Method for determining gradation of large-gap epoxy resin mixture

Abstract

The invention relates to the technical field of porous drainage pavement design, in particular to a macrovoid epoxy resin mixture grading determination method. The method mainly comprises the following steps: firstly, determining a target void ratio and a cementing material dosage, and then correcting the target void ratio to obtain a corrected target void ratio; calculating the dosage of coarse aggregate, the void ratio of coarse aggregate mineral aggregate and the dosage of mineral powder by using the corrected target void ratio and the corrected cementing material dosage so as to determine the dosage of fine aggregate and obtain the mix proportion of the large-void epoxy resin mixture; and carrying out key road performance verification on the prepared macrovoid epoxy resin mixture test piece so as to screen out the mix proportion of the macrovoid epoxy resin mixture meeting the corrected target void ratio and key road performance requirements. According to the method, the experimental quantity is reduced, the efficiency is improved, the result accuracy is improved, and the problem of uncertainty caused by randomness is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of porous drainage pavement design, and particularly relates to a method for determining the gradation of a large-void epoxy resin mixture. Background Art

[0002] Porous drainage asphalt pavement mainly uses porous asphalt mixture with a skeleton-void structure composed of asphalt binder and gap-graded aggregate as pavement materials. Compared with dense-graded asphalt mixture, the interior of porous asphalt mixture is rich in complex and interconnected void structures. Therefore, the strength of porous asphalt mixture is generally lower than that of dense-graded mixture. Although domestic and foreign research has adopted measures such as using high-viscosity asphalt, optimizing the gradation composition of coarse aggregates, and skeleton structure, the bearing capacity is still limited, it is difficult to withstand the axle load of trucks, and it is not applicable to areas with large traffic volume. In addition, during the service operation stage, due to the long-term influence of load and environmental factors, porous asphalt mixture is prone to fly-away, and will experience different degrees of blockage and attenuation phenomena, the permeability performance is significantly reduced, and the operation and maintenance cost is relatively high. Due to the limitation of the limited bonding force of asphalt, the void ratio of the mixture mainly concentrates in the range of 18% - 22%. Further increasing the void ratio will cause other properties of the mixture to decrease, while the void ratio is not large enough, which is likely to lead to blockage and rapid attenuation of the drainage function.

[0003] At present, for porous drainage pavement, the volume design method of Marshall specimens is mainly adopted for the mix proportion design of porous asphalt mixture. With the void ratio as the main design index, the specific gradation composition is determined based on experience, and the optimum asphalt content is obtained through the Sherenbourgh bleeding test and the Cantabro abrasion test. Among them, the Marshall design method of asphalt mixture belongs to an empirical design method. When conducting the mix proportion design, the determination of the optimum asphalt content is obtained through Marshall tests with multiple asphalt contents. The quantitative relationship between the binder content and the void ratio is not very clear, and it is mostly determined by the measured void ratio of the trial-mixed mixture under different binder contents. Usually, it takes 2 to 3 weeks to conduct the mix proportion design, the method is complex, and the test period is long. At the same time, the selection of the initial asphalt content is estimated based on local practical experience, and there is no relevant test and estimation method. In addition, it is impossible to establish a corresponding relationship with key properties such as mechanical properties and segregation behavior. Summary of the Invention

[0004] In order to solve the problems of insufficient strength, easy fly-away, easy blockage of voids, and insufficient void ratio that occur during the service of porous asphalt mixture, as well as the problems of complex method, long test period, and low result accuracy existing in the existing mix proportion design method of porous asphalt mixture, the present invention provides a method for determining the gradation of a large-void epoxy resin mixture. The method of the present invention can reduce the amount of experiments, improve the efficiency, while improving the accuracy of the results and avoiding the uncertain problems brought by randomness.

[0005] To achieve the above object, the technical solution of the present invention is as follows.

[0006] The present invention provides a method for determining the gradation of a large-void epoxy resin mixture, comprising the following steps: Determine the expected target void ratio of the large-void epoxy resin mixture; establish a relationship model between the binder dosage and the expected target void ratio and a prediction model for the key performance of the large-void epoxy resin mixture; then, according to the expected target void ratio, obtain the range of binder dosages that meet the requirements of the expected target void ratio and the key pavement performance requirements; the binder is an epoxy resin binder; obtain the correction coefficient of the expected target void ratio under different binder dosages, and then use the correction coefficient to correct the expected target void ratio to obtain the corrected target void ratio; obtain the relationship between the cumulative sieve residue of different particle-size coarse aggregates and the corrected target void ratio, and then use the corrected target void ratio to obtain the dosages of different particle-size coarse aggregates, calculate the void ratio of the coarse aggregate mineral aggregate, and the dosage of mineral powder; according to the binder dosage, the corrected target void ratio, the dosage of coarse aggregates, the void ratio of the coarse aggregate mineral aggregate, and the dosage of mineral powder, determine the dosage of fine aggregates, obtain the reference mix proportion of the large-void epoxy resin mixture, and prepare specimens of the large-void epoxy resin mixture; conduct key pavement performance verification on the specimens of the large-void epoxy resin mixture to screen out the mix proportion of the large-void epoxy resin mixture that meets the requirements of the corrected target void ratio and the key pavement performance requirements.

[0007] The present invention aims to prepare a large-void epoxy resin mixture by replacing traditional asphalt with epoxy resin, and proposes a corresponding mix proportion design method for the large-void epoxy resin mixture. The large-void epoxy resin mixture prepared by the present invention has the advantages of large voids, high strength, excellent anti-spalling performance, and good other pavement performance. The mix proportion design method for the large-void epoxy resin mixture proposed by the present invention can calculate the mix proportion that meets the required key performance according to the required void ratio, and only needs to be selected through verification of the key pavement performance, avoiding the randomness of determining the gradation composition and binder dosage of the porous mixture, and greatly reducing the amount of experiments, solving the problems of insufficient strength, easy spalling, easy blockage of voids, and insufficient void ratio that occur during the service of porous asphalt mixtures, as well as the problems of complex method, long test period, and low result accuracy existing in the existing mix proportion design methods of porous asphalt mixtures.

