CN113192574A - Design method for mixing proportion of spontaneous combustion coal gangue aggregate concrete with C30-C40 - Google Patents

Design method for mixing proportion of spontaneous combustion coal gangue aggregate concrete with C30-C40 Download PDF

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CN113192574A
CN113192574A CN202110452707.6A CN202110452707A CN113192574A CN 113192574 A CN113192574 A CN 113192574A CN 202110452707 A CN202110452707 A CN 202110452707A CN 113192574 A CN113192574 A CN 113192574A
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周梅
陈瑞雪
王忻怡
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Liaoning Technical University
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    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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Abstract

The invention discloses a mixing proportion design method of self-burning coal gangue aggregate concrete with C30-C40, belonging to the technical field of concrete preparation and the field of resource utilization of solid waste building materials. The invention utilizes spontaneous combustion coal gangue coarse aggregate, fine aggregate or coarse and fine aggregate to replace natural aggregate to prepare concrete, and comprises the following steps: (1) detecting performance indexes of various raw materials; (2) three parameters of the mix design are determined: water-to-gel ratio, unit water consumption and initial sand rate; (3) calculating the unit dosage of the cementing material and the dosage of the cement and the admixture, and determining the admixture dosage; (4) adjusting the sand rate according to the consistency of the mixture; (5) and calculating the unit dosage of the natural sand, the stone, the coal gangue and the pre-wetting water. The invention considers the characteristics of high water absorption rate, poor particle shape and the like of the spontaneous combustion coal gangue aggregate, has strong pertinence and good operability, realizes the large-scale utilization of the spontaneous combustion coal gangue in the field of building materials, relieves the problem of shortage of sandstone resources for concrete serving as a basic building material, and has remarkable social and economic benefits.

Description

Design method for mixing proportion of spontaneous combustion coal gangue aggregate concrete with C30-C40
Technical Field
The invention belongs to the technical field of concrete preparation and the field of resource utilization of solid waste building materials, and particularly relates to a mixing proportion design method of C30-C40 self-burning coal gangue aggregate concrete.
Background
The associated coal gangue produced by coal has huge accumulation and yield, occupies precious land resources, causes serious pollution to air, water sources and land in a mining area, and seriously threatens the health and safety of residents in the mining area. Therefore, the research on recycling of the coal gangue solid waste building materials is significant.
The spontaneous combustion coal gangue aggregate is rich in silicon and aluminum in quality, has bulk property in quantity, has dual similarity with natural siliceous aggregate, and is feasible to replace natural aggregate to prepare concrete. The spontaneous combustion coal gangue aggregate occupies a place in a 'solid waste' aggregate family due to the characteristics of good quality, large reserve, easy exploitation, low price and the like. The development of the foundation and application research of the spontaneous combustion coal gangue in the concrete has important practical significance.
When the spontaneous combustion coal gangue aggregate is used for preparing concrete, as a plurality of performance indexes of the spontaneous combustion coal gangue aggregate are between those of the lightweight aggregate and the common natural aggregate, when the mix proportion is designed, if a design method in JGJ55-2011 design rule of common concrete mix proportion or JGJ51-2002 technical rule of lightweight aggregate concrete is directly adopted, the design method is obviously unreasonable. The spontaneous combustion coal gangue is decarbonized by nature, and the coarse and fine aggregates of the spontaneous combustion coal gangue meeting the standard requirements can be prepared by controlling the particle size, particle shape and gradation of the aggregate of the spontaneous combustion coal gangue and controlling the content of the gangue which is not sufficiently combusted in the crushing process. However, since the spontaneous combustion coal gangue has large porosity, high water absorption, large crushing value, bad grain shape and the like, a traditional common concrete bauromid formula, a unit water consumption and a sand rate selection standard are directly adopted during concrete mix proportion design, and a large error is inevitably generated. A concrete mixing proportion design method based on the material characteristics (large water absorption, high needle sheet content and the like) of the spontaneous combustion coal gangue is established, and the method has an important guiding effect on the large-scale utilization of the spontaneous combustion coal gangue in the concrete.
