Normal temperature mixed asphalt mortar and integrated semi-flexible pavement material

Abstract

The present application relates to a kind of normal temperature mixed asphalt mortar, it includes: mixed asphalt and cement mortar;The mixed asphalt and cement mortar are mixed evenly after being respectively prepared, then are prepared;Mixed asphalt is the reactive normal temperature-emulsified asphalt obtained by reactive normal temperature asphalt and emulsified asphalt, and mixed asphalt contains defoaming agent;Cement mortar includes Portland cement, water, silica fume and additive;Reactive normal temperature asphalt is prepared by adding reactive liquidizer and modifier waterborne epoxy resin emulsion to matrix asphalt in flow state and shearing mixing.Mixed asphalt has better low temperature performance, and the integrated semi-flexible pavement construction pavement material is prepared using the mixed asphalt and RAP etc. Aggregate, can normal temperature or low temperature mixing and paving, retains the advantage of traditional perfusion type semi-flexible pavement, improves the low temperature crack resistance of semi-flexible pavement, does not need heating throughout, protects environment and reduces pavement material cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pavement construction, in particular to a normal-temperature mixed asphalt mortar and an integrated semi-flexible pavement material. BACKGROUND

[0002] Highway pavement is mainly divided into asphalt pavement and cement pavement, the mechanical properties of asphalt pavement will change constantly with the change of climate, in summer when the temperature is high, asphalt pavement often appears wave, bag, push, rut and other diseases; in winter when the temperature is low, asphalt pavement will appear brittle, deformation capacity is reduced, plus the repeated action of driving load, easy to cause asphalt pavement cracking and other diseases. Cement pavement has the common shortcomings of easy damage at the joint, complex construction procedure, poor pavement flatness after construction, low driving comfort and the like. At the same time, with the continuous increase of the number of vehicles, a large number of already built asphalt pavement needs large-scale repair and reconstruction, a large amount of waste asphalt mixture (RAP) will be produced in the process of repair and reconstruction. The random stacking of RAP not only will harm the natural environment, but also will consume huge space resources, which is contrary to the policy of sustainable development in China.

[0003] Asphalt pavement and cement pavement have their own advantages and disadvantages. Is there a kind of pavement that has the "soft" characteristics of asphalt pavement and the "stiff" advantages of cement pavement? After long-term efforts by domestic and foreign scholars, a pavement that meets both the "soft" characteristics of asphalt pavement and the "stiff" advantages of cement pavement has emerged. Domestic and foreign scholars call this special pavement perfusion semi-flexible pavement. Traditional semi-flexible pavement (SFP) refers to a pavement formed by perfusing a slurry mainly composed of cement-based materials in a high-void-ratio (up to 20-28%) large-void matrix asphalt mixture. This pavement structure has the advantages of seamless construction, high strength, high durability, good impermeability, etc. Compared with common asphalt pavement and cement pavement, semi-flexible pavement material is a composite material that combines the "stiff" and "soft" characteristics of asphalt pavement and cement pavement. Because of its unique preparation method and material composition, this pavement has the advantages of shock absorption and sound absorption of asphalt pavement, driving comfort, etc. At the same time, it also has the advantages of high bearing capacity and high anti-rutting performance of cement pavement. Its high-temperature stability, water stability, and fatigue resistance are all better than those of general asphalt pavement. It also has excellent properties such as oil resistance, acid resistance, heat resistance, water resistance, skid resistance, and easy coloring. However, the disadvantages and problems of semi-flexible pavement are also obvious, which further limits its development. These problems mainly include: first, due to its special material composition, semi-flexible pavement has poor low-temperature crack resistance. When the seasonal temperature difference is large and the minimum temperature is low, cracks are likely to occur, reducing its service life, especially in extremely cold winters in the three northeastern provinces. Second, the step-by-step forming process is complicated and energy-consuming and polluting. It needs to first mix and pave the large-void asphalt mixture, and then prepare the cement slurry on site for perfusion. This complex forming process not only requires multiple machines to work together, but also requires high-temperature heating of the large-void asphalt mixture during mixing and paving, which consumes a lot of energy and produces toxic exhaust gases. The construction has high requirements for environmental temperature, consumes a lot of manpower and financial resources, and causes serious environmental pollution. Therefore, semi-flexible pavement has not been widely used. SUMMARY

[0004] (I) Technical problems to be solved

[0005] To solve the above problems, the present application provides a normal-temperature mixed asphalt mortar and an integrated semi-flexible pavement material made of normal-temperature mixed asphalt mortar and coarse and fine aggregates or RAP. The integrated semi-flexible pavement material not only retains the advantages of traditional semi-flexible pavement, but also solves the problems of insufficient low-temperature crack resistance, complicated forming process, and high energy consumption and pollution of traditional semi-flexible pavement.

