Title:
Use of Metakaolin and Slag Geopolymer Adhesives for Fixing Tiles
Author(s):
Joseph Jean Assaad and Marianne Saba
Publication:
Materials Journal
Volume:
121
Issue:
3
Appears on pages(s):
3-14
Keywords:
blast-furnace slag; bond strength; ceramic tiles; geopolymer; metakaolin; polymer-modified mortar; thixotropy
DOI:
10.14359/51740702
Date:
5/1/2024
Abstract:
This paper assesses the suitability of geopolymers (GPs) for use
as adhesives for ceramic tile fixing, including their compliance
to the relevant EN 12004 specification. Two series prepared with
different percentages of metakaolin (MK), blast-furnace slag
(BFS), and limestone materials activated by an alkaline NaOH/
Na2SiO3 solution are investigated. Tested properties included the
thixotropy, setting, compressive strength, open time, and adhesion
bond strength under different exposure conditions (that is, dry, wet,
heat, or freezing-and-thawing cycles). Compared to cement-based
mortars containing adjusted proportions of cellulose and redispersible
polymers, the GPs exhibited higher thixotropy, reflecting
additional energy for spreading the material over the substrate,
yet better maintenance of the alternating patterns of ripples and
grooves at rest. The bond strengths tested under different exposure
conditions were remarkably high for the MK-based GP, given the
fine MK particle sizes that foster geopolymerization and crosslinking
of solid bonds in the hardened structure. The BFS-based GP
exhibited relatively lower bond strengths (compared to MK) due to
coarser particles. Such results can be of interest to civil engineers
and manufacturers of ready-to-use building materials that aim at
reducing the portland cement footprint while assuring performance
and sustainability of tiling applications.