clinker and the mineral admixtures. However, the difference between grindabilities of the different components of such cements may cause significant effects on the particle size distribution and many other pro...
Citation Formats
B. A. Bilginer and S. T. Erdoğan, “Effect of mixture proportioning on the strength and mineralogy of magnesium phosphate cements,” Construction and Building Materials, 2021, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/88634.