机制砂物理特性对水泥胶砂流变性能的影响及机理

针对机制砂混凝土和易性差、流动经时损失大以及易泌水、离析等问题,通过不同岩性和不同级配区间机制砂对水泥胶砂流变性能的影响及对减水剂的吸附特性分析,研究机制砂岩性、表面吸附性和表面电位等物理特性对水泥胶砂流变性的作用机理。结果表明:相较于钙质机制砂,硅质机制砂对水泥胶砂流动度的影响更大;机制砂颗粒级配越小,对水泥胶砂流动度的影响越大;机制砂胶砂流变性能与机制砂对减水剂的吸附性能和机制砂的内摩擦力有关,机制砂对减水剂吸附性能与表面吸附点的量成正比,母岩中层状结构黏土矿物含量越高,对减水剂的吸附性能越强;影响水泥胶砂流变性能的主要因素是机制砂对聚羧酸减水剂的吸附性能,而不是机制砂的颗粒粒径与比表面积。

Effect of Physical Characteristics of Manufactured Sand on Rheological Properties of Cement Mortar and Its Mechanism

Aiming at the problems of the poor workability,large loss of flowing time,easy bleeding and segregation of manufactured sand concrete,the mechanisms of such physical properties as the lithology,surface absorption and surface potential of manufactured sand on the rheological properties of cement mortar were studied by analyzing the influence of manufactured sand with different lithologies and gradation intervals on the rheological properties of cement mortar and the adsorption characteristics of superplasticizer.Results show that compared with calcareous manufactured sand,the influence of siliceous manufactured sand on the fluidity of cement mortar is greater.At the same time,the smaller the particle size gradation of manufactured sand is,the greater the influence is on the fluidity of cement mortar.The rheological properties of manufactured sand mortar are related to the absorption performance of manufactured sand on superplasticizer and the internal friction of manufactured sand.The adsorption performance of manufactured sand on superplasticizer is directly proportional to the amount of surface adsorption points.The higher the content of layered clay minerals in parent rock is,the stronger the adsorption performance of manufactured sand on superplasticizer is.The main factor affecting the rheological properties of cement mortar is the adsorption performance of manufactured sand on polycarboxylate superplasticizer,rather than the particle size and specific surface area of manufactured sand.