Abstract: The present disclosure relates to a high-strength concrete and a preparation method thereof. The high-strength concrete includes lignin, recycled fine powder, cement, water, sand, gravels and a water reducing agent. The recycled fine powder is recycled fine powder of discarded concrete, and is prepared by separating solid waste of discarded buildings, then performing impurity removal and crushing processing, and grinding same by a ball mill into dust with a particle size of less than 0.16 mm. The lignin is discarded wood lignin, which is prepared by crushing the wood, stirring and extracting a sodium hydroxide aqueous solution with a mass concentration of 5% for 1 to 2 hours at the temperature of 80 DEG C. to obtain a black lignin alkali solution, adding a hydrochloric acid solution with a mass concentration of 30% into the alkali solution for stirring, and making the pH reduced to 7.0 for standing and layering.

Abstract: The present disclosure relates to a high-strength concrete and a preparation method thereof. The high-strength concrete includes lignin, recycled fine powder, cement, water, sand, gravels and a water reducing agent. The recycled fine powder is recycled fine powder of discarded concrete, and is prepared by separating solid waste of discarded buildings, then performing impurity removal and crushing processing, and grinding same by a ball mill into dust with a particle size of less than 0.16 mm. The lignin is discarded wood lignin, which is prepared by crushing the wood, stirring and extracting a sodium hydroxide aqueous solution with a mass concentration of 5% for 1 to 2 hours at the temperature of 80 DEG C. to obtain a black lignin alkali solution, adding a hydrochloric acid solution with a mass concentration of 30% into the alkali solution for stirring, and making the pH reduced to 7.0 for standing and layering.

Abstract: The present invention relates to the field of metal additive manufacturing, and disclosed thereby is a method for printing a structure of a combustion chamber liner by using GRCop-84 spherical powder. The method mainly comprises the following steps: (1) establishing a model; (2) configuring printing parameters; (3) performing laser printing; (4) performing annealing treatment; and (5) performing surface sandblasting. The present invention uses GRCop-84 spherical powder as the material of a combustion chamber liner model, and said material has excellent electrical conductivity, thermal expansion, strength, creep resistance, ductility, fatigue and like properties, and the comprehensive performance thereof is excellent, which significantly improves the performance of a rocket engine. In the GRCop-84 spherical powder material of the present invention, Cr and Nb form a Cr2Nb phase, and the volume fraction of a second phase is about 14%, same being evenly distributed in a copper matrix.