scholarly journals Mechanical Properties and Water Stability of High Ductility Magnesium Phosphate Cement-Based Composites (HDMC)

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3169
Author(s):  
Hu Feng ◽  
Yang Wang ◽  
Aofei Guo ◽  
Xiangyu Zhao
Keyword(s):  
Mechanical Properties ◽  
Water Immersion ◽  
Potassium Dihydrogen Phosphate ◽  
Retention Rates ◽  
Magnesium Phosphate ◽  
Dihydrogen Phosphate ◽  
Water Stability ◽  
High Ductility ◽  
Toughness Index ◽  
Ambient Curing

In this study, the compressive test and four-point flexural test were carried out to explore the water stability as well as mechanical properties of high ductility magnesium phosphate cement-based composites (HDMC). The effects of ambient curing age (7 d and 28 d), water immersion age (7 d, 28 d, and 56 d), water/binder ratio (W/B), and magnesium oxide/potassium dihydrogen phosphate ratio (M/P) on the mechanical properties (compressive strength, first-crack strength, ultimate flexural strength, ductility index, and toughness index) and water stability of the HDMC were examined. The results showed that the 28-day ambient curing could lead to higher retention rates of strength, ductility, and toughness than 7-day ambient curing, indicating better water stability; however, it did not result in significant improvement in the mechanical properties of the HDMC. As the water immersion age increased, the mechanical properties of the HDMC with 7-day ambient curing showed an obvious downward trend; the mechanical properties of the HDMC with 28-day ambient curing did not show an obvious decrease and even could be increased in many cases, especially when the water immersion age was 56 days; and the change of water stability was consistent with that of the mechanical properties. If all indexes and their corresponding retention rates were considered comprehensively, the W/B ratio of 0.16 and the M/P ratio of 5 seemed to be the optimum values for the HDMC. The scanning electron microscopy analysis confirmed that the water immersion had a large adverse effect on the HDMC and thus reduced their mechanical properties.

The Effect of Phosphatic Composite on Magnesium Phosphate Cement Performance

2014 ◽  
Vol 809-810 ◽  
pp. 477-484
Author(s):  
Zhao Qing Qi ◽  
Hong Tao Wang ◽  
Jun Liang Dang ◽  
Shi Hao Zhang ◽  
Jian Hua Ding
Keyword(s):  
Setting Time ◽  
Potassium Dihydrogen Phosphate ◽  
Magnesium Phosphate ◽  
Dihydrogen Phosphate ◽  
Ammonium Dihydrogen Phosphate ◽  
Hydrogen Phosphate ◽  
Sodium Dihydrogen Phosphate ◽  
Disodium Hydrogen Phosphate ◽  
Potassium Dihydrogen ◽  
Sodium Dihydrogen

The capacity of 10%, 30%, and 50% ammonium dihydrogen phosphate were replaced with an equal amount of three phosphate (potassium dihydrogen phosphate, sodium dihydrogen phosphate, disodium hydrogen phosphate) respectively. Magnesium phosphate cement was made by phosphate of replaced, which strength, setting time, fluidity, hydration temperature, and the hydration products was researched. The results show that: MPC was made that replaced with the equal amount of three kind of phosphate, which has good mechanical properties. Setting time and fluidity change along with the replacment. Three kind of phosphate replace ammonium dihydrogen phosphate, which change the hydration process of MPC. When ammonium dihydrogen phosphate was replaced by an equal amount of disodium hydrogen phosphate, the temperature of hydration is only 69.4 °C. XRD showed that the diffraction peaks of composite’s magnesium phosphate cement increases.

scholarly journals The Effect of Nano-Particles and Water Glass on the Water Stability of Magnesium Phosphate Cement Based Mortar

