首页|Effect of coral sand on the mechanical properties and hydration mechanism of magnesium potassium phosphate cement mortar

Effect of coral sand on the mechanical properties and hydration mechanism of magnesium potassium phosphate cement mortar

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Damaged structures on coral islands have been spalling and cracking due to the dual corrosion of tides and waves.To ensure easy access to aggregate materials,magnesium potassium phosphate cement(MKPC)and coral sand(CS)are mixed to repair damaged structures on coral islands.However,CS is significantly different from land-sourced sand in mineral composition,particle morphology,and strength.This has a substantial impact on the hydration characteristics and macroscopic properties of MKPC mortar.Therefore,in this study we investigated the compressive strength,interfacial mechanical properties,and corrosion resistance of MKPC CS mortar.Changes in the morphology,microstructure,and relative contents of hydration products were revealed by scanning electron microscope-energy dispersive spectrometer(SEM-EDS)and X-ray diffraction(XRD).The results indicated that the compressive strength increased linearly with the interfacial micro-hardness,and then stabilized after long-term immersion in pure water and Na2SO4 solution,showing excellent corrosion resistance.Compared with MKPC river sand(RS)mortar,the hydration products of CS mortar were an intermediate product 6KPO2·8H2O with a relative content of 3.9%at 1 h and 4.1%at 12 h.The hydration product MgKPO4·6H2O increased rapidly after 7-d curing,with an increased growth rate of 1100%.Our results showed that CS promoted the nucleation and formation of hydration products of MKPC,resulting in better crystallinity,tighter overlapping,and a denser interfacial transition zone.The results of this study provide technical support for applying MKPC mortar as a rapid repair material for damaged structures on coral islands.

Magnesium potassium phosphate cement(MKPC)Coral sand(CS)Mechanical propertiesCorrosion resistanceHydration mechanism

Hao LIU、Huamei YANG、Houzhen WEI、Jining YU、Qingshan MENG、Rongtao YAN

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College of Civil Engineering and Architecture,Guilin University of Technology,Guilin 541004,China

Guangxi Key Laboratory of Geomechanics and Geotechnical Engineering,Guilin University of Technology,Guilin 541004,China

State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China

School of Intelligent Construction,Wuchang University of Technology,Wuhan 430002,China

Hydraulic Concrete Institute,China Three Gorges Corporation,Beijing 100038,China

The First Railway Survey and Design Institute Group Corporation,Xi'an 710043,China

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Key Technologies R&D Program of Guangxi Zhuang Autonomous RegionOpen Research Program of State Key Laboratory of Geomechanics and Geotechnical EngineeringChina

GUIKE AB22080073SKLGME021026

2024

浙江大学学报(英文版)(A辑:应用物理和工程)
浙江大学

浙江大学学报(英文版)(A辑:应用物理和工程)

CSTPCD
影响因子:0.556
ISSN:1673-565X
年,卷(期):2024.25(2)
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