Alkali-activated binders have the potential to consume various types of waste materials. Low initial molar ratios of SiO2/Al2O3 geopolymer mortars were considered in this article. Here we studied alkali-activated binders produced with photovoltaic glass powder in 5%; kaolin clay in 15%; ground granulated blast furnace slag in 30%; alumina-lime cement in 30%; and, interchangeably, fly ash from coal combustion in 5%, fly ash from biomass combustion in 5%, or granulated autoclaved cellular concrete in 5%. The influence of clay dehydroxylation, curing conditions, glass presence, and a kind of waste material was investigated. According to the experimental results, strength (compressive and tensile) gradually increased with increasing time and with the use of calcined clay. Significant improvement in compressive strength was seen with the additional 3 days curing time in 105 °C when non-sintered clay was used. The presence of photovoltaic glass in alkali-activated mortars immobilised mercury and arsenic but released zinc, chromium, and sulphates. The microscopic observations confirmed the greater densification of the microstructure of the binder made of calcined clay due to its greater surface development and dehydroxylation. The binder of non-calcined clay was granular, and the interfacial transitional zone was more porous. The C–A–S–H gel seemed to be the main phase. XRD examination confirmed the presence of C–A–S–H, C–S–H, zeolites, and many other phases in minor amount. The presented research was a pilot study, and its main goal was to develop it further.
Geopolymers, or mineral polymers, are binders formed as a result of the alkaline activation of anthropogenic or natural minerals. Recently, they have attracted the attention of many scientists who justify the need to reduce carbon dioxide emissions during cement production by using other materials. The paper lists the materials used in the production of geopolymer binders, describes the geopolymerization process, and characterizes the method of corrosion of cement binders in relation to the results of research carried out on geopolymer binders. The main focus was on the resistance of geopolymers to chemical factors such as acids, sulphates, carbon dioxide and ammonium salts. Chloride penetration was indicated in the context of water absorption depending on the geopolymeric matrix microstructure. The results of the research on the reaction of alkali-silicate geopolymers are also described. Research presented mainly by foreign research units confirmed that geopolymer binders are characterized by much better properties than cement binders.