RU2738072C1 - Crude mixture for production of light corrugated concrete - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to production of construction materials, particularly, to production of wall blocks. Raw mixture for light fibre concrete production contains, wt. %: Portland cement M500 D0 22.50–23.75, river sand 76.25–77.50, sewage sludge combustion ash 5.0–10.0 (based on said cement weight), tempering water to W/D 0.5.

EFFECT: technical result is upgraded strength of light corrugated concrete, recycling wastes.

1 cl, 4 tbl, 5 ex

Description

The invention relates to the production of building materials in the field of using incineration waste as fillers for concrete, makes it possible to efficiently utilize large-tonnage waste, for example, ash from incineration of sewage sludge, with the prospect of using useful products in an urban environment, in particular, for the production of wall blocks.

Known raw mixture for the preparation of ash-alkali concrete (RF patent No. 2554966, publ. 10.07.2015), including filler and binder, and the binder consists of fly ash II field with a true density ρ _and = 2590-2800 kg / m ³ and losses after ignition of 3.1-4.9% obtained from the combustion of KATEK's brown coal at the Irkutsk CHPP-7, and liquid glass with a silicate modulus n = 0.9-1.4 and density ρ = 1.36-1.38 g / cm ³ , made from the technogenic waste of the Bratsk Ferroalloy Plant - microsilica with a true density ρ _and = 2120-2280 g / cm ³ , and as a filler, screenings from crushing diabase masses into crushed stone with a true density of ρ _and = 2850-3120 kg are used / m ³ , crushing strength 10.4-13.1% with a grain ratio of fractions, wt%:

fr. 5 mm 55.0

fr. 2.5 mm 27.3 fr. 1.25 mm 2.75 fr. 0.63 mm 4.64 fr. 0.315 mm 3.62 fr. 0.14 mm 6.69

and a fineness modulus of 4.47 with the following ratio of the components of the raw mixture, wt%:

Specified fly ash II field 21.74-22.22 Specified liquid glass 11.12-13.04 Specified screenings from diabase crushing 65.22-66

The disadvantage of this composition is the use as a binder fly ash II field of the CHP, since this waste is limited in the use of only the considered CHP.

Known raw mixture for the manufacture of fine-grained concrete (RF patent No. 2613065, publ. 03/15/2017), which contains Portland cement, ash from coal combustion, characterized in that it additionally contains superplasticizer C-3, ground and sieved through a sieve No. 063 silicate glass, sieved through a sieve No. 5 electrocorundum with the following ratio of components, wt.%:

Portland cement 28.0-30.0 Ash from coal combustion 55.3-58.5 Superplasticizer C-3 0.5-0.7 Crushed and sieved through a sieve No. 063 silicate glass 9.0-12.0 Electrocorundum sifted through a sieve No. 5 2.0-4.0 With a water-cement ratio 0.4-0.5

The disadvantage of this mixture is the need for additional preparation of a large number of constituent components, as well as low strength characteristics of fine-grained concrete made from this raw mixture.

Known raw mix for the manufacture of lightweight concrete (RF patent No. 2259976, publ. 09/10/2005), which as components contains low-clinker slag Portland cement, granulated blast furnace slag, coal ash from power plants, foaming surfactant, chemical additive and water, additionally contains coal ash with a bulk density of 350 ... 500 kg / m ³ , consisting of glassy particles in the form of hollow microspheres, and as a surfactant and chemical additive - oxyethylene with the following ratio of components, wt%:

Low-clinker slag Portland cement 20 ... 25 Granulated blast furnace slag 19 ... 33 Coal ash 24 ... 35 Oxyethylene 0.02 ... 0.07 Water Rest

The disadvantage of this mixture is the use of a chemical additive (oxyethylene), which is characterized by increased fire and explosion hazard, and is also characterized by high toxicity.

