An unshaped product including, as weight percentages, A) particles (a) of at least one refractory material other than a glass and a glass-ceramic, and the main constituent(s) of which are alumina and/or zirconia and/or silica and/or chromium oxide: B) 2% to 15% of particles (b) of a hot binder chosen from glass-ceramic particles, particles made of a glass, and the mixtures of these particles, a glass being a noncrystalline material exhibiting a glass transition temperature of less than 1100° C., the hot binder not being in the solid state at 1500° C., C) less than 2% of particles (c) of hydraulic cement, D) less than 7% of other constituents, the particles (a) and (b) being distributed, as weight percentages in the following way: fraction