Effect of fly ash content on the properties of magnesium phosphate cement based on light burnt magnesium oxide
In this paper,the goal is to realize the 3d Printing of low-carbon magnesium phosphate cement mate-rials prepared from light-burned magnesium oxide as raw material.With the help of the self-developed mixing and extrusion function-based building 3d Printing equipment,the influence of different fly ash content on the properties and printing properties of magnesium phosphate cement materials prepared from light-burned magne-sium oxide was investigated.The influence of fly ash on its hydration products and crystal appearance was fur-ther analyzed by XRD and SEM micro-tests.The results show that the setting time of magnesium phosphate ce-ment prepared from light burned magnesium oxide is greatly shortened compared with that of heavy burned magnesium oxide.The addition of fly ash has a little effect on the setting time of the material,which is about 2-3 min,but it has a negative effect on the compressive strength and interfacial bond strength.When the content of fly ash is 30%of the mass of magnesium phosphate cement,the compressive strength and interfacial bond strength decrease by about 34.24%and 48.94%,respectively.When the content of fly ash is less than 20%,it can effectively improve the dry shrinkage rate of light-burned magnesia-based magnesium phosphate cement ma-terial and increase the volume stability.The active substances in fly ash participate in the hydration reaction,and the generated hydration products show good chemical compatibility with magnesium phosphate cement,making the structure more compact.When the content of fly ash is 20%-25%,the prepared light burned MgO-based magnesium phosphate cement for 3d Printing has good working performance,volume stability,extrusion performance and construction performance,and meets the mechanical requirements of 3d Printing for cement-based materials.
万方数据
维普
