A review on the effect of fly ash characteristics and their variations on the synthesis of fly ash based geopolymer

Abstract

Abstract. There are more than four decades since the last 1970s where geopolymers concrete was first introduced and developed to use as a replacement to conventional concrete material which uses cement as a binder. And since the last two decades, geopolymers which utilized fly ash as aluminosilicate source material, i.e. fly ash based geopolymers, have been investigated. Many researchers present how to produce the best fly ash based geopolymer with a various source of constituent material as well as mixing formula to achieve exceptional concrete performance. Although there is a similar trend towards factors affecting the result of fly ash based geopolymer synthesis, there is still remain a wide range in mixture proportion. The considerable variation in fly ash characteristics as source material in the synthesis can very likely be one of the causes of this problem. This paper attempts to identify the effect of source material variation of geopolymer concrete, particularly which use fly ash as source material and focuses on the variation of its characteristics and the effects to properties of concrete. From the reviews it concluded that different sources (and even the same source, but different batch) of fly ash materials will give some different characteristics of the fly ash, where it would affect the synthesis process of the fly ash based geopolymer concretes.

Role of Heat-Treated Laterite on the Strengthening of Geopolymer Designed with Laterite as Solid Precursor

“…It means that silica tetrahedral units become available for the polycondensation reactions. SiO4and AlO4units are able to form a new network where the negative charge of IV-fold coordinated Al 3+ is balanced by the positive charges of Na + ions from the alkaline solution [47,11]. The reaction process leads to the formation of a geopolymer gel that acts as the matrix phase, which bind unreacted particles, forming a composite geopolymer material.…”

Fresh and Hardened Properties of High Calcium Fly Ash-Based Geopolymer Matrix with High Dosage of Borax

“…Fly ash, either with low calcium (class F) or high calcium (class C) content, is a material rich in silica and alumina, and can be used as a precursor in making geopolymer. The activation of the source material occurs in the presence of a highly alkaline solution, commonly a combination of sodium hydroxide and sodium silicate (Wattimena et al 2017;Yildirim et al 2011). The ratio and content of the two alkalis determine the characteristics of the geopolymer concrete (Arioz et al 2012;Hardjito et al 2004;Mustafa et al 2011;Rangan 2010;Rattanasak and Chindaprasirt 2009;Thunuguntla and Gunneswara Rao 2018).…”

Characterization of novel shape‐stabilized phase change material mortar: Portland cement containing Na 2 SO 4 ·10H 2 O and fly ash for energy‐efficient building

“…Therefore, it was necessary to make reasonable use to eliminate solid waste. Research suggested that FA with large specific surface area and porosity can be used to adsorb PCM; besides, FA is also a commonly used concrete mineral admixture; thus, it is feasible to use FA as a carrier to adsorb Na 2 SO 4 ·10H 2 O.…”

“…Therefore, it was necessary to make reasonable use to eliminate solid waste. Research suggested that FA with large specific surface area and porosity can be used to adsorb PCM; besides, FA is also a commonly used concrete mineral admixture 27,28 ; thus, it is feasible to use FA as a carrier to adsorb Na 2 SO 4 ·10H 2 O. Therefore, in this paper, porous solid waste FA was chosen as an adsorption carrier of Na 2 SO 4 ·10H 2 O to form the Na 2 SO 4 ·10H 2 O/FA composite PCM (FAPCM).…”