Effect of fly ash on rheological properties of graphene oxide cement paste
Effect of fly ash on rheological properties of graphene oxide cement paste
复制标题
粉煤灰对氧化石墨烯水泥浆体流变性能的影响
DOI：
10.1016/j.conbuildmat.2017.01.126
复制
发表时间：
2017-05-01
影响因子：
7.4
通讯作者：
Dong, Yichen
中科院分区：
文献类型：
--
作者：
Wang, Qin;Cui, Xinyou;Dong, Yichen
氧化石墨烯(GO)具有增强水泥基复合材料的强度和韧性的潜力，但它可能会降低水泥浆体的流动性，从而降低混凝土的工作性。本文研究了一种简单经济的外加剂--粉煤灰，以改善GO存在下水泥净浆的流变性。通过对流变学参数的定量分析，发现掺入飞灰可以抵消GO对流动度的影响。研究了0.01wt%和0.03wt%两种GO掺量对飞灰的影响。水泥净浆的屈服应力和塑性粘度随掺量的增加而降低。当加入0.01wt%的GO和20wt%的飞灰时，浆体的屈服应力降低85.81%，塑性粘度降低29.53%。当GO掺量为0.03wt%、粉煤灰掺量为20wt%时，浆体的屈服应力降低50.33%，塑性粘度略有下降5.58%，复合浆体的滞回面积也随掺量的增加而减小。同时，结果表明，流动性与塑性粘度之间有很好的相关性。飞灰的“球状”效应、颗粒级配和用水量少，对改善水泥体系的流动性具有重要作用。此外，GO还可以抵消粉煤灰-水泥体系早期强度增长的延迟。当粉煤灰掺量小于15wt%时，3、7、28d的抗压强度和抗折强度均高于对照试件，说明掺加粉煤灰是获得理想性能的一种经济有效的方法。掺入粉煤灰和GO的好处可以帮助抵消GO-水泥浆体的流动性对混凝土工作性的影响。(C)2017爱思唯尔有限公司。保留所有权利。
While graphene oxide (GO) is found to have a potential to enhance the strength and toughness of cement based composites, it may reduce the cement paste fluidity and thus the workability of concrete. In this paper, a simple and economical additive, fly ash, is investigated to improve the rheological properties of cement paste when GO is present. Based on the quantitative analysis of the rheological parameters, it's shown that fly ash can offset the reduction of fluidity by GO. The effect of fly ash was studied with two dosages of GO, 0.01 wt% and 0.03 wt%. The yield stress and plastic viscosity of cement paste decreased with the increase of fly ash. At 0.01 wt% of GO and 20 wt% of fly ash, the yield stress of the paste decreased 85.81% and the plastic viscosity decreased 29.53% in comparison to the control sample (no fly ash or GO). At 0.03 wt% of GO and 20 wt% of fly ash, the yield stress of the paste is 50.33% lower and the plastic viscosity decreased slightly by 5.58%.The hysteresis area of the composite paste also decreased with the increase of fly ash. Meanwhile, the results indicated a good correlation between the fluidity and the plastic viscosity. The "ball" effect, grain size gradation and less water demand of fly ash can play an important role in improving the fluidity of the GO-cement systems. Moreover, GO can offset the delay in early-stage strength gain of fly ash-cement systems. When the dosage of fly ash is less than 15 wt%, the compressive and flexural strength of fly ash-GO-cement composites are all higher than the control sample at 3, 7, and 28 d. This indicates that the addition of fly ash is an economical and effective method to obtain desirable properties of GO-cement paste. The benefits of mixing fly ash and GO can help counteract the fluidity problems of the GO-cement paste on the workability of concrete. (C) 2017 Elsevier Ltd. All rights reserved.