Study on the rheological properties and flocculation characteristics of polyacrylamide-sodium silicate-cement composite slurry
MENG Xiangxi
YUE Bing
SUN Yida
ZHANG Shulei
ZHANG Xin
Abstract：The dynamic disasters of water inrush in deep strata are characterized by"large flow rate,high flow velocity,and strong recharge".In order to enhance the engineering applicabili-ty of cement slurry in the dynamic water grouting environment,it is urgent to accelerate the hydration process of the slurry and improve the stability of the slurry by optimizing the slurry ratio and performance regulation.In this study,Grouting materials with rapid setting and anti-dispersion characteristics were prepared using polyacrylamide(PAM)and sodium silicate as modifiers.Through analysis methods and equipment such as rheological property tests,uniax-ial compression tests,light scattering method and scanning electron microscopy,the compre-hensive influence of the dosings of two modifiers on the rheological and mechanical properties of grouting materials is investigated,and the synergistic mechanism of PAM and sodium sili-cate in the formation process of slurry flocs is studied.The influence of the size and strength of flocs on the anti-dispersion property of the slurry and the physical strength of the slurry stones is analyzed.The results show that:the flocs formed by PAM and sodium silicate enhance the internal friction between the slurry particles,which helps to construct a stable three-dimen-sional network and reduce the scouring loss of the slurry.With the increase of the dosage of PAM and sodium silicate,the size of the primary particle size keeps improving,and at the same time,the strength of the flocs in the slurry keeps increasing.When the dosage of sodium silicate reaches 15％,the strength of the flocs increases linearly.At this time,the promoting effect of sodium silicate on the hydration of the slurry dominates,and the slurry shows a"flash coagulation phenomenon".The rapid formation of the hydration gel blurs the process from the formation of the primary particle size to the formation of the secondary particle size of the flocs.Meanwhile,the cement with these two admixtures added exhibit the characteristics of an expansive non-Newtonian fluid,and there are phenomena of shear thickening and expansion.The mechanical properties of the slurry stone body specimens show significant differences when the sodium silicate content is 10％and 15％respectively.The mechanical strength of the specimens decrease significantly.Under a high sodium silicate content,the structure of the slurry stone body is relatively loose,and there are needle-like hydrates between the flocs.The research can provide theoretical support for revealing the flocculation synergy mechanism of anti-dispersion grouting materials.
Keywords：grouting materialcement pasteantidispersantrheological propertiesfloc prop-erties
Publication Date：2025-07-30
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：13( 837-849 )