Effect Of Dispersion Of Synthetic Fiber On The Resilience Of Phosphate Cement

Magnesium phosphate cement(MPC)is a cementitious material composed of magnesium oxide,soluble phosphate,and retarder.It is also called chemically bonded ceramics.It has fast coagulation,fast hardness,super early strength,and good volume stability.Advantages such as good bonding performance,can be used in the repair of concrete structures,pavement repair of concrete roads,toxic and nuclear waste solidification and other fields.Magnesium phosphate cement is mainly composed of ionic bonds,covalent bonds and hydrogen bonds,in which ionic bonds and covalent bonds have high resistance to distortion and the ability to hinder displacement movement;and the strength develops rapidly,cracks and cracks in the process of rapid setting and hardening.Defects are unavoidable;in addition,magnesium phosphate releases ammonia during the hydration process,and pores present at grain boundaries also cause stress concentration and other defects,all of which make magnesium phosphate cements more brittle.Synthetic fibers have good flexibility,surface treatment is simple,and performance span is large.Adding concrete can improve the toughness of concrete.In this paper,the use of carbon fiber in the modification of phosphate cement is attempted to use synthetic fiber to improve the toughness of magnesium phosphate cement,and the relationship between dispersion and toughness is established by exploring its dispersion.Firstly,the effects of synthetic fiber type,synthetic fiber content,and synthetic fiber dispersion method on the degree of expansion of magnesium phosphate cement mortar and the dispersibility of synthetic fiber were studied.Second,the compression strength and fracture resistance of magnesium phosphate cement mortar mixed with synthetic fiber were studied.The impact of toughness and other mechanical properties;due to the smooth surface of UHMWPE fiber,and the poor performance of the combination of magnesium phosphate cement,the final use of perchloric acid oxidation of UHMWPE fiber,to improve its surface properties,study the time of perchloric acid oxidation resistance of modified magnesium phosphate cement mortar Compression strength and fracture toughness effect.The results show that the synthetic fiber will reduce the expansion degree of magnesium phosphate cement mortar and increase its flexural strength,but the impact on the compressive strength is not obvious.Among them,the flexural strength of magnesium phosphate cement with PVA fiber is more obvious but its fracture toughness is improved.Not obvious;PAN fiber and phosphate cement compatibility is better,but its poor mechanical properties of phosphate cement improvement;UHMWPE fiber magnesium phosphate cement bending strength promotion is not obvious,but its fracture toughness increase is more obvious.Nitric acid has great effect on the surface modification of UHMWPE fiber,and can also improve the fracture toughness of its modified phosphate cement mortar.The dispersibility of synthetic fibers in MPC is a factor influencing the toughening effect.It was confirmed that increasing the dispersibility of UHMWPE fibers in phosphate cement improves the fracture toughness,but the treatment with pernitic acid does not improve its phosphate content.Dispersion in cement.