A Comprehensive Study of Fly Ash Based Geopolymers Activated at Room Temperature

• Main Author: Natali, Maria Elia <1984>
• Other Authors: Bignozzi, Maria
• Format: Doctoral Thesis
• Language: en
• Published: Alma Mater Studiorum - Università di Bologna 2016
• Subjects: ING-IND/22 Scienza e tecnologia dei materiali
• Online Access: http://amsdottorato.unibo.it/7373/

This research presents the overall results obtained by investigating the performances of fly ash based geopolymers activated at room temperature. Several characterization tests have been perfomed, starting from a deep understanding of the raw materials, in view of finding alternative solutions to the use of traditional hydraulic binders or ceramic materials via alkali-activation. Different types of geopolymer samples (i.e., pastes, mortars and reinforced mortars) have been formulated by varying the nominal Na2O/SiO2 molar ratio in the activating solutions (and in a specific case the curing conditions) and their chemical, physical, mechanical and microstructural performances have been evaluated comparing the results obtained by using different types of precursors and by a traditional cement-based binder. Specific attention has ben focused on durability issues such as high temperature applications and corrosion resistance of the embedded rebars in geopolymer mortars exposed to aggressive environments. Alkali-activation has been found to represent a valid approach in developing performant cement-free products but step forward are needed in order to optimize the solution chemistry and enhance physical and mechanical properties starting from a deep understand at nanoscale of the geopolymerization reaction mechanisms.