Electrical conductivity and rheological properties of ordinary Portland cement-silica fume and calcium hydroxide-silica fume pastes

Two groups of solids mixtures were prepared: (i) the first group includes four mixes having different ordinary Portland cement/silica fume (OPC/SF) weight ratios and (ii) the second group consists of four blends having different Ca(OH)(2)/SF molar ratios. Electrical conductivity measurements were carried out on the pastes of the First group mixes using two initial water-to-solid (W/S) ratios of 0.55 and 0.70 by weight; while the W/S ratios used for the second group mixes were 1.00 and 1.20 by weight. The measurements were done at 25 and 45 degreesC for each paste during setting and hardening processes after gauging with deionized water. Rheological properties were studied at room temperature for all mixes using various W/S ratios. The results obtained indicate clearly the effect of SF and W/S ratio on the rheological properties and electrical conductivity of all pastes under investigation. The relation between the electrical conductivity and rheological properties for different mixes were discussed based on the chemical nature and physical state of the hydration products formed at early ages of hydration. (C) 2002 Elsevier Science Ltd. All rights reserved.