[0008] In the present invention, the determination of the expected target void ratio of the large-void epoxy resin mixture is mainly determined according to the data of the rainfall intensity and traffic volume obtained at the location of the highway to be built.

[0009] Preferably, the expected target void ratio is 18% - 26%.

[0010] Preferably, the relationship model between the binder dosage and the expected target void ratio is: G jd = -0.2205× vv + 8.887; Wherein, G jd represents the dosage of the equal-voidage binder, %; vv represents the expected target voidage, %. j represents the binder; d represents the equal-voidage.

[0011] Preferably, the key performance prediction model of the large-void epoxy resin mixture is: ; ; ; ; ; Wherein, ∆ S represents the loss rate of flakiness; C w represents the permeability coefficient; R T represents the splitting strength; R C represents the compressive strength; E ' represents the compressive resilience modulus; G j represents the dosage of the binder, %; vv represents the expected target voidage, %; j represents the binder; the binder is an epoxy resin binder.

[0012] Preferably, the binder is an epoxy resin binder; by weight, the epoxy resin binder is prepared from the following raw materials: 90 to 95 parts of epoxy resin, 25 to 30 parts of polyurethane prepolymer, 60 to 65 parts of diluent, 43 to 48 parts of curing agent, 1 to 3 parts of accelerator.

[0013] The epoxy resin is bisphenol A type epoxy resin, and the specific model is E44. The polyurethane prepolymer is a polyether type polyurethane prepolymer, purchased from Jining Liyang Chemical Co., Ltd., and the NCO content in the polyether type polyurethane prepolymer is 5.1 wt% ± 0.2 wt%. The curing agent is trihydroxypropane tris(3-mercaptopropionate). The diluent is polypropylene glycol diglycidyl ether, and the number average molecular weight of polypropylene glycol diglycidyl ether is 600. The accelerator is 2,4,6 tris(dimethylaminomethyl)phenol.

[0014] Preferably, the correction coefficient of the expected target voidage under different binder dosages is: When the binder dosage is 3.0%, , R 2 = 0.995; where, k 3.0 represents the correction coefficient when the binder dosage is 3.0%.

[0015] When the binder dosage is 3.5%, , R 2 = 0.995; where, k 3.5 represents the correction coefficient when the binder dosage is 3.5%.

[0016] When the binder dosage is 4.0%, , R 2 = 0.995; where, k 4.0 represents the correction coefficient when the binder dosage is 4.0%.

[0017] When the binder dosage is 4.5%, , R 2 = 0.995; where, k 4.5 represents the correction coefficient when the binder dosage is 4.5%.

[0018] When the binder dosage is 5.0%, , R 2 = 0.995; where, k 5.0 represents the correction coefficient when the binder dosage is 5.0%.

[0019] Preferably, the method for correcting the predicted target void ratio using the correction coefficient is as follows: Establish a relationship between the predicted target void ratio and the corrected target void ratio: ; where, vv ′ represents the corrected target void ratio; vv represents the predicted target void ratio, %; k represents the correction coefficient; According to the correction coefficient of the predicted target void ratio under different binder dosages and the predicted target void ratio, substitute them into the relationship between the predicted target void ratio and the corrected target void ratio to calculate the corrected target void ratio.

[0020] Preferably, the relationship between the cumulative sieve residue of the sieve holes of coarse aggregates with different particle sizes and the corrected target void ratio is: A 13.2 + A 9.5 + A 4.75 + A 2.36 =66.12736 + 0.9274 vv ′ ，R 2 =0.667; A 9.5 =40.22719× A 13.2 -0.22435 , R 2 =0.931; A 4.75 =170.8763×( A 13.2 + A 9.5 ) -0.37481 , R 2 =0.959; Among them, A 9.5 represents the cumulative sieve residue on the 9.5 mm sieve opening; A 13.2 represents the cumulative residue on the 13.2 mm sieve opening; A 4.75 represents the cumulative sieve residue on the 4.75 mm sieve opening; A 2.36 represents the cumulative sieve residue on the 2.36 mm sieve opening; vv ′ represents the corrected target void ratio.

[0021] Preferably, the method for calculating the void ratio of coarse aggregate aggregate and the amount of mineral powder used is: Obtain the multiple linear relationship between the void ratio of coarse aggregate aggregate and the cumulative sieve residue of coarse aggregate sieve openings; then calculate the void ratio of coarse aggregate aggregate according to the cumulative sieve residue of coarse aggregate sieve openings.

[0022] Calculate the amount of mineral powder used at different target void ratios according to the surrounded stack density theory.

[0023] The multiple linear relationship between the void ratio of coarse aggregate aggregate and the cumulative sieve residue of coarse aggregate sieve openings is: ; Among them, VCA * represents the void ratio of coarse aggregate aggregate; VV 0 represents the compacted void ratio of coarse aggregate.

[0024] Preferably, the method for determining the amount of fine aggregate is as follows: According to the relational expression between different filler dosages, calculate the amount of fine aggregate; the relational expression between different filler dosages is: V 填充 =( VCA * - vv ′) × V 粗集料 = m 细集料 / ρ 细集料 + m 矿粉 / ρ 矿粉 + m 胶结料 / ρ 胶结料 ; Wherein, V 填充 represents the filling volume of fine aggregate, mineral powder and binder; VCA * represents the void ratio of coarse aggregate; vv ′ represents the corrected target void ratio; V 粗集料 represents the amount of coarse aggregate; m 细集料 represents the mass of fine aggregate; ρ 细集料 represents the density of fine aggregate; m 矿粉 represents the mass of mineral powder; ρ 矿粉 represents the density of mineral powder; m 胶结料 represents the mass of binder; ρ 胶结料 represents the density of binder; m 细集料 / ρ 细集料 represents the amount of fine aggregate; m 矿粉 / ρ 矿粉 represents the amount of mineral powder; m 胶结料 / ρ 胶结料 represents the amount of binder.

