Study On The Effect Of Silicate Compound,mixing Water And Curing Method On The Properties Of Magnesium Phosphate Cement

Magnesium phosphate cement(MPC)is a new type of phosphate binder prepared by acid-base neutralization reaction,which can be cured rapidly at room temperature.It has the characteristics of cement and ceramics.Because of its advantages of room temperature curing,fast hardening and high early strength,it plays an important role in repairing materials,curing hazardous wastes and metal protective coatings.However,due to the high hydration rate,high cost and poor water stability in the early stage of MPC,its large-scale application is limited.This paper explores the influence of silicate compounds,mixing water and curing conditions on the properties of magnesium phosphate cement,designs 8 mix proportions and makes864 small cube specimens.(1)The influence of mixing water and silicate compounds on the compressive strength of magnesium phosphate cement paste was studied,and the change rule of different mixing water and silicate compounds on the compressive strength of magnesium phosphate cement paste under air curing was obtained.(2)The influence of silicate compounds on the compressive strength and water stability of magnesium phosphate cement was studied under the condition of fresh water and seawater mixing,fresh water and seawater curing,different air pre curing time,and the influence of curing conditions on the strength and water stability of magnesium phosphate cement paste was studied.(3)The research on the influence of mixing water on the strength and water stability of magnesium phosphate cement paste shows that the compressive strength and water resistance of magnesium phosphate cement paste mixed with the same material in fresh water are higher than those in sea water when the curing age is 56 days and the air pre curing time is different.(4)The results show that when the total age of specimens is 56 days,the curing time has little effect on the strength and water resistance of fresh water and seawater potassium silicate and lithium silicate groups;the curing time of fresh water and seawater blank group and sodium silicate group is 7 days.(5)The main hydration product of magnesium phosphate cement is potash struvite(MKP),and the intensity of MKP diffraction peak is inversely proportional to MgO.The addition of silicate compounds will promote and inhibit the reaction of MgO under different mixing water and curing conditions.The study on the water stability of magnesium phosphate in this paper is conducive to the stable performance of MPC under harsh conditions,and provides a new idea for the application of MPC in practical engineering.