Method and system for crushing aggregate gradation with a jaw crusher

Abstract

The present application relates to the field of building material preparation, and particularly relates to a jaw crusher crushing aggregate grading method and system. The grading method comprises the following steps: obtaining a target specification; obtaining recycled aggregate produced by a jaw crusher at different jaw spacings; calculating and drawing a grading curve corresponding to each jaw spacing; determining whether the recycled aggregate produced at a single jaw spacing meets the target specification; if yes, the corresponding jaw spacing is the grading that meets the target specification; if not, at least two kinds of jaw spacing aggregates are selected according to the target specification; combined grading with different mass ratios is performed; and the combined grading that meets the target specification is selected from each combined grading. The present application can generate recycled aggregate that meets relevant specifications by using only a single jaw crusher. After obtaining the grading curve of the jaw crusher at different jaw spacings, the present application can generate a recycled aggregate grading scheme that meets the requirements according to the target specification.

Description

Technical Field

[0001] This invention relates to the field of building material preparation, specifically to a method and system for grading aggregates using a jaw crusher. Background Technology

[0002] In the renovation and widening of municipal arterial roads, the refurbishment and widening of cement concrete pavements inevitably generate a large amount of waste concrete. Recycling this waste concrete not only helps reduce the environmental impact of construction waste but also has significant economic and social benefits. To maximize resource utilization, research has found that using waste concrete as aggregate for the base layer of newly constructed roads is an efficient and reasonable recycling method.

[0003] However, for waste concrete aggregates to be suitable for road base construction, they must meet the gradation characteristics specified in relevant standards. Existing technologies often use crushers to process waste concrete. The recycled aggregates produced after crushing have different particle compositions and cannot be directly used in construction. Grading experiments are required to determine the appropriate aggregate blending ratio that meets the gradation characteristics specified in relevant standards. However, existing technologies often grade aggregates from multiple different crusher models when determining the recycled aggregate gradation. For example, Chinese patent application CN119296701A discloses a design method for a cement-stabilized crushed stone subbase based on gradation reorganization. This method grades aggregates from a primary jaw crusher (PE400×600) and a secondary hammer crusher (PC1000×800). Existing technologies lack a method for determining the aggregate gradation of a single jaw crusher, making it impossible to generate recycled aggregates that meet relevant standards when using only a single jaw crusher. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies that cannot generate recycled aggregates that meet relevant specifications when using a single jaw crusher, and to provide a method and system for grading aggregates crushed by a jaw crusher.

[0005] In a first aspect, the present invention provides a method for grading aggregates crushed by a jaw crusher, comprising the following steps:

[0006] S1. Obtain the target specifications;

[0007] S2. Obtain the recycled aggregate produced by the jaw crusher under different jaw spacings; calculate the mass percentage of each particle size of the recycled aggregate produced by the jaw crusher under each jaw spacing; and plot the gradation curve corresponding to each jaw spacing.

[0008] S3. Based on the gradation curves corresponding to each jaw spacing, determine whether the recycled aggregate produced by crushing under a single jaw spacing meets the target specifications; if it does, then the corresponding jaw spacing is the gradation that meets the target specifications; if it does not, then select at least two types of jaw spacing aggregates according to the target specifications.

[0009] S4. Perform different mass ratio combinations of the selected jaw spacing aggregates; calculate the mass percentage of each particle size of the recycled aggregate in each combination gradation; and plot the gradation curve of each combination gradation.

[0010] S5. Select the combination gradation that meets the target specification from the gradation curves of each combination gradation.

[0011] According to a preferred embodiment, before performing step S1, a crushing experiment is conducted using a jaw crusher to obtain the correspondence between the jaw spacing and the particle size of the recycled aggregate.

[0012] The setting of different jaw spacings in step S2 is based on the target specification and the corresponding relationship, so that the particle size composition of the recycled aggregate produced by crushing under different jaw spacings is different and meets the target specification.

[0013] According to a preferred embodiment, the target specification includes: a target upper limit gradation curve and a target lower limit gradation curve. A method for determining whether recycled aggregate produced by crushing under a single jaw spacing meets the target specification includes: determining whether the gradation curve of the recycled aggregate produced by crushing under a single jaw spacing is located between the target upper limit gradation curve and the target lower limit gradation curve; if so, it meets the target specification; if not, it does not meet the target specification. Step S5 includes: selecting a gradation curve located between the target upper limit gradation curve and the target lower limit gradation curve from the gradation curves of each combined gradation; the combined gradation corresponding to this gradation curve is the combined gradation that meets the target specification.

[0014] According to a preferred embodiment, the gradation curves corresponding to each jaw spacing drawn in step S2 are set according to the horizontal and vertical coordinates of the target upper limit gradation curve and the target lower limit gradation curve.

[0015] According to a preferred embodiment, the target specification includes: the fractal dimension of the recycled aggregate and the content of target-size particles in the recycled aggregate. The method for determining whether recycled aggregate produced by crushing under a single jaw spacing meets the target specification is as follows: calculate the fractal dimension and the content of target-size particles in the recycled aggregate produced by crushing under a single jaw spacing; determine whether it meets the target specification. Step S5 includes: calculating the fractal dimension and the content of target-size particles for each combined gradation; determining whether the combined gradation meets the target specification.

