Mix proportion design method and application of machine-made sand concrete doped with dry cleaning slurry wrapping medium

Abstract

The invention relates to a mix proportion design method and application of machine-made sand concrete doped with a dry cleaning and slurry wrapping medium, and aims to solve the technical problem of efficient resource utilization of the dry cleaning and slurry wrapping medium of a concrete mixing truck. By means of the machine-made sand concrete mix proportion design method, the slurry wrapping medium generated by dry cleaning of a concrete mixing truck can be completely utilized in a resource mode, the concrete mix proportion design efficiency is improved, the test period is shortened, the cement consumption is reduced, and the economic cost is reduced; the environment pollution caused by waste water and waste slurry generated by washing the concrete mixing transport vehicle is avoided, the development of the dry cleaning technology of the concrete mixing transport vehicle can be promoted, no waste is generated in cleaning of the concrete mixing transport vehicle, and the clean and sustainable green development of the premixed concrete industry is promoted.

Description

Technical Field

[0001] The present invention relates to the technical field of building material preparation, and in particular to a method for designing a mix ratio of machine-made sand concrete incorporating a dry-cleaning slurry medium and its application. Background Art

[0002] Concrete mixer trucks are a crucial link between concrete mixing plants and the construction site. Promptly washing concrete mixer trucks with high-pressure water after use prevents hardening of residual concrete within the tank and is a common cleaning method at concrete mixing plants. However, this cleaning method generates large amounts of highly alkaline wastewater or waste slurry. Extensive research and practical experience have shown that directly using this wastewater or waste slurry in concrete production can adversely affect concrete performance. Furthermore, JC / T2647-2021, the "Specifications for Wastewater Recycling and Utilization in Ready-Mixed Concrete Production Enterprises," stipulates that wastewater cannot be discharged directly beyond the plant boundaries and should not be used in the production of prestressed concrete, decorative concrete, high-strength concrete, concrete exposed to corrosive environments, or concrete using alkali-reactive or potentially alkali-reactive aggregates. Therefore, to prevent environmental pollution from wastewater or waste slurry, concrete mixing plants typically use processes such as sand and gravel separation, sedimentation, and filter pressing to treat wastewater, but these processes are complex and require significant site space.

[0003] Patent document CN 114558856 B describes a method and equipment for dry-cleaning slurry on the inner wall of a ready-mixed concrete tank truck; patent document CN 112974417 A describes a waterless equipment for cleaning a mixer truck; both such waterless dry-cleaning equipment and process methods use gravel as a medium and rely on the rotation of the truck to clean the concrete remaining on the inner wall, thus solving the problems of complex waste treatment processes, occupied space, and environmental pollution generated by water washing of concrete mixer trucks. However, the dry-cleaning process of concrete mixer trucks generates a large amount of dry-cleaning slurry medium, and how to resourcefully utilize such dry-cleaning slurry medium has become a key technical issue that needs to be urgently addressed.

[0004] The existing technology lacks effective technical support for the application of dry-cleaning slurry media of concrete mixer trucks as concrete aggregates, as well as the corresponding concrete mix design process. The inventors of this application have found that the main reasons are: first, the surface of the dry-cleaning slurry media of concrete mixer trucks is coated with a layer of mortar with a very wide range of performance variations, which is very different from ordinary aggregates in terms of particle shape, surface texture, water absorption rate, and mechanical properties. At present, the evaluation method for the basic characteristics of this dry-cleaning slurry media is unclear; second, when preparing new concrete with this dry-cleaning slurry media, a certain amount of powder and fine sand will be introduced, which has a relatively complex impact on the performance of concrete, and the influence law is still unclear; finally, there is currently a lack of a mix design method for preparing concrete with this dry-cleaning slurry media, which brings difficulties to actual production and application. Therefore, it is urgent to develop and research a mix design method for preparing machine-made sand concrete with dry-cleaning slurry media of concrete mixer trucks to promote the development of waste-free dry-cleaning technology for concrete mixer trucks and promote the clean, sustainable and green development of the ready-mixed concrete industry.

