RU2393129C1 - Heavy concrete - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to compositions for making concrete and can be used in making wall blocks and panels from the said blocks. The heavy concrete which is made from composite binder, coarse and fine filler and water contains a composite binder additive in form of magnesium silicate ore - wehrlite with the following ratio of components of the binder, in wt %: wehrlite 20, calcium sulphate dihydrate 3, portland cement clinker 77. The coarse filler used is crushed wehrlite and the fine filler used is dunite sand with the following ratio of components, in wt %: composite binder 16.0, dunite sand 34.0, crushed wehrlite 42.0, water 8.0.

EFFECT: increased strength of heavy concrete.

4 tbl, 4 ex

Description

The invention relates to concrete compositions and can be used to produce heavy concrete based on magnesium silicate rocks - verlites, dunites.

Known concrete containing, wt.%: Composite binder - 10.1-30, quartz sand - 12-30, crushed granite - 25-60, water - the rest (SU 1413081, 07/30/1988, 3 S.).

Known binder intended for the preparation of concrete, containing, wt.%: Verlite - 25-30, Portland cement clinker - 70-75, two-water gypsum - 2 (by weight of the mixture of verlite and Portland cement clinker) (RU 2320592, 03/27/2008).

The proposed concrete contains verlite crushed stone as coarse aggregate, dunitic sand as fine aggregate, and a composite binder with verlite in the amount of 20% as a binder.

Closest to the claimed invention, the composition of the same purpose, according to the combination of features, is concrete, containing in parts:

- Portland cement clinker  one - large crushed stone  4,5 - fine crushed stone  1.13

(The use of by-products of iron ore beneficiation in construction in the North. Leningrad: Stroyizdat. Leningrad Branch, 1986, p.146-151).

The disadvantage of using a known substance adopted as a prototype is a more significant consumption of cement. The proposed concrete can significantly reduce cement consumption in the binder and increase its strength compared to the prototype.

Therefore, it is proposed to create concrete based on composite binders using magnesium silicate rock.

The technical result of the invention is to increase the strength of concrete by introducing into the binder additives based on Transbaikalia rocks - verlites, which in combination with Portland cement clinker minerals leads to the active participation of the rock in the process of hydration and hardening of concrete.

The technical result is achieved by the fact that heavy concrete consists of composite cementitious, verlite crushed stone, dunitic sand in the following ratio of components, wt.%

- composite binder 16,0 - dunite sand 34.0 - verlite crushed stone 42.0 - water 8.0

As an additive, a composite binder contains magnesium silicate rock - verlite, in the following ratio of components, wt.%:

Verlite twenty Gypsum plaster 3 Portland cement clinker 77

The known mechanism of the process of hydration and hardening of Portland cement and concrete based on magnesium-containing tailings of the Kovdor GOK, which is a rock of ultrabasic composition. An important role in the formation of the mechanical properties of the material is played by the autoclave synthesis parameters. During hydrothermal synthesis under autoclave conditions, magnesium silicates and ferruginous magnesium silicates change their structure; in the (Mg, Fe) ₂ SiO ₄ - CaO - H ₂ O system, neoplasms of various calcium-magnesium composition are fixed, which ensure the strength of the autoclave.

In the claimed concrete, magnesium silicate rocks in the form of verlite and dunite, which are the natural raw materials of Transbaikalia, are used as additives in the composite binder, as well as coarse and fine aggregate. The formation of the mechanical properties of this material occurs in normal humidity conditions, which reduces the cost of the resulting products.

The analysis of the prior art by the applicant, including a search by patent and scientific and technical sources of information, and the identification of sources containing information about analogues of the claimed invention, allowed to establish that the applicant did not find analogues that are characterized by signs that are identical to all the essential features of the claimed invention. The definition of the prototype, as the closest in the set of essential features, allowed us to identify the set of essential in relation to the perceived technical result is to increase the strength of the binder, the distinctive features in the claimed substance set forth in the claims.

Therefore, the claimed invention meets the condition of "novelty."

The search results showed that the claimed invention does not derive explicitly from the prior art for the specialist, since the influence of the transformations provided for by the essential features of the claimed invention is not revealed from the prior art determined by the applicant, namely, the interaction of verlite with cement clinker minerals of the specified composition, which ensures a positive the reaction to achieve a technical result is an increase in strength.

Therefore, the claimed invention meets the condition of "inventive step".

Verlite and dunite of the Yoko-Dovyren massif, which are both a part of cement and a part of aggregates, are ultrabasic rocks of the following chemical composition, wt.% (See Table 1). Their reserves amount to billions of tons. Their quality is good. Alkali and fluid-containing minerals are absent. By this, the magnesium silicate rocks of the Yoko-Dovyren Massif compares favorably with the olivinite of the Kovdor Massif, which contains calcite, fluid and alkali-containing minerals. The chemical composition for comparison is given below, wt.%: (See table 2).

In this technical solution, verlite is used as an active binder in concrete in an amount of 20% for the first time. Also used for the first time: verlite crushed stone as a large aggregate in an amount of 42% and dunitic sand in an amount of 34%.

The effect of the water-solid ratio on the strength of concrete samples was studied, which varied from 40 to 60% by weight. The effect of hardening conditions on the strength of the resulting material was also studied.

The technology for producing concrete of the proposed composition is as follows.