[0016] According to a preferred embodiment, the calculation of the fractal dimension includes: selecting the mass of each particle size range component in the gradation, plotting the distribution curve of the cumulative mass of crushed aggregate with optimal mass ratio as a function of particle size; performing linear fitting on the distribution curve of the cumulative mass of crushed aggregate with optimal mass ratio as a function of particle size, and calculating the slope of the fitted line; and calculating the fractal dimension based on the slope of the line.

[0017] According to a preferred embodiment, the calculation of the target particle size content includes: obtaining the gradation parameters that determine the shape of the gradation curve based on each combined gradation curve; and calculating the definite integral of the target particle size.

[0018] According to a preferred embodiment, the method for determining whether the content of particles of the target particle size meets the target specification is as follows: calculate the integral area of ​​each combined gradation curve in the target particle size range, and determine whether the calculated integral area meets the numerical range given by the target specification.

[0019] According to a preferred embodiment, the different mass ratios set in step S5 include: for the combined gradation of two jaw spacing aggregates, the mass ratios include: 0:10, 2:8, 3:7, 5:5, 7:3, 8:2, 10:0.

[0020] On the other hand, the present invention also provides a jaw crusher aggregate gradation system, comprising: a memory, a processor, and a computer program stored in the memory. The processor executes the computer program to implement the steps of the method as described in any one of claims 1 to 9.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] The jaw crusher aggregate gradation method and system provided by this invention can generate recycled aggregates that meet relevant specifications using only a single jaw crusher. After obtaining the gradation curves of the jaw crusher at different jaw spacings, this invention can generate a recycled aggregate gradation scheme that meets the target specifications. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a preferred embodiment of the jaw crusher aggregate gradation method of the present invention;

[0024] Figure 2 This is a comparison diagram of the gradation curves corresponding to each jaw spacing and the target upper and lower limit gradation curves according to a preferred embodiment of the present invention.

[0025] Figure 3 This is a comparison graph of the combination gradation curve and the G-2-1 curve for different mass ratios of 30mm jaw spacing and 2mm jaw spacing according to a preferred embodiment of the present invention.

[0026] Figure 4 This is a comparison graph of the combination gradation curve and the G-2-1 curve for different mass ratios of 25mm jaw spacing and 2mm jaw spacing according to a preferred embodiment of the present invention.

[0027] Figure 5 This is a schematic diagram of linear fitting of 30mm jaw spacing recycled aggregate according to a preferred embodiment of the present invention;

[0028] Figure 6 This is a schematic diagram of linear fitting of 25mm jaw spacing recycled aggregate according to a preferred embodiment of the present invention;

[0029] Figure 7 This is a schematic diagram of linear fitting of 2mm jaw spacing recycled aggregate according to a preferred embodiment of the present invention;

[0030] Figure 8 This is a schematic diagram of linear fitting of recycled aggregates with different mass ratios of 30mm jaw spacing and 2mm jaw spacing according to a preferred embodiment of the present invention.

[0031] Figure 9 This is a schematic diagram of linear fitting of recycled aggregates with different mass ratios of 25mm jaw spacing and 2mm jaw spacing, according to a preferred embodiment of the present invention. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0033] Unless otherwise specified, the use of terms such as "upper," "lower," "left," "right," "center," "inner," and "outer" to indicate orientation or positional relationships in the description of specific embodiments of the present invention is based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is typically placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0034] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," and "parallel" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, or parallel, but rather that it can be slightly tilted or have a deviation. For example, "horizontal" merely means that its direction is more horizontal relative to "vertical," not that the structure must be completely horizontal, but that it can be slightly tilted. Alternatively, it can be simplified to mean that the corresponding device / component / element, when set in a "horizontal," "vertical," "suspended," or "parallel" direction, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the present invention.

[0035] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0036] Furthermore, in the description of the embodiments of the present invention, "several", "more than", and "a number of" represent at least two. The number can be any number, such as two, three, four, five, six, seven, eight, or nine, and can even exceed nine.

[0037] Furthermore, in the description of the technical solution of this invention, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "provided with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to common connection methods in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0038] Example 1

[0039] This embodiment provides a method for grading aggregates crushed by a jaw crusher. The grading method includes the following steps:

[0040] S1. Obtain the target specifications;

[0041] S2. Obtain the recycled aggregate produced by the jaw crusher under different jaw spacings; calculate the mass percentage of each particle size of the recycled aggregate produced by the jaw crusher under each jaw spacing; and plot the gradation curve corresponding to each jaw spacing.

[0042] S3. Based on the gradation curves corresponding to each jaw spacing, determine whether the recycled aggregate produced by crushing under a single jaw spacing meets the target specifications; if it does, then the corresponding jaw spacing is the gradation that meets the target specifications; if it does not, then select at least two types of jaw spacing aggregates according to the target specifications.

