Industrial CT (Computed Tomography)-based nondestructive evaluation method for grouting effect of grouted asphalt concrete

Abstract

The invention discloses a non-destructive evaluation method for grouting effect of grouted asphalt concrete based on industrial CT, which is applied to the field of grouting effect detection of grouted composite pavements, and comprises the following steps: calculating the connected void ratio of a matrix asphalt Marshall test piece, and calculating theoretical grouting quality based on the connected void ratio; forming an injection type composite Marshall test piece, obtaining the actual cement mortar injection amount, and calculating a first injection rate in combination with the theoretical grouting quality; carrying out three-dimensional reconstruction on the interior of the injection type composite Marshall test piece by utilizing industrial CT lossless scanning, and calculating the three-dimensional void ratio based on the three-dimensional void volume parameters; performing section pretreatment on the internal test piece subjected to three-dimensional reconstruction, and calculating a two-dimensional void ratio based on section void area parameters; and calculating a second grouting rate based on the three-dimensional void ratio and the two-dimensional void ratio, and evaluating the grouting effect in combination with the first grouting rate. According to the method, the grouting effect evaluation which fully considers the influence of the internal structure gaps of the grouting type asphalt concrete on the grouting effect is realized.

Description

Technical Field

[0001] The invention relates to the field of detection of grouting effect of poured composite pavement, and in particular to a non-destructive evaluation method of grouting effect of poured asphalt concrete based on industrial CT. Background Art

[0002] The poured composite pavement is a new type of pavement structure that pours cement mortar into the base asphalt pavement, pours the slurry into the mixture, and fills the gaps. This pavement combines the rigidity of cement concrete pavement and the flexibility of asphalt pavement, and has the characteristics of both pavements. Compared with cement concrete pavement, the poured composite asphalt pavement has better driving comfort and durability; compared with ordinary asphalt pavement, it has significant advantages in anti-rutting, anti-fatigue and wear resistance. In recent years, the use of "pouring" to pour cement-based slurry into flexible porous asphalt pavements, combining the rigidity of cement slurry after hardening with the flexibility of asphalt mixture itself, to obtain a semi-flexible pavement with greater rigidity, is one of the technical means to prevent and reduce asphalt pavement rutting in high temperature areas. At present, there are many related research progress on poured asphalt pavements, and a large number of indoor tests and field test road paving have been carried out, and certain research results have been achieved. The research on poured pavements mainly focuses on the structural design of semi-flexible pavements, new grouting materials, mechanical properties and road performance of semi-flexible pavements, while there is less research on the indicators and test methods of the cement mortar pouring effect of poured asphalt pavements.

[0003] After grouting of asphalt concrete pavement, the grouting effect needs to be evaluated. Due to the lack of evaluation methods for the grouting effect of poured composite asphalt pavement, the performance of poured composite asphalt pavement cannot be guaranteed. The grouting fullness is simply reflected by the quality difference of concrete specimens before and after grouting. The influence of the internal structure voids of asphalt concrete on the grouting effect is not considered, and the grouting effect after grouting cannot be directly reflected.

[0004] Therefore, how to provide a non-destructive evaluation method of the grouting effect of poured asphalt concrete based on industrial CT, which can fully consider the influence of the internal structure voids of poured asphalt concrete on the grouting effect, is an urgent problem to be solved by those skilled in the art. Summary of the invention

[0005] In view of this, the present invention proposes a non-destructive evaluation method for the grouting effect of poured asphalt concrete based on industrial CT.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A non-destructive evaluation method for the effect of asphalt concrete grouting based on industrial CT, comprising:

[0008] Step 1: Calculate the connected porosity of the matrix asphalt Marshall specimen, and calculate the theoretical grouting quality based on the connected porosity;

[0009] Step 2: Form a poured composite Marshall specimen, obtain the actual cement mortar poured amount, and calculate the first pouring rate in combination with the theoretical grouting quality;

[0010] Step 3: Use industrial CT non-destructive scanning to perform three-dimensional reconstruction of the interior of the poured composite Marshall specimen, and calculate the three-dimensional void ratio based on the three-dimensional void volume parameters;

[0011] Step 4: Preprocess the cross section of the internal specimen after 3D reconstruction, and calculate the 2D void ratio based on the cross section void area parameter;

[0012] Step 5: Based on the three-dimensional void ratio and the two-dimensional void ratio, calculate the second filling rate, and evaluate the grouting effect in combination with the first filling rate.

