Evaluation of the effects of coconut fiber and microcellulose crystalline on the properties of cementitious mortars

ABSTRACT The cementitious materials are the most used worldwide, in civil construction. Faced with this, research is needed to improve both its mechanical performance and its sustainable development. An alternative that seeks these improvements is the addition of materials of vegetable origin, such as coconut fiber and microcellulose crystalline. Therefore, the objective of the present work was to evaluate the influence of additions of coconut fiber (CF) and microcellulose crystalline (MCC) on the physical and mechanical properties of cementitious mortars. For a better delineation of the research, it was divided into three phases: characterization of the materials; analysis of mortars with additions of CF and mortars with MCC additions; analysis of mortars with additions of CF and MCC simultaneously. The following tests were performed: consistency index,compressive strength, flexural tensile strength, modulus of elasticity, water absorption, void index, specific mass, Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The results show that the incorporations of CF and MCC in contents above 0.2CF and 0.3MCC significantly improve the performance of mortars in terms of tensile strength in flexion, however do not contribute positively to the other mechanical properties of mortars, but without significant damage to its use. Studies of mortars with longterm CF and MCC are recommended to verify if mechanical properties undergo significant influences withage.摘要 胶凝材料是全球土木工程领域应用最为广泛的材料。鉴于此，亟需开展相关研究以同步提升其力学性能与可持续发展水平。寻求此类性能改良的可行方案之一是掺入植物基材料，例如椰纤维（Coconut Fiber, CF）与微晶纤维素（Microcellulose Crystalline, MCC）。因此，本研究旨在评估椰纤维与微晶纤维素的掺入对胶凝砂浆物理及力学性能的影响。为更清晰地规划研究内容，实验分为三个阶段：材料表征阶段；单掺椰纤维砂浆与单掺微晶纤维素砂浆的性能分析阶段；同时掺加椰纤维与微晶纤维素砂浆的性能分析阶段。本次实验开展了如下测试：稠度指数、抗压强度、抗弯拉强度、弹性模量、吸水率、孔隙率、表观密度、扫描电子显微镜（Scanning Electron Microscopy, SEM）与能谱分析（Energy Dispersive Spectroscopy, EDS）。结果表明，当椰纤维掺量高于0.2CF、微晶纤维素掺量高于0.3MCC时，可显著提升砂浆的抗弯拉性能，但对砂浆的其他力学性能无正向增益，不过亦未对其实际应用造成显著负面影响。建议开展长期掺加椰纤维与微晶纤维素的砂浆研究，以验证其力学性能是否会随养护龄期发生显著变化。