[0043] S4. Perform different mass ratio combinations of the selected jaw spacing aggregates; calculate the mass percentage of each particle size of the recycled aggregate in each combination gradation; and plot the gradation curve of each combination gradation.

[0044] S5. Select the combination gradation that meets the target specification from the gradation curves of each combination gradation.

[0045] According to a preferred embodiment, before performing step S1, a crushing experiment is conducted using a jaw crusher to obtain the correspondence between the jaw spacing and the particle size of the recycled aggregate. The different jaw spacings set in step S2 are determined based on the target specification and the corresponding relationship, ensuring that the recycled aggregate produced by crushing at different jaw spacings has a different particle size composition while still meeting the target specification.

[0046] See Figure 1 In this embodiment, the jaw crusher aggregate gradation method obtains the target specifications and then obtains the gradation curve for a single jaw spacing. Preferably, the method obtains the recycled aggregate produced by the jaw crusher at different jaw spacings and plots the gradation curves corresponding to each jaw spacing.

[0047] Determine whether the recycled aggregate produced by a single jaw spacing meets the target specifications.

[0048] If a single jaw spacing produces recycled aggregate that meets the target specifications, then that jaw spacing is the selected gradation that meets the target specifications.

[0049] If no recycled aggregate produced from a single jaw spacing meets the target specification, then at least two jaw spacing aggregates are combined and graded at different mass ratios, and then it is determined whether the recycled aggregate of the combined gradation meets the target specification. If the recycled aggregate of the combined gradation meets the target specification, then the jaw spacing combination and mass ratio corresponding to the combined gradation are the gradations selected that meet the target specification.

[0050] The jaw crusher aggregate gradation method provided in this embodiment can generate recycled aggregates that meet relevant specifications using only a single jaw crusher. Furthermore, after obtaining the gradation curves of the jaw crusher at different jaw spacings, this embodiment can generate a recycled aggregate gradation scheme that meets the target specifications.

[0051] Example 2

[0052] This embodiment is a further improvement on Embodiment 1, and the repeated content will not be described again. In this embodiment, according to a preferred implementation, the target specification includes: a target upper limit gradation curve and a target lower limit gradation curve. The method for determining whether the recycled aggregate produced by crushing under a single jaw spacing meets the target specification includes: determining whether the gradation curve of the recycled aggregate produced by crushing under a single jaw spacing is located between the target upper limit gradation curve and the target lower limit gradation curve; if yes, then it meets the target specification; if not, then it does not meet the target specification. Step S5 includes: selecting the gradation curve located between the target upper limit gradation curve and the target lower limit gradation curve from the gradation curves of each combined gradation, and the combined gradation corresponding to this gradation curve is the combined gradation that meets the target specification.

[0053] According to a preferred embodiment, the gradation curves corresponding to each jaw spacing drawn in step S2 are set according to the horizontal and vertical coordinates of the target upper limit gradation curve and the target lower limit gradation curve.

[0054] According to a preferred embodiment, step S4, which involves selecting at least two jaw spacing aggregates based on the target gradation curve, includes: determining the difference between each jaw spacing gradation curve and the target gradation curve, and attempting to combine two jaw spacing gradation curves to compensate for the difference between themselves and the target gradation curve. Step S5, which sets different mass ratios, includes the following mass ratios for the combined gradation of the two jaw spacing aggregates: 0:10, 2:8, 3:7, 5:5, 7:3, 8:2, 10:0.

[0055] Specifically, the jaw crusher aggregate gradation method provided in this embodiment was used for implementation testing.

[0056] Preferably, the target specification adopts the recommended gradation G-2-1 of the "Technical Specifications for Construction of Highway Pavement Base Course" (JTGT F20-2015). The upper limit gradation curve of the target is the upper limit gradation curve of the recommended gradation G-2-1, and the lower limit gradation curve of the target is the lower limit gradation curve of the recommended gradation G-2-1.

[0057] According to the "Technical Specifications for Construction of Highway Pavement Base Course" (JTGT F20-2015), the coarseness of cement concrete aggregates is classified with 4.75mm as the boundary. Aggregates larger than 4.75mm are considered coarse aggregates, and aggregates smaller than 4.75mm are considered fine aggregates. When graded crushed stone is used as a highway base course, the nominal maximum particle size for Class I and expressways should not exceed 26.5mm, and the nominal maximum particle size for Class II and lower-grade highways should not exceed 31.5mm. The specific gradation curve is divided into the following particle groups: 37.5-31.5mm, 31.5-26.5mm, 26.5-19mm, 19-9.5mm, 9.5-4.75mm, 4.75-2.36mm, 2.36-1.18mm, 1.18-0.6mm, 0.6-0.15mm, 0.15-0.075mm, and smaller than 0.075mm.

[0058] The "Technical Specifications for Construction of Highway Pavement Base Course" (JTGT F20-2015) recommends gradation G-2-1 for base courses of Class II and lower-grade highways. The recommended gradation range for G-2-1 is shown in Table 1.