Disclosure of Invention
Therefore, the technical scheme adopted by the invention is a design method for the mix proportion of the spontaneous combustion coal gangue aggregate concrete of C30-C40, which comprises the following steps:
(1) determining the type of raw materials of the spontaneous combustion coal gangue aggregate concrete, wherein the raw materials of the spontaneous combustion coal gangue aggregate concrete comprise a cementing material, aggregate, an additive and water, the cementing material comprises cement and a mineral admixture, and the mineral admixture comprises one, two or three of fly ash, silica fume and slag; the aggregate is composed of two of natural sand, natural broken stone, spontaneous combustion coal gangue sand and spontaneous combustion coal gangue, and the water is mixing water or is composed of mixing water and adsorption water;
(2) measuring technical property indexes of raw materials except the water reducing agent and the silica fume;
(3) and determining the formulated strength of the concrete. Calculating the preparation strength according to the specification of JGJ55-2011 'design rule of common concrete mix proportion', wherein the calculation method is as shown in a formula (1);
fcu,0＝fcu,k+1.645σ (1)
in the formula (f)cu,0The preparation strength of the spontaneous combustion coal gangue aggregate concrete is MPa;
fcu,kthe design strength of the spontaneous combustion coal gangue aggregate concrete is MPa;
sigma-standard difference of concrete strength, MPa;
the standard deviation sigma of concrete can be taken by referring to the value in table 1.
Figure BDA0003039411850000021
(4) Determining the water-to-gel ratio of the spontaneous combustion coal gangue aggregate concrete under the designed strength; the calculation formula of the SNC water-gel ratio is shown as a formula (2), the calculation formula of the NSC water-gel ratio is shown as a formula (3), and the calculation formula of the SSC water-gel ratio is shown as a formula (4);
Figure BDA0003039411850000022
Figure BDA0003039411850000023
Figure BDA0003039411850000024
in the formula: f. ofb-cement 28d mortar compressive strength measured value; the characteristic of the spontaneous combustion coal gangue aggregate is considered, and the pallium formula is corrected;
(5) determining the unit water consumption mw. According to the type and maximum particle diameter of the coarse aggregate and the slump value required by constructionAccording to the statistical data of a large number of experiments in the early stage, the unit water consumption m of the spontaneous combustion coal gangue aggregate concrete is corrected according to the statistical data of a large number of experiments in the early stage on the basis of fully considering the grain shape difference and the large porosity of the spontaneous combustion coal gangue aggregatew0See table 2 for details. Mixed with additive, if the water reducing rate of concrete is beta, 1m3The water consumption of the concrete can be calculated according to the formula (5):
mw＝mw0(1-β) (5)
in the formula: m isw-unit water usage; beta-water reducing rate.
TABLE 2 unit water consumption m of spontaneous combustion coal gangue aggregate concretew0/(kg·m-3)
Figure BDA0003039411850000031
And calculating the dosage of the cementing material. The calculation formula is as formula (6);
Figure BDA0003039411850000032
if the calculated dosage of the cementing material can not meet the requirements of workability and durability, the dosage is adjusted to m by referring to the regulation of design rule of common concrete mix proportion (JGJ55-2011)b1；
(6) Calculating the use amounts of the mineral admixture and the cement, wherein the calculation formulas are respectively shown as formulas (7) and (8);
mf0＝mb1βf (7)
mc0＝mb1-mf0 (8)
wherein, betafThe substitution rate of mineral admixture (the mixing amount of common fly ash is more than or equal to 20 percent, the mixing amount of silica fume is less than or equal to 3.5 percent, and the mixing amount of mineral powder is more than or equal to 10 percent);
(8) determining the dosage of the additive, and calculating the formula as formula (9);
ma0＝mb1βa (9)
wherein, betaaIs the mixing amount of the water reducing agent and the water reducing agent for high water contentThe mixing amount of the effective water reducing agent is generally controlled to be 1.5-2.5%. If the air-entraining type composite admixture is doped, the doping amount needs to be determined according to the durability requirement of specific working conditions;
(9) determination of reasonable Sand Rate value betasWhen the aggregate is natural sandstone, the final sand rate is the initial sand rate; when the aggregate is the spontaneous combustion coal gangue aggregate, the sand rate needs to be adjusted to be the final sand rate according to the water-to-gel ratio, the thickness degree of the spontaneous combustion coal gangue fine aggregate, the needle-sheet content of the spontaneous combustion coal gangue coarse aggregate and the like, and the adjustment can be determined by referring to table 3.