[0006] (II) Technical Solution

[0007] The technical solution of the present application is as follows:

[0008] In a first aspect, the present application provides a normal-temperature mixed asphalt mortar, which comprises: mixed asphalt and cement mortar; the mixed asphalt and cement mortar are mixed and uniformly stirred after being respectively prepared to obtain the normal-temperature mixed asphalt mortar.

[0009] The mixed asphalt is a reaction-type normal-temperature-emulsified asphalt obtained by mixing a reaction-type normal-temperature asphalt and an emulsified asphalt, and the mixed asphalt contains a defoaming agent.

[0010] The cement mortar comprises Portland cement, water, silica fume and an additive.

[0011] The reaction-type normal-temperature asphalt is prepared by adding a reaction-type liquefying agent and a modified water-based epoxy resin emulsion to a matrix asphalt in a flowable state and shearing and mixing; wherein the reaction-type liquefying agent is prepared by stirring and mixing unsaturated fatty acid as a liquefying agent base material, and adding an amphoteric ionic surfactant and a phenol polymer.

[0012] In a preferred embodiment of the present application, the mass ratio of pure matrix asphalt in the emulsified asphalt to pure asphalt in the reaction-type normal-temperature asphalt in the reaction-type normal-temperature-emulsified asphalt is 4:1-1:4.

[0013] The mass ratio of the emulsified asphalt to the pure asphalt in the reaction-type normal-temperature asphalt is defined as the emulsion-normal ratio, and when the emulsion-normal ratio is 4:1, 3:1, 2:1, 1:1, 1:2, 1:3 or 1:4, the softening point of the mixed asphalt decreases from 48.5℃ to 31.5℃; the softening point continuously decreases, which is related to the continuously increasing proportion of the reaction-type normal-temperature asphalt in the mixed asphalt, and the increasing proportion of the reaction-type normal-temperature asphalt also leads to the continuously increasing penetration index of the mixed asphalt. The low-temperature performance of the mixed asphalt is tested at 5℃, and the test results show that the ductility of the mixed asphalt at 5℃ increases from 10cm to 80cm and then decreases to 45cm, which shows a trend of first increasing and then decreasing, and reaches a peak at the emulsion-normal ratio of 1:1 and tends to be stable at the emulsion-normal ratios of 1:3 and 1:4. Comprehensive analysis shows that the comprehensive performance is relatively excellent when the emulsion-normal ratio is 1:2, 1:1 or 2:1.

[0014] According to the preferred embodiment of the present application, if the bitumen-cement ratio is defined as the ratio of the total mass of the pure bitumen in the reactive normal-temperature bitumen and the emulsified bitumen to the total mass of the cement and the silica fume, the bitumen-cement ratio is 0.10-0.25, preferably 0.1, 0.15, 0.20 or 0.25. Experiments show that with the increase of the bitumen-cement ratio, the bitumen film increases, the retarding effect on the cement hydration is obviously enhanced, the early hydration of the cement is restricted, and the production of the final hydration product is affected. Too large bitumen content will affect the development of the strength of the bitumen mortar. Therefore, the bitumen-cement ratio cannot be too high, especially cannot exceed 0.25.

[0015] According to the preferred embodiment of the present application, the water-cement ratio of the cement mortar is 0.25-0.35. The water-cement ratio is related to the bitumen-cement ratio. With the increase of the bitumen-cement ratio, i.e. the increase of the bitumen content, the water-cement ratio at which the mortar can exhibit the best performance also increases. When the bitumen-cement ratio is 0.20, the water-cement ratio is 0.30, the reactive normal-temperature-emulsified bitumen mortar can exhibit the best performance. This is mainly because the increase of the bitumen content increases the bitumen film in the mortar, which prevents the water from fully contacting the cement. The increase of the bitumen film also causes the water in the cement to be unable to be released, thereby increasing the water consumption.