[0025] Advantages of the present invention: 1. Based on the method for calculating and determining the reference mix proportion, combined with the key performance prediction model, the present invention proposes a mix design method for large-void epoxy resin mixtures, avoiding the randomness in determining the gradation composition and binder dosage of porous mixtures, better combining theoretical calculation and model prediction with indoor tests effectively, reducing the amount of experiments in the mix proportion design process, and reducing the waste of economic and time costs in the mix proportion design process of mixtures.

[0026] 2. Through the mix proportion design of large-void epoxy resin mixtures, the present invention can obtain the target void ratio, binder dosage, and mix proportion of large-void epoxy resin mixtures. The key performance and other road-using performances of the large-void epoxy resin mixtures prepared by the mix proportion design proposed by the present invention all meet the specification requirements of porous asphalt mixtures. Compared with the existing commonly used porous asphalt mixtures, the large-void epoxy resin mixtures prepared by the present invention not only have higher strength, but also have good deformation coordination ability, excellent permeability, can drain water quickly, and the key road-using performances are also significantly higher than those of the existing commonly used porous asphalt mixtures. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a flow chart of the mix proportion design of large-void epoxy resin mixtures provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0030] Although porous asphalt drainage pavements have a series of advantages, from the service conditions of the drainage pavements paved on a large scale in recent years, there are still several key problems that need to be solved urgently: First, the porous asphalt mixtures used belong to the skeleton-void type. A large number of void structures inside lead to a reduction in the cohesion of asphalt binders and the adhesion between asphalt and aggregates. The friction and interlock forces between aggregates become the main strength sources. Compared with traditional asphalt mixtures, the strength of porous asphalt mixtures is significantly reduced.

[0031] Second, due to the long-term immersion state of porous asphalt mixtures, they are severely damaged by water. Coupled with the continuous action of external loads, temperature and other factors, the adhesion between asphalt binders and aggregates is reduced, which easily leads to the occurrence of early pavement diseases such as loosening and spalling.

[0032] Thirdly, after long-term use of porous asphalt mixture, the internal voids are blocked, resulting in a decrease in the void ratio, which affects the drainage, noise reduction and other functional characteristics of the road surface.

[0033] Fourthly, both the functional characteristics and the basic road performance of porous asphalt mixture are closely related to the void ratio. Although a too large void ratio can obtain good functional characteristics, its mechanical properties and durability will all decay to varying degrees. Generally, the recommended range of void ratio is only 18% - 22%.

[0034] Regarding the above problems of porous drainage asphalt pavement, researchers and engineers at home and abroad have improved the strength and durability of porous asphalt mixture by optimizing the mixture proportion design method and using highly viscous modified asphalt, and have carried out regular maintenance on porous asphalt pavement to prevent void blockage. Although these methods have alleviated the prominent problems of porous asphalt pavement to a certain extent, their effects have not achieved the expected results or have not fundamentally solved the problems.

[0035] In addition, during the process of constructing asphalt concrete pavement with porous drainage asphalt mixture, construction generally needs to be stopped when the average ambient temperature is lower than 5°C, which results in that construction cannot be carried out most of the time in winter and cold regions; moreover, during the transportation and construction stages, porous drainage asphalt mixture needs to be kept heated, resulting in problems of high energy consumption and many required equipment during the process of constructing asphalt concrete pavement; and the properties of asphalt from different sources are also inconsistent, which leads to problems such as insufficient strength and easy void blockage of porous drainage asphalt mixture, as well as environmental pollution, limited construction conditions and high energy consumption.

[0036] The properties of each component of epoxy resin mixture are relatively stable, and it does not need to be heated. It only needs to be transported from the factory and mixed with mineral materials on site, and can be normally cured to form strength at low temperature, and can be constructed under different temperature conditions.

[0037] Compared with porous drainage asphalt mixture, epoxy resin porous mixture has high strength and large voids, and has obvious commercial advantages. It not only has stable and controllable performance, is not affected by construction temperature, but also has the advantages of energy saving and consumption reduction, and conforms to the current development trend of building materials.

[0038] In view of the influence of the void structure of traditional porous asphalt mixture on insufficient strength, etc., the research on preparing large-void mixture with epoxy resin in the present invention is expected to improve and solve the key problems of traditional porous asphalt mixture, break through the upper limit of the void ratio of traditional asphalt mixture, realize sustainable rapid drainage, and provide a new development idea for the better application and popularization of porous drainage pavement.

[0039] Based on this, the present invention provides an epoxy resin binder. The epoxy resin binder mainly uses epoxy resin as the main agent, polyurethane prepolymer as the toughening modifier, polythiol curing agent as the curing agent, polypropylene glycol diglycidyl ether as the diluent, and DMP-30 as the accelerator; wherein, the mass ratio of the epoxy resin to the polyurethane prepolymer is 93:27.

[0040] By weight, the epoxy resin binder is prepared from the following raw materials: 93 parts of epoxy resin, 27 parts of polyurethane prepolymer, 65 parts of diluent, 45 parts of curing agent and 3 parts of accelerator.

[0041] Preferably, the epoxy resin is preferably bisphenol A type epoxy resin, simply referred to as epoxy resin A, for example, bisphenol A type epoxy resin E44.

[0042] The polyurethane prepolymer is preferably a polyether type polyurethane prepolymer, purchased from Jining Liyang Chemical Co., Ltd., and the NCO content in the polyether type polyurethane prepolymer is 5.1 wt% ± 0.2 wt%.

[0043] The polythiol curing agent is trimethylolpropane tris(3-mercaptopropionate), also known as TMPMP, from Guangzhou Sanwang Chemical Industry.

