Abstract Cemented paste backfill (CPB) is considered to be a concentrated suspension in which tailings are bonded together by the hydraulic binder and water, and it has a high solid volume concentration (≥50 vol.%). Although the shear thinning and thickening of CPB has been extensively reported in literature, the shear history effects have been ignored in previous studies. In this paper, by using rheometer and Focused Beam Reflectance Measurement, the relationship between the rheological properties and microstructure of the paste under different shear histories was studied. The results have shown that at a low shear rate, CPB revealed shear thinning, low yield stress and low index parameters; while exhibited shear thickening, high yield stress and high consistency index when at high shear rates of shear history. This agreed with the general trends shown in the FBRM analysis. It was proposed that the action of shear is beneficial to particle dispersion, whereas a high shear rate history tends to promote the aggregation of particles. It was revealed that both shear thinning and thickening of paste are related to the situation of particles (flocculation, dispersion and aggregation), and shear history effects play an important role in rheological properties of CPB.

中文翻译：

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水泥浆回填土的剪切稀化和稠化

摘要 水泥浆回填（CPB）被认为是尾矿通过水硬性粘合剂和水粘结在一起的浓缩悬浮液，具有较高的固体体积浓度（≥50 vol.%）。尽管文献中广泛报道了 CPB 的剪切变稀和增稠，但以往的研究忽略了剪切历史效应。本文利用流变仪和聚焦光束反射测量，研究了不同剪切历史下糊状物的流变特性与微观结构之间的关系。结果表明，在低剪切速率下，CPB表现出剪切稀化、低屈服应力和低指数参数；同时在剪切历史的高剪切速率下表现出剪切增稠、高屈服应力和高稠度指数。这与 FBRM 分析中显示的总体趋势一致。有人提出剪切作用有利于颗粒分散，而高剪切速率历史往往会促进颗粒的聚集。结果表明，糊剂的剪切稀化和稠化均与颗粒的状态（絮凝、分散和聚集）有关，剪切历史效应对CPB的流变特性起着重要作用。