Abstract: The invention relates to uniformed concrete comprising, in percentages by weight, (d) 87% to 98% of particles comprising more than 90 wt.-% alumina, (c) 1% to 7% silica fume particles, (f) 1% to 8% particles of a hydraulic cement, the fraction of said particles having a size less than 40 ?m being distributed as follows, in percentage by weight in relation to the weight of the unformed concrete: fraction <0.5 ?m: ?4%, fraction <2 ?m: ?5%, fraction <10 ?m: ?19%, fraction <40 ?m: 34%-52%, fraction between 2 ?m and 40 ?m: 26.5%-34%, the concentration of Zro2, in percentage by weight on the basis of the uniformed concrete, being less than 2%, and the concentration of organic fibres, in percentage by weight on the basis of the uniformed concrete, being less than or equal to 0.03%.

Abstract: The invention relates to uniformed concrete comprising, in percentages by weight, (d) 87% to 98% of particles comprising more than 90 wt.-% alumina, (c) 1% to 7% silica fume particles, (f) 1% to 8% particles of a hydraulic cement, the fraction of said particles having a size less than 40 ?m being distributed as follows, in percentage by weight in relation to the weight of the unformed concrete: fraction <0.5 ?m: ?4%, fraction <2 ?m: ?5%, fraction <10 ?m: ?19%, fraction <40 ?m: 34%-52%, fraction between 2 ?m and 40 ?m: 26.5%-34%, the concentration of Zro2, in percentage by weight on the basis of the uniformed concrete, being less than 2%, and the concentration of organic fibres, in percentage by weight on the basis of the uniformed concrete, being less than or equal to 0.03%.

Abstract: An unwrought refractory composition, in particular for producing glass furnace hearths, includes a base mixture comprising in wt. %: 1 to 6% of a hydraulic cement, and 94 to 99% of particles of at least a refractory material mainly consisting of alumina (Al2O3), zirconia (ZrO2) and silica (SiO2), the fraction of the particles of the base mixture having a size less than 40 ?m being distributed in wt. % relative to the weight of the base mixture, as follows: fraction<0.5 ?m: ?4%; fraction<2 ?m: ?5%; fraction<10 ?m: ?16%; fraction<40 ?m: 29–45%, the refractory composition further comprising, in wt. % relative to the weight of the base mixture: 0.02 to 0.08% of organic fibers, and 0.075 to 1% of a surfactant.

Abstract: An unwrought refractory composition, in particular for producing glass furnace hearths, includes a base mixture comprising in wt. %: 1 to 6% of a hydraulic cement, and 94 to 99% of particles of at least a refractory material mainly consisting of alumina (Al2O3), zirconia (ZrO2) and silica (SiO2), the fraction of the particles of the base mixture having a size less than 40 &mgr;m being distributed in wt. % relative to the weight of the base mixture, as follows: fraction<0.5 &mgr;m: ≧4%; fraction<2 &mgr;m: ≧5%; fraction<10 &mgr;m: ≧16%; fraction<40 &mgr;m: 29-45%, the refractory composition further comprising, in wt. % relative to the weight of the base mixture: 0.02 to 0.08% of organic fibers, and 0.075 to 1% of a surfactant.