[0016] According to the preferred embodiment of the present application, if the silica fume ratio in the cement mortar is defined as the ratio of the mass of the silica fume to the total mass of the cement and the silica fume, the silica fume ratio is 0.01-0.10, preferably 0.03-0.09. The silica fume ratio is related to the bitumen-cement ratio and the water-cement ratio. With the increase of the bitumen-cement ratio, the bitumen film increases, which prevents the water from fully contacting the cement, and more water is needed for the cement to hydrate, so the water consumption increases. Meanwhile, the increase of the bitumen-cement ratio increases the content of the reactive normal-temperature bitumen in the mortar, and the increase of the content of the reactive normal-temperature bitumen requires more cement mortar to achieve solidification. The increase of the water-cement ratio enables the silica fume to further play its "ball bearing" role in the mortar, to a certain extent, increases the fluidity of the mortar, and improves the flexural performance of the mortar. The addition of the silica fume can improve the compressive strength of the paste, but the content should not be too high. The corresponding flexural strength increases to a certain level with the increase of the content of the silica fume, but the performance remains stable and does not increase any more.

[0017] According to the preferred embodiment of the present application, fine sand is further added to the cement mortar, and the ratio of the mass of the fine sand to the total mass of the cement and the silica fume is ≤0.1, preferably 0.1, and the minimum can be 0.

[0018] According to the preferred embodiment of the present application, when the bitumen-cement ratio is 0.10,

[0019] The water-cement ratio is 0.25, the silica-cement ratio is 0.03, and the mass ratio of pure base asphalt in the emulsified asphalt and pure base asphalt in the reactive normal-temperature asphalt is 1:2, at this time, the flow degree ( / s) of the normal-temperature mixed asphalt mortar is 26.1, the 7d compressive strength ( / MPa) is 21.2, the 7d bending strength ( / MPa) is 13.1, and the compression-bending ratio is 1.618;

[0020] Alternatively, the water-cement ratio is 0.25, the silica-cement ratio is 0.09, and the mass ratio of pure base asphalt in the emulsified asphalt and pure base asphalt in the reactive normal-temperature asphalt is 2:1, at this time, the flow degree ( / s) of the normal-temperature mixed asphalt mortar is 27.8, the 7d compressive strength ( / MPa) is 24.8, the 7d bending strength ( / MPa) is 14.4, and the compression-bending ratio is 1.722;

[0021] Alternatively, the water-cement ratio is 0.30, the silica-cement ratio is 0.06, and the mass ratio of pure base asphalt in the emulsified asphalt and pure base asphalt in the reactive normal-temperature asphalt is 2:1, at this time, the flow degree ( / s) of the normal-temperature mixed asphalt mortar is 26.5, the 7d compressive strength ( / MPa) is 20.8, the 7d bending strength ( / MPa) is 13.6, and the compression-bending ratio is 1.529;

[0022] Alternatively, the water-cement ratio is 0.25, the silica-cement ratio is 0.06, and the mass ratio of pure base asphalt in the emulsified asphalt and pure base asphalt in the reactive normal-temperature asphalt is 1:1, at this time, the flow degree ( / s) of the normal-temperature mixed asphalt mortar is 26.7, the 7d compressive strength ( / MPa) is 22.8, the 7d bending strength ( / MPa) is 13.7, and the compression-bending ratio is 1.664.

[0023] According to the preferred embodiment of the present application, when the asphalt-cement ratio is 0.15;

[0024] The water-cement ratio is 0.25, the silica-cement ratio is 0.06, and the mass ratio of pure base asphalt in the emulsified asphalt and pure base asphalt in the reactive normal-temperature asphalt is 1:1, at this time, the flow degree ( / s) of the normal-temperature mixed asphalt mortar is 27.2, the 7d compressive strength ( / MPa) is 18.7, the 7d bending strength ( / MPa) is 12.1, and the compression-bending ratio is 1.545;

[0025] Alternatively, the water-cement ratio is 0.25, the silica-cement ratio is 0.09, and the mass ratio of pure base asphalt in the emulsified asphalt and pure base asphalt in the reactive normal-temperature asphalt is 2:1, at this time, the flow degree ( / s) of the normal-temperature mixed asphalt mortar is 28.1, the 7d compressive strength ( / MPa) is 19.2, the 7d bending strength ( / MPa) is 11.8, and the compression-bending ratio is 1.627.

