Development of mortar for laying and coating with pineapple fibers

ABSTRACT Brazil is one of the largest producers of pineapple in the world, which, in addition to bringing substantial benefits, contributes to increasing waste generation in the stages of processing, aiming at its consumption. The Brazilian environmental legislation has been increasingly more restrictive with respect to the disposal of solid waste, whether domestic, industrial or agro-industrial, which has stimulated studies related to the use of these materials in several matrices. This study aimed to evaluate the potentiality of using the natural fiber of pineapple (Ananas comosus), extracted from its leaves, as reinforcing material in cementitious composites. For this purpose, natural fiber extracted from the pineapple crown was incorporated in different percentages in relation to the cement mass: 0, 2.5, 5, 7.5 and 10%, and the fibers obtained were submerged in aqueous NaOH solution with 5% concentration in volume, for 1 h at room temperature. The following variables were evaluated: consistency, water retention, incorporated air, mass density in hardened state, mechanical strength, water absorption by immersion and capillarity, besides verifying the influence of the mode of fiber incorporation. It was observed that the treatment with NaOH solution and the percentage of natural pineapple fiber incorporated in up to 5% in relation to the cement mass form mortars with technological feasibility.摘要：巴西是全球最大的菠萝生产国之一，其菠萝产业在创造可观经济效益的同时，也在菠萝加工及消费环节增加了废弃物产生量。巴西针对生活垃圾、工业固废及农产工业固废的处置法规日趋严格，这推动了相关研究，探索将此类废弃材料应用于多种基体中的可行性。本研究旨在评估从菠萝叶片提取的天然纤维（Ananas comosus）用作水泥基复合材料增强材料的潜力。为此，研究人员将从菠萝冠芽提取的天然纤维按占水泥质量的不同比例（0%、2.5%、5%、7.5%及10%）掺入砂浆体系中，并将所得纤维置于体积浓度为5%的氢氧化钠（NaOH）水溶液中，于室温下浸泡1小时。本研究评估的性能变量包括：稠度、保水性、含气量、硬化状态下的体积密度、力学强度、浸水吸水率及毛细吸水率，同时验证纤维掺入方式对各项性能的影响。研究结果表明，采用氢氧化钠溶液处理纤维，且掺入占水泥质量不超过5%的菠萝天然纤维所制备的砂浆具备技术可行性。