The effect of dolomite fillers and aggregates on Portland cement solutions stability in alkaline environment

The purpose of the study is to research the impact of dolomite and dolomite limestone deposits from the North-West of Russia in the cement slurry in alkaline media, introduced as a component with appropriate dispersion into the filler and aggregate. The X-ray diffraction and electron micro­scopy helped to establish that dolomite particles during the experiment are subject to dedolomitization and partially disintegrated into brusite Mg(OH)2 and calcite CaCO3; the cement matrix surrounding the dolomite grain developes a distinct "carbonate" groove 20-30 microns thick. At the same time the observed dedolomitization does not lead to the development of expansion failure of solution samples exceeding the maximum allowed value according to GOST 8269.0 (0.1 %). Samples with dolomite and other carbonate minerals in the cement and aggregate were characterized by less linear expansion than those without them (in the control mix). 

Author: A.S. Brykov, M.E. Voronkov, P.A. Antonov

Section: Science and production

Keywords: Portland cement, dolomite, dolostone, dedolomitization, aggregate, alkali-silica reaction