Magnesium phosphate cement

Qian, Jueshi; Yu, Jincheng; Jiangyu, Tang; Qin, Jihui; Yue, Yanfei; Yang, Fan; You, Cuihong

doi:10.1016/b978-0-12-391925-0.00011-x

Cited by 8 publications

(17 citation statements)

References 113 publications

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“…It is a new type of a mineral binder formed by through-solution acid-based reaction between phosphate salt and dead-burnt magnesia (calcinated at a temperature above 1300 • C) [4]. In contrast with ordinary Portland cementitious materials, MPC notably appears to have a fast hydration process, high early strength, good bonding at the repair interface, and good durability with low shrinkage and low permeability [1,[4][5][6][7][8]. For such merits, MPC has received increasing attention in many fields during the last few decades of development as rapid repair to damaged concrete structures.…”

Section: Introductionmentioning

confidence: 99%

“…ADP reacts with MgO to produce stable hydration products NH 4 MgPO 4 •6H 2 O (Struvite), which constructs the matrix of magnesium ammonium phosphate cement (MAPC). MAPC has a controllable setting time through the use of retarders, such as borax (NaB 4 O 7 •10H 2 O) and boric acid (H 3 BO 3 ) [5,10]. The setting time can be flexibly adjusted from several to tens of minutes [5,11], which meets the requirements of different application scenarios.…”

Section: Introductionmentioning

confidence: 99%

“…MAPC has a controllable setting time through the use of retarders, such as borax (NaB 4 O 7 •10H 2 O) and boric acid (H 3 BO 3 ) [5,10]. The setting time can be flexibly adjusted from several to tens of minutes [5,11], which meets the requirements of different application scenarios. As the setting time changes, the early strength development of MAPC was reported to vary in the range of 20-40 MPa for 1-h strength and reach over 45 MPa at 3 days [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

“…The hydration product of MKPC is K-struvite (MgKPO 4 •6H 2 O), which has a similar molecular structure and chemical properties to struvite [15]. MAPC has been considered to have greater potential in commercialization and scaled applications due to its relatively lower cost and higher early strength compared to other MPCs [5].…”

Section: Introductionmentioning

confidence: 99%

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An Experimental Investigation on the Effects of Limestone Fines in Manufactured Sands on the Performance of Magnesia Ammonium Phosphate Mortar

Mao¹,

Cao²,

Xin-cheng³

et al. 2022

Buildings

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Magnesium ammonium phosphate cement (MAPC) prepared with ammonium dihydrogen phosphate (NH4H2PO4, ADP) and dead-burned Magnesium oxide (MgO) is a new type of rapid patch repair material for concrete structures. In order to reduce the material costs of MAPC mortar, manufactured limestone sands, being a more widely-available resource with lower cost, was investigated in this study as an alternative to quartz sands for the preparation of MAPC mortar. The limestone fines in manufactured sands were found to be the key factor that influences properties of MAPC mortar by causing bubbling and volume expansion before hardening. As a result, the mechanical strength of MAPC mortar decreased with the increasing content of limestone fines due to increased porosity. According to microstructure analysis, the mechanism of these negative effects can be inferred as the reaction between limestone fines and ADP with the gas generation of CO2 and NH3. This reaction mainly occurred during a short period before setting while most limestone fines remained unreactive in the hardened MAPC mortar. Based on the above detailed experimental findings on the effects of limestone fines in manufactured sand on the properties of MAPC mortar, this paper pointed out that effective defoaming methods for inhibiting bubbling was the key to the utilization of manufactured sands in preparation of high performance MAPC mortar.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

An Experimental Investigation on the Effects of Limestone Fines in Manufactured Sands on the Performance of Magnesia Ammonium Phosphate Mortar

Mao¹,

Cao²,

Xin-cheng³

et al. 2022

Buildings

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“…Concrete structures in service have been experiencing performance degradation due to various interior or exterior actions such as sustained loading and environmental corrosions. Magnesium phosphate cement (MPC) has recently raised attention as rapid repair material for concrete structures [1,2]. MPC has the properties of chemically bonded ceramics and is quite different from ordinary Portland Cement (OPC) in terms of raw material characteristics, hydration process, and hydrate composition [3].…”

Section: Introductionmentioning

confidence: 99%

Preparation of Magnesium Ammonium Phosphate Mortar by Manufactured Limestone Sand Using Compound Defoaming Agents for Improved Strength and Impermeability

Mao

Cao

et al. 2022

Buildings

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Magnesium ammonium phosphate cement (MAPC) mortar has recently risen up as high performance rapid repair material for concrete structures. But high costs of the raw materials limit its restoration and maintenance projects on a wide application range. This study proposes the use of manufactured limestone sand with lower cost and wider range of sources in replacement of quartz sand as fine aggregates to produce MAPC mortar. However, the limestone fines of manufactured sand were initially found to have negative effects on the performance of MAPC mortar, causing significant blistering and volume expansion and decreased compressive strength and interfacial bonding strength. To minimize these negative effects, polyether modified silicone (PMS) defoamer and its compound use with mineral admixtures Portland cement and silica fume were investigated on the effectiveness in reducing expansion and improving other properties of MAPC mortar. Results showed that the compound use of PMS defoamer and Portland cement as a new defoaming formula effectively reduced the volume expansion from 7.92% to 0.91%. The compressive strength and interfacial bonding strength were significantly improved by over 34% and 60% respectively. Moreover, this defoaming formula showed improvements in water-tight performance and resistance to chloride penetration. According to the mercury intrusion porosimetry (MIP) analysis, the total porosity of MAPC mortar after defoaming treatment was decreased by about 40% and the pore structure was also modified to be finer by significantly reducing the harmful macropores. Overall, the use of manufactured limestone sands as fine aggregates turned out to be a feasible and economic approach for promoting the filed application of MAPC mortar.

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Injectability analysis of seawater-mixed magnesium phosphate cement slurry applied to a sand layer

Zhang

Zhang²,

Pei³

et al. 2022

Construction and Building Materials

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Magnesium phosphate cement

Cited by 8 publications

References 113 publications

An Experimental Investigation on the Effects of Limestone Fines in Manufactured Sands on the Performance of Magnesia Ammonium Phosphate Mortar

An Experimental Investigation on the Effects of Limestone Fines in Manufactured Sands on the Performance of Magnesia Ammonium Phosphate Mortar

Preparation of Magnesium Ammonium Phosphate Mortar by Manufactured Limestone Sand Using Compound Defoaming Agents for Improved Strength and Impermeability

Injectability analysis of seawater-mixed magnesium phosphate cement slurry applied to a sand layer

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