[0026] According to the preferred embodiment of the present application, when the asphalt-cement ratio is 0.20;

[0027] water-cement ratio is 0.30, silica-cement ratio is 0.03, and the mass ratio of pure base asphalt in the emulsified asphalt and pure base asphalt in the reactive normal-temperature asphalt is 1:1; at this time, the flow degree ( / s) of the normal-temperature mixed asphalt mortar is 27.1, the 7d compressive strength ( / MPa) is 17.8, the 7d flexural strength ( / MPa) is 10.8, and the compression-flexure ratio is 1.648;

[0028] Alternatively, the water-cement ratio is 0.30, the silica-cement ratio is 0.06, and the mass ratio of pure base asphalt in the emulsified asphalt and pure base asphalt in the reactive normal-temperature asphalt is 2:1; at this time, the flow degree ( / s) of the normal-temperature mixed asphalt mortar is 26.3, the 7d compressive strength ( / MPa) is 18.4, the 7d flexural strength ( / MPa) is 11.5, and the compression-flexure ratio is 1.600;

[0029] Alternatively, the water-cement ratio is 0.30, the silica-cement ratio is 0.09, and the mass ratio of pure base asphalt in the emulsified asphalt and pure base asphalt in the reactive normal-temperature asphalt is 1:2; at this time, the flow degree ( / s) of the normal-temperature mixed asphalt mortar is 28.5, the 7d compressive strength ( / MPa) is 16.5, the 7d flexural strength ( / MPa) is 10.3, and the compression-flexure ratio is 1.602.

[0030] According to the preferred embodiment of the present application, when the asphalt-cement ratio is 0.25;

[0031] the water-cement ratio is 0.30, the silica-cement ratio is 0.09, and the mass ratio of pure base asphalt in the emulsified asphalt and pure base asphalt in the reactive normal-temperature asphalt is 1:2; at this time, the flow degree ( / s) of the normal-temperature mixed asphalt mortar is 29.1, the 7d compressive strength ( / MPa) is 17.3, the 7d flexural strength ( / MPa) is 9.2, and the compression-flexure ratio is 1.880;

[0032] Alternatively, the water-cement ratio is 0.30, the silica-cement ratio is 0.03, and the mass ratio of pure base asphalt in the emulsified asphalt and pure base asphalt in the reactive normal-temperature asphalt is 1:1; at this time, the flow degree ( / s) of the normal-temperature mixed asphalt mortar is 29.5, the 7d compressive strength ( / MPa) is 16.3, the 7d flexural strength ( / MPa) is 8.2, and the compression-flexure ratio is 1.988.

[0033] In the normal-temperature mixed asphalt mortar of the present application, the addition of the reactive normal-temperature asphalt can significantly improve the flexural performance of the mortar; when the asphalt-cement ratio is 0.10 or 0.15, the overall mechanical strength of the asphalt mortar decreases more obviously with the increase of the water-cement ratio; and when the water-cement ratio is 0.25, the overall target performance is more excellent. Compared with the pure cement mortar test sample without mixed asphalt, the normal-temperature mixed asphalt mortar of the present application significantly improves the compression damage toughness of the mortar material.

[0034] According to the preferred embodiment of the present application, the emulsified asphalt is cationic emulsified asphalt or anionic emulsified asphalt, preferably anionic emulsified asphalt. The main component of the reactive diluent is an acidic substance, which also causes the modified reactive asphalt at room temperature to be acidic. This feature makes the demulsification speed faster during the mixing process of the modified reactive asphalt and the cationic emulsified asphalt, and the mixing effect is affected to a certain extent. When the emulsified asphalt is anionic emulsified asphalt, the modified reactive asphalt at room temperature and the anionic emulsified asphalt not only have a better mixing effect, but also can effectively release the flocculated cement particles and reduce the water-cement ratio during the subsequent preparation of the modified reactive asphalt at room temperature-emulsified asphalt mortar. In addition, the mechanical properties of the asphalt mortar can be enhanced to a certain extent.