Known concrete mixture (RF patent No. 2463271, publ. 10.10.2012), including cement, activated ash from a thermal power plant, sand, coarse aggregate and water, characterized in that fly ash is used, while the concrete mixture additionally contains a fine fraction of up to 3 mm and a coarse fraction from 5 mm to 20 mm of asphalt concrete granulate with the following ratio of components in the material by weight:

Cement 356 Fly ash 89 Sand 561 Large placeholder 685 Asphalt concrete granulate (fine size up to 3 mm) fifty Asphalt concrete granulate (large size 5 mm-20 mm) 468 Water 180

The disadvantages of this composition are the need to activate the CHP plant ash, as well as the need for the mixture in large volumes of coarse aggregate.

The closest in technical essence and the achieved result is a raw mixture for producing ash concrete (RF patent No. 2355657, publ. 20.05.2009), taken as a prototype, including liquid glass from microsilica with a density of 1.38 g / cm ³ , ash - ash from the hydro removal of the Omsk CHPP-5, obtained from the combustion of Ekibastuz coal, river sand and additionally - Portland cement M400 and water, with the following ratio of components, wt. %:

Portland cement М400 24.10-24.15 River sand 73.00-73.07 Specified liquid glass
(based on the weight of the specified Portland cement) 1.50-1.52 Specified ash
(based on the weight of the specified Portland cement) 9.8-10.0 Water up to V / C 0.5

The disadvantages of this raw mixture are the need for mixing the mixture with liquid glass from microsilica, as well as insufficient substantiation of the correspondence of the properties of the specified hydro removal ash as a component of ash concrete to regulatory documents.

The technical result is to create a composition with high strength properties.

The technical result is achieved by using Portland cement M500 D0, as ash used as ash from incineration of sewage sludge with the following ratio of components, wt%:

Portland cement М500 D0 22.50-23.75 river sand 76.25-77.50 sewage sludge incineration ash
(based on the weight of the specified cement) 5.0-10.0 mixing water up to V / C 0.5.

Raw mix for the production of lightweight ash concrete includes the following reagents and commercial products containing them:

- Portland cement M500 D0 in accordance with GOST 10178-85 “Portland cement and slag Portland cement. Specifications "(introduced on 01.01.1987). Standardized Portland cement does not contain active mineral additives. Its use in the specified dosage of 22.50-23.75 wt.% When using the M500 grade increases the strength of the final product;

- river sand for construction work, coarse or medium-grained in accordance with GOST 8736-2014 “Sand for construction work. Technical conditions "(introduced on 04.01.2015). The use of sand as a fine aggregate with a ratio of cement and sand components of 1: 3 ensures optimal packing density of concrete;

- mixing water in accordance with GOST 23732-2011 “Water for concrete and mortars. Technical conditions "(introduced on 10.01.2012) to a water-cement ratio W / C 0.5. The required amount of mixing water is specified during the study of the normal density of the cement paste in accordance with GOST 310.3-76 “Cements. Methods for determining normal density, setting time and uniformity of volume change ”(introduced 01.01.1978) using the Vic's device.

- ash from incineration of sewage sludge. Waste is generated from sewage sludge incineration plants. For incineration in fluidized bed furnaces, cake is sent - a dewatered mixture of raw sludge from primary clarifiers and excess activated sludge from sludge compactors. Externally, the waste is a brown fine powder. The ash test results are presented in Table 1. The waste is characterized as acidic (silicon) light ash. Coefficient of inhomogeneity of particle size distribution K _n = 0.45; dispersion (according to the residue on a sieve 0045) corresponds to the 3rd class. Ash meets the basic requirements for chemical composition (content of oxide forms of CaO, including the content of free CaO, MgO, SO ₃ , Na ₂ O), and is also included in the permissible range of moisture, density and size values. For acidic ashes, the total content of SiO ₂ + Fe ₂ O ₃ + Al ₂ O ₃ should not be less than 65% of the mass. The set value (61.87% by weight) is slightly lower than the required value. In view of the fact that the XRF method is semi-quantitative, the result can be considered satisfying the requirement. The use of ash in is permissible if, during further tests, the required indicators of ash concrete are provided.

