Comparison of dolostone and limestone as filler in blended cements

ANTONELA DI SALVO BARSI; MÓNICA A. TREZZA; EDGARDO F. IRASSAR

BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT (PRINT)

SPRINGER HEIDELBERG

Año: 2019

1435-9529

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