(10) WO 2021/023360 Al
(57) A method for production of concrete precast elements made of prestressed concrete, wherein concrete elements are formed of a concrete mixture containing 220 kg to 500 kg/m3 of sulphate-free cement having less than 0.5% by mass of sulphates (expressed as SO3) and an admixture of 0.2% - 4% by mass of cement of sodium or potassium carbonates or phosphates and 0.5% - 3% by mass of cement of lignosulphonates (advantageously sodium or potassium). The mixture may include also 5 - 8% of silica fume. Specific surface area of the cement may be higher than 3900 cm2 / g. The mixture with immersed prestressing steel bars undergoes thermal treatment at temperature of 69 - 98°C, preferably 80 - 85°C in a humid atmosphere for a time of 240 to 375 minutes.
(71) Applicant: PAWLUK, Jaroslaw Jerzy [PL/PL]; ul. Omankowskiej 11, 44-105 Gliwice (PL).
(84) Designated States (unless otherwise indicated, for every kind of regional protection available): ARIPO (BW, GH, GM, KE, LR, LS, MW, MZ, NA, RW, SD, SL, ST, SZ, TZ, UG, ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, RU, TJ, TM), European (AL, AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI, FR, GB, GR, HR, HU, EE, IS, IT, LT, LU, LV, MC, MK, MT, NL, NO, PL, PT, RO, RS, SE, SI, SK, SM,