Portland cement clinker, verlite and gypsum are combined in the required ratio and crushed in a 75T-DrM laboratory core mill to a specific surface area of 340 m ² / kg. Fine (dunitic sand) and coarse (verlite crushed stone) aggregate is introduced into the mixture prepared in this way, after which the mixture is thoroughly mixed for 5 minutes, and then the required amount of water is introduced. Samples - cubes of 10 × 10 × 10 (cm) in size are prepared from the obtained binder - 15-17% by weight, dunitic sand - 34%, verlite crushed stone - 42%, water - the rest. The samples are molded in a vibratory compactor. Samples in molds are stored for 24 hours in humid conditions, after which they are subjected to TBO or stored for 28 days in normal humidity conditions.

Example 1

Portland cement clinker, verlite and gypsum are crushed in a core mill of the type 75T-DrM to a specific surface area of 340 m ² / kg in the following ratio of components, wt.%:

- verlite twenty - two-water gypsum 3 - Portland cement clinker 77

Concrete samples are prepared from the prepared binder, coarse and fine aggregate in the following ratio of components, wt.%:

- composite binder 17 - dunite sand 34 - verlite crushed stone 42 - water 7

The mixture is stirred and shut with water in a water / cement ratio of 0.4. Some of the samples are subjected to heat-moisture treatment at a temperature of 90 ° C according to the regime of 1 + 5 + 2 hours, and part are stored for 28 days in normal humidity conditions. Samples are tested for compression. After 28 days of storage, the samples had a compressive strength of 33.1 MPa, an average density of 2467 kg / m ³ . After heat and moisture treatment, the compressive strength was 30.8 MPa, the average density did not change.

Example 2

Similar to example 1 with a water-cement ratio of 0.5.

The compressive strength after 28 days is 33.8 MPa, the average density of 2501 kg / m ³ . Strength after TVO - 31.2 MPa.

Example 3

It is carried out analogously to example 1 with a water-cement ratio of 0.6.

The compressive strength after 28 days is 29.7 MPa, the average density is 2536 kg / m ³ . R _cr after TVO - 26.9 MPa.

As a result of research (see Table 4), it was possible to establish that the water-cement ratio of 0.5 is optimal, where the strength of concrete samples is 33.8 MPa.

Characteristics of the resulting concrete are given in table 4 (examples 1-3). For comparison, the indicators of the known prototype are shown in table 3 (examples 1-4). In table 3, the following designations of the main components are taken:

C - Portland cement

Щ _кр - large crushed stone

Щ _m - small crushed stone

In - water

An analysis of the results of Tables 3 and 4 shows that

- concretes consisting only of Portland cement, coarse and fine aggregate, have reduced strength compared to the proposed concrete, which in addition to the specified components includes a mineral additive in the binder - verlite;

- in heavy concrete, the greatest increase in strength is observed after 28 days of normal moisture curing than with heat and moisture treatment.

- the composition of concrete is optimal, containing, in wt.%: composite binder - 16, dunitic sand - 34, verlite crushed stone - 42, water - 8, providing good strength indicators under normal-moisture hardening conditions.

Thus, the proposed concrete has the following advantages compared with the known:

- increased strength indicators compared with the prototype;

- reduced the amount of Portland cement clinker;

- reduced energy costs for its production by replacing ore dressing waste with verlite, the extraction of which is supposed to be open-pit;

- the cost of the additive used is 18 times cheaper than the cost of ore dressing waste, because verlite and dunitic sand are found in dump rocks.

The proposed composition differs from the prototype in that it does not contain ore dressing waste as a binder in concrete, but contains unconventional natural raw materials - verlite; as coarse aggregate - verlite crushed stone, and as fine aggregate - dunite sand.

Table 1 The chemical composition of magnesium silicate rocks, wt.% Component SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ FeO Cao MgO Na ₂ O K ₂ O Verlite 39.70 1.80 0.42 10.70 0.81 43.83 0.12 0,07 Dunite sand 38.40 2.10 2.93 9.95 0.46 43.20 0.05 0,03

table 2 The chemical composition of the prototype, wt.% Component SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ MnO P ₂ O ₅ Cao MgO K ₂ O + Na ₂ O TiO ₂ Tails of the Kovdorsky GOK 47.2 3.11 6.00 0.20 6.75 12.22 45.78 2,3 0.57

Table 3 The dependence of the strength of concrete based on the tails of the Kovdorsky GOK on the composition Composition of concrete C: U _cr : U _m Consumption of 1 m ³ material, kg R _compress MPa Ts Sh _{cr M} AT 1: 4.62: 1.16 275 1275 325 165 24.8 1: 4,50: 1,13 280 1260 315 177 23.7 1: 4.85: 1.19 291 1408 345 192 29.4 1: 4.10: 1.03 305 1260 313 175 22.2

Table 4 Indicators of physical and mechanical properties of concrete based on verlite Water cement ratio Ultimate compressive strength, MPa, after The average density, kg / m ³ 28 days TVO 0.5 31,2 28,4 2425 0.6 30.5 27.6 2498 0.7 27.7 22.4 2502

The proposed concretes were developed in the laboratory of chemistry and technology of natural raw materials at BIP SB RAS with the participation of the GIN SB RAS.

The foregoing indicates the feasibility of the invention to obtain the specified technical result, which allows us to conclude that the proposal meets the condition of "industrial applicability".

Claims (1)

Heavy concrete obtained from composite binder, coarse, fine aggregate and water, characterized in that it contains as an additive in composite binder magnesilicate rock - verlite in the ratio, wt.%: Verlite - 20, two-water gypsum - 3, Portland cement clinker - 77 ; Verlite gravel as a large aggregate; as fine aggregate - dunitic sand in the following ratio of components, wt.%:
composite binder 16,0 dunite sand 34.0 verlite crushed stone 42.0 water 8.0