Development of alkali activated adhesive applicable for alkali activated panels
May 27-June 1, 2018
The overall goal of InnoWEE project (Innovative pre‑fabricated components including different waste construction materials reducing building energy and minimising environmental impacts), is the development of optimized reuse of construction and demolition waste - CDW (concrete, bricks, mortars, glass, and wood) into prefabricated alkali‑activated panels to be used in energy‑efficient buildings. Moreover, one of the tasks is the development of an alkali‑activated adhesive that would bond together different types of alkali‑activated panels (high‑density panel - HDG and low density, wood‑based alkali‑activated panels - WGD).
The following parameters are important for the efficiency of the adhesive:
- chemical bonding between the AAM layer and the adhesive;
- matching between shrinkage and expansion, and
- mechanical interlocking (improved by a roughsurface).
For alkali‑activated adhesives it is known that the adherence of alkali‑activated mortars to the cement‑based substrate is poor (Vanconcelos et al., 2011). It was assumed that if the sand‑to‑binder ratio was low, then high shrinkage caused micro cracks on the contact surface, which decreased the bond strength. Zhang (Zhang et al., 2010) has also proposed a mechanism of chemical bonding where the dissolution of hydrated cement takes place and a new alkali‑activated gel containing calcium is formed so that good adherence is achieved.
Within the present study, the precursors selected for the adhesive preparation were slag and fly ash. KOH and K‑silicate were applied as alkali activators. Samples were mixed using the standard procedure for ceramic tile adhesives and then evaluated for shrinkage and compressive strength. Other parameters important for its application in real conditions are consistency and open time, were also determined.
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Vilma Ducman, Marco Natali, and Adriana Bernardi, "Development of alkali activated adhesive applicable for alkali activated panels" in "International Conference on Alkali Activated Materials and Geopolymers: Versatile Materials Offering High Performance and Low Emissions", J. Provis, University of Sheffield C. Leonelli, Univ. of Modena and Reggio Emilia W. Kriven, Univ. of Illinois at Urbana-Champaign A. Boccaccini, Univ. of Erlangen-Nuremberg A. Van Riessen, Curtin University, Australia Eds, ECI Symposium Series, (2018). https://dc.engconfintl.org/geopolymers/60