[0005] The information disclosed in this background technology section is only used to deepen the understanding of the background technology of the present disclosure and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0006] Through long-term research, the inventors discovered that the following factors must be considered when preparing machine-made sand concrete using a dry-cleaning slurry: ① The powder, fine sand, and moisture introduced by the dry-cleaning slurry have a significant nonlinear effect on concrete strength; ② The significant differences between the dry-cleaning slurry and natural aggregate in terms of macroscopic shape, microscopic angularity, and microtexture significantly impact concrete strength; and ③ The slurry on the surface of the dry-cleaning slurry has a certain influence on the final concrete interface transition zone. Therefore, considering these influencing factors, establishing a mathematical model for the relationship between the strength of machine-made sand concrete mixed with a dry-cleaning slurry and the water-binder ratio has become a key issue in the mix design process.

[0007] Based on this, the present invention proposes a method and application for designing a mix ratio of machine-made sand concrete incorporating a dry-cleaning slurry medium, aiming to solve the technical problem of efficient resource utilization of the dry-cleaning slurry medium generated by concrete mixer trucks. Specifically, the following steps are included: (1) Based on the amount of powder in the original mix ratio of the residual concrete in the concrete mixer truck f 0 and sand dosage S 0, the powder influence coefficient in the dry cleaning batting medium is determined by the following formula l : .

[0008] (2) Determine the replacement rate of 10-25 mm coarse aggregate by dry cleaning slurry medium d ; Determine the mixing strength of the machine-made sand concrete f cu,DCAC ; Determine the 28d compressive strength value of cementitious material mortar f b .

[0009] (3) The water-cement ratio of the machine-made sand concrete is determined by the following formula: w / b : ; Where, f b The 28d compressive strength of cementitious material mortar; f cu,DCAC Formulate strength for concrete; A 、 B represents the regression coefficient, A =0.458, B =0.209; l is the powder influence coefficient in the dry cleaning sizing medium; d The replacement rate of dry cleaning slurry medium for 10~25mm coarse aggregate.

[0010] (4) Determine the water consumption per unit volume of machine-made sand concrete using the following formula: m w : ; Where, m w0 The amount of water used for concrete without admixtures; oh is the water reduction rate of the admixture; d The replacement rate of 10~25mm coarse aggregate for dry cleaning pulping medium; C is the concrete strength grade value.

[0011] (5) The sand ratio of the machine-made sand concrete is determined by the following formula: β s : ; Where, β s0 is the sand ratio of ordinary machine-made sand concrete; d The replacement rate of dry cleaning slurry medium for 10~25mm coarse aggregate.

[0012] (6) Determine the amount of cementitious material in the machine-made sand concrete m b ; Determine the amount of fly ash m f , Granulated blast furnace slag powder dosagem sl and cement consumption m c .

[0013] (7) Based on assumed bulk density m cp , the amount of cement m c , the amount of fly ash m f , the amount of granulated blast furnace slag powder m sl , the water consumption m w And the sand ratio of the machine-made sand concrete β s Determine the total amount of coarse aggregate in the machine-made sand concrete m g And the amount of machine-made sand m s .

[0014] (8) Based on the proportion of 5~10mm natural gravel f , 5~10mm natural gravel dosage m g0 , 10~25mm natural gravel dosage m g1 , Replacement rate of dry cleaning slurry medium replacing 10~25mm coarse aggregate d , determine the amount of dry cleaning batting medium m g2 .

[0015] In some embodiments of the present disclosure, in step (2), the strength of the machine-made sand concrete is f cu,DCAC Calculated by the following formula: ; Where, f cu,k is the design strength grade of concrete; when the concrete strength guarantee rate is 95%, t Take 1.645; s is the standard deviation of concrete strength. When the concrete strength grade is C25~C45, s Take 5.0; when the concrete strength grade is C50~C55, s Take 6.0.

