EFFECTIVENESS OF ULTRA-FINE GROUND SLAG IN CEMENT BINDERS

Today it is generally recognized that the use of mineral fillers is one of significant reserves to enhance the efficiency of binders in cost as well as to improve the technical properties of cement composites. Mineral filler corresponding to the Portland cement fineness often replaces part of Portland cement. This technique allows saving Portland cement without reducing significantly the concrete strength. The ability to obtain ultra-fine mineral fillers from industrial by-products with high specific surface area appears with grinding technology development. Two types of ultra-fine ground granulated blast furnace slag with average grain size equal to 4.5 µm were obtained using modern grinding equipment such as centrifugal-elliptical mill and centrifugal dynamic classifier. Water-reducing effects of superplasticizer in Portland cement-slag compositions depending on types, quantity and fineness of slags as well as depending on С3А and R2О amounts in Portland cement clinker were studied. The results of reduction of binder amount per 1 kg of superplasticizer are presented and analyzed