TABLE 3 Sand content/percentage of spontaneous combustion coal gangue aggregate concrete
Figure BDA0003039411850000033
(10) The dosage of the coarse and fine aggregates is determined according to the assumed volume-weight method. Apparent density of concrete rho0cAmount of coarse aggregate mg0The amount of fine aggregate ms0Calculating the use amount of coarse and fine aggregates according to a calculation formula shown in formula (10);
Figure BDA0003039411850000041
where ρ is0cAccording to the apparent density of aggregate varieties, the strength grade of concrete and local statistical data, the aggregate varieties are 2100-2400 kg/m3Reasonably selecting the range;
(11) and calculating the additional water consumption of the spontaneous combustion coal gangue aggregate concrete. The additional dosage of the coarse aggregate which is the spontaneous combustion coal gangue is W1The calculation formula is as shown in formula (11), and the additional water consumption of the fine aggregate which is the spontaneous combustion coal gangue sand is W2The calculation formula is shown as formula (12);
W1＝mg×Wmg×k1 (11)
W2＝ms×Wms×k2 (12)
in the formula, WmgThe mass water absorption rate of the spontaneous combustion coal gangue is 1h,%;
Wmsmass water absorption of the spontaneous combustion coal gangue sand for 1 hour is up to percent;
k1-the spontaneous combustion coal gangue absorbs the water coefficient, take the value 0.8;
k2the water absorption coefficient of the spontaneous combustion coal gangue sand is 0.6.
The design requirements of the spontaneous combustion coal gangue aggregate concrete are as follows: the strength grade is C30-C40, and the slump is 35-50 mm.
The natural crushed stone and the spontaneous combustion coal gangue coarse aggregate have the particle size of 5-20 mm, and are qualified in gradation; the fine aggregate is natural river sand and spontaneous combustion coal gangue sand, the fineness modulus is 2.3-3.0, and the medium sand and spontaneous combustion coal gangue sand are coarse.
The cement is 42.5-grade ordinary portland cement (P.O).
The fly ash is II-grade fly ash, the mineral powder is S95 mineral powder, and the specific surface area of the silica fume is 20000m3/kg。
The additive is a polycarboxylic acid high-efficiency water reducing agent, and the water reducing rate is more than or equal to 20%.
The additional water of the spontaneous combustion coal gangue aggregate concrete needs to be mixed into the spontaneous combustion coal gangue aggregate 30-60 min in advance, and the mixture is uniformly stirred to prewet the spontaneous combustion coal gangue aggregate.
As a preferred embodiment of the design method, the dosage of each raw material in each cubic meter of the spontaneous combustion coal gangue aggregate concrete is shown in the table 4, and the unit is kg.
TABLE 4 self-ignition coal gangue aggregate concrete mixing ratio/(kg m)-3)
Figure BDA0003039411850000051
Compared with the design of the mix proportion of the common concrete, the mix proportion design of the spontaneous combustion coal gangue aggregate concrete of the invention has the following advantages:
in the mix proportion design, the characteristics of the spontaneous combustion coal gangue aggregate in the aspects of grain shape, surface texture, strength and the like are considered in each step of correcting the water-cement ratio, determining the unit water consumption, selecting the sand rate, introducing the additional water consumption and the like, and the prepared concrete can completely meet the design requirements. The self-burning coal gangue aggregate can effectively promote the large-scale utilization of the self-burning coal gangue aggregate in concrete, and can provide reference and guidance for engineering application of the self-burning coal gangue aggregate.
Drawings
FIG. 1 is a flow chart of an embodiment of the design method of the self-ignition coal gangue aggregate concrete mix proportion of the invention; FIG. 2 shows the appearance of coarse and fine aggregates of spontaneous combustion coal gangue.