[0016] In some embodiments of the present disclosure, in step (2), the 28d compressive strength value of the cementitious material mortar is f b Measured according to GB / T 17671 or calculated by the following formula: , ; Where, c f is the fly ash influence coefficient; c s is the influence coefficient of granulated blast furnace slag powder; f ce is the 28d compressive strength of cement mortar; c c is the cement strength surplus coefficient; f ce,g is the cement strength grade value; c f 、 c s The value is based on JGJ 55-2011.

[0017] In some embodiments of the present disclosure, in step (6), the amount of cementitious material in the machine-made sand concrete is m b Calculated by the following formula: ; Where, m w The water consumption per cubic meter of concrete; w / b is the water-cement ratio of concrete.

[0018] In some embodiments of the present disclosure, in step (6), the amount of fly ash in the machine-made sand concrete is m f , Granulated blast furnace slag powder dosage m sl , cement consumption m c Calculated by the following formulas: , , ; Where, m b is the amount of cementitious material; m f is the amount of fly ash; β f is the fly ash content; m sl is the amount of granulated blast furnace slag powder; β sl is the dosage of granulated blast furnace slag powder.

[0019] In some embodiments of the present disclosure, in step (7), the total amount of coarse aggregate in the machine-made sand concrete ism g , Amount of machine-made sand m s Calculated by the following formula: ; Where, m cp For the assumed bulk density, take 2350~2450; m c is the amount of cement used; m f is the amount of fly ash; m sl is the amount of granulated blast furnace slag powder; m w is the unit water consumption; β s is the concrete sand ratio.

[0020] In some embodiments of the present disclosure, in step (8), the amount of dry cleaning batting medium is calculated by the following formula: , , ; Where, f The ratio of 5-10 mm natural crushed stone in coarse aggregate is 25%-35%; m g0 The amount of 5~10mm natural gravel; m g1 The amount of natural crushed stone of 10~25mm; d The replacement rate of 10~25mm coarse aggregate for dry cleaning pulping medium; m g2 The amount of dry cleaning batting medium.

[0021] According to another aspect of the present disclosure, a method for preparing machine-made sand concrete incorporating a dry-cleaning slurry medium is provided, comprising the following steps: (1) According to the mix proportion obtained by the above-mentioned machine-made sand concrete mix proportion design method, weigh the required cement, fly ash, granulated blast furnace slag powder, water, machine-made sand, coarse aggregate and dry cleaning slurry medium; (2) Mix the coarse aggregate, machine-made sand, dry-cleaning slurry, cement, fly ash, and granulated blast furnace slag powder evenly, dry mix for 8-12 seconds, then add the admixture and half of the water, and stir for 85-95 seconds; (3) Add the remaining half of the water and stir for 85-95 seconds.

[0022] In some embodiments of the present disclosure, the cement is P·O 42.5 ordinary Portland cement.

[0023] In some embodiments of the present disclosure, the machine-made sand has a fineness modulus of 2.5-2.9, MB < 1.4, and a stone powder content ≤ 10%.

[0024] In some embodiments of the present disclosure, the coarse aggregate is composed of 5-10 mm and 10-25 mm crushed stones, with a mud content of ≤0.5% and a water absorption rate of ≤1%.

[0025] In some embodiments of the present disclosure, the admixture is a polycarboxylic acid-based high-performance water reducer, and its water reduction rate is ≥25%.

[0026] One or more technical solutions provided in the embodiments of this application have at least any of the following technical effects or advantages: 1. This application can fully utilize the slurry medium generated by dry cleaning of concrete mixer trucks, provide a theoretical basis for preparing machine-made sand concrete with dry cleaning slurry medium, greatly improve the efficiency of concrete mix design, shorten the test cycle, reduce cement consumption, reduce economic costs, avoid the environmental pollution caused by wastewater and waste slurry generated by water-washed concrete mixer trucks, realize waste-free cleaning of concrete mixer trucks, make concrete production green and environmentally friendly, energy-saving and carbon-reducing, and help the ready-mixed concrete industry achieve green transformation and upgrading.

