FIELD: building materials. SUBSTANCE: bundles of synthetic fibers may be used in concrete mortar and cement. They include about 10-10000 fibers per bundle. Fibers consist, mainly, of polyolefins such as polypropylene or polyethylene, derivatives of polyolefin, polyester, polyamide or their mixtures and are about 1 to about 30 mm long. Average cross-section of fibers is about 5 to about 50 mcm and length-diameter ratio is about 10 to about 1000. Separate fibers have a surface tension which allows formation of homogeneous dispersion of fibers in concrete, mortar or paste by common mixture with the help of common mixing equipment. Concrete based on cement, mortars and pastes include bundles of fibers. The invention also offers a method for production of fiber bundles and materials based on cement. EFFECT: higher efficiency. 25 cl, 1 tbl