Detailed Description
To better illustrate the objects, aspects and advantages of the present invention, the present invention will be further described with reference to specific examples. The cement adopted by each embodiment example is ordinary Portland P.O 42.5 cement; the natural coarse aggregate is locally 5-20 mm limestone macadam; the spontaneous combustion coal gangue is local coal gangue, and the coal gangue is sampled on site and is manually crushed, screened and compounded into 5-20 mm continuous gradation spontaneous combustion coal gangue coarse aggregate; the common fine aggregate is local natural river sand; the spontaneous combustion coal gangue sand is prepared by artificially crushing, screening and compounding spontaneous combustion coal gangue; the fly ash is II-grade ash; the mineral powder is S95 mineral powder; the water reducing agents are all polycarboxylic acid high-efficiency water reducing agents, and the water reducing rate is respectively 27% and 22%.
Example 1
The embodiment provides a design method of a self-ignition coal gangue coarse aggregate concrete (SNC) mixing proportion with the strength grade of C30, which specifically comprises the following steps:
(1) and determining the raw material type of the SNC. The raw materials of the SNC consist of cement, fly ash, natural river sand, spontaneous combustion coal gangue, mixing water, adsorption water and a water reducing agent;
(2) detecting technical property indexes of raw materials except the water reducing agent; the apparent density of the cement is 3100kg/m3, and the apparent density of the fly ash is 2700kg/m3(ii) a The apparent density of the spontaneous combustion coal gangue coarse aggregate is 2579kg/m3And a bulk density of 1076kg/m3A compact bulk density of 1220kg/m3The crushing index is 9.90 percent, and the water absorption rate in 1 hour is 9.87 percent; natural river sand with fineness modulus of 2.70, medium sand with apparent density of 2610kg/m3；
(3) The formulation strength of SNC was determined. According to JGJ55-2011 commonThe formulation strength f of the SNC to be formulated is calculated according to the specification in the design rule of concrete mix proportioncu,0＝30+1.645×5＝38.2MPa；
(4) Determining the water-gel ratio of the SNC at the designed strength:
Figure BDA0003039411850000061
(5) SNC Unit Water consumption m for determining C30 Strength Scalew＝240×(1-27％)＝175.2kg/m3；
(6) Calculating the dosage of the cementing material:
Figure BDA0003039411850000062
correcting the usage of the cementing material, wherein the calculation result has a calculation error of +/-2%, the calculation value of the usage of the cementing material needs to be corrected, and m isb1＝400kg/m3；
(7) Calculating the using amount of the fly ash mf＝400×20％＝80kg/m3Cement dosage C1＝400-80＝320kg/m3；
(8) Determining the dosage of the water reducing agent ma＝400×1.8％＝7.2kg/m3；
(9) Referring to Table 3, the reasonable sand ratio, β, was determineds＝53％；
(10) Calculating the dosage (m) of coarse and fine aggregatesg0、ms0)；
(11) The apparent density of concrete is empirically selected to be 2319kg/m3And calculating by using an assumed volume weight method, namely:
Figure BDA0003039411850000063
solving the simultaneous equation to obtain ms0＝924kg/m3，mg0＝820kg/m3；
(12) Calculating the additional water usage of the SNC: wa＝924×9.87％×0.8＝73kg/m3；
Example 2
The embodiment provides a design method of a mixing proportion of spontaneous combustion coal gangue fine aggregate concrete (NSC) with a strength grade of C35, which specifically comprises the following steps:
(1) the raw material type of the NSC is determined. The NSC is prepared from the raw materials of cement, fly ash, natural broken stone, spontaneous combustion coal gangue sand, mixing water, adsorption water and a water reducing agent;
(2) measuring technical property indexes of raw materials except the water reducing agent; the apparent density of the cement is 3100kg/m3The apparent density of the fly ash is 2700kg/m3(ii) a Apparent density of natural macadam 2715kg/m3A bulk density of 1470kg/m3Compact bulk density 1660kg/m3The crush index is 4.5%; the spontaneous combustion coal gangue sand has fineness modulus of 2.81, medium sand coarse and apparent density of 2357kg/m31h mass water absorption rate is 12%;