[0059] Table 1: Recommended G-2-1 Grading Range (%)

[0060]

[0061] In Table 1, particle size is expressed as the percentage of particles smaller than a certain size. Therefore, the percentage gradually decreases from 100% to the smallest particle size.

[0062] Crushing experiments were conducted using a jaw crusher to obtain the correlation between jaw spacing and the particle size of recycled aggregate. Preferably, crushing experiments were performed on the jaw crusher beforehand, and the correlation between jaw spacing and recycled aggregate particle size was found to be: when the jaw spacing of the jaw crusher is adjusted to 30 mm or less, recycled aggregate with a particle size smaller than 37.5 mm can be discharged relatively stably. Furthermore, when the jaw spacing at the discharge port is reduced by 5 mm, the particle size composition of the discharged recycled aggregate changes significantly.

[0063] When setting different jaw spacings at the discharge port of the jaw crusher, the spacing is decreased sequentially from 30mm particle size in 5mm increments. The selected jaw spacings are 30mm, 25mm, 20mm, 15mm, 10mm, 5mm, 2mm, and 0mm. Preferably, the 0mm jaw spacing does not mean there is no gap between the two jaws, but only represents the minimum jaw spacing of the jaw crusher.

[0064] The mass of crushed particles at each jaw spacing was obtained from crushing tests on waste concrete, as shown in Table 2.

[0065] Table 2: Particle mass of each jaw spacing

[0066]

[0067]

[0068] The mass percentage of crushed particles at each jaw spacing was obtained from crushing tests on waste concrete, as shown in Table 3.

[0069] Table 3: Percentage of crushed particle size groups at each jaw spacing

[0070]

[0071] Based on the mass percentage of crushed particles at each jaw spacing, a gradation curve corresponding to each jaw spacing is plotted. A comparison chart of the gradation curves corresponding to each jaw spacing and the target upper and lower limit gradation curves is shown below. Figure 2 As shown.

[0072] See Figure 2 There is no single jaw spacing gradation curve located between the upper limit gradation curve of G-2-1 and the lower limit gradation curve of G-2-1.

[0073] Combined gradation experiments with different mass ratios were conducted on aggregates with different jaw spacings to obtain combined gradations whose gradation curves lie between the upper limit gradation curve of G-2-1 and the lower limit gradation curve of G-2-1.

[0074] Preferably, before performing combined gradation, the recycled aggregates produced under different jaw spacings are first grouped.

[0075] Preferably, jaw spacings with similar mass percentages of crushed particles are first grouped together based on the mass percentage of the crushed particle group at a single jaw spacing.

[0076] Compared to the target upper and lower limit gradation curves, the recycled aggregates produced under 30mm and 25mm jaw spacings mainly consist of coarse particles with a diameter greater than 9.5mm, accounting for more than 50% of the total mass. Furthermore, the gradation curves between the two jaw spacings show a high degree of overlap, so these are grouped together and designated as Group 1. The recycled aggregates produced under 20mm, 15mm, and 10mm jaw spacings mainly consist of particles with a diameter from 4.75mm to 9.5mm, accounting for more than 50% of the total mass. These three jaw spacing aggregates are grouped together and designated as Group 2. Compared to the target upper and lower limit gradation curves, the aggregates produced under 5mm, 2mm, and 0mm jaw spacings mainly consist of fine aggregates with a diameter from 1.18mm to 4.75mm. These three jaw spacings are grouped together and designated as Group 3.

[0077] The gradation curves of the three jaw spacings of 20mm, 15mm, and 10mm are in good agreement with the recommended gradation curves, so the combination of aggregates with these three jaw spacings should be the main consideration when combining them.

[0078] Compared to the target specification, the third group of jaw spacing produced more fine aggregate but lacked coarse aggregate; while compared to the target specification, the first group of jaw spacing produced more coarse aggregate but lacked fine aggregate. Therefore, it was mainly combined with the first group, which had more coarse aggregate. Since the second group had a higher content of needle-like and flaky aggregates, a combination of the first and third groups was used for subsequent analysis.

[0079] The aggregate produced by 20mm, 15mm, and 10mm jaw spacing has a particle size concentrated between 4.75mm and 9.5mm. It lacks both coarse and fine particles, so it needs to be mixed with aggregates with large jaw spacing (30mm, 25mm) and small jaw spacing (5mm, 2mm, and 0mm) at the same time. This involves mixing three types of aggregates, which is quite complicated in terms of process. Therefore, aggregates produced by 0mm, 15mm, and 10mm jaw spacing are not used.

[0080] Preferably, the gradation curves are fused according to the mass ratio of the combined gradation. The method of curve fusion is as follows: multiply the gradation curves of each jaw spacing in the combined gradation by the mass ratio and then add them together to obtain the gradation curve of the mixed aggregate after being combined and graded according to the corresponding mass ratio, that is, the combined gradation curve.