[0027] 2. The dry-cleaning slurry medium in this application is coated with a slurry containing a certain amount of powder particles with a particle size of less than 75 microns (including cement, fly ash, granulated blast furnace slag powder, and other cementitious materials, as well as stone powder). The cementitious materials in the powders can continue to hydrate to produce hydration products such as CSH gel, while the stone powder in the powders acts as a micro-aggregate filler, both of which contribute to improving concrete strength. Furthermore, as the powder content of the dry-cleaning slurry medium increases, the strength of the concrete increases accordingly. Because concrete with a high water-to-binder ratio requires less cementitious materials, the powder introduced by the dry-cleaning slurry medium significantly enhances concrete strength.

[0028] 3. This application constructs the dry cleaning batter medium powder influence coefficient l、 Sand content influence coefficient g , intensity contribution rate G、 Based on the parameters such as the dosage characteristic parameters and a large number of experiments, further theoretical analysis and mathematical modeling were conducted to obtain a mathematical model of the relationship between the mix strength of machine-made sand concrete with dry-cleaning slurry coating medium and the water-binder ratio. This model has a high calculation accuracy (the error range is between -5.06% and 9.75%). The construction process is as follows: , , , , , ; In the above formulas: l is the influence coefficient of dry cleaning batting medium powder, %; g is the influence coefficient of sand content in dry cleaning slurry coating medium, %; f 0 is the amount of powder in the original mix ratio of the residual concrete in the mixer truck, kg / m 3 ; S 0 is the amount of sand in the original mix ratio of the residual concrete in the mixer truck, kg / m 3 ; G is the contribution rate of dry cleaning batting medium strength, %; f cu,DCAC ( w / b , l , g ) represents the compressive strength of machine-made sand concrete prepared with dry-cleaning slurry medium at a certain water-binder ratio, MPa; f cu ( w / b ) represents the compressive strength of natural coarse aggregate and manufactured sand concrete with the same water-binder ratio, MPa; w / b is the water-binder ratio; f cu,DCAC Strength of machine-made sand concrete prepared for dry-cleaning slurry medium, MPa; f cu is the strength of natural coarse aggregate machine-made sand concrete, MPa; is the characteristic parameter of dry cleaning slurry medium dosage; d is the dry cleaning batting medium replacement rate, %; A =0.458, B =0.209.

[0029] 4. This application constructs the water consumption of dry-cleaning slurry medium machine-made sand concrete m w , sand rate β s The calculation model is used to determine the mix ratio of concrete, which has important theoretical guiding significance for the mix ratio determination of machine-made sand concrete based on dry-cleaning slurry medium. DETAILED DESCRIPTION

[0030] In order to better understand the technical solution of the present application, the above technical solution will be described in detail below in conjunction with specific implementation methods.

[0031] Unless otherwise specified, the raw materials involved in the following examples are all commercially available conventional raw materials; the preparation methods, detection methods and experimental methods involved are all conventional methods unless otherwise specified.

[0032] Example 1 This example uses a concrete mixer truck dry-cleaning slurry as a medium to prepare machine-made sand concrete, and designs its mix proportions. In this example, the strength grade of the machine-made sand concrete design technical requirements is C30, with a strength guarantee rate of 95%. The machine-made sand construction requirements are a slump of 180-200mm. The other materials used are of the following specifications: P·O 42.5 ordinary Portland cement, with a cement strength surplus coefficient of 1.22; Class F II fly ash content. β f 30%; S95 grade granulated blast furnace slag powder content β sl The fineness modulus of manufactured sand is 2.8; natural crushed stone of two grades, 5-10mm and 10-25mm, are mixed at a mass ratio of 3:7; the dry-cleaning slurry medium is 10-25mm natural crushed stone obtained by dry-cleaning a concrete mixer truck; the amount of powder in the original mix ratio of the residual concrete in the mixer truck tank is f 0 is 554kg / m 3 , sand consumption S 0 is 708kg / m 3 ; Tap water (mixing water); Polycarboxylic acid-based high-performance water-reducing agent, with a water-reducing rate of 28% and a dosage of 1.7% of the total amount of cementitious materials.

