@phdthesis {2370,
	title = {Development of foam one-part geopolymers},
	year = {2016},
	month = {2016-06-22 00:00:00},
	pages = {117},
	school = {Universidade do Minho},
	abstract = {
The production of ordinary Portland cement (OPC) as the essential constituent of concrete requires considerable energy, releasing a significant amount of carbon dioxide and other greenhouse gases (GHGs) into atmosphere. Environmental concerns regarding the high CO2 emissions related to the production of OPC led to research efforts on the development of eco-efficient alternative binders. Geopolymers constitute promising inorganic binders alternative to OPC which are based on aluminosilicates by-products and alkali activators. The geopolymerization is a complex chemical process evolving dissolution of raw materials, transportation, orientation and polycondensation of the reaction products. However, there are still many drawbacks associated with traditional two part geopolymer mixes (containing alkaline species and soluble silicates). The caustic alkaline solutions make the handling and application of geopolymers difficult. The use of sodium silicate is responsible for a high carbon footprint of two part geopolymers. The durability of these binders is also subject of some controversy. For instance, current two part geopolymeric mixes can suffer from a high amount of efflorescence originated by the fact that alkaline or soluble silicates that are added during processing cannot be totally consumed during geopolymerisation. This phenomenon is responsible for an increase in geopolymer permeability and reduced durability. Therefore, the study of new and improved geopolymer mixes is needed. The discovery of one-part geopolymers is considered as a key event on the evolution of low carbon dioxide geopolymer technology in the {\textquotedblleft}just add water{\textquotedblright} concept as it happens with OPC. However so far they were associated with very low compressive strength. Some authors even report a compressive strength decrease with time for one-part geopolymers based on calcined red mud and sodium hydroxide blends. The present thesis aimed to develop one part geopolymer mixtures with acceptable performance to be of some use for the construction industry. The mechanical properties and the durability performance of the new one-part geopolymer mixtures were studied. A numerical model to predict the compressive strength of one part-geopolymers was suggested. Hydration products results assessed with SEM/EDS and FTIR spectra were presented. The use of one part geopolymers for production of lightweight foam mortars with the improved thermal performance was studied. Comparisons to foam two part geopolymer mortars were made concerning properties, cost and global warming potential assessment.
},
	keywords = {Foam geopolymers, One-part geopolymers, thermal performance.},
	author = {Abdollahnejad, Z. and Aguiar, J. B. and Pacheco-Torgal, F.}
}