[0044] The number average molecular weight of polypropylene glycol diglycidyl ether is 600.

[0045] The Chinese name of DMP30 is 2,4,6-tris(dimethylaminomethyl)phenol.

[0046] The preparation process of the epoxy resin binder is as follows: The epoxy resin and the polyurethane prepolymer are repeatedly stirred according to a mass ratio of 7:2 to modify the epoxy resin with the polyurethane prepolymer to obtain a modified epoxy resin; then a diluent is added to the modified epoxy resin and mechanically stirred for 2 to 3 minutes at a stirring rate of 500 r / min to 1500 r / min to obtain a first mixed liquid; the curing agent and the accelerator are respectively added to the first mixed liquid and mechanically stirred for 2 to 3 min at the same stirring rate to obtain a second mixed liquid, and finally the second mixed liquid together with the stirring container is placed in a vacuum drying oven at a constant temperature of 25°C for vacuum treatment until all the bubbles in the second mixed liquid disappear to obtain the epoxy resin binder.

[0047] The present invention collects and sorts out the research results related to PAC, analyzes the existing PAC grading distribution law and the relationship between the void ratio and the grading; according to the functions of different particle size particles in the coarse aggregate skeleton void structure and their influence on the void ratio, the relationship between the dosage of different particle size coarse aggregates and the target void ratio is established, so as to establish a key performance prediction model for large void epoxy resin mixtures.

[0048] Based on the void filling theory, control the sum of the volumes of the target voids, fine aggregate, mineral powder, and binder to be equal to the void volume of the compacted coarse aggregate skeleton, and determine the dosages of the fine aggregate, mineral powder, and binder.

[0049] Adopt a method combining theoretical calculation and laboratory tests to correct the target void ratio, and establish a calculation and determination method for the reference mix proportion of large void epoxy resin mixture that meets the requirements of the target void ratio.

[0050] The performance research of large void epoxy resin mixture includes key performances and other pavement performances. Conduct laboratory tests on the key performances of large void epoxy resin mixture such as void volume characteristics, anti-stripping performance, permeability performance, and mechanical performance, analyze the changes in the key performances of the mixture under different target void ratios and binder dosages, and establish a prediction model for the key performances of large void epoxy resin mixture.

[0051] Use high-temperature rutting test, immersion Marshall test, and low-temperature splitting test to verify other pavement performances of large void epoxy resin mixture. Based on the calculation and determination method of the reference mix proportion, combined with the prediction model of the key performances of large void epoxy resin mixture, establish a mix proportion design method for large void epoxy resin mixture.

[0052] This invention draws on the research results of traditional porous asphalt mixture, and proposes a calculation and determination method for the reference mix proportion of large void epoxy resin mixture through mathematical statistics, theoretical calculation, and laboratory test methods. Establish a quantitative relationship between the target void ratio and the passing rate of sieve holes larger than 2.36 mm, and calculate and determine the dosage of coarse aggregate based on this relationship to obtain the voids between the coarse aggregate skeletons; According to the void filling design idea, calculate and determine the dosages of fine aggregate and mineral powder corresponding to different binder dosages that meet the requirements of the target void ratio.

[0053] From the verification results of other pavement performance tests such as the high-temperature stability, low-temperature crack resistance, and water stability of the mixture, it can be seen that the mixtures with different target void ratios and binder dosages all meet the specification requirements, and the binder dosage has little influence on them. Therefore, the mix proportion design of large void epoxy resin mixture needs to focus on considering and controlling the key pavement performance indicators. Using the flying loss permeability coefficient splitting strength compressive strength and compressive resilience modulus

[0054] In the present invention, the void ratio range of the large-void epoxy resin mixture is between 18% and 26%. Within the void ratio range of 18% to 24% commonly used in road surfaces, its performance is superior to that of porous asphalt mixtures; meanwhile, within the void ratio range of 24% to 26%, the key road performance can meet the specification requirements, breaking through the upper limit of the void ratio of porous asphalt mixtures, and its functional characteristics are significantly superior to those of porous asphalt mixtures. In view of this, the present invention proposes a mix design method applicable to large-void epoxy resin mixtures, and its design process is as Figure 1 shown.

[0055] The technical solution of the present invention will be further described below through specific embodiments. In the following embodiments, unless otherwise specified, the methods are all conventional methods; the reagents and materials, unless otherwise specified, can all be obtained in the market.

[0056] As Figure 1 , a method for determining the gradation of a large-void epoxy resin mixture includes the following steps: Step 1, determine the expected target void ratio of the large-void epoxy resin mixture.

[0057] The specific method is: according to the data of the rainstorm intensity and traffic volume at the location of the road surface to be constructed, to determine the expected target void ratio of the large-void epoxy resin mixture, and the expected target void ratio meets the key road performance requirements of the large-void epoxy resin mixture. The expected target void ratio is 18% to 26%.

[0058] Among them, the condition for meeting the key road performance requirements is that the test results of multiple key performances meet the road performance requirements, which is recorded as qualified; otherwise, it is recorded as unqualified. The key performances include flushing loss rate, permeability coefficient, splitting strength, compressive strength, and compressive resilience modulus.

[0059] Step 2, establish a relationship model between the binder dosage and the expected target void ratio and a prediction model for the key performance of the large-void epoxy resin mixture.

[0060] Step 2.1, establish a relationship model between the binder dosage and the expected target void ratio.

[0061] The specific method is: define the binder dosage when the measured void ratio of the large-void epoxy resin mixture is equal to the expected target void ratio as the binder dosage at equal void ratio; according to the linear relationship between the binder dosage at equal void ratio and the expected target void ratio, establish a relationship model between the binder dosage at equal void ratio and the expected target void ratio: ; Among them, represents the binder dosage at equal void ratio, %; represents the expected target void ratio, %; j represents the binder;d Indicates equal void ratio.

[0062] Step 2.2, establish a key performance prediction model for large void epoxy resin mixture.

