Experimental and computational investigation of magnesium phosphate cement mortar

Tests on magnesium potassium phosphate composite mortars with different water-to-binder ratios and molar ratios of magnesium-to-phosphate

“…The two compounds of struvite-K (MgKPO 4 Á6H 2 O) and unreacted magnesia (MgO) were detected, regardless of M mp value, whereas no KH 2 PO 4 characteristic peaks could be found. This indicates that the complete reaction for KH 2 -PO 4 was done in the hydration [14]. Distinct peaks for struvite-k were observed at 2h % 20.9°, 30.9°, 21.6°, and 34°.…”

“…The chemical reaction of MKPCs is based on the dissolution of MgO and KH 2 PO 4 . This reaction quickly forms struvite-K (MgKPO 4 Á6H 2 O), resulting in quick setting and high early strength [13,14]. The strength development ratio of MKPC mortars was significantly affected by the value of M mp (Fig.…”

“…According to the setting reaction mechanism of MPC demonstrated by Soudée and Péra [12], the dissolution of magnesia is an acid-base reaction between basic surfaces of MgO and the acid potassium dihydrogen phosphate solution generated by the instantaneous dissolution of dihydrogen potassium phosphate in water. The setting reaction in the MKPC system is derived from reactions of Mg 2+ ions with K + and PO 4 3À ions, which form magnesium potassium phosphate hexahydrate (MgKPO 4 Á6H 2 O) as the primary hydration product of struvite-k [13,14]. Hence, the setting time depends on the structure of MgO surface and the KH 2 PO 4 concentration of the solution [12].…”

Effects of graphene oxide on the properties and microstructures of the magnesium potassium phosphate cement paste

“…Magnesium phosphate cement (MPC) is a type of binary chemically bonded ceramic which is usually formed by through-solution acid-base reaction between dead burned magnesia and phosphate, such as ammonium phosphate and potassium dihydrogen phosphate [1][2][3]. It has been regarded as a good candidate to replace Portland cement and widely investigated in recent years due to its many advantages, such as rapid setting time, higher mechanical behavior and lower drying shrinkage [4][5][6].…”

Amorphous phase of volcanic ash and microstructure of cement product obtained from phosphoric acid activation

“…These cements are also known as chemically bonded ceramic phosphates [13][14][15]. The high mechanical performance of the letter is due to the presence of crystalline product phases such as struvite (MgNH 4 PO 4 •6H 2 O) [18,21,22] or (K)-struvite (MgKPO 4 •6H 2 O) [11,23,24]. Both the semicrystalline nature of magnesia and the exothermic reaction involved during its dissolution in phosphoric acid favour the formation of these phases [13,15].…”