掺合料对水泥浆体流变性能的影响

Effect of admixture on rheological properties of cement paste

文章采用RS-SST型流变仪研究矿物掺合料(偏高岭土、硅灰、粉煤灰、矿粉)对水泥浆体流变性能的影响.试验结果表明:矿物掺合料掺入后,水泥复合浆体的流变模型并未改变,但会影响新拌浆体的流变性能;随剪切速率的增大,掺入矿物掺合料的浆体发生显著的剪切稀化现象,随后浆体塑性粘度逐渐趋于稳定;随着偏高岭土、硅灰和矿粉掺量的增大,复合浆体中屈服应力、塑性黏度及滞回环面积显著增大,稳定性提高;由于粉煤灰具有"滚珠效应",在粉煤灰-水泥复合浆体中屈服应力远低于未掺矿物水泥浆体的屈服应力.

In this paper, the influence of mineral admixture （meta-kaolin, silica fume, fly ash, ore powder） on the rheological properties of cement slurry was studied by RS-SST rheometer. The test results show that the rheo- logical model of the cement composite slurry does not change after the mineral admixture is mixed, but it will af- fect the rheological properties of the fresh slmry; with the increase of shear rate, the mineral admixture is incor- porated. The slurry has a significant shear thinning phenomenon, and then the plastic viscosity of the slurry gradually stabilizes; with the increase of metakaolin, silica fume and mineral powder, the yield stress, plastic viscosity and hysteresis loop in the composite slurry area is significantly enharced and its stability is improved. Because the fly ash has a ＂ball effect＂, the yield stress in the fly ash-cement composite slurry is much lower than that of the undoped mineral cement.