[0081] For example, when the combined gradation is a combination of the first jaw spacing and the second jaw spacing, and the mass of the crushed aggregate at the first jaw spacing is equal to the mass of the crushed aggregate at the second jaw spacing, the combined gradation curve of the first jaw spacing and the second jaw spacing is equal to the gradation curve of the first jaw spacing × X / (X+Y) + the gradation curve of the second jaw spacing × Y / (X+Y).

[0082] The combined gradation curve is compared with the target upper and lower limit gradation curves. When the combined gradation curve is between the target upper and lower limit gradation curves, it meets the target specifications. The jaw spacing combination and mass ratio corresponding to the combined gradation curve are the gradations that meet the target specifications.

[0083] For example, the composite gradation curves of 30mm jaw spacing:2mm jaw spacing mass ratios of 3:7, 5:5, and 7:3 are compared with the G-2-1 curve. The comparison results are as follows: Figure 3 As shown.

[0084] See Figure 3 Only when the mass ratio of the mixed aggregates is 5:5, the combined gradation curve of 30mm jaw spacing and 2mm jaw spacing is located between the upper and lower limit gradation curves of G-2-1. Therefore, the mass ratio of the combined gradation: 30mm jaw spacing: 2mm jaw spacing is 5:5, and this combined gradation scheme is a gradation that meets the target specification.

[0085] For example, the combined gradation curves of 25mm jaw spacing:2mm jaw spacing mass ratios of 0:10, 2:8, 3:7, and 5:5 are compared with the G-2-1 curve. The comparison results are as follows: Figure 4 As shown.

[0086] See Figure 4 Only when the mass ratio of the mixed aggregates is 5:5, the combined gradation curve of 25mm jaw spacing and 2mm jaw spacing is located between the upper and lower limit gradation curves of G-2-1. Therefore, the mass ratio of the combined gradation: 25mm jaw spacing: 2mm jaw spacing is 5:5, and this combined gradation scheme is a gradation that meets the target specification.

[0087] Example 3

[0088] This embodiment is a further improvement on Embodiments 1 and 2, and the repeated content will not be described again. The target specification in Embodiment 2 is given through a standard gradation curve. This method is only applicable when recycled aggregates are constructed according to existing standard technical specifications. However, in the case of non-standard construction using recycled aggregates, it is usually impossible to give target specifications using upper and lower target gradation curves. In the case of non-standard construction using recycled aggregates, the target specification is usually given by the fractal dimension of the recycled aggregates and the content of target particle size particles in the recycled aggregates.

[0089] In this embodiment, according to a preferred implementation, the target specification includes: the fractal dimension of the recycled aggregate and the content of target size particles in the recycled aggregate. The method for determining whether the recycled aggregate produced by crushing under a single jaw spacing meets the target specification is as follows: calculate the fractal dimension and the content of target size particles in the recycled aggregate produced by crushing under a single jaw spacing; determine whether it meets the target specification. Step S5 includes: calculating the fractal dimension and the content of target size particles for each combined gradation; determining whether the combined gradation meets the target specification.

[0090] According to a preferred embodiment, the calculation of the fractal dimension includes: selecting the mass of each particle size range component in the gradation, plotting the distribution curve of the cumulative mass of crushed aggregate with optimal mass ratio as a function of particle size; performing linear fitting on the distribution curve of the cumulative mass of crushed aggregate with optimal mass ratio as a function of particle size, and calculating the slope of the fitted line; and calculating the fractal dimension based on the slope of the line.

[0091] According to a preferred embodiment, the calculation of the target particle size content includes: obtaining the gradation parameters that determine the shape of the gradation curve based on each combined gradation curve; and calculating the definite integral of the target particle size.

[0092] The method for determining whether the particle content of the target particle size meets the target specification is as follows: calculate the integral area of ​​each combined gradation curve in the target particle size range, and determine whether the calculated integral area meets the numerical range given by the target specification.

[0093] According to a preferred embodiment, the gradation parameters of each combined gradation curve within the target particle size range are calculated using a first calculation equation. The first calculation equation is:

[0094]

[0095] In the formula, p represents the content of particles smaller than a certain particle size; d represents the particle size; b and m are gradation parameters, and b and m determine the shape of the gradation curve; d max This represents the maximum particle size.

[0096] According to a preferred embodiment, the different mass ratios set in step S5 include: for the combined gradation of two jaw spacing aggregates, the mass ratios include: 0:10, 2:8, 3:7, 5:5, 7:3, 8:2, 10:0.

[0097] Preferably, the target specifications in this embodiment are: 1) the fractal dimension of the aggregate gradation is between 2.36 and 2.40; 2) particles with a diameter greater than 19 mm should account for no less than 30% of the total mass.

[0098] Preferably, for target specification 2), particles with a diameter greater than 19 mm should account for no less than 30% of the total mass. In this embodiment, this is expressed as the gradation area formed by the aggregate gradation curve in the range of 4.75 mm to 19 mm in the gradation curve being between 9.87 and 10.12, that is, the definite integral value of the gradation curve from 4.75 mm to 19 mm is 9.87 ≤ S ≤ 10.12.

