engleski

SYNERGISTIC ACTION OF A TERNARY SYSTEM OF PORTLAND CEMENT – LIMESTONE – SILICA FUME IN CONCRETE

Some experimental investigations on a synergistic action when a ternary system of Portland cement – silica fume – limestone is used in mortar or concrete are present in this paper. Standard laboratory tests (pore size distribution, micromorphology, compressive strength and sulphate resistance in both sodium and magnesium sulphate solutions) were performed on mortars made with 70 % (by mass) of Portland cement (PC), type CEM II/B-S and 30 mass % of cement replacement materials consisted of various combination of fine ground limestone filler (LF) and silica fume (SF). In addition, to these ternary systems, binary blends, such as Portland cement and fine ground limestone filler, and Portland cement and silica fume, along with 100 % Portland cement mortars, were investigated for comparison. It was found that SF-blends developed higher mechanical strengths than LF-blends for the same replacement of cement. Replacement of PC by 15 mass % of LF caused reduction in the compressive strength. When SF was added together with LF, the mortars show considerable increase in the compressive strength and show both a lower expansion than a control sulphate-resisting mortar, respectively, independent of the type of sulphate solutions due to pore size refinement microstructure of mortars.

Portland cement, silica fume, limestone filler, pore size distribution, sulphate attack, mortars

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