Title: Control of Physical Deterioration of Foamed Geopolymers Exposed to High Temperature

Author(s): Zhuguo Li

Publication: Symposium Paper

Volume: 362

Issue:

Appears on pages(s): 179-188

Keywords: crack, expanded perlite particle, fire resistance, foamed geopolymer, stone powder, shrinkage

DOI: 10.14359/51740882

Date: 6/5/2024

Abstract:
Foamed geopolymers possess excellent fire resistance similar to ordinary geopolymers and can also provide good thermal insulation when using lightweight aggregates, making them ideal for fire-resistant coatings. However, foamed geopolymers are susceptible to significant and uneven shrinkage, which can result in cracks and breakage when heated due to the dehydration of the weakly bound water in the C-A-S-H or N-ASH gels. To address this issue, this study incorporated the expanded perlite particles (EPP) and replaced a portion of fly ash with crushed stone powder (CSP) in a ground granulated blast furnace slag/fly ash-based geopolymer that was foamed using fine metallic silicon powder. The EPP and CSP acted as inactive precursors to form a stable particle skeleton with a continuous gradation in the foamed geopolymers. Experimental results indicate that the suitable inclusion of CSP and EPP effectively mitigated geometrical deterioration and cracking under elevated temperatures. The foamed geopolymers with these additives showed no warping or cracking, even as they decreased in dimension and bulk density when heated on a one-side surface. It is considered that continuous gradation of CSP and EPP particles formed a stable particle skeleton within the foamed geopolymer to effectively diminish the shrinkage caused by the thermal decomposition of gels.