(3) the formulated intensity of the NSCs was determined. According to the specification of JGJ55-2011 'design rule for mixing proportion of common concrete', calculating the preparation strength of NSC required to be prepared as fcu,0＝35+1.645×5＝43.2MPa；
(4) Determining the water-to-gel ratio of the NSC at the designed strength:
Figure BDA0003039411850000071
(5) NSC Unit Water consumption m for determining C35 Strength Scalew＝228×(1-22％)＝178kg/m3；
(6) Calculating the dosage of the cementing material:
Figure BDA0003039411850000072
correcting the usage of the cementing material, wherein the calculation result has a calculation error of +/-2%, the calculation value of the usage of the cementing material needs to be corrected, and m isb1＝440kg/m3；
(7) Calculating the using amount of the fly ash mf＝440×20％＝88kg/m3Cement dosage C1＝440-88＝352kg/m3；
(8) Determining the dosage of the water reducing agent ma＝440×2.3％＝10.12kg/m3；
(9) Referring to Table 3, determinationReasonable sand ratio of betas＝48％；
(10) Calculating the dosage (m) of coarse and fine aggregatesg0、ms0)；
(11) The apparent density of the concrete is selected according to the experience 2289kg/m3And calculating by using an assumed volume weight method, namely:
Figure BDA0003039411850000073
solving the simultaneous equation to obtain ms0＝802kg/m3，mg0＝869kg/m3；
(11) Calculate the additional water usage for NSC: wa＝802×12％×0.6＝58kg/m3；
Example 3
The embodiment provides a design method of a mix proportion of self-ignition coal gangue all light concrete (SSC) with a C40 strength grade, which specifically comprises the following steps:
(1) determining the kind of the raw material of the SSC. The SSC is prepared from the raw materials of cement, fly ash, spontaneous combustion coal gangue sand, mixing water, adsorption water and a high-efficiency water reducing agent;
(2) measuring technical property indexes of raw materials except the water reducing agent; the apparent density of the cement is 3100kg/m3The apparent density of the fly ash is 2700kg/m3(ii) a The apparent density of the spontaneous combustion coal gangue coarse aggregate is 2579kg/m3And a bulk density of 1076kg/m3A compact bulk density of 1220kg/m3The crushing index is 9.90 percent, and the water absorption rate in 1 hour is 9.87 percent; the fineness modulus of the spontaneous combustion coal gangue sand is 2.81, the medium sand is coarse, and the apparent density is 2357kg/m31h mass water absorption rate is 12%;
(3) the formulation strength of the SSC is determined. Calculating the preparation strength f of the SSC to be prepared according to the regulation of JGJ 55-2011' design rule of common concrete mix proportioncu,040+1.645×5＝48.2MPa；
(4) Determining the water-to-gel ratio of the SSC at the designed strength:
Figure BDA0003039411850000074
(5) m SSC unit water consumption for determining C40 strength gradew＝209×(1-22％)＝163kg/m3；
(6) Calculating the dosage of the cementing material:
Figure BDA0003039411850000081
correcting the usage of the cementing material, wherein the calculation result has a calculation error of +/-2%, the calculation value of the usage of the cementing material needs to be corrected, and m isb1＝480kg/m3；
(7) Calculating the using amount of the fly ash mf＝480×20％＝96kg/m3Cement dosage C1＝480-96＝384kg/m3；
(8) Determining the dosage of the water reducing agent ma＝480×2.2％＝10.56kg/m3；
(9) Referring to Table 3, the reasonable sand ratio, β, was determineds＝54％；
(10) Calculating the dosage (m) of coarse and fine aggregatesg0、ms0)；
(11) The apparent density of the concrete is selected according to experience to be 2120kg/m3And calculating by using an assumed volume weight method, namely:
Figure BDA0003039411850000082
solving the simultaneous equation to obtain ms0＝797kg/m3，mg0＝679kg/m3；
(11) Calculating the additional water consumption of the coarse aggregate in the SSC: wag＝679×9.87％×0.8＝54kg/m3Additional water consumption of fine aggregate: was＝797×12％×0.6＝57kg/m3。
TABLE 5 blending ratio of concrete raw materials in examples 1 to 3
Figure BDA0003039411850000083
Test blocks of the same specification and dimensions of 100mm × 100mm × 100mm and 100mm × 100mm × 300mm were prepared according to the mixing ratios in examples 1 to 3, and the compression strength, the split tensile strength, the axial compression strength, the modulus of elasticity, and the apparent density of concrete were measured, and the results are shown in table 6.
