Damage and Deterioration of Magnesium Phosphate Cement under Dry-Wet Cycles and Its Mechanism
ZHOU Yu
JIN Haisen
ZHOU Zihan
LIANG Qinyuan
TANG Qiongqiong
Abstract：To evaluate the durability of magnesium phosphate cement under dry-wet cycles and reveal its deterioration mechanism,20,40,and 60 dry-wet cycles were conducted on magnesium phosphate cement specimens.The degradation process of macroscopic strength and deformation parameters as well as the crack propagation law were analyzed through uniaxial compression tests and X-ray computed tomography(X-CT).The changes in phase composition,content and morphology of hydration products were characterized by X-ray diffraction(XRD),thermogravimetry(TG),and scanning electron microscopy(SEM).The results show that in the early stage of dry-wet cycles,the secondary hydration effect increases the compressive strength and elastic modulus of magnesium phosphate cement,but then gradually decreases with the increase of dry-wet cycles,and the failure mode changes from brittle to plastic.Due to the increase in crack and pore connectivity induced by dry-wet cycles,the fracture mode changes from tensile failure to tensile-shear failure.The deterioration mechanism of magnesium phosphate cement is mainly controlled by the dissolution of K-struvite,thermal expansion and dry-wet shrinkage caused by moisture.
Keywords：dry-wet cyclemagnesium phosphate cementdamage and deteriorationfracture mode
Publication Date：2025-08-30
Online Publishing Date：2025-09-05(First online date of this platform, not the publication date of the document)
Pages：10( 707-716 )