FIELD: composites. SUBSTANCE: fiberglass strands are impregnated with non-abrasives solid particles, which provide formation of hollow spaces at least 3 mcm in size between adjacent fibers in strand, which strengthens composite material. Coated fibrous strand is formed by a multitude of glass fibers, more than 5 mcm in diameter, impregnated with dry residue of water-based sizing composition containing solid particles with diameter at least 3 mcm. Solid particles, hardness of which does not exceed that of glass fibers, are formed from at least one ceramic material selected from metal nitrides, oxides, carbides, sulfides, borides, silicates, carbonates, and mixture thereof. EFFECT: increased strength of composite. 68 cl, 8 dwg, 11 tbl
