Mix design, properties and cost analysis of fly ash-based geopolymer foam

Abstract

h i g h l i g h t sMix design of fly ash foam geopolymer. Mixtures with 0.1 W/(m K) therm. conductivity and a 6 MPa comp. strength were achieved. Foaming agents cost represent less than 10% of foam geopolymer cost. a b s t r a c tThis study has investigated the joint effect of several mix parameters on the properties of foam geopolymers. The mix parameters analysed through a laboratory experiment of 54 different mortar mixes were, sodium silicate/sodium hydroxide mass ratio (2.5, 3.5, 4.5), activator/binder mass ratio (0.6, 0.8, 1.0), chemical foaming agent type (hydrogen peroxide (H 2 O 2 ) and sodium perborate (NaBO 3 )) and foaming agent mass ratio content (1%, 2%, 3%). Properties, SEM and FTIR analysis and cost analysis are included. The results show that the sodium perborate over performs hydrogen peroxide leading to a lower overall thermal conductibility of foam geopolymers. Mixtures with a low thermal conductivity of around 0.1 W/ (mÁK) and a compressive strength of around 6 MPa were achieved. The cost analysis show that the foaming agents are responsible for a small percentage of foam geopolymers total cost being that the alkaline activators are responsible for more than 80%.

Thermal Resistance Variations of Fly Ash Geopolymers: Foaming Responses

“…The other absorption bands at ~3300 cm −1 and ~1640 cm −1 were attributed to the OH stretching vibration and bending vibration, respectively. The band at ~1470 cm −1 was the CO 3 2− ion resulted from the reaction of atmospheric CO 2 with residual sodium content49. With increasing temperature, the sodium carbonate band disappeared as it started to decompose at 400 °C, as aforementioned.…”

Fabrication and Fireproofing Performance of the Coal Fly Ash-Metakaolin-Based Geopolymer Foams

“…Coal fly ash (CFA) is a by-product from coal-fired power plants with excellent pozzolanic activity [19,20], which is widely proposed as a geopolymer precursor and has great potential to modify the mechanical strength of MK-based geopolymer foams. Meanwhile, characteristics of the CFA with spherical and fine particles, and lower requirement during the hydration reaction would increase its dispersibility and workability in MK-based geopolymer gel [21,22], leading to the obvious improvement in the rheological property of geopolymer slurry.…”

Synthesis and Characterization of Porous Fly Ash-Based Geopolymers Using Si as Foaming Agent

“…e main challenge on inorganic insulation materials' development is related to the production of a high porous material with sufficient mechanical properties. Geopolymer foams can be produced by the introduction of foaming agents such as hydrogen peroxide [18][19][20][21], metal powders [22][23][24], or silica fumes [25][26][27]. eir foaming action is due to the oxygen or hydrogen formation in alkaline conditions according to the following reactions:…”