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.

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.

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.

scholarly journals Optimization of Waste Inertization Systems Based on Chemically Bonded Phosphate Ceramics

2018 ◽  
Vol 69 (11) ◽  
pp. 2987-2990
Author(s):  
Elena Dumitrescu ◽  
Ecaterina Andronescu ◽  
Alina Monica Mares
Keyword(s):  
Magnesium Oxide ◽  
Setting Time ◽  
Potassium Dihydrogen Phosphate ◽  
Hazardous Wastes ◽  
Solid Matrix ◽  
Dihydrogen Phosphate ◽  
Potassium Dihydrogen ◽  
Suitable Material ◽  
Setting Process ◽  
Compositional Properties

This paper presents the experimental results for optimization of the waste inertization systems based on Chemically Bonded Phosphate Ceramics (CBPCs). Through this process, the hazardous wastes containing heavy metals are transformed, by chemical reactions and binding in a solid matrix, into non-hazardous wastes. It was studied the obtaining mode of chemically bonded phosphate ceramics from magnesium oxide and potassium dihydrogen phosphate. Since the CBPCs system is a fast setting system it was studied the effect of retarders (boric acid and calcium lignosulphonate) used in concentrations of 1, 2 and 3% (based on the amount of magnesium oxide and potassium dihydrogen phosphate) above the setting process. It was determined the setting time and compressive strength of the obtained samples. The optimal variant has been established to obtain a suitable material in terms of both mechanical and compositional properties.

scholarly journals Experimental Study on the Evaluation of Physical Performance and Durability of Cement Mortar Mixed with Water Repellent Impregnated Natural Zeolite

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3288 ◽  
Author(s):  
Chang Bok Yoon ◽  
Han Seung Lee
Keyword(s):  
Natural Zeolite ◽  
Test Specimen ◽  
Cement Mortar ◽  
Chloride Penetration ◽  
Chloride Diffusion ◽  
Water Repellent ◽  
Chloride Diffusion Coefficient ◽  
Accelerated Carbonation ◽  
Penetration Test ◽  
Water Penetration

To complement the shortcomings of concrete surface treatment technology and improve the durability of concrete structure, the purpose of this study was to impregnate water-repellent performance into natural zeolite, which has many pores inside, to achieve water-repellent performance inside concrete. The physical performance and durability of cement mortar mixed with water-repellent natural zeolite was evaluated. Cement mortars were prepared by mixing ZWR1%, 3%, and 5% (ZWR: Zeolite + Water Repellent impregnation) in cement powder, and compressive strength, contact angle, water penetration test, resistance chloride penetration test, chloride diffusion coefficient, and accelerated carbonation test were evaluated. When the mixing ratio of ZWR increased, the compressive strength of the test specimen was reduced compared to OPC. In contact angle measurement, water penetration test, chloride penetration resistance test, chloride diffusion coefficient, and accelerated carbonation test, the ZWR-containing samples showed superior properties compared to OPC. It was found that the durability test results improved as the amount of mixing was increased, and the durability of the test specimen containing 5% ZWR was found to be the best.

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.

ON THE USE OF SLAG CEMENT COMPOSITIONS IN THE CONSTRUCTION OF WELLS

2017 ◽  
pp. 80-85
Author(s):  
V. P. Ovchinnikov ◽  
O. V. Rozhkova ◽  
N. A. Aksenova ◽  
P. V. Ovchinnikov
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Elevated Temperatures ◽  
Cement Mortar ◽  
Setting Time ◽  
Rheological Parameters ◽  
Slag Cement ◽  
Furnace Slag

In the article studies of oil-filled compositions with the addition of blast-furnace slag for strength at elevated temperatures are presented. The rheological parameters of the slag cement slag cement mortar, as well as the setting time, were studied. Conclusions are drawn about the prospects of further study of slag cementcontaining compositions.

scholarly journals The Influence of Water Reducing Agents on Early Hydration Property of Ferrite Aluminate Cement Paste

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 731
Author(s):  
Chunlong Huang ◽  
Zirui Cheng ◽  
Jihui Zhao ◽  
Yiren Wang ◽  
Jie Pang
Keyword(s):  
Setting Time ◽  
Critical Role ◽  
Hydration Product ◽  
Reducing Agents ◽  
Reducing Agent ◽  
Hydration Process ◽  
Early Hydration ◽  
Cement Pastes ◽  
Hydration Rate ◽  
Aluminate Cement