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3755 ◽  
Author(s):  
Hu Feng ◽  
Xiangyu Zhao ◽  
Gang Chen ◽  
Changwei Miao ◽  
Xiaocong Zhao ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Water Glass ◽  
Water Immersion ◽  
Nano Particles ◽  
Magnesium Phosphate ◽  
Composition Analysis ◽  
Water Stability ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

This paper experimentally presented the water stability of magnesium phosphate cement (MPC) modified by nano-Al2O3 (NA), nano-Fe2O3 (NF) and water glass (WG). The optimal addition of 6% NA, 2% NF and 1% WG significantly improved the water stability of MPC mortar by 86%, 101% and 96% after 28 days of water immersion, respectively. X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) were used to analyze the water stability of MPC modified by NA, NF and WG. The results of the micrograph and composition analysis revealed that the proper amount of NA, NF or WG could fill the micro pores and improve the hydration of interior structures of MPC mortar. Thus, the microstructural compactness was satisfied to keep a good water stability of MPC mortar.

Lightweight magnesium phosphate cement composites with struvite recovered from wastewater

2020 ◽  
Author(s):  
Parisa Setayesh Gar ◽  
Sergey Lobanov ◽  
Matteo Pernechele ◽  
Cristina Zanotti
Keyword(s):  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Potassium Dihydrogen Phosphate ◽  
Magnesium Phosphate ◽  
Main Reaction ◽  
Dihydrogen Phosphate ◽  
Main Reaction Product ◽  
Lightweight Composites ◽  
Phosphate Source

A feasibility study was performed to utilize struvite, in combination with magnesium oxide (MgO), to develop magnesium phosphate cement. The struvite was a wastewater by-product from a sewage treatment plant in British Columbia, Canada. To achieve MgO-phosphate reactivity in water, two types of recycled struvite were used: heated struvite and newberyite (i.e. rehydrated struvite). A more common phosphate source, Potassium Dihydrogen Phosphate (KDP) was also adopted and replaced in different proportions by recycled struvite. Perlite was incorporated to produce lightweight composites for building applications at different strength-density ratios. Microstructural/chemical analyses were complemented with compressive strength tests at different ages. Reactivity with MgO was achieved for both heated struvite and newberyite. The main reaction product was cattite but reactivity of less soluble newberyite was lower. KDP had the fastest reaction leading to the formation of K-struvite. The lightweight composites achieved up to 90% of their strength in 7 days.

Elastic-Plastic Deformation of KDP Crystals under Nanoindentation

2013 ◽  
Vol 773-774 ◽  
pp. 705-711 ◽  
Author(s):  
Jing Peng ◽  
Liang Chi Zhang ◽  
Xin Chun Lu
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Potassium Dihydrogen Phosphate ◽  
Dislocation Nucleation ◽  
Dihydrogen Phosphate ◽  
Potassium Dihydrogen ◽  
Diamond Indenter ◽  
The Common ◽  
Kdp Crystals ◽  
Yielding Point

This paper investigates the mechanical properties of potassium dihydrogen phosphate (KDP) crystals with the aid of nanoindentation using a conical diamond indenter. It was found that when unloading is after the first pop-in, the common method of obtaining elastic modulus from the unloading curve of nanoindentation is no longer applicable, because the unloading is inelastic. The study revealed that the pop-in could be due to dislocation nucleation and propagation, and that the first pop-in occurs under a stress below that of the major dislocation burst. Hence, the macroscopic yielding point, which is usually regarded as the onset of plasticity of a material, is nanoscopically not a critical point of the first dislocation in KDP. The study found that the elastic modulus of KDP indenting on its (001) plane is 52.8±3.8GPa. The hardness of the material is 1.89±0.05GPa.

