This study examined bleeding in cement paste as affected by cellulose nanofibres prepared with varying the content of carboxyl groups that were grafted onto the fibre surface. Alongside the conventional ASTM test method, bleeding was further evaluated using a turbidity scanner. A linear correlation was obtained between the bleeding heights as found from the two techniques. The results demonstrate that adding cellulose nanofibre (CNF) significantly reduces the bleed-water volume. Besides, the layer of bleed water in mixtures containing the CNF was more turbid. Clearly, the water retention capacity of CNF hinders the cement grains from settling down and thereby the nanofibres obstruct the upward migration of free water. As well, the higher the carboxyl content, the higher the fibre dosage permissible. And, although it was independent of the amount of carboxyl groups, bleeding was progressively less with an increase in the nanofibre dosage. However, in the presence of a superplasticizer, the cellulose nanofibres were less effective in reducing the bleeding.

这项研究检查了水泥浆中的泌水受到纤维素纳米纤维的影响，纤维素纳米纤维制备的羧基含量不同，接枝到纤维表面上。除了传统的 ASTM 测试方法外，还使用浊度扫描仪进一步评估渗色。从两种技术中发现的出血高度之间获得了线性相关性。结果表明，添加纤维素纳米纤维 (CNF) 显着降低了渗水量。此外，含有CNF的混合物中的渗出水层更混浊。显然，CNF 的保水能力阻碍了水泥颗粒的沉降，从而纳米纤维阻碍了自由水的向上迁移。同样，羧基含量越高，允许的纤维剂量就越高。和，尽管它与羧基的数量无关，但随着纳米纤维剂量的增加，渗出逐渐减少。然而，在存在超塑化剂的情况下，纤维素纳米纤维在减少渗色方面的效果较差。