[0035] According to the preferred embodiment of the present application, the additive comprises a defoaming agent, an expanding agent, and a water reducing agent; the defoaming agent is mixed in an amount of 0.4-1% (preferably 0.5%) of the total mass of silica fume and cement, the expanding agent is 0.4-1% (preferably 0.5%) of the total mass of silica fume and cement, and the water reducing agent is mixed in an amount of 1-2% of the total mass of silica fume and cement.

[0036] When the water reducing agent is a naphthalene series water reducing agent or a polycarboxylic acid water reducing agent, the optimal amount of the naphthalene series water reducing agent is 2% of the total mass of silica fume and cement, and the optimal amount of the polycarboxylic acid water reducing agent is 1% of the total mass of silica fume and cement.

[0037] According to the preferred embodiment of the present application, the reactive asphalt at room temperature is prepared by adding 20-30 parts by mass of a reactive liquefying agent and 10-20 parts by mass of an aqueous epoxy resin emulsion modifier to 50-60 parts by mass of a base asphalt that is in a flowable state after being heated at a high temperature, and then mixing them by shearing stirring. The reactive liquefying agent is prepared by adding alkyl dimethyl betaine and phenol polymer to an unsaturated fatty acid as a liquefying agent base material and then stirring and mixing them. The mass ratio of the unsaturated fatty acid, the alkyl dimethyl betaine, and the phenol polymer is 15-25:5-10:1-5. The unsaturated fatty acid is at least one of myristoleic acid, trans-oleic acid, oleic acid, linoleic acid, erucic acid, palmitoleic acid, and ricinoleic acid. The alkyl dimethyl betaine is C10-20 alkyl dimethyl betaine. The phenol polymer is tri-(dimethylaminomethyl) phenol polymer. The technology of the reactive asphalt at room temperature is a technology developed by the inventors' team and has been applied for patent protection.

[0038] According to the preferred embodiment of the present application, 10-20 parts by weight of a coupling agent are further added to the reactive asphalt at room temperature. The coupling agent is a silane coupling agent, preferably C10-20 alkyl triethoxysilane.

[0039] According to the preferred embodiment of the present application, the base asphalt in the reactive asphalt at room temperature is 70# asphalt as the base asphalt.

[0040] In a second aspect, the present application provides a preparation method of the asphalt mortar at room temperature, which comprises:

[0041] S1, mixing the reactive asphalt at room temperature and the emulsified asphalt by shearing mixing mode (such as a shearing instrument), and adding a defoaming agent with a mass ratio of 0.4-0.6% (preferably 0.5%) before shearing starts, the shearing rotation speed is 1200-1800 rpm (preferably 1500 rpm), and the shearing stirring is performed at room temperature for 5-20 min to prepare the reactive asphalt at room temperature-emulsified asphalt;

[0042] mixing the portland cement, water, silica fume and the additive agent uniformly to prepare the cement mortar, wherein the additive agent comprises the defoaming agent, the expanding agent and the water reducing agent;

[0043] S2, mixing the reactive asphalt at room temperature-emulsified asphalt and the cement mortar, and preparing the asphalt mortar slurry after sufficient mixing at room temperature.

[0044] Before the reactive asphalt at room temperature-emulsified asphalt is prepared, the reactive asphalt at room temperature is prevented from directly contacting the cement powder particles to avoid the early solidification of the reactive asphalt at room temperature and affect the mechanical strength of the subsequent asphalt mortar. In the preparation of the reactive asphalt at room temperature-emulsified asphalt, the defoaming agent plays an important role, and the purpose is to eliminate the foam to obtain dense and uniform mixed asphalt, and the shearing stirring time is preferably not more than 20 min.

[0045] In a third aspect, the present application provides an integrated semi-flexible pavement material which is prepared by integrally mixing and stirring the asphalt mortar at room temperature and the large-void base mixture grading. Different from the traditional semi-flexible pavement material, the integrated mixing and stirring process does not need to be performed in steps, and the stirring temperature is room temperature (slightly lower temperature) or not more than 60°C, so that heating stirring is not needed, the energy consumption is low, the construction pollution is small, the construction environment temperature requirement is low, and the pavement material has excellent low-temperature resistance.