[0033] The specific steps of the mix design method for machine-made sand concrete with dry-cleaning slurry are as follows: (1) According to the amount of powder in the original mix ratio of the residual concrete in the mixer truck tank f 0 is 554kg / m 3 Amount of sand S 0 is 708kg / m 3 , determine the powder influence coefficient of dry cleaning batting medium l : .

[0034] (2) Determine the replacement rate of dry cleaning slurry medium for 10~25mm coarse aggregate d =100%.

[0035] (3) Based on the design strength grade of concrete f cu,k and standard deviation of concrete strength s Get the mixed strength of dry-cleaned slurry medium machine-made sand concrete f cu,DCAC The mix strength of concrete is obtained by the following formula: f cu,DCAC : ; In the formula, when the concrete strength guarantee rate is 95%, t Take 1.645; when the concrete strength grade is C25~C45, s Take 5.0 MPa.

[0036] (4) Refer to JGJ 55-2011 "Ordinary Concrete Mix Design Code", fly ash influence coefficient c f Take 0.75, the influence coefficient of granulated blast furnace slag powder c s Take 1.0, the cement strength surplus coefficient c c Take 1.22, cement strength grade value f ce,g Take 42.5 and obtain the 28d compressive strength of mortar by the following formula: f b : .

[0037] (5) Based on the 28d compressive strength of cementitious mortar f b , concrete mix strength f cu,DCAC , regression coefficient A 、 B ( A =0.458, B =0.209), powder influence coefficient in dry cleaning batting medium l The replacement rate of 10~25mm coarse aggregate by dry cleaning pulping medium d , to obtain the initial water-binder ratio of dry-cleaned slurry-coated concrete with machine-made sand w / b : ; Obtain .

[0038] (6) According to the provisions of JGJ 55-2011 "Ordinary Concrete Mix Design Code" on concrete water consumption, based on the concrete slump requirements and the maximum particle size of natural crushed stone coarse aggregate, the water consumption per cubic meter without admixture is obtained. m w0 235kg / m 3 , then based on the water reduction rate of the admixture oh , dry cleaning batting medium replacement rate d and concrete strength grade C , obtain the unit water consumption of dry-cleaning mortar medium machine-made sand concrete when adding admixtures m w : .

[0039] (7) Considering the replacement rate of dry cleaning batting medium d Based on 100%, determine the sand rate of the dry cleaning slurry medium machine-made sand concrete β s , β s0 The sand ratio of ordinary machine-made sand concrete is determined according to Table 1 (the sand ratio in the table is when medium-sized machine-made sand is used. For coarse sand or fine sand, the sand ratio should be increased or decreased accordingly based on the actual situation. When the coarse aggregate is single-graded, or has a broken gradation and has an extremely poor particle shape, the sand ratio should be appropriately increased). C30 ordinary machine-made sand concrete sand ratio β s0 Take 45%: .

[0040] Table 1 Selection of sand ratio for ordinary machine-made sand concrete with different strength grades .

[0041] (8) Unit water consumption of machine-made sand concrete based on dry-cleaning slurry medium m w and concrete water-cement ratio w / b Determine the amount of cementitious materials used in dry-cleaning slurry-coated concrete with machine-made sand m b : .

[0042] (9) Calculation of fly ash usage m f , Granulated blast furnace slag powder dosage m sl and cement consumption m c : , , .

[0043] (10) Using the assumed bulk density method, based on the assumed bulk density m cp , cement consumption m c , fly ash dosage m f , Granulated blast furnace slag powder dosage m sl , unit water consumption m w and dry cleaning slurry medium machine-made sand concrete sand ratio β sObtain the total amount of coarse aggregate in dry-cleaned slurry-coated medium machine-made sand concrete m g , Amount of machine-made sand m s , assuming the concrete density m cp 2380kg / m 3 ,but: , ; Obtain: m s =787kg, m g =1087kg.

