Ground blast furnance slag as a blinder in cementitious composites

Proizvodnja cementa je velik porabnik energije in hkrati povzroča emisije toplogrednih plinov v ozračju, ki so odgovorne za globalno segrevanje. Za doprinos k rešitvi tega problema se številne raziskave v svetu osredotočajo na uporabo odpadnih in sekundarnih materialov ter surovin, ki imajo lastnosti, podobne portlandskemu cementu, ter jih je mogoče dodati v beton kot delno zamenjavo cementa, ne da bi pri tem ogrozili njegovo trdnost in trajnost. V diplomskem delu smo kot delno zamenjavo portlandskega cementa uporabili železarsko žlindro, sekundarno surovino, ki nastane pri proizvodnji železa v visokih pečeh. V okviru eksperimentalnega dela smo žlindro v laboratorijskem mlinu zmleli do ustrezne finosti, ki smo jo kontrolirali z Blainovim permeabilimetrom. Po recepturi za standardno cementno kašo smo izdelali preizkusne vzorce, kjer smo cement nadomestili z 10, 20, 30, 40 in 50 masnimi odstotki drobno mlete žlindre. Na vseh vzorcih smo izvedli standardne upogibne in tlačne preizkuse. Na podlagi pridobljenih rezultatov lahko zaključimo, da delni nadomestek cementa z drobno mleto žlindro ni bistveno vplival na spremembo mehanskih lastnosti preizkusnih vzorcev. Glede na rezultate v diplomskem delu predvidevamo, da se z uporabo drobno mlete žlindre lahko tudi do 50 % zmanjša poraba cementa in s tem cena betonske mešanice.The production of cement is a major consumer of energy and also causes greenhouse gas emissions into the atmosphere. These are responsible for global warming. As a contribution to finding a solution for this problem, several researches focus on the use of waste, secondary and raw materials. These have similar properties than Portland cement and it is possible to add them to the cement as a partial substitution thereof, without affecting its soundness and durability. In the dissertation, steel slaga secondary raw material produced in the process of steel production in blast furnaces, was used as a partial substitution for Portland cement. In the experimental part, the slag was ground in a laboratory mill until it reached the optimum fineness, which was measured with the Blaine permeability meter. According to the recipe for cement pulp, samples were produced where cement was substituted with 10, 20, 30, 40 and 50 weight percentage of finely ground slag. Standard bending and compressive strength tests were carried out on the samples. Based on the acquired results it can be concluded that the partial substitution of cement with finely ground slag did not significantly influence the mechanical properties of the samples. The results acquired in the dissertation suggest that the use of finely ground slag can reduce the consumption of cement by 50% and therefore also reduce the price of the concrete mix