[0063] The specific method is: taking the target void ratio and binder dosage as prediction variables, establish a key performance prediction model for large void epoxy resin mixture. The key performance prediction model for large void epoxy resin mixture is:

[0064] ; ; ; ; ; Wherein, Indicates the loss rate of flaking; Indicates the permeability coefficient; Indicates the splitting strength; Indicates the compressive strength; Indicates the compressive resilience modulus; Indicates the binder dosage, %; Indicates the expected target void ratio, %; j Indicates the binder; the binder is an epoxy resin binder.

[0065] The binder dosage is 3.0% - 5.0%; the expected target void ratio is 18% - 26%.

[0066] The key performance prediction model for large void epoxy resin mixture is a multiple non-linear model of the key performance of large void epoxy resin mixture and the prediction variables.

[0067] The expected target void ratio and binder dosage have a significant impact on the key pavement performance of large void epoxy resin mixture. In the implementation mode of the present invention, key performance tests are respectively carried out on the expected target void ratio and binder dosage. Among them, the values of the expected target void ratio are 18%, 20%, 22%, 24%, 26%; in order to obtain the performance changes under different void ratios and binder dosages, the implementation mode of the present invention reasonably determines the expected target void ratio and binder dosage, and uses Matlab software to respectively conduct multiple non-linear regression analysis on the key performance change trends of the key performance under the dual factors of the expected target void ratio and binder dosage, so as to establish a multiple non-linear model of the key performance of large void epoxy resin mixture and the prediction variables.

[0068] Step 3: Then, according to the expected target void ratio, obtain the range of binder dosage that meets the expected target void ratio and key pavement performance requirements; the binder is an epoxy resin binder.

[0069] The specific method is as follows: Based on the data of rainfall intensity and traffic volume at the location of the highway to be constructed, determine the expected target void ratio of the large void epoxy mixture, substitute it into the binder dosage - expected target void ratio relationship model and the key performance prediction model of the large void epoxy mixture, and obtain the range of binder dosage that meets the expected target void ratio and key pavement performance requirements; select three binder dosages at equal intervals. For example, the range of binder dosage that meets the expected target void ratio and key pavement performance requirements is 3% - 5%.

[0070] Correct the expected target void ratio, and based on the corrected target void ratio, obtain the coarse aggregate dosage, and then obtain the dosages of each size fraction of aggregates according to the mathematical relationship among the aggregates of each size fraction.

[0071] Prepare three reference mix specimens, verify the key pavement performance of the three reference mix specimens, and obtain the target mix ratio of the mixture with the best performance that meets the target void ratio and key pavement performance indicators.

[0072] The key performance prediction model mainly divides the range of binder dosage according to the speculated key performance such as permeability coefficient and splitting strength after determining the target void ratio.

[0073] Step 4: Obtain the correction coefficient of the expected target void ratio under different binder dosages, and then use the correction coefficient to correct the expected target void ratio to obtain the corrected target void ratio.

[0074] In the embodiment of the present invention, the expected target void ratio is corrected by the correction coefficient to obtain the corrected target void ratio. Among them, the relationship formula between the expected target void ratio and the corrected target void ratio is:

[0075] ; where represents the corrected target void ratio; represents the expected target void ratio, %; k represents the correction coefficient.

[0076] Through laboratory tests, the measured porosity of the large-void epoxy resin mixture and the test results of the predicted target porosity were analyzed under different binder dosages, such as 3.0%, 3.5%, 4.0%, 4.5% or 5.0%, and different predicted target porosity rates, such as 18%, 20%, 22%, 24% or 26%. It can be seen that there is a certain correlation between the measured porosity and the predicted target porosity. Based on this, the relationship between the predicted target porosity and the corrected target porosity was determined.

[0077] By fitting the correction coefficient and the predicted target porosity under different binder dosages, the fitting relationship between the correction coefficient and the predicted target porosity under different binder dosages was determined: When the binder dosage is 3.0%, , R 2 = 0.995; where, k 3.0 represents the correction coefficient when the binder dosage is 3.0%.

[0078] When the binder dosage is 3.5%, , R 2 = 0.995; where, k 3.5 represents the correction coefficient when the binder dosage is 3.5%.

[0079] When the binder dosage is 4.0%, , R 2 = 0.995; where, k 4.0 represents the correction coefficient when the binder dosage is 4.0%.

[0080] When the binder dosage is 4.5%, , R 2 = 0.995; where, k 4.5 represents the correction coefficient when the binder dosage is 4.5%.

[0081] When the binder dosage is 5.0%, , R 2 = 0.995; where, k 5.0 represents the correction coefficient when the binder dosage is 5.0%.

[0082] According to the predicted target void ratio and binder dosage that meet the set key performance selected, determine the fitting relationship between the correction coefficient and the predicted target void ratio under different binder dosages; then, according to the relationship formula between the predicted target void ratio and the corrected target void ratio, calculate the corrected target void ratio.

[0083] Step 5: Obtain the relationship formula between the cumulative sieve residue of coarse aggregates with different particle sizes and the corrected target void ratio, and then use the corrected target void ratio to obtain the dosage of coarse aggregates with different particle sizes, and calculate the void ratio of coarse aggregate mineral mixture and the dosage of mineral powder.

[0084] Step 5.1: Calculate the dosage of coarse aggregates.

[0085] PAC-13 is a porous asphalt concrete. Taking PAC-13 as the research object, it includes coarse aggregates with four particle sizes of 13.2mm, 9.5mm, 4.75mm and 2.36mm, and forms a framework void structure through interlocking and filling.

[0086] In the embodiment of the present invention, coarse aggregates with two particle sizes of 13.2mm and 9.5mm are used as the main framework aggregates of the large-void epoxy resin mixture. Among them, there is an interlocking relationship between coarse aggregates with two particle sizes of 9.5mm and 13.2mm; while coarse aggregates with a particle size of 4.75mm can be filled in the framework structure formed by coarse aggregate particles with two particle sizes of 13.2mm and 9.5mm.

