Abstract: The disclosed process to obtain a modifier for cement systems comprises a synthesis of the modifier by a process of polymerization in a soft alkaline catalysis. This contributes to the formation of a product with a low molecular mass and viscosity. The concentration of the homogeneous aqueous solution is from 40-58% and the specific production of the process is Q=0.25 to 3.00 kg per hour in comparison with the specific production of the known prototype which is Q=0.03 to 0.04 kg per hour. One of the most important characteristics of the new process used to obtain the disclosed modifier is the fact that synthesis is achieved without external heat sources. Also, synthesis is achieved either by a periodic process or a continuous process.

Abstract: A composition of hydraulic cement is disclosed, having low water demand, high strength and low fragility. The cement comprises finely ground Portland cement clinker, calcium sulfate and a dry modifier containing an organic water reducing component in a weight percent ratio of 91 to 97:2 to 7:0.085 to 4, respectively. The clinker particles comprise three fractions, I, II and III chemically bonded with the organic water reducing component and having respective particle sizes: I--0.05 to 10 mkm in a weight percent of 15.3 to 34.3; II--10.1 to 30 mkm in a weight percent of 37.2 to 77.5; III--30.1 to 80 mkm in a weight percent of 4.2 to 19.6; plus a fraction IV--having a particle size more than 80 mkm in a weight percent less than 4.9 and free of the modifier. The calcium sulfate comprises a fraction of particles of a size 0.5 to 15 mkm, free of the modifier. The dry modifier is chemically bonded with the three clinker fractions in the following weight percent quantities: I--0.045 to 1.7; II--0.02 to 2.

Abstract: The cementitious material comprises an initial mixture of portland cement clinker and a modifier ranging in weight from approximately 0.5% to 5%, preferably 1%, of the weight of the clinker. The modifier is selected from a group comprising (a) a melamine formaldehyde-sodium bisulfite copolymer, and (b) sodium naphthalene sulfonate. The portland cement clinker and the modifier are intimately mixed and caused to react together in a solid state reaction by energetically grinding them together in a highly energetic ball-and-tube grinding mill to a high degree of fineness of at least approximately 5000 Blaine. Modified cementitious materials are produced by providing an additional constituent in the initial mixture comprising a hard, dense, substantially inert mineral material ranging up to 70% of the mixture by weight. The percentages of the portland cement clinker and the modifier are correspondingly reduced. The modified initial mixture is ground as before.

Abstract: Precast or poured columns are erected in a plurality of rows. Precast concrete beams are placed on temporary supports between the columns in each row. The beams are slightly shorter than the distance between the columns and are not supported by the columns. Precast concrete floor slabs are placed between the precast beams of adjacent rows, with the ends of the slabs partially overlapping the beams. Temporary forms are placed around the upper portions of the columns and under the end portions of the beams and the adjacent floor slabs. Concrete is then poured to form monolithic concrete members extending over the upper sides of the beams and filling the spaces between the ends of the slabs and also the spaces between the ends of the beams and the ends of the columns for uniting the beams, slabs and columns. After sufficient curing of the poured concrete, the forms and the temporary supports are removed.