Analisis Karakteristik Fisik Mortar Geopolimer Berbahan Dasar Fly Ash dan GGBFS dengan Metode Taguchi (Studi Eksperimental)

Abstract

In cement production, a combustion process is carried out which produces CO2 which produces 5% of CO2 production in the world, if this continues it will have a major impact on global warming, so that environmentally friendly concrete (green concrete) is needed. One of the efforts to implement green concrete is to utilize geopolymer. Geopolymer is a reaction process of an alkaline solution (such as a combination of NaOH and Na2SiO3) with Silica (Si) and Aluminum (Al) found in pozzolanic minerals such as fly ash which will form a binder. In this study, geopolymer test specimens were made with variations of 5 level 3 factors, namely molarity (8M, 10M, 12M, 14M and 16M), ratio of fly ash mixture to GGBFS (90:10 ; 80:20 ; 70:30 ; 60:40 and 50:50) and curing time (3 days, 7 days, 14 days, 28 days and 56 days). Testing of the mechanical properties of the geopolymer mortar in the form of testing the setting time, mortar consistency, and compressive strength test as well as analysis of the microstructural characteristics of the samples was carried out using a SEM (Scanning Electron Microscope). The analysis used the taguchi method through Minitab 16 software. From the results of the study it was found that the lower the molarity of the alkaline activator, the higher the slump flow diameter and the longer the initial setting and final setting of the binder. The lower the fly ash content, the higher the average compressive strength of the geopolymer mortar. The average compressive strength based on curing time increased from 3 days curing to 56 days curing time. The average compressive strength based on the highest molarity was when the molarity was 8 M then 12 M, 16 M, 14 M and 10 M. The maximum average compressive strength of geopolymer mortar was 77.33 MPa, namely in the A1B5C5 combination. Based on the analysis using the Taguchi method, the most optimum combination is the combination of A3B5C5 with 12 M mixing, 50:50 fly ash and GGBS, and cured for 56 days.