[0046] The large-void base mixture grading has a void ratio of 20-28%, and is composed of limestone aggregate and pretreated RAP, wherein the pretreatment is the adhesion improvement treatment by using the reactive asphalt at room temperature-emulsified asphalt mortar.

[0047] The RAP is subjected to screening treatment, the RAP incorporation mode is determined according to the particle size distribution rule, and a part of the limestone aggregate with the same grading is directly replaced, and the RAP is subjected to surface pretreatment by using the reactive asphalt at room temperature-emulsified asphalt mortar before use. For example, if the limestone aggregate grading is AC-13, the RAP is obtained by screening after the RAP milling of the original asphalt pavement with the grading of AC-13.

[0048] Preferably, if the selected limestone aggregate gradation is AC-13, the RAP is screened from the RAP milling of the original asphalt pavement with the gradation of AC-13.

[0049] Experiments prove that when the void ratio of the large-void matrix mixture gradation is 25%, the average filling rate of the integral semi-flexible pavement material of the present application is as high as 98.95%. This shows that the present application has a higher filling rate of the slurry than the traditional cast semi-flexible pavement material by directly mixing the normal-temperature mixed asphalt slurry and the large-void matrix mixture gradation, and confirms the feasibility of the process of the integral semi-flexible pavement material of the present application.

[0050] According to the preferred embodiment of the present application, the RAP content in the large-void matrix mixture gradation ranges from 30% to 50%.

[0051] According to the preferred embodiment of the present application, when the RAP content is 30%, the pure asphalt (total pure asphalt from reactive normal-temperature asphalt and emulsified asphalt) content is 3.30-3.43%, preferably 3.37%; when the RAP content is 40%, the pure asphalt content is 3.30-3.37%, preferably 3.34%; and when the RAP content is 50%, the pure asphalt content is 3.27-3.34%, preferably 3.31%.

[0052] The test results show that the integral semi-flexible pavement material not only retains the excellent high-temperature performance of SPF, with a dynamic stability of more than 9000 times / mm, but also improves the low-temperature crack resistance, and the integral semi-flexible pavement material with a sand ratio of 0.20 and a RAP content of 30% can be used in cold winter and cold (warm) regions; the water stability and anti-skid performance of the integral semi-flexible pavement material are both good.

[0053] (Three) Beneficial Effects

[0054] (1) The normal-temperature mixed asphalt slurry of the present application is prepared by uniformly mixing the mixed asphalt and the cement slurry, and the mixed asphalt is prepared by mixing the reactive normal-temperature asphalt and the emulsified asphalt. Compared with the emulsified asphalt, the mixed asphalt has better low-temperature performance. By comparing the 7d compressive strength, the flexural strength and the compression-folding ratio of the reactive normal-temperature-emulsified asphalt slurry under different sand ratios, it can be found that the addition of the reactive normal-temperature-emulsified asphalt can significantly improve the flexural performance of the slurry. When the sand ratio is 0.10 or 0.15, the overall mechanical strength of the asphalt slurry decreases obviously with the increase of the water-cement ratio, and when the water-cement ratio is 0.25, the overall target performance is excellent, and the compression failure toughness of the pure slurry material is significantly improved.

[0055] (2) In the process of preparing asphalt mortar at room temperature, the addition of cement mortar can compensate for the deficiency of reactive asphalt at room temperature in high-temperature performance to a certain extent; the excellent ability of reactive asphalt at room temperature to resist cracking at low ambient temperature can compensate for the poor ability of asphalt mortar to resist cracking at low temperature, so as to achieve the effect of performance complementation. The addition of silica fume can play a "ball bearing" role in the mortar, increase the fluidity of the mortar, and improve the bending performance of the mortar. The addition of silica fume can also improve the compressive strength of the mortar.

