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为了提高混凝土的搅拌均匀性,在普遍使用的双卧轴搅拌机上,通过改变搅拌叶片总数量不变条件下的返回叶片数量以及连续和非连续的排布方式,分析了对搅拌过程中混凝土混合料围流运动的影响,并在相同混凝土配合比和投料顺序、搅拌时间下,通过4种拌缸长宽比(长宽比为0.8和0.9的宽短形,1.1和1.2的窄长形)的搅拌性能试验,采用新拌混凝土拌合物中砂浆密度和单位体积粗骨料质量变异系数的均匀性分析方法,确定了双卧轴搅拌机返回叶片的合理数量与排布方式。研究结果表明:对于不同的返回叶片数量与排布方式,搅拌机内的轴向和轴间循环运动随之改变,因而给定搅拌时间内的搅拌均匀性发生变化;与排布方式相比,返回叶片数量对搅拌均匀性的影响程度更为显著;合理的单轴返回叶片数量与单轴搅拌叶片总数量和拌缸长宽比形式密切相关,建议宽短形拌缸的单轴返回叶片数量与单轴叶片总数量的比值控制在0.2以内,窄长形拌缸的控制在0.3以内;单轴返回叶片数量在1个以上时,建议返回叶片采用非连续正排列方式,以促使返回料流快速形成。
In order to improve the mixing uniformity of concrete, the change of the number of returning blades and the continuous and non-continuous arrangement of the blades in the commonly used twin-shaft mixer were analyzed. The effect of confining flow movement was studied. The aspect ratios of four mixers (width-width ratio of 0.8 and 0.9, narrow length of 1.1 and 1.2) were obtained under the same concrete mix ratio, feeding sequence and stirring time. Of the mixing performance test, the use of fresh concrete mixture mortar density and unit volume of coarse aggregate quality coefficient of variation of the uniformity analysis method to determine the return of the twin-shaft mixer leaves a reasonable number and arrangement. The results show that the axial and axial cyclic motions in the agitator vary with the number of return blades and the arrangement of the agitator, so the agitation uniformity changes within a given agitation time. Compared with the arrangement, The number of blades has more significant influence on the uniformity of mixing. The number of uniaxially-returning blades is closely related to the total number of uniaxial stirring blades and the aspect ratio of mixing drum. It is suggested that the number of uniaxial return blades The ratio of the total number of uniaxial blades is controlled within 0.2, and the control of narrow and long mixing cylinders is within 0.3. When the number of uniaxial return blades is more than one, it is suggested to return the blades in a non-continuous positive arrangement to promote the rapid return flow form.