[0087] According to the mathematical statistics method, fit the relationship between the cumulative sieve residues of coarse aggregates with three particle sizes of 13.2mm, 9.5mm, and 4.75mm to determine the relationship formula between the cumulative sieve residues of coarse aggregates with three particle sizes of 13.2mm, 9.5mm, and 4.75mm: A 9.5 =40.22719× A 13.2 -0.22435 , R 2 =0.931; A 4.75 =170.8763×( A 13.2 + A 9.5 ) -0.37481 , R 2 =0.959; Among them, A 9.5 represents the cumulative sieve residue of the 9.5mm sieve hole; A 13.2Represents the cumulative sieve residue on the 13.2 mm sieve opening; A 4.75 Represents the cumulative sieve residue on the 4.75 mm sieve opening.

[0088] The internal voids of the large-void epoxy resin mixture are mainly a complex structure formed by fine aggregates, mineral powder, and binder filling part of the voids between aggregates. In the porous mixture specification, the total content of coarse aggregates with particle sizes of 13.2 mm, 9.5 mm, 4.75 mm, and 2.36 mm is as high as over 80%. The total mass of coarse aggregates is an important factor affecting the void ratio. Therefore, through analysis by mathematical statistics methods, it can be known that there is a significant linear relationship between the total amount of coarse aggregates and the total amount of the modified target void ratio.

[0089] Fit the cumulative sieve residue on the sieve openings of coarse aggregates with particle sizes of 13.2 mm, 9.5 mm, 4.75 mm, and 2.36 mm and the modified target void ratio to obtain the fitting relationship formula between the cumulative sieve residue on the sieve openings of coarse aggregates with particle sizes of 13.2 mm, 9.5 mm, 4.75 mm, and 2.36 mm and the modified target void ratio: A 13.2 + A 9.5 + A 4.75 + A 2.36 =66.12736 + 0.9274 vv ′ ，R 2 =0.667; Among them, A 9.5 Represents the cumulative sieve residue on the 9.5 mm sieve opening; A 13.2 Represents the cumulative sieve residue on the 13.2 mm sieve opening; A 4.75 Represents the cumulative sieve residue on the 4.75 mm sieve opening; A 2.36 Represents the cumulative sieve residue on the 2.36 mm sieve opening; vv ′ represents the modified target void ratio.

[0090] It should be noted that the cumulative sieve residue on the 9.5 mm sieve opening is the amount of coarse aggregates with a particle size of 9.5 mm; the cumulative sieve residue on the 13.2 mm sieve opening is the amount of coarse aggregates with a particle size of 13.2 mm; the cumulative sieve residue on the 4.75 mm sieve opening is the amount of coarse aggregates with a particle size of 4.75 mm; the cumulative sieve residue on the 2.36 mm sieve opening is the amount of coarse aggregates with a particle size of 2.36 mm.

[0091] Select the dosage of coarse aggregate with a particle size of 13.2 mm. The cumulative sieve residue percentage corresponding to 13.2 mm is between 0% and 10%. Substitute the corrected target void ratio and the corresponding binder dosage into the relational formula between the cumulative sieve residues of coarse aggregates with three particle sizes of 13.2 mm, 9.5 mm, and 4.75 mm, and the fitting relational formula between the cumulative sieve residues of coarse aggregates with particle sizes of 13.2 mm, 9.5 mm, 4.75 mm, and 2.36 mm and the corrected target void ratio to determine the dosages of coarse aggregates with particle sizes of 9.5 mm, 4.75 mm, and 2.36 mm.

[0092] In the embodiment of the present invention, by specifying the target void ratio and the cumulative sieve residue of the 13.2 mm sieve hole, and then according to the relational formula between the cumulative sieve residues of coarse aggregates with three particle sizes of 13.2 mm, 9.5 mm, and 4.75 mm, and the fitting relational formula between the cumulative sieve residues of coarse aggregates with particle sizes of 13.2 mm, 9.5 mm, 4.75 mm, and 2.36 mm and the corrected target void ratio, the dosages of coarse aggregates with particle sizes of 9.5 mm, 4.75 mm, and 2.36 mm can be calculated respectively.

[0093] Step 5.2, calculate the void ratio of the coarse aggregate.

[0094] In order to obtain the influence relationship between the cumulative sieve residues of coarse aggregates with particle sizes of 13.2 mm, 9.5 mm, 4.75 mm, and 2.36 mm on the void ratio of the coarse aggregate, take the cumulative sieve residues of coarse aggregates with particle sizes of 13.2 mm, 9.5 mm, 4.75 mm, and 2.36 mm as the four factors of the orthogonal test respectively, and within the statistical range of the cumulative sieve residues of the coarse aggregate, select different cumulative sieve residues of the coarse aggregate, use a vibrating table to conduct filling tests on the coarse aggregate with different combined dosages, and perform curve regression analysis on the obtained data to obtain the multiple linear relational formula between the void ratio of the coarse aggregate and the cumulative sieve residues of the coarse aggregate: ; Among them, VCA * represents the void ratio of the coarse aggregate; VV 0 represents the compacted void ratio of the coarse aggregate.

[0095] From the dosages of coarse aggregates with particle sizes of 13.2 mm, 9.5 mm, 4.75 mm, and 2.36 mm, calculate the void ratio of the coarse aggregate according to the multiple linear relational formula between the void ratio of the coarse aggregate and the cumulative sieve residues of the coarse aggregate.

[0096] Step 5.3, calculate the dosage of mineral powder.

[0097] According to the enclosed stack density theory, simplify the mineral powder into an average particle size of D 矿粉Equal-sized spheres, and the powder consumption within the ranges of 18% - 24% and 24% - 26% of the target void ratio is calculated. The calculation results are shown in Table 1.

