Comparison of dolostone and limestone as filler in blended cements

TREZZA, MÓNICA A.; TREZZA, MÓNICA A.; IRASSAR, EDGARDO FABIÁN; IRASSAR, EDGARDO FABIÁN; DI SALVO BARSI, ANTONELA; DI SALVO BARSI, ANTONELA

BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT (PRINT)

SPRINGER HEIDELBERG

Año: 2020 vol. 79 p. 243 - 253

1435-9529

A dolostone from Sierras Bayas (Buenos Aires Province, Argentina) is characterized for use as supplementary cementitious material (SCM). This comparative study with usual limestone filler includes the results of grindability and the performance of blended cements with 20% filler. Carbonate stones were ground in a laboratory ball mill to attain the objective (d50 < 4 μm). For blended cements, the mini-slump, setting time and hydration heat were determined on paste with a water-to-cementitious material ratio (w/cm) of 0.40. Compressive strength was determined on mortar (w/cm= 0.50) up to 90 days, and the mineralogical composition of the hydrated pastes was determined by XRD and thermogravimetry at 28 days. Results show that the grinding time of the dolostone is shorter than that of limestone, and the volume of fine particles (< 10 μm) is increased. Dolostone filler (Dfiller) cement shows behaviour analogous to limestone filler (L-filler) cement. Both fillers decrease the initial mini-slump, and the mini-slump loss rate is similar, the setting time is shorter and the heat released increases. The overall performance of blended cement appears independent of the mineralogical composition. For L-filler, the effects are more pronounced at early ages. The compressive strength of the L-filler is higher than that of the D-filler at early ages, and later the opposite is true. Preliminary analysis on hydration products and portlandite content does not justify this behaviour. The D-filler is a viable alternative as a partial replacement of portland cement, after that the chemical stability in the alkaline paste environment will be confirmed.