刘平 方小婉 何飞亮 娄宗科

摘 要：基于骨料堆积与浆体填充包裹模型，计算在不同水胶比及浆骨比条件下的浆体包裹层厚度，探究浆体包裹层厚度对自密实混凝土工作性能的影响。结果表明：浆体包裹层厚度存在最佳值，在一定范围内，随着浆体包裹层厚度的增加，自密实混凝土的坍落扩展度逐渐增大，拌和物流动至直径为500 mm时所用的时间T500逐渐减小，钢筋间隙通过能力提高，拌和物的流动性得到显著改善;当浆体包裹层厚度过大时，拌和物出现离析，工作性能反而变差。通过建立坍落扩展度随浆骨比变化的定量关系式，能够确定满足工作性能要求的浆骨比，进而降低自密实混凝土中胶凝材料的用量。

关键词：自密实混凝土;浆骨比;浆体包裹层厚度;工作性能

中图分类号：TU528.01 文献标志码：A

doi：10.3969/j.issn.1000-1379.2021.08.027

引用格式：刘平，方小婉，何飞亮，等.浆体包裹层厚度对自密实混凝土性能的影响[J].人民黄河，2021，43（8）：148-151，158.

Abstract： Based on the model of aggregate stacked and slurry filled and wrapped，the effect of paste thickness on coated aggregates on workability of self-compacting concrete was investigated under different conditions of water-binder ratio and paste-aggregate ratio. The results show that there is an optimum value for the paste thickness on coated aggregates. In a certain range， with the increase of the paste thickness on coated aggregates， the slump flow and passing ability of self-compacting concrete increase gradually and the time of T500 decreases gradually， thus improving the flow ability significantly. When the paste thickness on coated aggregates is too large， the mixture appears segregation and workability is worse. By establishing a quantitative relation between slump flow and paste-aggregate ratio， the paste-aggregate ratio can be determined to meet the requirement of workability， so as to reduce the amount of cementitious material of self-compacting concrete.

Key words： self-compacting concrete; paste-aggregate ratio; paste thickness on coated aggregates; workability

自密实混凝土以大流动性为突出特点，是一种在浇筑过程中无须振捣，能够仅依靠自重作用自由流淌，穿过钢筋间隙，均匀密实填充模板或结构内部的每个角落，硬化后具有良好力学性能和耐久性能的混凝土[1-2]。与同等强度的普通混凝土相比，自密实混凝土中胶凝材料用量较大，因而水泥浆体填充骨料堆积所形成的空隙后，用于包裹骨料的浆体层厚度也相对较大。相关研究[3-5]表明，浆体包裹层厚度对混凝土的流动性能、力学性能和耐久性能均有很大影响。……