[0098] Table 1 Calculation Results of Powder Consumption Note: S 粗 represents the surface area of coarse aggregate; N 总 represents the total number of powder spheres; V 粉 represents the total volume of powder; m 粉 represents the mass of powder; A 矿粉 represents the powder consumption.

[0099] Step 6: Based on the binder consumption, the corrected target void ratio, the coarse aggregate consumption, as well as the void ratio of the coarse aggregate and the powder consumption, to determine the fine aggregate consumption, obtain the reference mix proportion of the large-void epoxy resin mixture, and prepare specimens of the large-void epoxy resin mixture.

[0100] The method for calculating the fine aggregate consumption is as follows: Based on the binder consumption, the corrected target void ratio, the coarse aggregate consumption, as well as the void ratio of the coarse aggregate and the powder consumption calculated according to the above steps, substitute them into the relationship formula between different filler consumptions to calculate the fine aggregate consumption.

[0101] The filler is used to fill the void volume of the compacted skeleton of the coarse aggregate excluding the target voids. The filler includes fine aggregate, powder, and binder.

[0102] The relationship formula between different filler consumptions is: V 填充 = ( VCA * - vv ′) × V 粗集料 = m 细集料 / ρ 细集料 + m 矿粉 / ρ 矿粉 + m 胶结料 / ρ 胶结料 ; where V 填充It represents the filling volume of fine aggregate, mineral powder and binder, that is, the volume of coarse aggregate mineral aggregate that needs to be filled to remove the target void ratio, which is obtained through theoretical calculation; VCA * It represents the void ratio of coarse aggregate mineral aggregate, which is actually measured; vv ′ represents the corrected target void ratio; V 粗集料 It represents the dosage of coarse aggregate; m 细集料 It represents the mass of fine aggregate; ρ 细集料 It represents the density of fine aggregate; m 矿粉 It represents the mass of mineral powder; ρ 矿粉 It represents the density of mineral powder; m 胶结料 It represents the mass of binder; ρ 胶结料 It represents the density of binder; m 细集料 / ρ 细集料 It represents the dosage of fine aggregate; m 矿粉 / ρ 矿粉 It represents the dosage of mineral powder; m 胶结料 / ρ 胶结料 It represents the dosage of binder.

[0103] In the embodiment of the present invention, three dosages of binder are selected. According to the relational expressions between different dosages of fillers, the mix proportions of the large-void epoxy resin mixture corresponding to the three dosages of binder can be calculated, and the specimens of the large-void epoxy resin mixture are prepared.

[0104] Step 7, conduct key pavement performance verification on the specimens of the large-void epoxy resin mixture to screen out the mix proportion of the large-void epoxy resin mixture that meets the requirements of the corrected target void ratio and key pavement performance.

[0105] The specific method is: detect whether the key performance of the mix proportion of the large-void epoxy resin mixture is qualified. If it is qualified, it is determined that the design of the mix proportion of the large-void epoxy resin mixture is completed. If it is not qualified, return to Step 1 for re-design.

[0106] Specifically, according to the mix proportion of the large-void epoxy resin mixture, specimens of the large-void epoxy resin mixture are prepared, and key performance verification is conducted on the specimens of the large-void epoxy resin mixture through indoor tests. The mix proportion of the large-void epoxy resin mixture with the best key performance is selected as the target mix proportion that meets the requirements of the corrected target void ratio and key performance indicators.

[0107] Table 2 Test Results of Target Void Ratio and Key Performance Indicators of Large-Void Epoxy Resin Mixture Note: The existing commonly used porous asphalt mixtures are obtained by querying papers and statistics of actual engineering situations.

[0108] According to the requirements of the porous asphalt pavement specification, the flushing loss rate should not be greater than 15%, the permeability coefficient should not be less than 0.2 cm / s, the compressive strength of the porous asphalt mixture with a 20% void ratio is about between 1.44 MPa and 3.78 MPa, the compressive resilience modulus is not less than 700 MPa; the splitting strength of the porous asphalt mixture is mostly between 0.3 MPa and 1 MPa. Based on these four indicators, a range of binder dosages that meet the requirements is divided, and three dosages are taken at equal intervals for key pavement performance tests.

[0109] As can be seen from the results in Table 2, through the mix design of the large-void epoxy resin mixture in the embodiments of the present invention, the target void ratio, binder dosage, and mix ratio of the large-void epoxy resin mixture can be obtained. The key performance and other pavement performance of the large-void epoxy resin mixture prepared by the mix design proposed in the embodiments of the present invention all meet the requirements of the porous asphalt mixture specification.

[0110] Compared with the existing commonly used porous asphalt mixtures, the large-void epoxy resin mixture prepared in the embodiments of the present invention not only has a higher compressive strength, but also has good deformation coordination ability, excellent permeability ability, can drain quickly, and the key pavement performance is also significantly higher than that of the existing commonly used porous asphalt mixtures.

[0111] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for determining the gradation of a large-void epoxy resin mixture, characterized in that, It includes the following steps: Determine the expected target air voids of the large-void epoxy resin mixture; Establish a relationship model between the binder dosage and the expected target air voids, as well as a prediction model for the key performance of the large-void epoxy resin mixture; then, according to the expected target air voids, obtain the range of binder dosages that meet the requirements of the expected target air voids and key pavement performance requirements; the binder is an epoxy resin binder; Obtain the correction coefficient of the expected target air voids under different binder dosages, and then use the correction coefficient to correct the expected target air voids to obtain the corrected target air voids; Obtain the relationship formula between the cumulative sieve residue of different particle size coarse aggregates and the corrected target air voids, and then use the corrected target air voids to obtain the dosages of coarse aggregates of different particle sizes, and calculate the voids in the mineral aggregate of the coarse aggregates and the dosage of mineral powder; According to the binder dosage, the corrected target air voids, the dosage of coarse aggregates, the voids in the mineral aggregate of the coarse aggregates, and the dosage of mineral powder, determine the dosage of fine aggregates, obtain the reference mix proportion of the large-void epoxy resin mixture, and prepare specimens of the large-void epoxy resin mixture; Verify the key pavement performance of the large-void epoxy resin mixture specimens to screen out the mix proportion of the large-void epoxy resin mixture that meets the requirements of the corrected target air voids and key pavement performance requirements.

