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针对氯氧镁水泥早强快硬特性导致其制备的混凝土存在长距离运输时不易搅拌、难泵送等施工受限问题。通过旋转黏度试验测定了氯氧镁水泥浆体在不同剪切速率下的剪切应力及塑性黏度值,采用幂律(Power-law)流体模型拟合氯氧镁水泥流变曲线,并通过该模型分析氯氧镁水泥材料组成设计参数MgO、MgCl_2、H_2O的物质的量比对氯氧镁水泥浆体的剪切应力、塑性黏度及流变特性的影响。研究结果表明:Power-law模型适用于氯氧镁水泥浆体流变曲线拟合,其拟合判定系数均大于0.9,拟合度高,并且可以对稠度系数、流变指数等流变参数进行较好的描述;氯氧镁水泥浆体的剪切应力随剪切速率的增大而增大,而塑性黏度随剪切速率的增大先迅速降低后趋于平稳;剪切速率相同时,氯氧镁水泥浆体的剪切应力随MgO与MgCl_2物质的量比增大而增大,随H_2O与MgCl_2物质的量比增大而减小;随着水泥水化的进行,浆体剪切应力和塑性黏度均增大,当MgO、MgCl_2与H_2O的物质的量比为7∶1∶15时浆体最稳定。
Aiming at the problems that the magnesium oxychloride cement is hard to be stirred and hard to be pumped when it is transported for a long distance due to the early strength and quick hardening properties of the magnesium oxychloride cement, The shear stress and plastic viscosity of magnesium oxychloride cement slurry under different shear rates were measured by rotational viscosity test. The rheological curves of magnesium oxychloride cement were fitted by Power-law fluid model. The effects of MgO, MgCl 2 and H 2 O molar ratios on the shear stress, plastic viscosity and rheological properties of magnesium oxychloride cement paste were analyzed by using the model. The results show that the Power-law model is suitable for the rheological curve fitting of magnesium oxychloride cement paste, the coefficients of fitting of which are all greater than 0.9, the fitting degree is high, and the rheological parameters such as consistency coefficient, rheological index The shear stress of magnesium oxychloride cement paste increases with the increase of shear rate, while the plastic viscosity decreases rapidly and then tends to be stable with the increase of shear rate. When the shear rate is the same, The shear stress of magnesium oxychloride cement paste increases with the increase of the mass ratio of MgO and MgCl 2, and decreases with the increase of the ratio of H 2 O and MgCl 2. With the hydration of cement, The stress and the plastic viscosity increase, the slurry is the most stable when the mass ratio of MgO, MgCl 2 and H 2 O is 7: 1: 15.