Abstract: An ultra-high performance composite concrete, with low cement and fiber content and having good mechanical properties as well as good impacts, shocks and projectile protection properties, includes hydraulic binder, aggregates, an admixture of metal fibers. Particularly, the composite concrete includes 70% to 85% of particles (A) having a particle size distribution which ranges from 0.01 to 3 mm up to particle size distribution which ranges from 0.01 to 0.50 mm; 2% to 10% of particles (B) having particle size of between 0.01 and 1 .mu.m; 3% to 20% of hydraulic binder; 0.1 to 3% of a dispersant or plasticizer; 0.05% to 8.5% of fibers; and, mixing water, wherein the percentages being weight percentages based on the sum of the weights of constituents a) to d).

Abstract: A pulverulent composition for admixture with a refractory aggregate and water to provide refractory articles, including bricks for the construction of thermal enclosures, comprises as a first portion, 70-96% by weight of silica, either vitreous or amorphous, of which the particles have a diameter lower than 1 .mu.m; as a second portion, 4-30% by weight of a compound capable of supplying 1-20% by weight of alkaline earth oxide; and as a third portion, 0.5-3% by weight of a fluidizing or dispersing agent.