The ferrite aluminate cement (FAC) could rapidly lose fluidity or workability due to its excessive hydration rate, and greatly reduce the construction performance. Chemical admixtures are commonly used to provide the workability of cement-based materials. In this study, to ensure required fluidity of FAC, chemically different water reducing agents are incorporated into the FAC pastes. The experiments are performed with aliphatic water reducing agent (AP), polycarboxylic acid water reducing agent (PC) and melamine water reducing agent (MA), respectively. Influence of the water reducing agents on fluidity, setting time, hydration process, hydration product and zeta potential of the fresh cement pastes is investigated. The results show that PC has a better dispersion capacity compared to AP and MA. Besides decreasing water dosage, PC also acts as a retarder, significantly increasing the setting times, delaying the hydration rate and leading to less ettringite in the hydration process of FAC particles. The water reducing agents molecules are adsorbed on the surface of positively charged minerals and hydration products, however, for PC, steric hindrance from the long side chain of PC plays a critical role in dispersing cement particles, whereas AP and MA acting through an electrostatic repulsion force.

scholarly journals Optical Absorption Spectra of Vanadyl Ion (Impurities) in Three Host Crystal Compounds

1985 ◽  
Vol 40 (11) ◽  
pp. 1164-1166
Author(s):  
O. P. Agarwal ◽  
Prem Chand
Keyword(s):  
Optical Absorption ◽  
Potassium Dihydrogen Phosphate ◽  
Optical Data ◽  
Dihydrogen Phosphate ◽  
Host Crystal ◽  
Optical Absorption Study ◽  
Potassium Dihydrogen ◽  
Vanadyl Complexes ◽  
Vanadyl Ion ◽  
Magnesium Ammonium

Results of the optical absorption study of vanadyl ion doped in magnesium ammonium sulphate hexahydrate, rubidium sulphate and potassium dihydrogen phosphate single crystals at RT are reported. The nature of optical bands suggests a C4v symmetry of the Vanadyl complexes in conformity with the EPR results. Powder EPR data and optical data are correlated to obtain the MO coefficients.

scholarly journals Validated Simultaneous Gradient Ultra-Performance Liquid Chromatographic Quantification of Some Proton Pump Inhibitor Drug Residues in Saudi Pharmaceutical Industrial Wastewater

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4358
Author(s):  
Sherif A. Abdel-Gawad ◽  
Hany H. Arab ◽  
Alhumaidi B. Alabbas
Keyword(s):  
Proton Pump ◽  
Industrial Wastewater ◽  
Mobile Phase ◽  
Solid Phase ◽  
Potassium Dihydrogen Phosphate ◽  
Ultra Performance Liquid Chromatography ◽  
Dihydrogen Phosphate ◽  
Separation Pattern ◽  
Inhibitor Drug ◽  
Wastewater Samples

Monitoring and quantification of active pharmaceutical ingredients (APIs) in the environment constitute important and challenging tasks, as they are directly associated with human health. Three commonly used proton pump inhibitors (PPIs), namely, omeprazole sodium (OMP), pantoprazole sodium (PNT), and lansoprazole sodium (LNZ) are well separated and quantified using ultra-performance liquid chromatography (UPLC) in pharmaceutical industrial wastewater. The separation of the studied drugs was performed on a stationary phase with a WatersTM column (100 × 2.1 mm, 1.7 µm). The mobile phase was composed of methanol:0.05 M potassium dihydrogen phosphate buffer (adjusted to pH 7.5 using NaOH) (50:50, v/v). The elution process was done in gradient mode by changing the relative proportions of the mobile phase components with time to get an optimum separation pattern. The flow rate of the developing system was adjusted to 0.8 mL/minute. Detection of the separated drugs was performed at 230 nm. The studied drugs were quantified in the concentration range of 10–200 ng/mL for all drugs. The cited method was fully validated according to the international conference on harmonization (ICH-Q2B) guidelines, then it was applied successfully for quantification of the studied PPIs in real wastewater samples after their solid phase extraction (SPE).

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