Cellulose nanomaterials (CNMs) by different production methods have been studied in cementitious systems, but the effects of contrasting types of CNMs on cement properties have not been delineated. This study is a side-by-side comparison of rheology, setting times, and compressive strength of cement paste incorporated with cellulose nanocrystals (CNCs) from acid hydrolysis vs. mechanically fibrillated cellulose nanofibers (CNFs).

This study demonstrates that CNF gels increase the viscosity of cement paste (control) due to the entangled nanofiber network. In contrast, the shorter and more mobile CNCs reduce the viscosity and provide longer slump retention than a polycarboxylate superplasticizer. CNCs work as a set retarder, but CNFs show about half the deferring effect on setting times.

Both CNMs delivered a similar increase in compressive strength (17–18%), but their optimum amount differed in conjunction with their respective morphology and percolation limits. This study underscores the distinct effects of CNCs vs. CNFs and shows, indeed, these different nanomaterials have contrasting effects on various properties of the cement paste and should be appropriately specified for concrete applications.

已经在水泥体系中研究了不同生产方法的纤维素纳米材料 (CNM)，但尚未描述对比类型的 CNM 对水泥性能的影响。本研究对掺入酸水解纤维素纳米晶体 (CNC) 的水泥浆与机械原纤化纤维素纳米纤维 (CNF) 的流变学、凝结时间和抗压强度进行了并排比较。

该研究表明，由于缠结的纳米纤维网络，CNF 凝胶会增加水泥浆（对照）的粘度。相比之下，与聚羧酸减水剂相比，较短且流动性更强的 CNC 可降低粘度并提供更长的坍落度保持率。CNC 可用作设置延迟器，但 CNF 对凝结时间的延迟效果大约只有一半。

两种 CNM 的抗压强度都有相似的增加（17-18%），但它们的最佳用量因各自的形态和渗透限制而异。这项研究强调了 CNCs 与 CNFs 的不同影响，并表明，事实上，这些不同的纳米材料对水泥浆的各种性能有不同的影响，应该适当地指定用于混凝土应用。