Mechanical properties of high-ductility magnesium phosphate cement composite cured at low temperatures

2021 ◽  
pp. 103275
Author(s):  
Hu Feng ◽  
Ahmed Jawad Shaukat ◽  
David Rin ◽  
Pu Zhang ◽  
Danying Gao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Temperatures ◽  
Cement Composite ◽  
Magnesium Phosphate ◽  
High Ductility

Revealing the mechanical properties of potassium dihydrogen phosphate crystals by nanoindentation

2016 ◽  
Vol 31 (8) ◽  
pp. 1056-1064 ◽  
Author(s):  
Y. Zhang ◽  
L.C. Zhang ◽  
M. Liu ◽  
F.H. Zhang ◽  
K. Mylvaganam ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Potassium Dihydrogen Phosphate ◽  
Dihydrogen Phosphate ◽  
Potassium Dihydrogen ◽  
Image Position

Abstract

scholarly journals Fundamental Properties of Magnesium Phosphate Cement Mortar for Rapid Repair of Concrete

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Joon Woo Park ◽  
Ki Hwan Kim ◽  
Ki Yong Ann
Keyword(s):  
Cement Mortar ◽  
Setting Time ◽  
Potassium Dihydrogen Phosphate ◽  
Hydration Product ◽  
Chloride Penetration ◽  
Magnesium Phosphate ◽  
Dihydrogen Phosphate ◽  
Penetration Test ◽  
Fundamental Properties ◽  
Air Void

Fundamental properties of magnesium phosphate cement (MPC) were investigated in this paper. The setting time and compressive and bond (i.e., flexural and tensile bond) strengths were measured to assess the applicability, and hydration product was detected by the X-ray diffraction. The specimens were manufactured with magnesia and potassium dihydrogen phosphate (K2HPO4) was added to activate hydration process. The Borax (Na2B4O7·10H2O) was used as a retarder to mitigate overwhelming rapid hardening. Mercury intrusion porosimetry was used to examine the pore structure of MPC mortar, and simultaneously rapid chloride penetration test was performed. As a result, the compressive strength of MPC mortar was mostly achieved within 12 hours; in particular, the MPC mortar at 4.0 of M/P ranked the highest value accounting for 30.0 MPa. When it comes to tensile and flexural bond to old substrate in mortar patching, the MPS had the higher tensile and flexural strengths, accounting for 1.9 and 1.7 MPa, respectively, compared to OPC mortar patching. Unlike Portland cement mortar, the MPC mortar contained mainly air void rather than capillary pores in the pore distribution. Presumably due to reduced capillary pore in the MPC, the MPC indicated lower penetrability in the chloride penetration test.

Anisotropic Analysis on Processed Surface of KDP Single Crystals

2009 ◽  
Vol 76-78 ◽  
pp. 223-228 ◽  
Author(s):  
Chun Peng Lu ◽  
Hang Gao ◽  
Ben Wang ◽  
Qiang Guo Wang ◽  
Xiao Ji Teng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Slip System ◽  
Surface Quality ◽  
Potassium Dihydrogen Phosphate ◽  
Physical And Mechanical Properties ◽  
Surface Damage ◽  
Dihydrogen Phosphate ◽  
Strong Anisotropy ◽  
Machined Surface ◽  
Kdp Crystals

Strong anisotropy of physical and mechanical properties of Potassium Dihydrogen Phosphate (KDP) crystals significantly affects surface quality during processing the samples. Different processing direction, along [100], [110], and [120] crystallographic orientations, are chosen on (001) crystal plane in order to evaluate the anisotropic characterizations on the processed surface. Scanning electronic microscopy (SEM) is employed to observe the machined surface damage, defects and profiles. At the same time, surface quality is measured by Zygo surface profiler to estimate the processed surface quality. The results show that the machined surfaces along three different orientations under the same processing conditions behave quite differently from each other. Strong anisotropy and complex slip system of KDP crystals lead to several different asymmetric damages on the machined surface. Surface roughness (Ra) values along [100] are the smallest, that along [120] are in average, and that along [110] are largest. Moreover, many illustrations are given to understand the anisotropic nature during processing, including slip system, mechanical properties during processing, and technical parameters, etc.

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