| Popis: |
Cements on the market today contain more than 20% cement substitutes such as finely ground limestone, granulated blast furnace slag, and coal fly ash. The use of these wastes as secondary materials in cement production results in a reduction of CO2 emissions by 400 million tons per year. While fly ash from coal-fired power plants and slag from the iron industry are the most commonly used replacement cements, other waste materials with hydraulic and pozzolanic properties are increasingly being investigated. One of the European Union's goals is to make secondary raw materials available for use in the construction sector to reduce dependence on the import of raw materials. The new European project AshCycle – Integration of undeutilizilized ashes into material cycles by industry-Urban symbiosis focuses on waste streams, various incineration ashes (ashes from municipal solid waste incineration, ashes from sewage sludge incineration, and wood biomass ashes), that are still landfilled but have a potentially wider use in the construction sector. In this study, wood biomass ash (WBA) was used to develop two blended cements where different chemical (loss of ignition, particle size distribution, oxide content and, minerology) and physical properties of the cement composites (workability, setting time and soundness) were determined and compared with commercially available CEM II cement. The commercially available cement CEM II contains 80% Portland cement clinker and up to 20% mixed admixture (combination of blast furnace slag (S) and silicon fly ash (V), up to 5% of additional ingredient and setting regulator (natural gypsum). Preliminary results of the chemical properties of the new blended cements and the physical properties of the cement composites showed that all tested blended cements and pastes meet the criteria of the EN 197-1 standard. |