[0044] (11) Based on the proportion of 5~10mm natural gravel f , 5~10mm natural gravel dosage m g0 , 10~25mm natural gravel dosage m g1 , Replacement rate of dry cleaning slurry medium replacing 10~25mm coarse aggregate d , calculate the amount of dry cleaning batting medium m g2 , because the replacement rate of dry cleaning pulping medium to replace 10~25mm coarse aggregate d =100%, that is m g1 = 0, f = 0.3, calculate the amount of 5~10mm natural crushed stone and dry cleaning coating medium: ; .

[0045] By arranging the values ​​obtained above, the mix ratio of machine-made sand concrete mixed with dry-cleaning slurry medium is obtained as follows: m b : m w : m g0 : m g2 : m s =1 : 0.51 : 0.97 : 2.27 : 2.35.

[0046] The dry-cleaning slurry medium preparation machine-made sand concrete mix design method in this example greatly improves the mix design efficiency, shortens the test cycle, reduces cement consumption, lowers economic costs, avoids environmental pollution caused by wastewater and waste slurry generated by water-washed concrete mixer trucks, achieves waste-free cleaning of concrete mixer trucks, and makes concrete production green, environmentally friendly, energy-saving and carbon-reducing.

[0047] Example 2 This example is based on the mix ratio design method in Example 1. Under the premise that other conditions remain unchanged, the dry cleaning sizing medium replacement rate is d The value is taken as 50%, and then the actual amount of each component of the medium machine-made sand concrete mixed with dry cleaning paste is obtained (see Table 2).

[0048] Example 3 This example is based on the mix ratio design method in Example 1. Under the premise that other conditions remain unchanged, the dry cleaning sizing medium replacement rate is d The value is taken as 75%, and then the actual amount of each component of the medium machine-made sand concrete mixed with dry cleaning paste is obtained (see Table 2).

[0049] Example 4 This example is based on the mix design method in Example 1. Under the premise that other conditions remain unchanged, different powder dosages of the original mix ratio of residual concrete are selected. f 0 and sand dosage S 0, 587 kg / m 3 and 632 kg / m 3 , and then the actual amount of each component of the machine-made sand concrete mixed with dry-cleaning slurry medium was obtained (see Table 2).

[0050] Example 5 This example is based on the mix design method in Example 1. Under the premise that other conditions remain unchanged, different powder dosages of the original mix ratio of residual concrete are selected. f 0 and sand dosage S 0, respectively 640 kg / m 3 and 600kg / m 3 , and then the actual amount of each component of the machine-made sand concrete mixed with dry-cleaning slurry medium was obtained (see Table 2).

[0051] The concrete mix proportions and amounts of various raw materials for Examples 1 to 5 are shown in Table 2, wherein the fly ash content is 30% of the cementitious material content; the granulated blast furnace slag powder content is 10% of the cementitious material content; and the water reducer content is 1.7% of the total cementitious material content.

[0052] Table 2 Concrete mix ratio and amount of each raw material .

[0053] Example 6 The raw materials used in Examples 1 to 5 were used to prepare machine-made sand concrete mixed with a dry-cleaning slurry medium. The specific steps are as follows: (1) According to the calculated mix ratio of dry-cleaning grouting medium and machine-made sand concrete, weigh the required mass of P·O 42.5 ordinary Portland cement, fly ash, granulated blast furnace slag powder, water, machine-made sand, natural coarse aggregate (5-10 mm and 10-25 mm natural crushed stone), and dry-cleaning grouting medium.

[0054] (2) Add coarse aggregate, machine-made sand, dry-cleaning slurry medium, cement, fly ash, and granulated blast furnace slag powder into the mixer in sequence. After dry mixing for 10 seconds, add polycarboxylic acid-based high-performance water reducer and half of the water, and continue mixing for 90 seconds.