[0099] Following the same procedure as in Example 2, the particle size mass percentages for jaw spacings of 30mm, 25mm, 20mm, 15mm, 10mm, 5mm, 2mm, and 0mm were obtained. The fractal dimension of the crushed aggregate at each jaw spacing was then calculated.

[0100] The fractal dimension is calculated using the formula D = 3 - k, where D ∈ (2, 3). The method for calculating k is as follows: Select the mass of each particle size range component of the crushed aggregate at each jaw spacing, and plot the distribution curve of the cumulative mass of the crushed aggregate with the optimal mass ratio as a function of particle size. Let lg[(M i (d i The absolute value of )) / M0], lg(d i / d max The absolute values ​​of M are the ordinate and the abscissa, respectively. i (d i ) is the aperture d iThe cumulative mass of all crushed particles of the mixed aggregate passing through a square-hole sieve (mm), in g; d i The standard sieve aperture is shown in mm. The distribution curve of the cumulative mass of crushed aggregate with optimal mass ratio is fitted using the least squares method, and the slope of the fitted straight line is calculated and denoted as k. The corresponding fractal dimension D is then calculated based on k.

[0101] Taking the calculation of the fractal dimension of crushed aggregate generated by a single jaw spacing of 30mm, 25mm, and 2mm as an example, let d be the aperture of the i-th layer of square-hole screens from top to bottom. i (d i >d i +1), the total mass of aggregate passing through this sieve is M. i (d i The total mass of the aggregate sample before crushing is M0, and the maximum particle size of the aggregate sample is d. max The formula can be transformed into:

[0102] lg[M i (d i ) / M0]=(3-D)lg(d i / d max )

[0103] The ratio M of the cumulative mass of aggregate undersize at each stage after screening from the three selected jaw spacings to the mass before crushing. i (d i ) / M0 and the ratio of each pore size to the maximum aggregate size d i / d max The relationships between them are shown in Tables 4, 5, and 6.

[0104] Table 4: Results of Crushing, Screening, and Conversion of Recycled Aggregates with a Jaw Spacing of 30mm

[0105]

[0106] Table 5: Results of Crushing, Screening, and Conversion of Recycled Aggregates with a Jaw Spacing of 25mm

[0107]

[0108] Table 6: Results of Crushing, Screening, and Conversion of Recycled Aggregates with a 2mm Jaw Spacing

[0109]

[0110] M i (d i ) / M0 and d i / d max After taking the logarithm, the data is plotted on a coordinate graph, and then linear regression analysis is performed on the points in the coordinate graph.

[0111] See Figure 5 30mm jaw spacing: lg[M i (d i ) / M0]=0.69829lg(d i / d max +0.19846

[0112] R 2 =0.9432, a good fit; 3-D ​​= 0.698; the fractal dimension D of the recycled aggregate produced at a 30mm jaw spacing is 2.302.

[0113] See Figure 6 25mm jaw spacing: lg[M i (d i ) / M0]=0.69432lg(d i / d max +0.23465

[0114] R 2 =0.94305, a good fit; 3-D ​​= 0.694; the fractal dimension D of the recycled aggregate produced at a 25mm jaw spacing is 2.306.

[0115] See Figure 7 2mm jaw spacing: lg[M i (d i ) / M0]=y=0.64563lg(d i / d max -0.1011

[0116] R 2 =0.98038, a good fit; 3-D ​​= 0.646; the fractal dimension D of the recycled aggregate produced at a 2mm jaw gap is 2.354.

[0117] Preferably, the fractal dimension of the crushed aggregate at each jaw spacing is calculated to be between 2.30 and 2.36, which does not meet the target specification of the fractal dimension of aggregate gradation being between 2.36 and 2.40. Therefore, it is not necessary to determine whether the content of target particle size in the recycled aggregate meets the target specification.

[0118] At this point, different mass ratios of aggregates with different jaw spacings are combined to form different composite gradations, and it is determined whether the fractal dimension and the content of target particle size particles of each composite gradation meet the target specifications.

[0119] Preferably, recycled aggregates produced with 30mm and 2mm jaw spacings are combined in different proportions, with the mass ratios of 30mm and 2mm jaw spacing aggregates being 0:10, 2:8, 3:7, 5:5, 7:3, 8:2, and 10:0 for gradation. For each mass ratio of 30mm and 2mm jaw spacing, the ratio M of the cumulative mass of aggregate passing through each stage of screening after sieving to the mass before crushing is... i (d i ) / M0 and the ratio of each pore size to the maximum aggregate size d i / d max The relationships between them are shown in Table 7.

[0120] Table 7: Cumulative Mass and Particle Size Under Screen of Combined Jaw Spacing Grades with 30mm and 2mm Jaw Spacing

[0121]

[0122] By performing linear fitting on the data in Table 7 within the same rectangular coordinate system, the double logarithmic fitting relationship between the cumulative mass under each stage of the screen and the particle size of recycled aggregates with different combination ratios is shown below. Figure 8 As shown.

[0123] right Figure 8 In the table, linear regression analysis was performed on points belonging to the same mass ratio combination of 30mm and 2mm jaw spacing to obtain the fractal dimension table of different mass ratio combinations of 30mm and 2mm jaw spacing, as shown in Table 8.

