Study On Low PH And Ultra Fine Phoshoaluminate Grouting Material

This paper is based on the project “deep geological disposal with phosphorus aluminates cement sealing material applied basic research” of National Key Laboratory of silicate building materials.Herein,deep geological disposal of cement based materials enclosed demand is studied,aiming at excogitating design and performance control methods of suitable crack width of 100 μm,low PH,high fluidization and durability aluminum phosphate acid salt mud based fissure sealing material.The laboratory-made phosphoaluminate cement,with two-time grinding,is mixed with grinding medium and micro grinding agent to prepare ultrafine cement.With the help of measurement of water retention,rheological poperty,mechanical property,PH,volume stability and Simulation of grouting liquid in the interior of the irrigation,the influences of and water cement ratio,water retaining agent,mineral admixture,water reducing agent,expanding agent and other controlling materials to the grouting materials are investigated.Proper material dosage of each regulation is found,and deep geological disposal of phosphorus in aluminum acid salt clay based fissure sealing materials(GRPCSM)is prepared.This paper mainly studies as follows:(1)Grinding medium and different grinding agents are mixed in the cement to conduct two-time grinding.Laser particle size distribution,SEM and hydration heat test are utilized for evaluation of effects of different grinding aids.The results show that adding 0.09% glycerol grinding agent D95 of the system is 13.35 m.Meeting the requirements of superfine cement.Meanwhile,phenomenon of retarding hydration is found,and cement hydration is relatively adequate.(2)The influences of water cement ratio,water retaining agent,mineral admixture,water reducer and MgO and other controlling agents on properties of ultrafine cement materials.Experimental results show that the water cement ratio can obviously improve the fluidity of grouting material,but also undermine the stability of the slurry.Water retaining agent base bentonite and Hydroxypropyl methyl cellulose ether on the one hand,can improve the stability of the slurry,on the other hand,can increase the viscosity of the slurry.Water reducing agent as a surfactant improves the rheological properties of slurry and increases the water separation rate and shrinkage.Adding expansive agent MgO can compensate system contraction,and the larger activity of MgO,the better its compensation effect.(3)GRPCSM is designed as fly ash powder 20%,Slag Powder 10%,4% MgO-1 expansive agent,1.5% polycarboxylate superplasticizer water retaining agent(sodium bentonite 10%,Hydroxypropyl methyl cellulose ether,0.2%).The experimental results show that the experimental designed GRPCSM slurry has good stability and irrigation,and the strength of GRPCSM grows steadily without shrinkage.However,the viscosity of designed GRPCSM is less than 50 mPa·s,which does not meet the viscosity requirements of the project.The experiments show,when the ratio of cement :SL:MgO-1: polycarboxylate superplasticizer: Hydroxypropyl methyl cellulose ether =is 80:20:4:1.5:0.2,100μm crack width,low PH,high fluidization Paluminates cement crack sealing materials can be prepared.