WAY DETERMINING WATERPROOFNESS OF CEMENT MATERIALS Russian patent published in 2002 - IPC

FIELD: building material industry, quality test of concrete, mortars and cement stones. SUBSTANCE: way determining waterproofness of cement materials includes drying of samples to constant mass, splitting of samples into two parts, hydraulic insulation of their side surfaces, saturation with water through surfaces of split in the course of 1 and 5 min correspondingly and determination of water absorption of materials. There are also found equivalent capillary pressure in material, index of kinetics of water saturation of material and volume of capillary pores of solvent part of material. Waterproofness of material is determined by formula where P_i - is sought-for waterproofness, MPa, found by way of consistent substitution of numerical values of P_i in formula till calculated parameter λ′ hits interval determined by inequality 0,95λ<λ′<1,05λ; P_c is equivalent capillary pressure emerging with water saturation of materials, MPa; n is index of degree of kinetics of water saturation of material found by formula , where are arithmetical means of mass difference of water-saturated and dried samples per 1 and 5 min correspondingly; λ is criterion determined by formula , where V_ki is volume of capillary pores of material, cm³; ΔV_k1 is volume of water absorbed by capillaries in the course of 1 min, cm³; τ′ is relative reduced time depending on dimensions and forms of tested samples which was tabulated. EFFECT: increased accuracy and reduced duration of determination. 6 tbl