[0013] Optionally, in step 1, the connected porosity of the matrix asphalt Marshall specimen is calculated as follows:

[0014]

[0015] Among them, P 1 is the connected porosity; V is the volume of the matrix asphalt Marshall specimen, in cm 3 ; V 矿 is the volume of mineral material and closed voids, in cm 3 ; V 矿 =(m 干 -m 水 ) / ρ 水 ;m 干 is the mass of the base asphalt Marshall specimen in air, in g; m 水 is the mass of the matrix asphalt Marshall specimen in water, in g; ρ 水 is the density of water in g / cm 3 .

[0016] Optionally, in step 1, the theoretical grouting quality is calculated based on the connected porosity as follows:

[0017] m 理 =V·P 1 ·ρ 桨 ;

[0018] Among them, m 理 is the theoretical grouting mass, in g; V is the volume of the matrix asphalt Marshall specimen, in cm 3 ;P 1 is the connected porosity; ρ 桨 is the density of cement mortar, in g / cm3 .

[0019] Optionally, in step 2, the actual cement mortar injection amount is obtained as follows:

[0020] m 实 =m 2 -m 1 ;

[0021] Among them, m 实 is the actual grouting mass, in g; m 2 is the mass of the poured composite Marshall specimen after molding, in g; m 1 It is the mass of the poured composite Marshall specimen before being poured with cement mortar, in g.

[0022] Optionally, in step 2, based on the actual cement mortar injection amount and combined with the theoretical grouting quality, the first injection rate is calculated as follows:

[0023]

[0024] Among them, P 2 is the first filling rate; m 实 is the actual amount of cement mortar injected, in g; m 理 is the theoretical grouting mass, in g.

[0025] Optionally, in step 3, the three-dimensional void fraction is calculated based on the three-dimensional void volume parameter as follows:

[0026]

[0027] Among them, P 3 is the three-dimensional void ratio; n is the number of three-dimensional voids; V i is the volume of the i-th three-dimensional void, in cm 3 ; V is the volume of the base asphalt Marshall specimen, in cm 3 .

[0028] Optionally, in step 4, the internal specimen after three-dimensional reconstruction is subjected to cross-section preprocessing, specifically:

[0029] Perform uniform cross-section processing on the internal specimen after 3D reconstruction, and perform grayscale processing on each cross-section image;

[0030] The contrast, brightness and gamma value of each cross-sectional image after grayscale processing are processed to obtain the cross-sectional void area parameters of each cross-sectional image.

[0031] Optionally, in step 4, the two-dimensional void fraction is calculated based on the cross-sectional void area parameter as follows:

[0032]

[0033] Among them, P 4 is the two-dimensional void ratio; t is the number of sections; S i is the gap area of ​​the g-th section; S is the area of ​​each section.

[0034] Optionally, in step 5, based on the three-dimensional void ratio and the two-dimensional void ratio, a second filling rate is calculated as follows:

[0035]

[0036] Among them, P 5 is the second infusion rate; P 0 is the porosity of the matrix asphalt Marshall specimen; P 二 is the two-dimensional void ratio; P 三 is the three-dimensional void ratio; P 1 is the connected porosity of the matrix asphalt Marshall specimen.

[0037] Optionally, in step 5, the grouting effect is evaluated based on the second injection rate in combination with the first injection rate, specifically: the average value of the first injection rate and the second injection rate is calculated, and if the average value is greater than 90%, the grouting effect is evaluated as good; if the average value is greater than or equal to 70% and less than or equal to 90%, the grouting effect is evaluated as average; if the average value is less than or equal to 70%, the grouting effect is evaluated as poor.

[0038] It can be seen from the above technical solution that, compared with the prior art, the present invention proposes a non-destructive evaluation method for the grouting effect of poured asphalt concrete based on industrial CT. The theoretical grouting quality is calculated based on the connected porosity of the matrix asphalt Marshall specimen, and compared with the actual cement mortar injection amount obtained by the quality of the poured composite Marshall specimen before and after molding, to obtain the first injection rate, and the second injection rate is obtained by combining the three-dimensional porosity and two-dimensional porosity of the poured composite Marshall specimen obtained by non-destructive scanning based on industrial CT, and the grouting effect is comprehensively evaluated, realizing the grouting effect evaluation that fully considers the influence of the internal structural voids of the poured asphalt concrete on the grouting effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0040] Figure 1 It is a schematic diagram of the method flow of the present invention.

[0041] Figure 2 It is a schematic diagram of the three-dimensional reconstruction result of the present invention.

[0042] Figure 3 It is a schematic diagram of the grayscale processing result of the present invention.

