Carbonation of cement-based materials may lead to durability problems, so that it is necessary to find a way to reduce the effect of carbonation on concrete durability. This study investigated the effects of cellulose nanofibrils (CNFs) on the durability of carbonated cement-based materials. Two dosages of CNFs were used to prepare cement pastes and mortars. Before and after accelerated carbonation (4 % CO₂ concentration and 57 % relative humidity), their microstructure, mineralogical composition, moisture retention capacity, drying kinetics, and water absorption were measured. Results show that the contents of hydration products (CH, C-S-H, and ettringite) slightly decrease with the increase of CNFs dosage. After carbonation, the carbonation ratios of hydration products decrease with CNFs dosage so that more hydration products remain in the carbonated materials. The calcite content was found to increase with the dosage of CNFs which may help the transformation of other metastable calcium carbonates to calcite. The coarsening effect of carbonation on pore structure was clearly observed in measured pore size distribution for all materials, while our results show that this effect is weakened by CNFs. Moisture transport is clearly accelerated by carbonation, but the acceleration rate is diminished with the increasing dosage of CNFs, suggesting that CNFs are able to reduce the microstructural damage by carbonation.

水泥基材料的碳化可能会导致耐久性问题，因此有必要找到一种方法来降低碳化对混凝土耐久性的影响。本研究调查了纤维素纳米纤丝 (CNF) 对碳酸化水泥基材料耐久性的影响。两种剂量的 CNF 用于制备水泥浆和砂浆。加速碳酸化前后（4 % CO ₂浓度和 57% 相对湿度），测量它们的微观结构、矿物组成、保水能力、干燥动力学和吸水率。结果表明，随着CNFs用量的增加，水化产物（CH、CSH和钙矾石）的含量略有下降。碳酸化后，水化产物的碳酸化率随着 CNFs 用量的增加而降低，从而使更多的水化产物留在碳酸化材料中。发现方解石含量随着 CNF 的剂量而增加，这可能有助于其他亚稳态碳酸钙转化为方解石。在测量的所有材料的孔径分布中清楚地观察到碳化对孔结构的粗化效应，而我们的结果表明，这种效应被 CNF 削弱了。