Utilization of Biomass Ash to Produce Eco-friendly Geopolymer

• Main Author: Rizki Fernando - Nim: 13013115 , Mhd.
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/23056
• Institution: Institut Teknologi Bandung

Increasing of construction development in Indonesia is followed by the increase of construction materials demand, one of them is Portland cement. Portland cement industry is an energyintensive industry that emits high CO2 gas emission. One of environment-friendly materials that can replace Portland cement as construction material is geopolymer. Geopolymer is a silicaalumina-based inorganic polymer which can utilize various industrial wastes such as fly ash, slag or biomass ash as its precursor. High biomass consumption in Indonesia makes high opportunity to utilize biomass ash as precursor of geopolymer to replace Portland cement. Therefore, a review of the feasibility of biomass ash usage instead of Portland cement was carried out in this research. <br /> <br /> <br /> In this research, geopolymers were made by varying ash composition consisting of coconut shell ash, rice husk ash and flyash according to the simplex-centroid mix design. The research begins with a preliminary experiment to determine the ratio of raw materials in each of the main experimental variations consisting of activators/precursors and Na2SiO3/KOH. Further experiments were carried out by producing a 5x5x5 cm cubic sized geopolymer mortar. Tests performed on geopolymers were mortar compressive strength tests at 7 days, setting time test using Vicat equipment and chemical bond identification using FTIR. The feasibility of geopolymer as a substitute for Portland cement is determined by SNI 15-2049-2004 standard. <br /> <br /> <br /> Based on compressive strength test, coconut shell-based and rice husk-flyash mix geopolymers meet the specified standard of having a compressive strength above 2 MPa at the age of 7 days after production. Rice husk-based geopolymer does not meet the standard because it only has a compressive strength of 1.4 MPa. The setting time test shows that coconut shell and flyash based geopolymers have relatively fast setting time and conform to the minimum setting time standard of 45 min, while rice husk-based geopolymer has a long setting time compared to other geopolymer. FTIR testing on geopolymer samples indicates that there is an asymmetrical Al-O or Si-O bond indicating a geopolymerization reaction is occured. <br />