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采用流变仪和激光共聚焦显微镜对不同氧化石墨烯(GO)掺量的新拌水泥浆体的流变参数以及浆体微观形态进行了定量化研究,并采用Modified-Bingham(M-B)模型和Herschel-Bulkley(H-B)模型对所测数据进行了拟合处理,提出了GO影响新拌水泥浆体的作用机理。结果表明,GO的掺入可以使新拌浆体中在减水剂作用下分散的水泥颗粒发生再次凝聚,形成重组絮凝结构,且随着GO掺量的增加,重组絮凝结构的数量越多,从而使得浆体流变性发生显著变化。一方面,新拌浆体的塑性粘度、屈服应力以及触变性随GO掺量的提高而显著增加。另一方面,GO的掺入提高了新拌浆体的临界剪切速率,使其在较大剪切速率下的流变行为仍然表现为剪切变稀;降低了浆体的剪切增稠程度,提高了浆体的稳定性。
Rheological parameters and laser confocal microscopy were used to quantitatively study rheological parameters and microstructure of fresh cement paste with different graphene oxide (GO) content. Modified-Bingham (MB) model and Herschel-Bulkley (HB) model was fitted to the measured data and the mechanism of GO affecting fresh cement paste was proposed. The results show that the incorporation of GO can re-agglomerate the cement particles dispersed in the slurry under the action of water reducer to form a reorganized flocculation structure. With the increase of the content of GO, the more the flocculation structure, So that the slurry rheology changes significantly. On the one hand, the plastic viscosity, yield stress and thixotropy of the fresh slurry increase significantly with the increase of GO content. On the other hand, the incorporation of GO increased the critical shear rate of the fresh slurry, resulting in the rheological behavior of the slurry still thinning at shear rate and reducing the shear thickening of the slurry Degree, improve the stability of the slurry.