Table 1 - The results of testing the composition and properties of waste as a component of the raw mixture.

P / p No. Index Value Demand Compliance with the requirement one 2 3 4 5 one Ci,%
masses. SiO ₂ 34.66 ≥ 25% + 2 Fe ₂ O ₃ 13.93 see SiO ₂ + Fe ₂ O ₃ + Al ₂ O ₃ 3 Al ₂ O ₃ 13.28 4 SiO ₂ + Fe ₂ O ₃ + Al ₂ O ₃ 61.87 ≥65% for a single result + * 5 CaO 8.68 <10% Sour ash ≤ 10% + 6 MgO 3.53 ≤ 5% + 7 SO ₃ 1.86 ≤ 5% + 8 Na ₂ O 1.35 ≤ 3% + nine Humidity,% 0.46 ≤ 1% + ten Sieve residue 008,% 43 ≤ 30% Greater sieve residue allowed eleven Sieve residue 0045,% 60 > 40% Fineness class 3 12 True density, g / cm ³ 2.64 > 2 g / cm ³ Dense filler 13 Acidity modulus 1.83 > 1 Sour ash 14 CaO free,% 0.56 ≤ 1% + 15 Bulk density, g / cm ³ 0.62 <0.8 g / cm ³ Light ash ≤ 1.3 g / cm ³ For lightweight concrete

* The XRF method is semi-quantitative, therefore the obtained value is considered satisfying the requirement.

To obtain comparative data on the strength characteristics of ash concrete under the same conditions, beams were prepared from the proposed raw mixture. Ash-cement dough is made by hand using a bowl and a spatula. Tests of specimen strength in bending (using a device for a PI press) and in compression (using a hydraulic bench press) were performed at the standard age of 28 days of storage in a normal hardening chamber at a temperature of 20 ± 2 ° C and a relative humidity of 95% according to GOST 10180- 2012 “Concrete. Methods for determining the strength of control samples "(introduced on 07.01.2013), GOST 12730.1-78" Concrete. Methods for Determining Density "(introduced 01.01.1980).

According to the test results, the samples of ash concrete were assigned a class or grade according to the following parameters: density (grade D), bending strength (class Btb) and compressive strength (class B, grade M) in accordance with GOST 25820-2014 “Light concretes. Specifications "(introduced on 07.01.2015).

The composition of the raw mixture using the proposed components in the specified ranges of ratios, wt.% (Table 2), allows you to provide the following properties of the mixture shown in table 3.

Table 2 - Composition of the tested samples of ash concrete. P / p No. Portland cement Sewage sludge incineration ash River sand The total content of cement and sand components V / C Wt% Wt%
(from the mass of cement) Wt% Wt% The control 25 0 75 one hundred 0.5 one 23.75 5 76.25 one hundred 0.5 2 22.5 ten 77.5 one hundred 0.5 3 21.25 15 78.75 one hundred 0.8 4 twenty twenty 80 one hundred one 5 18.75 25 81.25 one hundred 1,2 6 17.5 thirty 82.5 one hundred 1.4 7 12.5 fifty 87.5 one hundred 1.4

Table 3 - Test results of samples of ash concrete. P / p No. Wt% cement replaced by ash Density Flexural strength Compressive strength g / cm ³ Grade D MPa Btb class MPa Class B Brand M The control 0 1.35 1300 2.16 2 19.50 15 200 one 5 1.33 2.05 16.84 2 ten 1.31 2.00 15.69 3 15 1.28 1200 1.42 1,2 10.25 ten 150 4 twenty 1.28 1.23 9.40 7.5 one hundred 5 25 1.25 1.17 0.8 7.29 5 75 6 thirty 1.20 1.11 7.25 7 fifty 1.10 1100 0.73 0,4 3.74 3.5 fifty

According to the results of the tests, the preservation of the strength properties of concrete was confirmed when ash was replaced with up to 10% of cement by weight in the composition of the cement-sand mixture, which is characterized by the established class and grade of ash concrete (D1300 / Btb2 / B15 / M200).