[0043] Figure 4 It is a schematic diagram of the contrast, brightness and gamma value processing results of the present invention. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] Embodiment 1:

[0046] Embodiment 1 of the present invention discloses a method for nondestructive evaluation of the effect of asphalt concrete grouting based on industrial CT, such as Figure 1 As shown, including:

[0047] Step 1: Calculate the connected void ratio of the base asphalt Marshall specimen, and calculate the theoretical grouting quality based on the connected void ratio. The voids include closed voids and connected voids. The connected void ratio is the ratio of the voids that run through the asphalt concrete and are connected to each other to the total voids.

[0048] The connected porosity of the matrix asphalt Marshall specimen is calculated as follows:

[0049]

[0050] Among them, P 1 is the connected porosity; V is the volume of the matrix asphalt Marshall specimen, in cm 3 ; V 矿 is the volume of mineral material and closed voids, in cm 3 ; V 矿 =(m 干 -m 水 ) / ρ 水 ;m 干 is the mass of the base asphalt Marshall specimen in air, in g; m 水 is the mass of the matrix asphalt Marshall specimen in water, in g; ρ 水 is the density of water in g / cm 3 .

[0051] The theoretical grouting quality is calculated based on the connected porosity as follows:

[0052] m 理 =V·P 1 ·ρ 桨 ;

[0053] Among them, m 理 is the theoretical grouting mass, in g; V is the volume of the matrix asphalt Marshall specimen, in cm 3 ;P 1 is the connected porosity; ρ 桨 is the density of cement mortar, in g / cm 3 .

[0054] Step 2: Form a poured composite Marshall specimen, obtain the actual amount of cement mortar poured, and calculate the first pouring rate based on the theoretical grouting quality.

[0055] Forming and pouring composite Marshall test pieces, specifically:

[0056] First, seal the bottom of the base asphalt Marshall specimen and weigh its mass as m 1 The base asphalt Marshall specimen is fixed on a cement vibration table and vibrated for 90 seconds while grouting to fully fill the connected gaps of the base asphalt Marshall specimen. After the grouting is completed, the excess cement slurry on the surface of the specimen is wiped off with a rubber rake until the coarse aggregate is exposed. The outside of the test mold is wiped clean with a rag and its mass is weighed as m 2 After standard curing, the specimens were demoulded and their heights were measured. Specimens with heights outside the range of 63.5±1.3mm were removed.

[0057] Get the actual cement mortar injection amount as follows:

[0058] m 实 =m 2 -m 1 ;

[0059] Among them, m 实 is the actual grouting mass, in g; m 2 is the mass of the poured composite Marshall specimen after molding, in g; n 1 It is the mass of the poured composite Marshall specimen before being poured with cement mortar, in g.

[0060] Based on the actual cement mortar injection volume and the theoretical grouting quality, the first injection rate is calculated as follows:

[0061]

[0062] Among them, P 2 is the first filling rate; m 实 is the actual amount of cement mortar injected, in g; m 理is the theoretical grouting mass, in g.

[0063] Step 3: Use industrial CT non-destructive scanning to perform three-dimensional reconstruction of the interior of the poured composite Marshall specimen, such as Figure 2 As shown, the three-dimensional void fraction is calculated based on the three-dimensional void volume parameter.

[0064] The internal structure of the poured composite Marshall specimen was reconstructed in three dimensions using industrial CT non-destructive scanning, specifically:

[0065] The poured composite Marshall specimen was reconstructed in three dimensions using VG Studio MAX software to obtain the overall three-dimensional image. Then, the defect expansion module in the supporting software was used to design the maximum and minimum values ​​of the void volume to be calculated to 900 mm 3 and 0mm 3 Finally, the volume and number of three-dimensional voids are calculated.

[0066] Based on the three-dimensional void volume parameter, the three-dimensional void fraction is calculated as follows:

[0067]

[0068] Among them, P 3 is the three-dimensional void ratio; n is the number of three-dimensional voids; V i is the volume of the i-th three-dimensional void, in cm 3 ; V is the volume of the base asphalt Marshall specimen, in cm 3 .

[0069] Step 4: Perform cross-section preprocessing on the internal specimen after 3D reconstruction, and calculate the 2D void ratio based on the cross-section void area parameter.

