Investigation of Heat Released during Geopolymerization with Fly Ash based Geopolymer

Abstract

Geopolymerization consists of several chemical reactions that has been reported widely as an exothermic reaction. Previous studies on heat released during geopolymerization used metakaolin and fly ash of F class as a precursor for geopolymer. Meanwhile, in this study, fly ash of C class is used and a preliminary study has been conducted on determining the exothermic reaction of the geopolymerization with various ratios of solid-to-liquid ranging from 1.5 to 2.5. The amount of heat released was determined by using Differential Scanning Calorimeter. It was proven that different solid-to-liquid ratio affected the amount of heat released during geopolymerization as the highest amount of the heat released were recorded at the optimum solid-to-liquid ratio of 2.0.

Performance of Superplasticizers in Alkaline Environment of Self Compacting Geopolymer Mortar

“…This is because of the increase in OHanions concentration, resulting in the quick dissolution of fly ash particles at early stages (Naghizadeh and Ekolu 2021). The increase in solid to liquid content beyond a certain limit ultimately resulted in quick hardening and gelation due to an excessive rise in an exothermic reaction (Mohamed et al 2019). The configuration of SCGM paste because of rapid gel formation is shown in Fig.…”

Setting Behavior and Phase Evolution on Heat Treatment of Metakaolin-Based Geopolymers Containing Calcium Hydroxide

“…If it is possible to reduce or control the setting time of geopolymers in the desired time, they could be used in a wider variety of fields where OPC and rapid-setting cement are used, such as in 3D printing and building maintenance. In order to control the setting of geopolymers, three setting control methods have been suggested: (1) the increasing of curing temperatures (heat curing), (2) the use of source materials with a high calcium content, and (3) the addition of calcium compounds [ 14 , 15 , 16 ]. Heat curing can significantly reduce setting time and accelerate geopolymerization [ 15 ], but it is difficult to apply to the production of site-poured concrete.…”

“…The use of source material with high calcium content such as class C fly ash can lead to fast setting at room temperature. The initial and final setting times for fly ash-based geopolymers fabricated using class C fly ash and cured at room temperature are 30 min and 1 h, respectively [ 16 ]. However, it is difficult to quantitatively control the setting of geopolymers because setting time is only unaffected by the calcium content in the fresh mix.…”