Analysis of the data obtained shows that lightweight ash concrete based on the proposed raw mix is characterized by rather high strength indicators, corresponding to the strength indicators of concrete according to the prototype. At the same time, the proposed raw mixture is more technological than the known analogs, since when used as a binder ash, incineration of sewage sludge does not require additional processing of the component and the introduction of additives.

The composition is illustrated by the following examples (table 4):

Example # 1.

For the production of wall blocks from ash concrete, 1000 kg of a raw mixture is required based on ash from incineration of sewage sludge, while the ratio of cement and sand components is set as 1: 3, the water-cement ratio W / C is 0.5, and ash replaces 10 wt.% Of cement ... The density of the building material will be 1.31 g / cm ³ , the compressive strength is 15.69 MPa.

Example # 2.

For the production of wall blocks from ash concrete, 450 kg of a raw mixture is required based on ash from incineration of sewage sludge, while the ratio of cement and sand components is set as 1: 3, the water-cement ratio W / C is 0.5, and the ash replaces 6 wt.% Of cement ... The density of the building material will be 1.33 g / cm ³ , the compressive strength is 16.5 MPa.

Example No. 3.

For the production of wall blocks from ash concrete, 212 kg of a raw mixture based on ash from incineration of sewage sludge is required, while the ratio of cement and sand components is set as 1: 3, the water-cement ratio W / C is 0.5, and ash replaces 7.5 wt. % of cement. The density of the building material will be 1.32 g / cm ³ , the compressive strength is 16.1 MPa.

Example No. 4.

To perform floor screed work on an area of 100 m ² , 2200 kg of a raw mixture is required based on ash from incineration of sewage sludge, while the ratio of cement and sand components is set as 1: 3, the water-cement ratio W / C is 0.5, and ash replaces itself 9.5 wt% cement. The density of the building material will be 1.31 g / cm ³ , the compressive strength is 16 MPa.

Example No. 5. To perform floor screed work on an area of 315.25 m ² , 6935.5 kg of raw mixture is required based on ash from incineration of sewage sludge, while the ratio of cement and sand components is set as 1: 3, the water-cement ratio W / C is 0.5, and ash replaces 8.3 wt.% cement. The density of the building material will be 1.31 g / cm ³ , the compressive strength is 16 MPa.

Table 4 - The results of calculating the composition of the raw mixture.

P / p No. Portland cement Sewage sludge incineration ash River sand The total content of cement and sand components V / C Weight, kg Wt% Weight, kg Wt% (based on cement weight) Weight, kg Wt% Weight, kg Wt% one 237.50 23.75 23.75 ten 762.50 76.25 1000 one hundred 0.5 2 105.75 23.5 6.35 6 344.25 76.5 450 one hundred 0.5 3 48.76 23 3.66 7.5 163.24 77 212 one hundred 0.5 4 500.50 22.75 47.55 9.5 1699.50 77.25 2200 one hundred 0.5 5 70.93 22.5 5.89 8.3 244.32 77.5 315.25 one hundred 0.5

The proposed raw mix for the production of lightweight ash concrete has a significant resource-saving effect by reducing the need for cement for the production of concrete. Also, an advantage in the introduction of building material is the useful disposal of waste by involving it in economic circulation with the prospect of using it for the repair of highways, the production of wall blocks, and the improvement of urban areas.

Claims (2)

Raw mix for the production of lightweight ash concrete, including ash, Portland cement, river sand and water, characterized in that Portland cement M500 D0 is used, ash from incineration of sewage sludge is used as ash with the following ratio of components, wt%: Portland cement М500 D0 22.50-23.75 river sand 76.25-77.50 sewage sludge incineration ash (based on the weight of the specified cement) 5.0-10.0 mixing water up to V / C 0.5