Study on the influence of phosphogypsum on the performance of magnesium oxychloride cement
YANG Longlong
ZHANG Lijuan
DONG Jinmei
ZHENG Weixin
SHENG Chenghui
ZHOU Jing
Abstract：The effects of incorporating PG,fly ash(FA),and phosphoric acid(PA)on the setting time,flowability,compressive strength,and water resistance of Magnesium oxychloride cement(MOC)were investigated.The underlying mechanisms were analyzed through X-ray diffraction(XRD),thermogravimetric analysis(TGA),scanning electron microscopy(SEM),and mercury intrusion porosimetry(MIP).The results showed that under air-cured conditions,compared with the unadmixed group,when the PG content was 100％,the final setting time of the MOC paste was prolonged by 69.05％,the flowability increased by 41.57％,and the 28-day compressive strength decreased by 46.9％.However,after immersion in water,the compressive strength of the unadmixed MOC group decreased rapidly,and its compressive strength could not be measured after 14 days.In contrast,the MOC with 100％PG and 1％PA retained a compressive strength of 86％after 28 days of water immersion,indicating a significant improvement in water resistance.This is because the incorporation of PG reduces the formation of the 5·1·8 phase,leading to a decrease in the strength of MOC under air-cured conditions.It can also inhibit the hydrolysis of the 5·1·8 phase,thereby enhancing the water resistance of MOC.
Keywords：phosphogypsummagnesium oxychloride cementcompressive strengthwater resistance
Publication Date：2025-04-25
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：8( 96-102,153 )