A Review on Degradation Improvement of Sisal Fiber by Alkali and Pozzolana for Cement Composite Materials

Abstract

Sisal fiber employment in concrete improves its post-crack strength, but sisal fiber degrades due to moisture and cement mineralization. Many researchers used alkaline and pozzolanic techniques to treat sisal fiber in cement com- posite materials. However, which treatment method is most effectively used to modify sisal fiber for sustainable use in cementing materials has yet to be well known. Therefore, this review highlights the effect of alkaline and pozzolanic materials on sisal fiber treatment. The review of various studies found employment of 1–1.5% of treated sisal fiber by alkaline or pozzolana reduces workability and improves the mechanical properties, especially as many authors found the treatment of sisal fiber by pozzolanic material averagely improves compressive strength and splitting tensile strength of cementing materials by 21.75% and 36.53%, while alkaline treatment 12.83% and 14.92% respectively, compared to control mixture. Besides these, many studies found the treatment of sisal by either alkaline or pozzolana signifi- cantly lessens water absorption capacity, improves the thermal resistivity of the fiber, improves fiber adhesion with the matrix, makes rougher micro- structure of fiber surface. However, many studies reported alkaline treatment to have drawbacks in the disposal of alkaline chemicals that increase envir- onmental pollution, at high concentrations cause fiber deterioration, and chemical production cost. 摘要 在混凝土中使用Sisal纤维提高了其裂缝后强度，但由于水分和水泥矿化而 降解. 许多研究人员使用碱性和火山灰技术处理水泥复合材料中的剑麻纤 维. 然而，哪种处理方法最有效地用于改性剑麻纤维，使其可持续地用于 胶结材料，目前尚不清楚. 因此，本文着重介绍了碱性和火山灰材料对剑 麻纤维处理的影响. 对各种研究的回顾发现，使用1-1.5%的经碱性或火山 灰处理的剑麻纤维可降低工作性并提高机械性能，特别是许多作者发现， 与对照混合物相比，用火山灰材料处理剑麻纤维平均可提高21.75%和 36.53%的胶凝材料抗压强度和劈拉强度，而碱性处理分别可提高12.83% 和14.92%. 除此之外，许多研究发现，用碱性或火山灰处理剑麻可以显著 降低吸水能力，提高纤维的热阻，提高纤维与基体的附着力，使纤维表面 微观结构更加粗糙. 然而，许多研究报告称，碱性处理在处理碱性化学品 方面存在缺陷，这会增加环境污染，导致纤维在高浓度下变质，化学品生 产成本.