TABLE 6 spontaneous combustion coal gangue aggregate concrete performance test results
Figure BDA0003039411850000084
As can be seen from Table 6, the strength grade of the concrete prepared from the spontaneous combustion coal gangue in the form of coarse aggregate, fine aggregate and coarse and fine aggregate meets the design requirements, and the apparent density of the concrete is obviously reduced along with the increase of the spontaneous combustion coal gangue aggregate, so that the concrete is favorable for reducing the self weight of the structure.
Verification experiment I
The mix proportion designed according to the design method is shown in Table 7, and the mechanical properties of the concrete are shown in Table 8.
TABLE 7C30 spontaneous combustion coal gangue all light concrete (SSC) mixing ratio/(kg m)-3)
Figure BDA0003039411850000091
TABLE 8C30 spontaneous combustion coal gangue all light concrete (SSC) Performance index
Figure BDA0003039411850000092
As can be seen from Table 8, the slump of the concrete mixture of 35 mm-50 mm meets the design requirements, the compressive strength of the concrete of 28d meets the design requirements, and the absolute value of the difference between the measured value of the apparent density of the concrete and the design value does not exceed 2% of the design value, which indicates that the mix proportion designed according to the invention meets the design requirements and can guide the engineering practice.
Verification experiment 2
The mixing ratio designed according to the design method is shown in Table 9, and the test results of the chloride ion permeability resistance and the freezing resistance are shown in Table 10.
TABLE 9C40 blending ratio of spontaneous combustion coal gangue coarse aggregate concrete (NSC) (/ kg. m)-3)
Figure BDA0003039411850000093
TABLE 10C 40 durability index for pyrophoric gangue coarse aggregate concrete (NSC)
Figure BDA0003039411850000094
As can be seen from Table 10, the electric flux of the spontaneous combustion coal gangue coarse aggregate concrete is within the range of 1000-2000 ℃, and belongs to the category of low chloride ion permeability; under 125 freeze-thaw cycles, the loss of the dynamic elastic modulus is less than 40 percent, the loss of the mass is less than 5 percent, and the freezing resistance grade F is met125And (4) requiring.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.

Claims (8)

  1. The design method of the mix proportion of the spontaneous combustion coal gangue aggregate concrete from C30 to C40 is characterized by comprising the following steps:
    (1) determining the type of raw materials of the spontaneous combustion coal gangue aggregate concrete, wherein the raw materials of the spontaneous combustion coal gangue aggregate concrete comprise a cementing material, aggregate, an additive and water, the cementing material comprises cement and a mineral admixture, and the mineral admixture comprises one, two or three of fly ash, mineral powder and silica fume; the aggregate is composed of two of natural sand, natural macadam, spontaneous combustion coal gangue sand and spontaneous combustion coal gangue, the admixture is composed of one or two of a water reducing agent and an air entraining agent, and the water is composed of mixing water and aggregate pre-wetting additional water;
    (2) detecting technical property indexes of raw materials except additives and silica fume;
    (3) and determining the formulated strength of the concrete. Calculating the preparation strength according to the specification of JGJ55-2011 'design rule of common concrete mix proportion', wherein the calculation method is as shown in a formula (1);
    fcu,0＝fcu,k+1.645σ (1)
    in the formula: f. ofcu,0The preparation strength of the spontaneous combustion coal gangue aggregate concrete is MPa;
    fcu,kthe design strength of the spontaneous combustion coal gangue aggregate concrete is MPa;
    sigma-standard deviation of concrete strength, MPa.
    (4) And determining the water-glue ratio. The formula for calculating the water-cement ratio of the spontaneous combustion coal gangue coarse aggregate concrete (SNC for short) is shown as a formula (2), the formula for calculating the water-cement ratio of the spontaneous combustion coal gangue fine aggregate concrete (NSC for short) is shown as a formula (3), and the formula for calculating the water-cement ratio of the spontaneous combustion coal gangue coarse and fine aggregate concrete (SSC for short) is shown as a formula (4);
    Figure FDA0003039411840000011
    Figure FDA0003039411840000012
    Figure FDA0003039411840000013
    in the formula: f. ofbCement 28d mortar compressive strength measured value.