[0070] The cross-section preprocessing of the internal specimen after 3D reconstruction is carried out as follows:

[0071] VG Studio MAX software was used to perform uniform cross-section processing along the height of the internal specimen after 3D reconstruction to obtain a preset number of 2D cross-section images, and Matlab software image analysis technology was used to perform grayscale processing on each cross-section image, such as Figure 3 As shown;

[0072] Image J three-dimensional image analysis software was used to process the contrast, brightness, and gamma value of each grayscale processed cross-sectional image. Figure 4 As shown, the gap information of each cross-sectional image is extracted to obtain the cross-sectional gap area parameters of each cross-sectional image, including the gap area of ​​each cross-sectional image.

[0073] Based on the cross-sectional void area parameter, the two-dimensional void ratio is calculated as follows:

[0074]

[0075] Among them, P 4 is the two-dimensional void ratio; t is the number of sections; S i is the gap area of ​​the g-th section; S is the area of ​​each section.

[0076] Step 5: Based on the three-dimensional void ratio and the two-dimensional void ratio, calculate the second filling rate, and evaluate the grouting effect in combination with the first filling rate.

[0077] Based on the three-dimensional void ratio and the two-dimensional void ratio, the second infusion ratio is calculated as follows:

[0078]

[0079] Among them, P 5 is the second infusion rate; P 0 is the porosity of the matrix asphalt Marshall specimen; P 二 is the two-dimensional void ratio; P 三 is the three-dimensional void ratio; P 1 is the connected porosity of the matrix asphalt Marshall specimen.

[0080] Based on the second filling rate and combined with the first filling rate, the grouting effect is evaluated as follows:

[0081] The average value of the first injection rate and the second injection rate is calculated. If the average value is greater than 90%, the grouting effect is evaluated to be good; if the average value is greater than or equal to 70% and less than or equal to 90%, the grouting effect is evaluated to be average; if the average value is less than or equal to 70%, the grouting effect is evaluated to be poor.

[0082] Embodiment 2:

[0083] Embodiment 2 of the present invention discloses a process for specifically evaluating the grouting effect by using the nondestructive evaluation method for the grouting effect of asphalt concrete based on industrial CT described in Embodiment 1, including:

[0084] The first filling rate is calculated using step 1 and step 2 in Example 1. The calculation results are shown in Table 1.

[0085] Table 1 Calculation results of the first filling rate

[0086]

[0087] The three-dimensional void ratio was calculated using step 3 in Example 1. The calculation results are shown in Table 2.

[0088] Table 2 Calculation results of three-dimensional void fraction

[0089]

[0090] The two-dimensional void fraction was calculated using step 4 in Example 1. The calculation results are shown in Table 3.

[0091] Table 3 Calculation results of two-dimensional void fraction

[0092]

[0093] The second filling rate is calculated using step 5 in Example 1. The calculation results are shown in Table 4.

[0094] Table 4 Calculation results of the second injection rate

[0095]

[0096] Based on the second filling rate and combined with the first filling rate, the grouting effect is evaluated as follows:

[0097] The average of the first and second perfusion rates was 93.85%, indicating that the perfusion effect was good;

[0098] The difference between the first filling rate and the second filling rate is 0.5%, which is less than 3%, which proves the feasibility of calculating the filling rate of the poured asphalt concrete based on the industrial CT technology of the present invention.

[0099] The embodiment of the present invention discloses a non-destructive evaluation method for the grouting effect of poured asphalt concrete based on industrial CT. The theoretical grouting quality is calculated based on the connected porosity of the matrix asphalt Marshall specimen, and compared with the actual cement mortar injection amount obtained by the quality of the poured composite Marshall specimen before and after molding, to obtain a first injection rate, and the second injection rate is obtained by combining the three-dimensional porosity and two-dimensional porosity of the poured composite Marshall specimen obtained by non-destructive scanning based on industrial CT, and the grouting effect is comprehensively evaluated, realizing the grouting effect evaluation that fully considers the influence of the internal structural voids of the poured asphalt concrete on the grouting effect.

[0100] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0101] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A non-destructive evaluation method for the effect of asphalt concrete grouting based on industrial CT, characterized in that: include: Step 1: Calculate the connected porosity of the matrix asphalt Marshall specimen, and calculate the theoretical grouting quality based on the connected porosity; Step 2: forming a poured composite Marshall specimen, obtaining the actual cement mortar poured amount, and calculating the first pouring rate in combination with the theoretical grouting quality; Step 3: Using industrial CT nondestructive scanning to perform three-dimensional reconstruction of the interior of the poured composite Marshall specimen, and calculating the three-dimensional void ratio based on the three-dimensional void volume parameter; Step 4: Preprocessing the cross section of the internal specimen after the three-dimensional reconstruction, and calculating the two-dimensional void ratio based on the cross-sectional void area parameter; Step 5: Based on the three-dimensional void ratio and the two-dimensional void ratio, a second filling rate is calculated, and combined with the first filling rate, a grouting effect is evaluated.