2. The method for determining the gradation of the large-void epoxy resin mixture according to claim 1, characterized in that The expected target air voids are 18% - 26%.

3. The method for determining the gradation of the large-void epoxy resin mixture according to claim 1, wherein The relationship model between the binder dosage and the expected target air voids is: G jd =-0.2205× vv +8.887； Among them, G jd represents the dosage of the binder with equal porosity, %; vv represents the expected target porosity, %.

4. The grading determination method of the large-void epoxy resin mixture according to claim 3, characterized in that, The prediction model for the key performance of the large-void epoxy resin mixture is: ； ； ； ； ； Among them, ∆ S represents the scattering loss rate; C w represents the permeability coefficient; R T represents the splitting strength; R C represents the compressive strength; E ' represents the compressive resilience modulus; G j represents the binder dosage, %; vv represents the expected target void ratio, %; j represents the binder; the binder is an epoxy resin binder.

5. The method for determining the gradation of the large-void epoxy resin mixture according to claim 1, wherein By weight, the epoxy resin binder is prepared from the following raw materials: 90 - 95 parts of epoxy resin, 25 - 30 parts of polyurethane prepolymer, 60 - 65 parts of diluent, 43 - 48 parts of curing agent, and 1 - 3 parts of accelerator.

6. The method for determining the gradation of the large-void epoxy resin mixture according to claim 1, characterized in that, The correction coefficient of the expected target air voids under different binder dosages is: When the binder dosage is 3.0%, , R 2 = 0.995; among them, k 3.0 represents the correction coefficient when the binder dosage is 3.0%; When the amount of binder is 3.5%, , R 2 = 0.995; among which, k 3.5 represents the correction coefficient when the amount of binder is 3.5%; When the binder dosage is 4.0%, , R 2 = 0.995; among them, k 4.0 represents the correction coefficient when the binder dosage is 4.0%; When the amount of binder is 4.5%, , R 2 = 0.995; among them, k 4.5 represents the correction coefficient when the amount of binder is 4.5%; When the binder dosage is 5.0%, , R 2 = 0.995; among which, k 5.0 represents the correction coefficient when the binder dosage is 5.0%.

7. The method for determining the gradation of the large-void epoxy resin mixture according to claim 1, characterized in that The method of using the correction coefficient to correct the expected target air voids is: Establish a relationship formula between the expected target air voids and the corrected target air voids: ； Among them, vv ′ represents the corrected target void ratio; vv represents the predicted target void ratio, %; k represents the correction coefficient; According to the correction coefficient of the expected target air voids under different binder dosages and the expected target air voids, substitute them into the relationship formula between the expected target air voids and the corrected target air voids to calculate the corrected target air voids.

8. The method for determining the gradation of the large-void epoxy resin mixture according to claim 1, characterized in that The relationship formula between the cumulative sieve residue of different particle size coarse aggregates and the corrected target air voids is: A 13.2 + A 9.5 + A 4.75 + A 2.36 =66.12736+0.9274 vv ′ ，R 2 =0.667； A 9.5 =40.22719× A 13.2 -0.22435 ， R 2 =0.931； A 4.75 =170.8763×（ A 13.2 + A 9.5 ） -0.37481 ， R 2 =0.959； Among them, A 9.5 represents the cumulative percentage retained on the 9.5 mm sieve; A 13.2 represents the cumulative percentage retained on the 13.2 mm sieve; A 4.75 represents the cumulative percentage retained on the 4.75 mm sieve; A 2.36 represents the cumulative percentage retained on the 2.36 mm sieve; vv ' represents the corrected target void ratio.

9. The method for determining the gradation of the large-void epoxy resin mixture according to claim 8, wherein The method of calculating the voids in the mineral aggregate of the coarse aggregates and the dosage of mineral powder is: Obtain the multiple linear relationship formula between the voids in the mineral aggregate of the coarse aggregates and the cumulative sieve residue of the coarse aggregates; then, according to the cumulative sieve residue of the coarse aggregates, calculate the voids in the mineral aggregate of the coarse aggregates; According to the enclosed stack density theory, calculate the dosage of mineral powder for different target air voids; The multiple linear relationship formula between the voids in the mineral aggregate of the coarse aggregates and the cumulative sieve residue of the coarse aggregates is: ； Among them, VCA * represents the void ratio of coarse aggregate mineral aggregate; VV 0 represents the compacted void ratio of coarse aggregate.

10. The method for determining the gradation of the large-void epoxy resin mixture according to claim 1, wherein The method of determining the dosage of fine aggregates is: Calculate the dosage of fine aggregates according to the relationship formula between different filler dosages; The relationship formula between different filler dosages is: V 填充 =（ VCA * - vv ′）× V 粗集料 = m 细集料 / ρ 细集料 + m 矿粉 / ρ 矿粉 + m 胶结料 / ρ 胶结料 ； Among them, V 填充 represents the filling volume of fine aggregate, mineral powder and binder; VCA * represents the void ratio of coarse aggregate; vv ′ represents the corrected target void ratio; V 粗集料 represents the amount of coarse aggregate; m 细集料 represents the mass of fine aggregate; ρ 细集料 represents the density of fine aggregate; m 矿粉 represents the mass of mineral powder; ρ 矿粉 represents the density of mineral powder; m 胶结料 represents the mass of binder; ρ 胶结料 represents the density of binder; m 细集料 / ρ 细集料 represents the amount of fine aggregate; m 矿粉 / ρ 矿粉 represents the amount of mineral powder; m 胶结料 / ρ 胶结料 represents the amount of binder.

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