    (5) Determining the unit water consumption mw. According to the type and the maximum grain diameter of the used coarse aggregate and the slump value required by construction, the design specification of the mix proportion of common concrete is referred, and the grain shape difference and the large porosity of the spontaneous combustion coal gangue aggregate are fully consideredOn the basis, the unit water consumption m of the spontaneous combustion coal gangue aggregate concrete is corrected according to statistical data of a large number of previous testsw0The details are shown in Table 1. Mixed with additive, if the water reducing rate of concrete is beta, 1m3The water consumption of the concrete can be calculated according to the formula (5):
    mw＝mw0(1-β) (5)
    in the formula: m isw-unit water usage; beta-water reducing rate.
    TABLE 1 unit water consumption m of spontaneous combustion coal gangue aggregate concretew0/(kg·m-3)
    Figure FDA0003039411840000021
    (6) And calculating the dosage of the cementing material. The calculation formula is as formula (6);
    Figure FDA0003039411840000022
    if the calculated dosage of the cementing material can not meet the requirements of workability and durability, the dosage is adjusted to m by referring to the regulation of design rule of common concrete mix proportion (JGJ55-2011)b1；
    (7) And calculating the dosage of the mineral admixture and the dosage of the cement. The calculation formulas are respectively shown as formulas (7) and (8);
    mf0＝mb1βf (7)
    mc0＝mb1-mf0 (8)
    wherein, betafThe mineral admixture has a mineral admixture substitution rate (the common fly ash mixing amount is more than or equal to 20 percent, the silica fume mixing amount is less than or equal to 3.5 percent, and the mineral powder mixing amount is more than or equal to 10 percent);
    (8) and determining the admixture mixing amount. The calculation formula is as formula (9);
    ma0＝mb1βa (9)
    wherein, betaaThe mixing amount of the water reducing agent is controlled to be 1.5 to 2.5 percent for the high-efficiency water reducing agent;
    (9) determination of reasonable Sand Rate value betas. When the aggregate is natural sandstone, the final sand rate is the initial sand rate; when the aggregate is the spontaneous combustion coal gangue aggregate, in order to meet the workability requirement of construction, the sand rate is adjusted to be the final sand rate according to the water-to-gel ratio, the thickness degree of the spontaneous combustion coal gangue fine aggregate, the needle sheet content of the spontaneous combustion coal gangue coarse aggregate and the like, and the adjustment can be selected by referring to table 2.
    TABLE 2 spontaneous combustion coal gangue aggregate concrete sand ratio%
    Figure FDA0003039411840000023
    (10) The dosage of the coarse and fine aggregates is determined according to the assumed volume-weight method. Apparent density of concrete rho0cAmount of coarse aggregate mg0The amount of fine aggregate ms0Calculating the use amount of coarse and fine aggregates according to a calculation formula shown in formula (10);
    Figure FDA0003039411840000031
    where ρ is0cReasonably selecting the aggregate according to the apparent density of the aggregate variety, the strength grade of the concrete and local statistical data within the range of 2100-2400 kg;
    (11) calculating the additional water consumption of the spontaneous combustion coal gangue aggregate concrete; the additional dosage of the spontaneous combustion coal gangue coarse aggregate is W1The calculation formula is as shown in formula (11), and the additional water consumption of the spontaneous combustion coal gangue fine aggregate sand is W2The calculation formula is shown as formula (12);
    W1＝mg×Wmg×k1 (11)
    W2＝ms×Wms×k2 (12)
    in the formula, WmgMass water absorption of the spontaneous combustion coal gangue coarse aggregate for 1 hour is up to percent;
    Wmsmass water absorption of the spontaneous combustion coal gangue fine aggregate for 1 hour is up to percent;
    k1the coefficient of water adsorption of the spontaneous combustion coal gangue coarse aggregate is 0.8;
    k2the coefficient of water adsorption of the spontaneous combustion coal gangue fine aggregate is 0.6.
  2. 2. The spontaneous combustion coal gangue aggregate concrete of claim 1, wherein the design requirement of the spontaneous combustion coal gangue aggregate concrete is as follows: the strength grade is C30-C40, and the slump is 35-200 mm.