2. According to the method of nondestructive evaluation of asphalt concrete grouting effect based on industrial CT in claim 1, it is characterized in that: In step 1, the connected porosity of the matrix asphalt Marshall specimen is calculated as follows: Wherein, P1 is the interconnected porosity; V is the volume of the matrix asphalt Marshall specimen, in cm 3 ; V 矿 is the volume of mineral material and closed voids, in cm 3 ; V 矿 =(m 干 -m 水 ) / ρ 水 ;m 干 is the mass of the base asphalt Marshall specimen in air, in g; m 水 is the mass of the matrix asphalt Marshall specimen in water, in g; ρ 水 is the density of water in g / cm 3 .

3. The method for nondestructive evaluation of asphalt concrete grouting effect based on industrial CT according to claim 1 is characterized in that: In step 1, the theoretical grouting quality is calculated based on the connected porosity as follows: m 理 =V·P1·ρ 桨 ; Among them, m 理 is the theoretical grouting mass, in g; V is the volume of the matrix asphalt Marshall specimen, in cm 3 ; P1 is the interconnected porosity; ρ 桨 is the density of cement mortar, in g / cm 3 .

4. The method for nondestructive evaluation of asphalt concrete grouting effect based on industrial CT according to claim 1 is characterized in that: In step 2, the actual cement mortar injection amount is obtained as follows: mreal=m2-m1; Among them, m 实 is the actual grouting mass, in g; m2 is the mass of the poured composite Marshall specimen after forming, in g; m1 is the mass of the poured composite Marshall specimen before being poured with cement mortar, in g.

5. The method for nondestructive evaluation of asphalt concrete grouting effect based on industrial CT according to claim 1 is characterized in that: In step 2, based on the actual cement mortar injection amount and combined with the theoretical grouting quality, the first injection rate is calculated as follows: Wherein, P2 is the first injection rate; m 实 is the actual amount of cement mortar injected, in g; m 理 is the theoretical grouting mass, in g.

6. The method for nondestructive evaluation of asphalt concrete grouting effect based on industrial CT according to claim 1 is characterized in that: In step 3, the three-dimensional void fraction is calculated based on the three-dimensional void volume parameter as follows: Wherein, P3 is the three-dimensional void ratio; n is the number of three-dimensional voids; V i is the volume of the i-th three-dimensional void, in cm 3 ; V is the volume of the base asphalt Marshall specimen, in cm 3 .

7. The method for nondestructive evaluation of asphalt concrete grouting effect based on industrial CT according to claim 1 is characterized in that: In step 4, the internal specimen after the three-dimensional reconstruction is subjected to cross-section preprocessing, specifically: Performing uniform cross-section processing on the three-dimensionally reconstructed internal specimen, and performing grayscale processing on each cross-section image; Contrast, brightness and gamma value processing are performed on each cross-sectional image that has undergone the grayscale processing to obtain a cross-sectional void area parameter of each cross-sectional image.

8. The method for nondestructive evaluation of asphalt concrete grouting effect based on industrial CT according to claim 1 is characterized in that: In step 4, the two-dimensional void fraction is calculated based on the cross-sectional void area parameter as follows: Wherein, P4 is the two-dimensional porosity; t is the number of sections; S i is the gap area of ​​the g-th section; S is the area of ​​each section.

9. The method for nondestructive evaluation of asphalt concrete grouting effect based on industrial CT according to claim 1 is characterized in that: In step 5, based on the three-dimensional void ratio and the two-dimensional void ratio, a second filling rate is calculated as follows: Wherein, P5 is the second filling rate; P0 is the void ratio of the base asphalt Marshall specimen; P 二 is the two-dimensional void ratio; P 三 is the three-dimensional porosity; P1 is the connected porosity of the matrix asphalt Marshall specimen.

10. The method for nondestructive evaluation of asphalt concrete grouting effect based on industrial CT according to claim 1 is characterized in that: In step 5, based on the second injection rate and in combination with the first injection rate, the grouting effect is evaluated, specifically: the average value of the first injection rate and the second injection rate is calculated, and if the average value is greater than 90%, the grouting effect is evaluated to be good; if the average value is greater than or equal to 70% and less than or equal to 90%, the grouting effect is evaluated to be average; if the average value is less than or equal to 70%, the grouting effect is evaluated to be poor.

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