Chemical Treatment of Agricultural Waste Fibers from Pineapple Leaves and Manila Hemp used in Fiber-Reinforced Concrete Hollow Blocks

Abstract

This research examines how chemically treated agricultural waste materials such as pineapple leaf and manila hemp (also known as Abaca) can affect the performance of concrete hollow blocks that are reinforced with fiber. The goal of this work is to find eco-friendly options for building materials due to the problems created when disposing of agricultural waste. The fiber is blended together in a 50/50 ratio (half pineapple and half manila hemp) and added to the concrete hollow blocks at varying amounts (0.25%, 0.50%, 0.75% and 1.00% by weight of cement), with a control mix containing no fiber. To help with adhesion between the fiber and the matrix, to reduce the water absorbed by the fibers and to improve durability, the fibers were chemically treated with a 4% sodium hydroxide solution. During the experimental procedure, composite mixtures were prepared, cast into molds, cured (7, 14 and 28 days) and tested to determine their compressive strength, density, workability, impact resistance (drop test) and cost effectiveness. A statistical analysis of the data collected is also be conducted to determine the optimum fiber amount. The findings showed that the addition of 0.25% of the fiber to the concrete hollow blocks resulted in an increase in compressive strength early in the curing process as well as providing the best overall performance compared to the other mixtures tested. Increasing the fiber amount to levels above 0.25% resulted in less workability of the mixture, clustering of fibers, more voids within the concrete and ultimately a decrease in compressive strength. The control mix was found to have greater strength during the latter part of the curing process, which is due to the inherent poor grading of the fine aggregates used in the study and not due to the presence of the fibers. Additionally, specimens made with fiber reinforcement exhibited improved crack and impact resistance with lower fiber percentages. To summarize, the results of this study indicate that chemically treated pineapple leaf and manila hemp fibers exhibit sufficient strength as reinforcement for non-load bearing concrete hollow blocks when used in optimum amounts. The research findings expand on the body of knowledge related to developing sustainable, cost effective and environmentally friendly building materials and confirm gaps in previous research regarding the use of hybrid natural fibers systems for concrete hollow block applications.