Experimental Study On Properties Of Modified Microfine Cement Grouting Materials

This paper mainly focuses on the traditional cement grouting material with large particle size,it is difficult to inject fine cracks or pores;the setting time is difficult to control;it is easy to produce water and water bleeding;the stone body has insufficient compressive strength;in the underground project with underground moving water,the grouted stone body exhibits water-resistant corrosion resistance and insufficient impermeability,which greatly affects the grouting effect.A modified microfine cement grouting material was developed to improve the grouting effect of the actual project.The use of microfine cement as a grouting material improves the low compressive strength of traditional cement grouting materials and the difficulty of injecting fine cracks.Ultrafine fly ash and graphene oxide are used as admixtures to make up for each other and improve the working properties of grouting materials.Mainly using the combination of macroscopic test and microscopic test,the coagulation time,stability,fluidity,compressive strength,water corrosion resistance,impermeability and shrinkage of modified microfine cement grouting materials have been carried out.Related studies have analyzed the effects of the main factors such as ultrafine fly ash content,water-cement ratio and graphene oxide content on the above properties.At the same time,the traditional cement grouting material with water-cement ratio of 0.4 and microfine cement grouting material with water-cement ratio of 0.4 and modified microfine cement grouting material with water-to-binder ratio of 0.4,ultrafine fly ash content of 20%,and graphene oxide content of 0.09% was compared.The test results show that the setting time of the modified microfine cement grouting material can be adjusted and controlled by adjusting various dosages;the stability of microfine cement grouting material is better than that of traditional cement single-liquid grouting material,the stability of modified microfine cement grouting material is best,and the incorporation stability of ultra-fine fly ash and graphene oxide have a certain promotion effect;the cement single-liquid grouting material is Bingham fluid,the fluidity of traditional cement grouting material is better than that of modified microfine grouting material,the fluidity of microfine cement grouting material can be improved by blending ultrafine fly ash.In addition,the modified microfine cement grouting material can smoothly flow on the glass plate;the incorporation of ultra-fine fly ash will reduce the early strength of the grouted stone body.The strength of the later stage of the stone with ultra-fine fly ash content of 20% and 40% is obviously increased,but the amount of ultra-fine fly ash should not exceed 60%.The strength of the modified microfine cement grouting material with a graphene oxide content of 0.09% is the largest;the water-resistant corrosion resistance and impermeability of the modified microfine cement grouting material are superior to those of traditional cement grouting materials;the traditional cement grouting material has the smallest shrinkage,the modified microfine cement grouting material is in the middle,and the microfine cement grouting material is the largest,ultra-fine fly ash can inhibit the shrinkage of modified microfine cement grouting materials,and the incorporation of graphene oxide is unfavorable for shrinkage.The XRD analysis shows that the peak intensity of CH crystal of modified microfine cement grouting material is higher than that of traditional cement grouting material when curing for 3d.Most of the ultrafine fly ash in the modified microfine cement grouting material has not undergone alkali excitation reaction;after curing for 28 days,the peak intensity of the C-S-H crystal modified by the microfine cement grouting material is higher than that of the traditional cement grouting material.The alkali-excited reaction has occurred in the ultra-fine fly ash in the modified microfine cement grouting material.The SEM analysis shows that the modified microfine cement grouting material has the highest internal compactness,and the microfine cement grouting material is in the middle,while the traditional cement grouting material has a loose internal structure.After 28 d moving water scouring,the density of traditional cement single-liquid grouting material is significantly reduced,and the microfine cement grouting material has better compactness.The internal structure of the modified microfine cement grouting material has little difference compared with the standard curing stone structure.