[0124] Table 8: Fractal Dimension of Recycled Aggregate Combinations with 30mm Jaw Spacing and 2mm Jaw Spacing

[0125]

[0126] From the data in Table 8, we can see that among the recycled aggregate combinations with different mass ratios of 30mm and 2mm, the fractal dimension ranges of the three mass ratios of 3:7, 5:5 and 7:3 satisfy the target specifications.

[0127] Furthermore, the content of target particle size particles in three recycled aggregate combinations with 30mm and 2mm jaw spacing at mass ratios of 3:7, 5:5 and 7:3 were calculated respectively.

[0128] The target specification requires that the integral area of ​​the gradation curve in the 4.75mm to 19mm range be 9.87≤S≤10.12.

[0129] This embodiment determines whether the target specification requirements are met by calculating the definite integral values ​​of the combined gradation curves of three recycled aggregate combinations with mass ratios of 3:7, 5:5, and 7:3 and jaw spacings of 30mm and 2mm, from 4.75mm to 19mm.

[0130] First, the gradation curves of three combined schemes with jaw spacing mass ratios of 3:7, 5:5, and 7:3 for 30mm and 2mm jaws are fitted using the first calculation equation to obtain the gradation parameters b and m for each combined gradation curve; then, the definite integral of the following formula is performed:

[0131]

[0132] The results are shown in Table 9.

[0133] Table 9: Mass ratio gradation coefficients and definite integral values ​​for 30mm and 2mm jaw gaps

[0134]

[0135] As shown in Table 9, the 30mm and 2mm jaw spacings only meet the target specifications when the mass ratio is 5:5.

[0136] Preferably, recycled aggregates produced with 25mm and 2mm jaw spacings are combined in different proportions, with the mass ratios of 25mm and 2mm jaw spacing aggregates being 0:10, 2:8, 3:7, 5:5, 7:3, 8:2, and 10:0 for gradation. For each mass ratio of 25mm and 2mm jaw spacing, the ratio M of the cumulative mass of aggregate passing through each stage of screening after sieving to the mass before crushing is... i (d i ) / M0 and the ratio of each pore size to the maximum aggregate size d i / d max The relationships between them are shown in Table 10.

[0137] Table 10: Cumulative Mass and Particle Size Under Screen of Combined Jaw Spacing Grades (25mm and 2mm Jaw Spacing)

[0138]

[0139] By performing linear fitting on the data in Table 7 within the same rectangular coordinate system, the double logarithmic fitting relationship between the cumulative mass under each stage of the screen and the particle size of recycled aggregates with different combination ratios is shown below. Figure 9 As shown.

[0140] right Figure 9 In the table, linear regression analysis was performed on points belonging to the same mass ratio combination of 25mm and 2mm jaw spacing to obtain the fractal dimension table of different mass ratio combinations of 25mm and 2mm jaw spacing, as shown in Table 11.

[0141] Table 11: Fractal Dimension of Recycled Aggregate Combinations with 25mm Jaw Spacing and 2mm Jaw Spacing

[0142]

[0143] From the data in Table 11, we can see that among the recycled aggregate combinations with different mass ratios of 30mm and 2mm, the four fractal dimension ranges that meet the target specifications are 0:10, 2:8, 3:7 and 5:5.

[0144] Furthermore, the content of target particle size particles was calculated for four recycled aggregate combinations with 25mm and 2mm jaw spacing, with mass ratios of 0:10, 2:8, 3:7 and 5:5, respectively.

[0145] The target specification requires that the integral area of ​​the gradation curve in the 4.75mm to 19mm range be 9.87 ≤ S ≤ 10.12. Since the 25mm and 2mm jaw spacing gradations with a mass ratio of 0:10 do not contain particles larger than 9.5mm, this gradation combination is discarded.

[0146] This embodiment determines whether the target specification requirements are met by calculating the definite integral values ​​of the combined gradation curves of three recycled aggregate combinations with mass ratios of 2:8, 3:7, and 5:5 and jaw spacings of 25mm and 2mm, from 4.75mm to 19mm.

[0147] First, the gradation curves of three combined schemes with jaw spacing mass ratios of 2:8, 3:7, and 5:5 for 25mm and 2mm jaws are fitted using the first calculation equation to obtain the gradation parameters b and m for each combined gradation curve; then, the definite integral of the following formula is performed:

[0148]

[0149] The results are shown in Table 12.

[0150] Table 12: Mass ratio gradation coefficients and definite integral values ​​for 25mm and 2mm jaw gaps

[0151]

[0152] As shown in Table 12, the 25mm and 2mm jaw spacings only meet the target specifications when the mass ratio is 5:5.

[0153] Specifically, this embodiment is used to perform aggregate gradation for jaw crusher crushing. Given the target specifications that the fractal dimension of the aggregate gradation is between 2.36 and 2.40, and that particles with a diameter greater than 19 mm should account for no less than 30% of the total mass, the aggregate gradation list that meets the target specifications is shown in Table 13.

