凝灰岩机制砂混凝土工作性的流变学分析

Rheological Analysis of Workability for Tuff Manufactured Sand Concrete

机制砂的生产与应用是我国混凝土行业走向低碳发展的良好契机,但机制砂的复杂特性导致混凝土工作性较差且难以预测。为研究基于流变学特性的机制砂混凝土工作性的影响因素及变化规律,从机制砂特性及混凝土配合比参数两个角度展开,建立了流变学特性与工作性的二维、三维关系模型,并采用灰色关联度分析法,对基于流变学分析的凝灰岩机制砂混凝土工作性影响机制进行因素显著性分析。结果表明,动态屈服应力和塑性黏度与混凝土的工作性关系密切,随着石粉含量、机制砂取代率和砂率的增加,动态屈服应力呈先减小后增大的趋势,机制砂特性与混凝土各项流变性能之间的关联度在强相关的区间内,通过合理调配各因素的水平可以达到实际工程所需要的最佳工作性。

The production and application of manufactured sand(MS)provide an excellent opportunity for China’s concrete industry to move towards low-carbon development.However,the complex characteristics of MS lead to poor workability and difficulty in prediction of concrete.In order to study the influencing factors and variation laws of workability for MS concrete based on rheological properties,this paper explored from two aspects:the characteristics of MS and concrete mix proportion parameters.Two-dimensional and three-dimensional relationship models between rheological properties and workability were established,and the significance of factors affecting the workability of tuff MS concrete based on rheological analysis was analyzed by grey relational analysis method.The experimental results show that the dynamic yield stress and plastic viscosity are closely related to the workability of concrete.With the increase of powder content,MS replacement rate,and sand ratio,the dynamic yield stress decreases first and then increases.The correlation between MS characteristics and various rheological properties of concrete is in a strongly correlated range.By properly adjusting the levels of these factors,the optimal workability required for actual engineering can be achieved.