[0056] (3) Based on the above-mentioned asphalt mortar at room temperature, an integrated semi-flexible pavement material can be prepared by adding coarse and fine aggregates. The cement hydration product and the asphalt film generated by the reaction of reactive asphalt at room temperature and emulsified asphalt are interwoven to form a relatively dense network structure of cement particles, asphalt film, and cement hydration product, thereby improving adhesion. Compared with traditional semi-flexible pavement materials, the steps of cement grouting and heating of the base mixture are omitted, and the cold mixing (mixing at room temperature or low temperature) process can be used throughout the construction process, which not only retains the advantages of traditional semi-flexible pavement materials, but also improves the poor low-temperature cracking resistance of semi-flexible pavement materials. The traditional hot mixing process with high energy consumption and high pollution is changed, and the whole process does not need heating, which speeds up the construction process. The coarse and fine aggregates are partially derived from RAP, which not only handles the accumulation of waste asphalt mixture, but also recycles and reuses the resources, protects the environment, and reduces the cost of pavement materials. BRIEF DESCRIPTION OF DRAWINGS

[0057] Figure 1 SEM images of four kinds of asphalt mortar at room temperature with cement mortar ratio of 0.1, 0.15, 0.20, and 0.25 for the pure cement mortar of Comparative Example 1.

[0058] Figure 2 The structure of the aggregate with gradation AC-13 is still maintained after the RAP milling and screening of the asphalt pavement with original gradation AC-13.

[0059] Figure 3 The wrapping effect before and after water boiling of the reactive asphalt at room temperature-emulsified asphalt (emulsified asphalt ratio 1:1) pretreated RAP.

[0060] Figure 4 The process diagram of loading test on the middle section of the beam at a temperature of 10°C for testing the low-temperature cracking resistance of the integrated semi-flexible pavement material. DETAILED DESCRIPTION

[0061] For better explanation of the present application, in order to facilitate understanding, the present application is described in detail below through specific embodiments combined with the drawings. In the following examples, when the fraction is not specifically mentioned, it means the mass fraction, and if not mentioned, it means the mass percentage.

[0062] The present application mainly utilizes the respective properties and advantages of reactive normal temperature asphalt and emulsified asphalt to complement each other. The reactive normal temperature asphalt is used to enable the mixed asphalt mortar to be mixed and paved at normal temperature and to improve the low temperature performance. The reactive normal temperature asphalt is easy to solidify with cement. The use of emulsified asphalt can dilute the reactive normal temperature asphalt and reduce the solidification reaction speed. With the increasing proportion of reactive normal temperature asphalt in the reactive normal temperature-emulsified asphalt, the high temperature performance of the reactive normal temperature-emulsified asphalt is significantly reduced, and the low temperature performance is greatly improved. The reason for this phenomenon may be that the modifiers such as polymeric reaction agent, surfactant, and unsaturated fatty acid in the reactive normal temperature asphalt also have a modifying and diluting effect on the evaporation residue of the emulsified asphalt, so that the light components in the mixed asphalt increase and the viscosity is obviously lower than that of the general emulsified asphalt. At the same time, with the increasing proportion of the reactive normal temperature asphalt in the mixed asphalt, the softening point of the reactive normal temperature-emulsified asphalt is reduced, the penetration is increased, and the ductility is significantly improved under the action of the modifiers such as polymeric reaction agent, surfactant, and unsaturated fatty acid. This shows that with the increasing proportion of the reactive normal temperature asphalt in the mixed asphalt, the low temperature cracking resistance of the mixed asphalt is improved to a certain extent, and the cracking of the reactive normal temperature-emulsified asphalt at low temperature is effectively prevented.

[0063] Example 1

[0064] The present application provides a normal temperature mixed asphalt mortar, which comprises mixed asphalt and cement mortar; the mixed asphalt and the cement mortar are mixed and uniformly stirred after being prepared respectively to obtain the normal temperature mixed asphalt mortar. Specifically, the preparation method is as follows:

[0065] (1) Preparation of reactive normal temperature asphalt: 55 parts of base asphalt (70# asphalt is used as the base asphalt) is heated to 140°C, and 23 parts of reactive liquidizer is added under the shear stirring at 80 rpm. The stirring is performed for 15 min until the reactive normal temperature asphalt is completely dispersed and uniform. The reactive liquidizer is prepared by stirring and mixing castor oil acid, dodecyl dimethyl betaine, and tri- (dimethylaminomethyl) phenol polymer at a mass ratio of 10:3:1.5.

