Carbonate rocks as fillers in blended cements: Physical and mechanical properties

摘要

This study investigated the physical and chemical effects of dolostone (DF) as fillers (10 to 30% by weight) in blended portland cements (BPC) and compared with limestone (LF) ground with similar fineness. The addition of both fillers increases the packing density of BPC up to 40% replacement and the standard mortar, while the water film thickness was greater than those corresponding to PC up to a w/cm similar to 0.45. For increasing filler replacement, the mini-slump decreases, the setting time is in advance and the hydration heat curves show a shorter dormant period, acceleration of C3S-hydration and greater sulfate depletion. These phenomena were more significant for LF. The hydrated compounds and it apparition sequence were similar at 20 degrees C for DF and LF, but no sign of harmful dedolomitization reaction was found at 40 degrees C during 365 days. The compressive strength of the mortar after 28 days depends on the percentage of filler replaced, regardless of its mineralogical composition. Results suggest that DF, as occurs with LF, is a suitable addition as main component to BPC with satisfactory and stable properties. (C) 2020 Elsevier Ltd. All rights reserved.