  3. 3. The method of claim 1, wherein the coarse aggregate has a particle size of 5-20 mm and is qualified in gradation; the fine aggregate is natural river sand and spontaneous combustion coal gangue sand, the fineness modulus is 2.3-3.0, and the fine aggregate is medium sand, wherein the spontaneous combustion coal gangue sand is coarse.
  4. 4. The method of claim 1, wherein the cement is a 42.5 grade Portland cement (P-O).
  5. 5. The method of claim 1 wherein the admixture is one, two or three of class ii fly ash, S95 mineral fines or silica fume.
  6. 6. The method of claim 1, wherein the admixture is one of a polycarboxylic acid high-efficiency water reducing agent or a water reducing agent and air entraining agent composite admixture, and the water reducing rate is 20-25%.
  7. 7. The method of claim 1, wherein the additional water is added into the spontaneous combustion coal gangue aggregate 30-60 min in advance and is uniformly stirred to realize the pre-wetting treatment of the spontaneous combustion coal gangue aggregate.
  8. 8. The design method of claim 1, wherein the amount of raw materials used per cubic meter of the spontaneous combustion coal gangue aggregate concrete is as shown in Table 3, and the unit is kg.
    TABLE 3 self-ignition coal gangue aggregate concrete mixing ratio/(kg m)-3)
    Figure FDA0003039411840000041
    。
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CN113609709A (en) * 2021-09-06 2021-11-05 江西科技学院 Design method for mix proportion of magnesium oxychloride cement concrete building mortar
CN114213074A (en) * 2022-01-18 2022-03-22 鞍钢矿山建设有限公司 Method for calculating mixing proportion of common concrete
CN114772997A (en) * 2022-03-31 2022-07-22 中国矿业大学 Reinforced mining solid waste concrete and preparation method thereof
CN115340324A (en) * 2022-08-22 2022-11-15 长江南京航道工程局 Geopolymer concrete mix proportion design method based on dredged sand and artificial soft stone
CN115611571A (en) * 2022-09-19 2023-01-17 广州大学 Coal gangue pervious concrete and preparation method thereof
CN116143480A (en) * 2022-10-18 2023-05-23 辽宁工程技术大学 Spontaneous combustion coal gangue full-light concrete brick and preparation method and application thereof
CN116730686A (en) * 2023-06-25 2023-09-12 亚泰集团长春建材有限公司 Concrete mix proportion design method adopting granite waste stone powder as aggregate
CN118125754A (en) * 2023-12-25 2024-06-04 西安科技大学 Silica fume modified full gangue coarse aggregate concrete and preparation method thereof

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113609709A (en) * 2021-09-06 2021-11-05 江西科技学院 Design method for mix proportion of magnesium oxychloride cement concrete building mortar
CN113609709B (en) * 2021-09-06 2022-02-01 江西科技学院 Design method for mix proportion of magnesium oxychloride cement concrete building mortar
CN114213074A (en) * 2022-01-18 2022-03-22 鞍钢矿山建设有限公司 Method for calculating mixing proportion of common concrete
CN114213074B (en) * 2022-01-18 2023-02-14 鞍钢矿山建设有限公司 Method for calculating mixing proportion of common concrete
CN114772997A (en) * 2022-03-31 2022-07-22 中国矿业大学 Reinforced mining solid waste concrete and preparation method thereof
CN115340324A (en) * 2022-08-22 2022-11-15 长江南京航道工程局 Geopolymer concrete mix proportion design method based on dredged sand and artificial soft stone
CN115611571A (en) * 2022-09-19 2023-01-17 广州大学 Coal gangue pervious concrete and preparation method thereof
CN116143480A (en) * 2022-10-18 2023-05-23 辽宁工程技术大学 Spontaneous combustion coal gangue full-light concrete brick and preparation method and application thereof
CN116730686A (en) * 2023-06-25 2023-09-12 亚泰集团长春建材有限公司 Concrete mix proportion design method adopting granite waste stone powder as aggregate
CN118125754A (en) * 2023-12-25 2024-06-04 西安科技大学 Silica fume modified full gangue coarse aggregate concrete and preparation method thereof

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