cement matrix was mainly composed of johannsenite a small amount of xonotlite the expected cement mineral at this temperature was detected the presence of hausmannite mn 3 o 4 was not noted a solid blend was prepared with the following composition 35 by volume of blend bvob dyckerhoff black label class g cement median particle size 15 u03bcm 40 bvob silica sand median particle size u02dc 315 u03bcm 10 bvob silica flour median particle size u02dc 3 u03bcm 5 bvob hematite median particle size u02dc 32 u03bcm and 10 bvob hematite median particle size u02dc 3 u03bcm to this mixture 1 5 by weight of blend bwob bentonite was added the difference between this blend and the one of example 1 is the replacement of 10 bvob micromax u2122 with the same volume of very fine hematite a fluid was prepared with the following composition 4 17 l tonne of blend silicone antifoam agent 66 8 l tonne retarder a blend of sodium pentaborate and pentasodium edtmp u2014 weight ratio 9 3 0 75 bwob styrene sulfonate maleic anhydride copolymer dispersant narlex d72 available from akzo nobel 0 8 bwob fluid loss additive uniflac u2122 and sufficient water to prepare a slurry with a solid volume fraction svf of 0 61 the slurry density was 2280 kg m 3 19 03 lbm gal the slurry was placed in a uca instrument and cured at a final temperature of 302 u00b0 c 575 u00b0 f and.