[0055] (3) Finally, add the remaining mixing water and continue stirring for 90 seconds to obtain dry-cleaned slurry-coated medium machine-made sand concrete.

[0056] In the above preparation method, the machine-made sand is well-graded medium sand with a fineness modulus of 2.8, MB < 1.4, and a stone powder content of no more than 10%; the coarse aggregate is two types of natural crushed stone of 5-10 mm and 10-25 mm, with a mud content of no more than 0.5% and a water absorption rate of no more than 1%; the dry-cleaned slurry medium is 10-25 mm natural crushed stone obtained by dry-cleaning a concrete mixer truck, and is used to replace 10-25 mm natural crushed stone of equal mass.

[0057] The machine-made sand concrete prepared using the raw materials in Examples 1 to 5 was tested for cohesion, bleeding rate, slump, 28d compressive strength, and impermeability grade according to the methods specified in GB / T 50080-2016 "Standard for Test Methods for Performance of Ordinary Concrete Mixtures", GB / T 50081-2019 "Standard for Test Methods for Physical and Mechanical Properties of Concrete", and GB / T 50082-2009 "Standard for Test Methods for Long-term Performance and Durability of Ordinary Concrete". The results are shown in Table 3.

[0058] Table 3 Concrete performance test results .

[0059] Through the above-mentioned concrete workability, mechanical and durability test tests, it can be seen that the dry-cleaning slurry medium machine-made sand concrete obtained by the machine-made sand concrete mix design and concrete preparation method with the addition of dry-cleaning slurry medium in this application has good cohesion, no water seepage, good anti-seepage performance, and the slump and 28d compressive strength can meet the design requirements.

[0060] Although some preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0061] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of the inventive concept. Thus, if such changes and modifications fall within the scope of the claims of this application and their equivalents, this application is intended to include such changes and modifications.

Claims

1. A method for designing the mix ratio of machine-made sand concrete incorporating a dry-cleaning slurry medium, characterized in that: The following steps are involved: (1) Based on the amount of powder in the original mix ratio of the residual concrete in the concrete mixer truck f 0 and sand dosage S 0, the powder influence coefficient in the dry cleaning batting medium is determined by the following formula λ : ； (2) Determine the replacement rate of 10-25 mm coarse aggregate by dry cleaning slurry medium δ ; Determine the mix strength of the machine-made sand concrete f cu,DCAC ; Determine the 28d compressive strength value of cementitious material mortar f b ; (3) The water-cement ratio of the machine-made sand concrete is determined by the following formula: w / b : ； Where, A 、 B represents the regression coefficient, A =0.458, B =0.209; λ is the powder influence coefficient in the dry cleaning sizing medium; δ The replacement rate of 10~25mm coarse aggregate for dry cleaning pulping medium; (4) Determine the water consumption per unit volume of machine-made sand concrete using the following formula: m w : ； Where, m w0 The amount of water used for concrete without admixtures; ω is the water reduction rate of the admixture; δ is the dry cleaning sizing medium replacement rate; C is the concrete strength grade value; (5) The sand ratio of the machine-made sand concrete is determined by the following formula: β s : ； Where, β s0 is the sand ratio of ordinary machine-made sand concrete; δ The replacement rate of 10~25mm coarse aggregate for dry cleaning pulping medium; (6) Determine the amount of cementitious material in the machine-made sand concrete m b ; Determine the amount of fly ash m f , Granulated blast furnace slag powder dosage m sl and cement consumption m c ; (7) Based on assumed bulk density m cp , the amount of cement m c , the amount of fly ash m f , the amount of granulated blast furnace slag powder m sl , the unit water consumption m w And the sand ratio of the machine-made sand concrete β s Determine the total amount of coarse aggregate in the machine-made sand concrete m g , Amount of machine-made sand m s ; (8) Based on the proportion of 5~10mm natural gravel φ , 5~10mm natural gravel dosage m g0 , 10~25mm natural gravel dosage m g1 , Replacement rate of dry cleaning slurry medium replacing 10~25mm coarse aggregate δ , determine the amount of dry cleaning batting medium m g2 .

