Experimental Study On The Performance Of FA Modified C-S Double Liquid Grouting Material Under Dynamic Water Conditions

This paper mainly focus on the difficulty of controlling the gel time and the low late strength of the stones and the poor durability of traditional single-fluid grouting materials and traditional double-liquid grouting materials,In addition,considering the existence of underground moving water in actual projects.The erosion of the stone body results in a serious decrease of the compressive strength.A modified C-S double-liquid grouting was prepared and researched,which can effectively improve the late strength and durability of the stone,and ensure the workability of the slurry.In this paper,the gel time is regulated by adding disodium hydrogen phosphate,and adding ultra-fine fly ash,on the one hand,it can improve the density of the stone body by its smaller particle size.On the other hand,the alkali-activated of fly ash can improve the late strength and the durability of the stone body.This paper mainly through the combination of macro tests and micro tests studied the gel time,stability,flowability,compressive strength and durability of modified C-S double-liquid grouting material,comparing with traditional double liquid grouting material and traditional cement single liquid grouting material.At the same time,the influences of the main factors,such as ultrafine fly ash content,water-cement ratio,volume ratio of liquid A and liquid B,and disodium hydrogen phosphate content,were analyzed on the above properties of the modified C-S double-liquid grouting material.The macro-test results show that the gel time of the modified double-liquid slurry can be controlled in a few seconds to one hour,and the effect of the disodium hydrogen phosphate on the gel time is remarkable;the stability of the double slurry is obviously better than the single liquid slurry,and the stability of the modified double liquid slurry is the best of the three grouting materials,its water evolution rate is almost 0,the rate of stone is close to 100%.In fluidity,single liquid slurry can be used as Bingham fluid,and double slurry is Newton fluid,and the yield stress of double liquid slurry is smaller.In addition,the modified double liquid slurry can flow smoothly on glass.The addition of ultra-fine fly ash has a reduction on the early strength of the stone body,but the trend of the later strength increases obviously.,the compressive strength of 28d is higher than that of the traditional double slurry stone body,but the addition of ultra-fine fly ash can not too much.When the volume reaches 60%,the early and late strength are low,and the maximum value of the compressive strength can be reached when the volume ratio is 1.5:1 according to the test.In the end,the modified double fluid slurry has better water resistance under flowing water conditions.Through the microscopic experimental study of modified C-S double liquid grouting material and traditional double liquid grouting material at different ages and different curing conditions,Firstly,the modified C-S double liquid grouting material stone structure is more compact than the traditional two-fluid grouting material.The pore structure is mostly small pores with pore diameter of 0?1 ? m.After 28 days of hydrodynamic curing,the compactness of the modified C-S double fluid grouting material remains good.However,the traditional two-fluid grouting material stones were subjected to hydrodynamic erosion and severe erosion.The proportion of harmful macropores was significantly increased,and even the stone structure was destroyed.Secondly,the XRD test shows that ultrafine fly ash has not yet undergone alkali-promoting reactions under alkaline conditions at 3 days of hydration because of its low activity.With the increase of age,the degree of hydration increased,and the alkaline flyout occurred in most of ultrafine fly ash at 28 days.This also makes a further demonstration of the above-mentioned macroscopic experiment from the microscopic point of view.