Influence Of Ground Mineral Admixtures On Rheological Behavior Of Cement-Based Grouting Materials

Fly ash, slag and their compound were ground by the activation of mechanical means. This thesis has created a new rheological model by discussing the rule of pure cement's shearing strength varied with the shearing time. And then the thesis dealt with the influence of the mixing time,W/C and the temperature on the rheological parameters.Through analysis of grouting and filling mechanism of cement-based material and impact factors in micro-cracks, this thesis put forward the design principle for it. The research on the relationship between materials composition and performance shows that the viscosity of the C₁ cement paste increases with the increment of the percentage of fly ash and the compound, but the rule changes when slag is added, the viscosity of C₁ cement paste increases, and the yield value decreases. The viscosity of the C₂ cement paste increases with the increment of the percentage of the fly ash, but the rule was opposite when slag is added. The addition of the compound makes the viscosity of C₂ cement paste increases, and the yield value of it decreases in the meanwhile. The results show that there is a suitable particle diameter distribution for ground mineral admixtures, and the suitable particle diameter distribution may comply with the dense packing powder theory. The rheological behavior and the stability of the materials were all taken into consideration to make sure the ideal composition of cement-based grouting materials.By means of many test methods, this thesis studied the relationship between microstructure and performance. The results show that the addition of the ground mineral admixtures improved the rheological behavior, the stability of the cement paste and many other properties. The cement-based grouting materials designed in this research can meet the requirement of the reality and engineering.