[0154] Table 13 Gradation that meets the target specifications

[0155]

[0156]

[0157] Through comparison, when the combined mass ratio of crushed aggregates with a jaw gap of 30mm and 2mm is 5:5, the aggregate gradation meets the target specification requirements; when the combined mass ratio of crushed aggregates with a jaw gap of 25mm and 2mm is 5:5, the aggregate gradation meets the target specification requirements.

[0158] Example 4

[0159] This embodiment provides a jaw crusher aggregate gradation system, including: a memory, a processor, and a computer program stored in the memory. The processor executes the computer program to implement the steps of the jaw crusher aggregate gradation method as described in Embodiments 1, 2, and 3.

[0160] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for grading aggregates crushed by a jaw crusher, characterized in that, Includes the following steps: S1. Obtain the target specifications; S2. Obtain the recycled aggregate produced by the jaw crusher under different jaw spacings; calculate the mass percentage of each particle size of the recycled aggregate produced by the jaw crusher under each jaw spacing. And plot the gradation curves corresponding to each jaw spacing; S3. Based on the gradation curves corresponding to each jaw spacing, determine whether the recycled aggregate produced by crushing under a single jaw spacing meets the target specifications; if it does, then the corresponding jaw spacing is the gradation that meets the target specifications. If not, at least two types of jaw spacing aggregates shall be selected according to the target specifications; S4. Perform different mass ratio combinations of the selected jaw spacing aggregates; calculate the mass percentage of each particle size of the recycled aggregates in each combination gradation. And plot the gradation curves for each combination of gradations; S5. Select the combined gradation that meets the target specifications from the gradation curves of each combined gradation; Before performing step S1, a crushing experiment is conducted using a jaw crusher to obtain the correspondence between the jaw spacing and the particle size of the recycled aggregate. The setting of different jaw spacings in step S2 is based on the target specification and the corresponding relationship, so that the particle size composition of the recycled aggregate produced by crushing under different jaw spacings is different and meets the target specification. The target specifications include: the fractal dimension of the recycled aggregate, and the content of target size particles in the recycled aggregate; The method for determining whether the recycled aggregate produced by crushing under a single jaw spacing meets the target specification is as follows: Calculate the fractal dimension and the content of target-size particles in the recycled aggregate produced by crushing under a single jaw spacing; determine whether it meets the target specifications. Step S5 includes: calculating the fractal dimension and the content of target particle size particles for each combined gradation; and determining whether the combined gradation meets the target specification.

2. The method for aggregate gradation using a jaw crusher according to claim 1, characterized in that, The target specifications are replaced with: target upper limit gradation curve and target lower limit gradation curve; The method for determining whether recycled aggregate produced by crushing under a single jaw spacing meets the target specification is replaced by: Determine whether the gradation curve of the recycled aggregate produced by crushing under a single jaw spacing is located between the target upper limit gradation curve and the target lower limit gradation curve; if yes, then the target specification is met; if not, then the target specification is not met. Step S5 is replaced by: selecting a gradation curve located between the target upper limit gradation curve and the target lower limit gradation curve from the gradation curves of each gradation combination. The gradation combination corresponding to this gradation curve is the gradation combination that meets the target specification.

3. The method for aggregate gradation using a jaw crusher according to claim 2, characterized in that, The gradation curves corresponding to each jaw spacing drawn in step S2 are set according to the horizontal and vertical coordinates of the target upper limit gradation curve and the target lower limit gradation curve.

4. The method for aggregate gradation using a jaw crusher according to claim 1, characterized in that, The calculation of the fractal dimension includes: Select the mass of each component in each particle size range of the gradation and plot the distribution curve of the cumulative mass of crushed aggregate with the optimal mass ratio as a function of particle size; The cumulative mass of crushed aggregate with the optimal mass ratio is linearly fitted to the distribution curve of the relationship between the crushed particles and the particle size, and the slope of the fitted line is calculated. The fractal dimension is calculated based on the slope of the line.

5. The method for aggregate gradation in a jaw crusher according to claim 4, characterized in that, The calculation of the target particle size content includes: The gradation parameters that determine the shape of the gradation curve are obtained from each combination gradation curve; Calculate the definite integral of the target particle size.

6. The method for aggregate gradation in a jaw crusher according to claim 4, characterized in that, The method for determining whether the particle content of the target particle size meets the target specification is as follows: Calculate the integral area of ​​each gradation curve in the target particle size range, and determine whether the calculated integral area meets the numerical range given by the target specification.

7. The method for aggregate gradation using a jaw crusher according to claim 1, characterized in that, The different mass ratio settings in step S5 include: for the combined gradation of two jaw spacing aggregates, the mass ratios include: 0:10, 2:8, 3:7, 5:5, 7:3, 8:2, 10:

0.

8. A jaw crusher aggregate gradation system, comprising: A memory, a processor, and a computer program stored on the memory, characterized in that the processor executes the computer program to implement the steps of the method as claimed in any one of claims 1 to 7.

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