A robust mix design method for self-compacting concrete
A robust mix design method for self-compacting concrete
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DOI：
10.1016/j.conbuildmat.2022.128927
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发表时间：
2022-09-06
影响因子：
7.4
通讯作者：
Jia, Chaojun
中科院分区：
文献类型：
--
作者：
Liu, Linghui;Lei, Mingfeng;Jia, Chaojun
原材料性能对自密实混凝土的工作性有很大影响。本文探索了一种实现自密实混凝土配合比设计的稳健方法。提出了一个将剩余层组成模型和基于流变学的工作性准则相结合的理论框架来分析混凝土的新拌性能。在该框架下，基于膜厚的组成模型建立了混凝土含量与膜厚和骨料特性之间的相关性。悬浮细胞模型可以量化膜的分离、承载和润滑作用，从而表征混合物的流动性和稳定性。此外，推导出的流变阈值定义了新鲜混合物的流动扩散条件。通过实验验证了该框架的有效性，并结合坍落流动试验进行了阈值标定，显著提高了框架的精度。在膜厚和流变性协调下，对自密实混凝土配合比设计稳健性分析的两个广义自密实区进行了理论计算。通过对广义SCZ评价规律的分析，基于膜厚的SCZ和基于浆体流变性的SCZ面积能够反映自密实混凝土设计中组分含量和浆体流变性控制的可靠性。在此基础上，提出了一种平衡两个范围的自密实混凝土配合比稳健设计方法。关于将配合比设计框架扩展到其他类型的SCC、工业应用和加固结构的讨论证明了该框架的广泛适用性。
Raw material properties greatly influence the workability of self-compacting concrete (SCC). This paper explored a robust approach to realize the mix design of SCC. A theoretical framework, which combines the excess layer composition model and rheology-based workability criteria, was proposed to analyze the fresh behaviors of the concrete. In the framework, the film-thickness-based composition model established the correlation between concrete's content with the film's thickness and the aggregate's characterization. The suspending cell model could quantify the film's separating, bearing, and lubricating effects, therefore characterizing the mixture's flowability and stability. Besides, the derived rheology threshold defined the fresh mixture's flow spread conditions. The framework was experimentally verified, and the experiment-based threshold calibration referring to the slump flow test significantly improved the framework's accuracy. Two generalized self-compacting zones (SCZs) for analyzing the robustness of SCC mix design, under the coordinate of film's thickness and rheology, were theoretically calculated. Through the analysis of the evaluation law of generalized SCZs, the area of the film-thickness-based SCZ and paste-rheology-based SCZ were able to reflect the control reliability of component content and paste rheology in SCC designing. On this basis, a robust mix design method of SCC was proposed by balancing the two ranges. The discussion on the extension of mix design framework to other types of SCC, industrial application, and reinforced structures demonstrated the framework's broad applicability.