Rosnita Mohamed, Rafiza Abd Razak, Mohd Mustafa Al Bakri Abdullah, Raa Khimi Shuib, Subaer
Geopolymerization had been discussed and concluded by previous researches as an exothermic reaction in which mostly had been determined by using calorimetric method. Calorimetric method enables to detect the amount of heat released or heat absorbed during a reaction and the peaks formed in its data also determine either the reaction is exothermic or endothermic. Researches on heat evolved during geopolymerization were usually being carried out for kinetic studies purpose. However, correlation on the heat evolved during the process to the properties of geopolymers are rarely reported. This study is conducted to determine the effect of heat evolved of geopolymerization during setting with various solid-to-liquid ratios (1.5,2.0,2.5) applied and correlate the heat evolved calculated with compressive strength of class C fly ash geopolymers. In this study, class C fly ash was used as a raw materials and alkali activator used was combination of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3). The amount of heat evolved and the peaks observation were determined by using Differential Scanning Calorimeter. The compressive strength was carried out for age of 1-day and 3-days using 50mmx50mmx50mm cubes of geopolymers as this study focused on early strength of geopolymers. The geopolymerization was resulted as an exothermic reaction and the exothermic peaks formation were varied with variation in solid-to-liquid ratio. The optimum ratio of solid-to-liquid ratio obtained in this study in which gave the highest amount of heat evolved (-96.2871 J/g) and highest compressive strength for 1-day age (26.825 MPa) was 2.0. The heat evolved was concluded as significantly affect the early strength of geopolymers for age of 1-day as it has a positive correlation and best fitted when plotted on a graph. © 2019 Author(s).
Center of Excellence Geopolymer and Green Technology (CEGeoGTech), School of Materials Engineering, Universiti Malaysia Perlis (UniMAP), D/A Pejabat Pos Besar, Kangar, Perlis, 01000, Malaysia; Faculty of Engineering Technology, Universiti Malaysia Perlis (UniMAP), D/A Pejabat Pos Besar, Kangar, Perlis, 01000, Malaysia; School of Materials and Minerals Resources Engineering, Universiti Sains Malaysia, Nibong Tebal, Pulau Pinang, 14300, Malaysia; Geopolymers and Green Material Group, Physics Department, FMIPA, Universitas Negeri Makassar, Indonesia
