TY JOUR TI FEATURES OF FIBER OF THE DIFFERENT COMPOSITION AS AN ELEMENT OF THE SELF-CLEANING SURFACE KW fiber KW hydrophobic additive KW cement stone KW contact angle of wetting KW strength JO Bulletin of Belgorod State Technological University named after. V. G. Shukhov AU Ischenko, A.V. AU Ogurtsova, Y.N. AU Strokova, V.V. PY 2017 IS 2 PB Belgorod State Technological University named after V.G. Shukhov