Degradation of cellulose is the primary cause for the premature failure of natural fibers in the alkaline environment of cementitious systems. However, the degradation behavior and kinetics of cellulosic fibers in cementitious composites have not been thoroughly understood. In this study, the aging kinetic of cellulose exposing to pore solutions of cementitious materials is experimentally investigated and a model for service-life prediction of cellulose in cement is developed. To assess the impact of cement hydration on degradation behavior of cellulosic fibers and understand the correlations between fiber degradation and alkaline environment of cement, an approach to directly assess degradation rate of the embedded fibers was developed by determining fiber's tensile properties, thermal decompositions, crystallinity, and microstructures. The results indicate a strong dependence of degradation of sisal fiber on alkalinity of cement pore solutions. By incorporating 30 wt% metakaolin clay, the hydration of cement was modified and a mild environment was generated. Concentration of OH⁻ was reduced and the pore solution becomes from oversaturated to unsaturated for calcium hydroxide after 7 days. As a result, tensile strength loss of the aged fiber was mitigated and the service life of cellulose was extended by 13.7 times.

纤维素的降解是天然纤维在胶结体系碱性环境中过早破坏的主要原因。然而，胶凝复合材料中纤维素纤维的降解行为和动力学尚未得到充分了解。在这项研究中，实验研究了纤维素暴露于水泥质材料孔隙溶液中的老化动力学，并开发了预测纤维素在水泥中使用寿命的模型。为了评估水泥水化对纤维素纤维降解行为的影响，并了解纤维降解与水泥碱性环境之间的关系，通过确定纤维的拉伸性能，热分解，结晶度，开发了一种直接评估包埋纤维降解率的方法。和微结构。结果表明剑麻纤维降解强烈依赖于水泥孔隙溶液的碱度。通过掺入30 wt％的偏高岭土，水泥的水合得到了改善，并产生了温和的环境。OH浓度^-减少，孔隙溶液变得从7天后过饱和与不饱和为氢氧化钙。结果，减轻了老化纤维的拉伸强度损失，并且纤维素的使用寿命延长了13.7倍。