Effects of fly ash, mixing procedure and type of air-entraining agent on coalescence of entrained air bubbles in mortar of self-compacting concrete at fresh state
Effects of fly ash, mixing procedure and type of air-entraining agent on coalescence of entrained air bubbles in mortar of self-compacting concrete at fresh state
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DOI：
10.1016/j.conbuildmat.2018.04.138
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发表时间：
2018-08
影响因子：
7.4
通讯作者：
Nipat Puthipad;M. Ouchi;Anuwat Attachaiyawuth
中科院分区：
文献类型：
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作者：
Nipat Puthipad;M. Ouchi;Anuwat Attachaiyawuth
本文报道了一项旨在防止含粉煤灰自密实混凝土（SCC）新鲜砂浆中细小夹带气泡聚结的实证研究。还研究了混合过程中加气剂（AEA）的添加时间。还研究了各种类型的 AEA。在实施实验时，假设砂浆的流动性会影响细小气泡的聚结。新鲜状态下的加气SCC砂浆的空气尺寸分布由空气空隙分析仪（AVA）测定。分析 120 分钟内空气尺寸分布的变化以评估气泡合并。结果表明，在 SCC 中使用粉煤灰可以导致细小气泡更高程度的聚结。不同类型的 AEA 会产生不同程度聚结的气泡。此外，在超塑化剂 (SP) 之后向混合物中添加 AEA 可抑制气泡的聚结。显然，通过仔细选择 AEA 和混合程序可以降低气泡的聚结程度。
In this paper, an empirical study aimed at preventing the coalescence of fine entrained air bubbles in the fresh mortar of self-compacting concrete (SCC) containing fly ash is reported. The time of addition of the air-entraining agent (AEA) during mixing is also investigated. Various types of AEA are also studied. In implementing the experiment, mortar flowability is assumed to affect the coalescence of fine air bubbles.The air size distribution of the air-entrained SCC mortar in the fresh state is determined by an Air Void Analyser (AVA). Changes in the air size distribution over a 120 min period are analysed to evaluate bubble coalescence. The results suggest that the use of fly ash in the SCC can result in a higher degree of coalescence of the fine air bubbles. The various types of AEA resulted in air bubbles with different degrees of coalescence. Further, adding the AEA to the mix after the superplasticiser (SP) inhibits the coalescence of air bubbles. Evidently, the degree of coalescence of air bubbles can be reduced by careful selection of the AEA and the mixing procedure.