(1. 河南理工大学 土木工程学院，焦作 454000；
2. 北京科技大学 土木与资源工程学院，北京 100083；
3. 山东黄金集团有限公司充填工程实验室，莱州 261441)
摘 要: 为研究搅拌对膏体流变性能的影响，通过控制搅拌速度制备膏体样品，并测试其细观结构、流变、电位及离子浓度等参数，从物理化学角度分析速度对膏体流变的影响。结果表明：膏体搅拌存在速度阈值(本研究中该值为1000~1500 r/min)，当搅拌速度小于阈值时，由于膏体中各类膜包裹的颗粒被搅拌分散，细观结构尺寸随搅拌速度增加而变小，膏体流变参数随搅拌速率增加而降低，其流变曲线符合Bingham模型；而当搅拌速度超过阈值时，强搅拌剪切促进了早期水化物及无机盐离子溶解到溶液中，其离子浓度升高，颗粒表面电势由-0.7655 mV变为-0.4760 mV，测得细观结构及流变参数均随搅拌速度增加而变大，且流变曲线更符合H-B模型(n＜1)。结合Hattori-lzumi理论和Debye-Hückel理论，通过引入剪切速率因子，建立颗粒表面电化学与吸附力、流变与颗粒聚集状态关系方程，分析了搅拌剪切对膏体流变特征的影响机制，为膏体搅拌技术发展提供理论支撑。
关键字: 全尾砂膏体；搅拌速度；细观结构；双电层；流变模型
（1. School of Civil and Engineering, Henan Polytechnic University, Jiaozuo 454000, China;
2. School of Civil and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China;
3. Filling Engineering Laboratory of Shandong Gold Group, Laizhou 261441, China）
Abstract:In order to study the effect of mixing on the rheological properties of cemented paste backfill(CPB), the CPB samples were prepared by controlling the mixing speed, and the parameters such as microstructure, rheology, potential and ion concentration were tested. The effect of mixing speed on the rheological properties of the paste was analyzed from the perspective of physics and chemistry. The results show that there is a speed threshold for CPB mixing (in this study, the value is in the range from 1000 r/min to 1500 r/min). When the mixing speed is less than the threshold, because all kinds of film wrapped particles in the CPB are mixed and dispersed, the mesostructure size decreases with the increase of mixing speed, and the rheological parameters of the CPB decrease with the increase of mixing speed. The rheological curve conforms to Bingham model. When the mixing speed exceeds the threshold, strong mixing shear promotes the dissolution of early hydrate and inorganic salt ions into the solution, the ion concentration increases, and the particle surface potential changes from -0.7655 mV to 0.476 mV. The measured microstructure and rheological parameters increase with the increase of mixing speed, and the rheological curve is more in line with the H-B model (n＜1). Combined with Hattori-lzumi theory and Debye-Hückel theory, by introducing shear rate factor, the relationship equations between particle surface electrochemistry and adsorption force, rheology and particle aggregation state are established, and the influence mechanism of mixing shear on the rheological characteristics of paste is analyzed, which provides theoretical support for the development of paste mixing technology.
Key words: cemented paste backfill; mixing speed; microstructure; electric double layer; rheological model
