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The combustion of fossil fuels results in creating a lot of solid wastes such as fly ash and slag. However, these environmentally unfriendly materials can be used as a raw material for alkali activation – geopolymerization. Although these wastes have been successfully used in industrial production for several decades, its use does not achieve the level of its potential. Today, to achieve a sustainable construction industry, alternative cement has been extensively investigated. Geopolymer (GP) is a kind of material that is obtained from the alkaline activator, and it can be produced from industrial wastes or by-products. The aim of this work was to describe the improvement of mechanical properties of alkali-activated binders – geopolymers made of fly ash and blast furnace slag. The effect of the addition of waste glass in three different values feed into fly ash or GGBFS, and its impact on mechanical properties (compressive and flexural strengths) of geopolymers was examined. The highest value of compressive strength was achieved with 20% waste glass addition to a fly ash sample on 90th day 58,9 MPa. The waste glass was added in the form of broken and crushed glass particles. Při spalování fosilních paliv vzniká velké množství pevných odpadů, jako je popílek a struska. Tyto ekologicky nešetrné materiály však lze využít jako surovinu pro alkalickou aktivaci - geopolymeraci. Přestože se tyto odpady již několik desetiletí úspěšně používají v průmyslové výrobě, jejich využití nedosahuje úrovně svého potenciálu. V současné době se v zájmu dosažení udržitelného stavebnictví intenzivně zkoumají alternativní cementy. Geopolymer (GP) je druh materiálu, který se získává z alkalického aktivátoru a lze jej vyrábět z průmyslových odpadů nebo vedlejších produktů. Cílem této práce bylo popsat zlepšení mechanických vlastností alkalicky aktivovaných pojiv - geopolymerů vyrobených z popílku a vysokopecní strusky. Byl zkoumán vliv přídavku odpadního skla ve třech různých hodnotách přídavku do popílku nebo GGBFS a jeho vliv na mechanické vlastnosti (pevnost v tlaku a ohybu) geopolymerů. Nejvyšší hodnoty pevnosti v tlaku bylo dosaženo při přídavku 20 % odpadního skla do vzorku popílku 90. den 58,9 MPa. Odpadní sklo bylo přidáno ve formě rozbitých a rozdrcených skleněných částic.

Crystalline admixtures and industrial by-products can be used in cement-based materials in order to improve their mechanical properties. The research examined long-term curing and the exposure to environmental actions of polymer–cement mortars with crystalline admixture (CA) and different by-products, including Bengħisa fly ash and Globigerina limestone waste filler. The by-products were introduced as a percentage replacement of the cement. A crystallization additive was also added to the mixtures in order to monitor the improvement in durability properties. The mechanical properties of the mortar were assessed, with 20% replacement of cement with fly ash resulting in the highest compressive strength after 540 days. The performance was analyzed with respect to various properties including permeable porosity, capillary suction, rapid chloride ion penetration and chloride migration coefficient. It was noted that the addition of fly ash and crystalline admixture significantly reduced the chloride ion penetration into the structure of the polymer cement mortar, resulting in improved durability. A microstructure investigation was conducted on the samples through Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS). Crystals forming through the crystalline admixture in the porous structure of the material were clearly observed, contributing to the improved properties of the cement-based polymer mortar., peer-reviewed

Dealing with waste materials, particularly hazardous waste, is a serious problem. Disposal areas keep growing, and the costs incurred are high. Disposing of such waste reduces negative environmental impacts and offers considerable financial savings. This paper focuses on the possibilities of incorporating pollutants found in hazardous wastes as fillers in coatings based on polymers (epoxide and polyurethane). These coatings are intended mainly for concrete and metal bases and offer secondary protection against adverse weather conditions. Important physical and mechanical properties of the newly developed materials were determined, they include surface hardness, impact resistance, tensile properties, and chemical resistance. These properties were also compared to those of the reference filler. At the same time, the influence of aggressive media on the properties of these materials was observed, in particular on flexural characteristics. The microstructures of the developed coatings were tested using a high-resolution optical microscope, before and after exposure to the chemicals. The positive effect of using progressive fillers, such as solidified hazardous waste (a solidification product (SF)), was witnessed by their constructive contribution to the materials&rsquo, physical and mechanical properties. The use of solidification products is unambiguously advantageous from technical, ecological, and economical stand points (utilization of hazardous waste as a progressive filler instead of landfilling, improvement of tensile properties, reduction in the price of coating system, and incorporation of the pollutants into the polymer matrix).

This paper presents newly developed polymer-cement composites.The primary binder (cement) was partially substituted byuse of blast-furnace slag and high-temperature fly ash. A lightweightaggregate – agloporite (grain size in range 1–2 mm) wasused among other components. This porous aggregate is producedfrom energy by-products (fly ash). Attention was focusedon the behavior of the composites when exposed to elevatedtemperatures (400 °C–1,000°C). The influence of several differentmethods of temperature decrease was assessed – slow(in furnace 1°C/min) and rapid (laboratory ambient 22°C andwater bath 18°C). Specific dimensional changes were determined,including strength characteristics and bulk density.Structural deterioration and microstructural changes of selectedspecimens were investigated by analytical techniques (SEM andCT). Compressive and bending tensile strength changed variouslydepending on temperature changes, including severalcooling conditions. Deterioration reactions (especially cracks)which were formed in investigated composite structures correspondedwith results of physico-mechanical testing. That wasconfirmed by using the CT and SEM.The fact that the agloporite has a positive effect on thermalresistance of developed polymer-cement composites wasproved. Almost no cracks or other failures were identified (byusing CT and SEM) in interfacial transition zones of agloporiteafter thermal stress. This indicates very good bond adhesionbetween the matrix and the porous aggregates during extremetemperature conditions (in case of different cooling methods).

Aluminosilicate materials can be transformed into very compact binding material by the process called alkaline activation. The paper presents results of alkaline activation of fly ash and waste fine-grained brick body. Prepared geopolymers were tested for the compressive and flexural strengths, bulk density, and microstructure was examined by means of SEM. The results of investigated parameters showed the differences in relation to the ratio of fly ash to brick binder. Hlinitokřemičitanové materiály lze transformovat do velmi kompaktního materiálu procesem alkalické aktivace. Článek prezentuje výsledky alkalické aktivace popílku a odpadního cihelného prachu. Připravené geopolymery byly testovány na pevnost v tlaku a tahu za ohybu, stanovena byla objemová hmotnost a studována byla mikrostruktura elektronovým mikroskopem. Výsledky zkoumaných parametrů ukázaly rozdíly ve vztahu k poměru mísených složek.