2. The method for designing the mix ratio of machine-made sand concrete according to claim 1, characterized in that: In step (2), the strength of the machine-made sand concrete is f cu,DCAC Calculated by the following formula: ； Where, f cu,k is the design strength grade of concrete; when the concrete strength guarantee rate is 95%, t Take 1.645; σ is the standard deviation of concrete strength; when the concrete strength grade is C25~C45, σ Take 5.0; when the concrete strength grade is C50~C55, σ Take 6.

0.

3. The method for designing mix proportion of machine-made sand concrete according to claim 1, characterized in that: In step (2), the 28d compressive strength value of the cementitious material mortar is f b Measured according to GB / T 17671 or calculated by the following formula: ， ； Where, γ f is the fly ash influence coefficient; γ s is the influence coefficient of granulated blast furnace slag powder; f ce is the 28d compressive strength of cement mortar; γ c is the cement strength surplus coefficient; f ce,g is the cement strength grade value; γ f 、 γ s The value is based on JGJ 55-2011.

4. The method for designing mix proportion of machine-made sand concrete according to claim 1, characterized in that: In step (6), the amount of cementitious material in the machine-made sand concrete is m b Calculated by the following formula: ； Where, m w The water consumption per cubic meter of concrete; w / b is the water-cement ratio of concrete.

5. The method for designing mix proportion of machine-made sand concrete according to claim 1, characterized in that: In step (6), the amount of fly ash in the machine-made sand concrete is m f , Granulated blast furnace slag powder dosage m sl , cement consumption m c Calculated by the following formula: ， ， ； Where, m b is the amount of cementitious material; m f is the amount of fly ash; β f is the fly ash content; m sl is the amount of granulated blast furnace slag powder; β sl is the dosage of granulated blast furnace slag powder.

6. The method for designing mix proportion of machine-made sand concrete according to claim 1, characterized in that: In step (7), the total amount of coarse aggregate in the machine-made sand concrete is m g , Amount of machine-made sand m s Calculated by the following formula: ； Where, m cp For the assumed bulk density, take 2350~2450; m c is the amount of cement used; m f is the amount of fly ash; m sl is the amount of granulated blast furnace slag powder; m w The water consumption per unit; β s is the concrete sand ratio.

7. The method for designing mix proportion of machine-made sand concrete according to claim 1, characterized in that: In step (8), the amount of dry cleaning sizing medium is calculated by the following formula: ， ， ； Where, φ The ratio of 5-10 mm natural crushed stone in coarse aggregate is 25%-35%; m g0 The amount of 5~10mm natural gravel; m g1 The amount of natural crushed stone of 10~25mm; δ The replacement rate of 10~25mm coarse aggregate for dry cleaning pulping medium; m g2 The amount of starch medium used for dry cleaning.

8. A method for preparing machine-made sand concrete incorporating a dry-cleaning slurry medium, characterized in that: The following steps are involved: (1) According to the mix ratio obtained in claim 1, weigh the required cement, fly ash, granulated blast furnace slag powder, water, machine-made sand, coarse aggregate and dry cleaning slurry medium; (2) Mix the coarse aggregate, machine-made sand, dry-cleaning slurry, cement, fly ash, and granulated blast furnace slag powder evenly, dry mix for 8-12 seconds, then add the admixture and half of the water, and stir for 85-95 seconds; (3) Add the remaining half of the water and stir for 85-95 seconds.

9. The preparation method according to claim 8, characterized in that The cement is P·O42.5 ordinary Portland cement; the admixture is a polycarboxylic acid-based high-performance water-reducing agent with a water-reducing rate of ≥25%.

10. The preparation method according to claim 8, characterized in that The machine-made sand has a fineness modulus of 2.5-2.9, MB < 1.4, and a stone powder content of ≤10%; the coarse aggregate is composed of 5-10 mm and 10-25 mm crushed stones, with a mud content of ≤0.5% and a water absorption rate of ≤1%.