影响新拌水泥基浆体剪切变稠行为关键因素的研究

项目名称： 影响新拌水泥基浆体剪切变稠行为关键因素的研究

项目编号： No.51208515

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 建筑环境与结构工程学科

项目作者： 元强

作者单位： 中南大学

项目金额： 25万元

中文摘要： 自密实混凝土、自流平砂浆和灌浆料等水泥基材料被广泛应用于混凝土结构、基础加固和预应力构件等领域，为保证工程质量，要求这类水泥基浆体的屈服应力很小，粘度随剪切速率增加而增加，表现为剪切变稠。如何控制水泥基材料的剪切变稠行为以适应工程施工要求是工程施工中常遇到的问题，国内外对此研究报道较少。本申请拟以流变学、表面物理化学和胶凝材料学为基础，针对新拌水泥浆体的剪切变稠行为，将其关键影响因素分为颗粒间的相互作用及其物理特征。采用平均液膜厚度和颗粒圆度表征颗粒的物理特征；采用电声衰减法测浓浆的zeta电位，结合颗粒对减水剂的吸附量来表征颗粒间相互作用；采用流变仪测量不同组成水泥基浆体的流变曲线，得出流变指数、屈服应力、粘度等流变参数。在此基础上，得出各关键因素对水泥基浆体剪切变稠行为的影响规律，为丰富和完善自密实混凝土和自流平砂浆等水泥基材料的配合比设计理论与方法、开发新型外加剂提供理论指导。

中文关键词： 水泥基材料；流变；剪切增稠；；

英文摘要： Cement-based materials, such as self-compacting concrete, self-levelling mortar and cement grout, are widely used in concrete structures, base reinforcement and prestressed elements. To ensure the quality of structures, the yield stress of materials are often very small, and their viscosity increases with shear rate, namely shear thickening. How to control the shear thickening behavior of cement-based materials is a question, which often arises in practice. This is seldomly studied in literature. This proposal aims at the shear thickening behavior of fresh cement-based paste. Based on rheology science, physical chemistry of surface, cementitious material science, the key factors affecting shear thickening behavior of cement-based paste are classified into the interactions between paritcles and the physical characteristics of particles. The average liquid film thickness(LFT) wrapped particles and the roundness of particles are used to represent the physical characteristics of particles; the zeta potential of particles of concentrated paste measured by electroacoustic method, combined with the adsorption of superplasticizer, are used to evaluate the influence of interactions between particles on the shear thickening behavior; rheometer is used to measure the rheological curves of cement-based paste with different

英文关键词： cement-based mateirals；rheology；shear thickenning；；