| CPC C04B 14/28 (2013.01) [B28C 7/16 (2013.01); C04B 16/02 (2013.01); C04B 18/243 (2013.01); E04G 21/04 (2013.01); C04B 14/26 (2013.01); C04B 2111/00344 (2013.01)] | 13 Claims |

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1. A method of pressure-pumping a ready-mixed concrete, comprising:
pouring a preceding material for pumping into an outlet of a hopper connected to a pump,
subsequently, pouring the ready-mixed concrete into the outlet of the hopper over the preceding material,
pressure-pumping the preceding material and the ready-mixed concrete together towards a piping connected to an outlet of the pump, so that a lubricant layer comprising the preceding material is formed on an inner surface of a piping,
pressure-pumping a top end portion of the ready-mixed concrete so as to push a rear end of the preceding material inside the piping,
wherein the preceding material comprises calcium carbonate, cellulose nanofibers and erythorobic acid,
wherein the calcium carbonate comprises porous calcium carbonate, hydrotalcite-containing porous calcium carbonate, and sedimentary calcium carbonate,
wherein the porous calcium carbonate and the hydrotalcite-containing porous calcium carbonate are processed by treating the ready-mixed concrete sludge yielded in a ready-mixed concrete plant, for a particle size adjustment and an ingredient adjustment, and the sedimentary calcium carbonate has a uniform particle shape by chemical treatment, and
wherein an amount of the cellulose nanofibers is 0.005 wt % to 0.008 wt %.
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