SU1669717A1 - Method for forming multiple-layer concrete members - Google Patents

Abstract

The invention relates to the construction, in particular, to the technology of manufacturing concrete and reinforced concrete products. The purpose of the invention is to increase the density and uniformity of the upper layer of the product. During the molding of layered concrete products, a concrete mixture containing heavy and light aggregates is laid, a perforated loading plate is applied and vibrated until the aggregates are separated in height, and the pressure of the prigruz is determined by the formula P = (0.95 ... 1.0 ) ^. (ρ _p ρ _l.3 / ρ _{l.3.4 ^-..} ρ _l.3 G H, N / m ^2, where ρ _p ^-.. density of the matrix, kg / ^m3

ρ _l.3 - bulk fill density, kg / m ³

ρ _l.3.k - the density of the lightweight filler in the piece, kg / m ³

G - free fall acceleration, m / s ²

H - required thickness of the upper layer, m. 1 tab.

Description

The invention relates to the construction, in particular, to the technology of manufacturing concrete and reinforced concrete products.

The purpose of the invention is to increase the density and uniformity of the upper layer of the product.

During the molding of layered concrete products, a concrete mixture containing heavy and light aggregates is laid, a perforated loading slab is applied and vibrated until the aggregates are separated in height, and the pressure of the weights is determined by the formula P (0.95 ... 1, 0) х (рррнз / рш-ryu) gh (n / m2), where рр is the density of the mortar part of the concrete mix, kg / m;

RPZ - bulk density of the easy filler, kg / m;

RLZK - lightweight aggregate density in the piece, kg / m3;

h is the required thickness of the layer with a lightweight aggregate; in the product, m;

q - free fall acceleration, m / s2.

The use of a perforated plate, the pressure of which on the surface of the product is

P - (0.95 ... 1.0) x (rffl.z / rp.e.k -rp.z) gh (I / m2), provides for the production of layered products of dense macrostructure of a layer with a lightweight filler practically throughout its thickness and with a quality surface. Vibrating the concrete mix under a perforated plate with a pressure less than the specified one does not provide a dense layer macrostructure with a lightweight aggregate throughout its thickness, and the surface of the product is large-pore. Vibrating - under a perforated plate with a pressure greater than the specified one, does not provide the required surface quality of the product as a result of its immersion in the concrete mix. In addition, a full discussion of

Xi

Xj

layer distribution of aggregates across the thickness of the product does not occur.

The use of a solid slab does not ensure the required surface quality, as air accumulates under it, which leads to the formation of cavities and cavities on the surface of the product.

As an example, studies were conducted on the manufacture of layered products according to the proposed method and the prototype method on three concrete mixes with a layer thickness of 135 mm in the product with lightweight aggregate.

Granite rubble was used as a heavy filler, and expanded clay gravel was used as a lightweight.

Compounds 1.2 and 3 are distinguished by the fact that lightweight aggregate has a density in the piece, respectively, kg / m: 1020, 900, and 750, and bulk density is 630 and 380. The density of the mortar part of the concrete mix is the same for all the compositions and is equal to 1,650 kg / m. The flow rate of all components per 1 m3 of concrete mixture in terms of volume for all compositions is the same.

Example. The selection of the composition of the concrete mix on a mixed aggregate is carried out according to the generally accepted method of selecting the compositions of heavy concrete with the replacement of a part of the heavy aggregate by a light one. All components of the concrete mix components are mixed in a concrete mixer. The filling of the form with the prepared concrete mix is carried out in one step. After filling the mold with a concrete mixture, it vibrates under a perforated plate, the diameter of the holes of which does not exceed 5 mm.

The pressure P is determined for each of the three compositions by substituting into the calculation formula the corresponding values of the densities and thickness of the layer on a lightweight aggregate.

A perforated plate with the required pressure is placed on the surface of the concrete mix, after which it is subjected to vibration, during which the layer-by-layer distribution of heavy and light aggregates over the thickness of the product takes place.

After a set of 70-75% strength, the manufactured products are cut in a vertical section and the characteristic of the layer with lightweight aggregate is determined, and

surface quality of the product - according to GOST 13015.0-83.

The table shows the characteristics of the layer with a lightweight aggregate and the surface quality of products manufactured according to the preferred method with different plate pressures, both perforated and solid, as well as the same characteristics of the products made using the prototype method.

As can be seen from the table, use

The proposed method for the manufacture of layered products from a concrete mixture with heavy and light aggregates provides, in comparison with a prototype, the production of a layered product with a dense macrostructure.

a layer with a light filler throughout its thickness with a high-quality surface of the product, multi-layered products with a dense macrostructure as compared with a large-porous one, have greater durability, resistance in various conditions, improve the protection of reinforcement against corrosion, etc.

Claims (1)

The invention The method of forming laminated concrete products, including laying of a concrete mix containing heavy and light aggregates, vibrating to the height of the aggregates, in order to increase the density and homogeneity of the upper layer of the product, the vibration is carried out when applying a perforated slab-prigruz, the pressure of which is determined by the formula p- (0.95 ... 1.0) .e // e: .k-rl.e) d (n / m2), where / er is the density of the mortar part of the concrete mix, kg / cm3; -. . RPZ - bulk bulk density of the filler, kg / m, rp.z.k - the density of lightweight filler in piece, kg / m; q - acceleration of free fall, m / s7 h is the required thickness of the upper layer, m Mo suggestion method A 20 473 499 512 468 527 555 570 585 614 492 554 10% of the layer thickness with lightweight aggregate macrostructure is granular, 90% - the macrostructure is dense 53 thicknesses of the macrostructure layer granular, 95% - dense, with a light filler Thick macrostructure is dense Thick macrostructure is dense The macrostructure is dense (n ncefi thickness of the layer-by-layer distribution of the filler is not reached) 12% of the layer thickness with a lightweight aggregate macrostructure is granular, 88% is macrostructure dense 7% of the layer thickness with a lightweight aggregate macrostructure is granular, 93% of the macrostructure is dense Thick macrostructure is dense Thick macrostructure is dense Macrostructure is dense throughout Layer distribution of filler not achieved 11% of the thickness of the layer with a lightweight aggregate to the macrostructure of the granular, 89% - the macrostructure is dense 62 layer thick with lightweight aggregate thorny macrostructure, 94% - poppy structure is dense Thick macrostructure is dense Thick macrostructure is dense Thick macrostructure is dense Filler distribution not reached Prototype 38% of the layer thickness with a lightweight aggregate macro structure is dense 44Z layer thickness with lightweight aggregate macrostructure is granular, 562 macrostructure is dense 52Z thickness of the layer with a lightweight aggregate macrostructure granular, 48% - the macrostructure is dense The pressure corresponding to the calculation formula. Editor N. Shitev Compiled by V. Lebedev Tehred M. Morgenthal Sinks with a diameter 16 and 5 mm deep Sinks with a diameter 17 and 5 mm deep Sinks with a diameter 18 and 6 mm deep Sinks with a diameter of 18 and a depth of 7 mm, nodules 7 mm Projections 10 mm, depressions 10 mm Projections 10 mm, depressions 10 mm Projections 10 mm, depressions 10 mm Proofreader O. Tsiple