[0066] (2) Preparation of reactive normal temperature-emulsified mixed asphalt: BC-1 type cationic middle crack type emulsified asphalt for mixing is selected and mixed with the reactive normal temperature asphalt, so that the mass fraction ratio of the pure asphalt in the emulsified asphalt and the reactive normal temperature asphalt (hereinafter referred to as the emulsified asphalt ratio) is 1:2.

[0067] The reactive cold asphalt and the emulsified asphalt were mixed by using a shear instrument, and 0.5% of defoaming agent was added before the start of shearing, the shearing speed was 1500 rpm, and the reactive cold-emulsified asphalt was prepared by shearing and stirring for 20 min at room temperature.

[0068] (3) Preparation of cement mortar: P. I 62.5 grade Portland cement, 80 mesh corundum, silica fume, defoaming agent, expanding agent and water reducing agent were mixed to prepare cement mortar. The water-cement ratio (the ratio of water to the sum of the mass of cement and silica fume) was 0.25, the silica fume ratio (the ratio of the mass of silica fume to the sum of the mass of cement and silica fume) was 0.09, and the mass ratio of corundum and silica fume to the sum of the mass of cement and silica fume was 0.1. The defoaming agent was 0.5% of the total mass of silica fume and cement, the expanding agent was 0.5% of the total mass of silica fume and cement, and the polycarboxylic acid water reducing agent was 1% of the total mass of silica fume and cement.

[0069] (4) The reactive cold-emulsified mixed asphalt of step (2) was mixed with the cement mortar of step (3) to prepare a cold mixed asphalt mortar. When mixing, the mass ratio of pure asphalt to the sum of the mass of silica fume and cement (i.e. the asphalt-silica fume ratio) was 0.10, based on the amount of pure asphalt in the reactive cold-emulsified mixed asphalt.

[0070] Examples 2-9

[0071] Examples 2-9 were based on Example 1, the water-cement ratio (A) of step (3) was changed between 0.25, 0.30 and 0.35, and the silica fume ratio (B) of step (3) was changed between 0.03, 0.06 and 0.09, and the mass fraction ratio of emulsified asphalt to pure asphalt in the reactive cold-emulsified mixed asphalt (hereinafter referred to as the emulsified asphalt-reactive cold asphalt ratio) was changed between 1:1, 2:1 and 1:2 in step (2). The specific changes are shown in the following table (Table 1):

[0072] Table 1:

[0073]

[0074] Comparative Example 1

[0075] The comparative example was a pure cement-based mortar, the water-cement ratio was 0.30, the silica fume ratio was 0.06, and the fine sand content was 0.1.

[0076] The cold mixed asphalt mortar of Examples 1-9 and the pure cement mortar of Comparative Example 1 were made into test pieces, and the flowability ( / s), 7d compressive strength ( / MPa), 7d flexural strength ( / MPa) and compression-flexure ratio of the mortars of Examples 1-9 and Comparative Example 1 were compared. The comparison results are shown in Table 2 (Table 2) below:

[0077] Table 2:

[0078]

[0079] From the above table, it can be seen that when the pitch-cement ratio = 0.1, the performance of the normal-temperature mixed asphalt mortar of Examples 1-3 and 5 is optimal, the fluidity, the bending strength, etc. are much greater than those of Comparative Example 1, and the compression-bending ratio is lower than that of Comparative Example 1, indicating that the normal-temperature mixed asphalt mortar of the application has greater toughness.

[0080] Examples 10-14

[0081] Examples 10-14 are based on Example 1, and the mixing ratio of the reactive normal-temperature-emulsified mixed asphalt and the cement mortar in step (4) is adjusted, and the ratio of the mass of pure asphalt to the mass of silica fume to the sum of the mass of cement and the mass of silica fume (i.e. the pitch-cement ratio) is increased to 0.15. That is, the amount of the reactive normal-temperature-emulsified mixed asphalt is increased based on Example 1.

[0082] Then, the water-cement ratio (A) of step (3) is adjusted to vary between 0.25 and 0.30, and the silica fume ratio (B) of step (3) is adjusted to vary between 0.03, 0.06 and 0.09, and when the reactive normal-temperature-emulsified mixed asphalt is prepared in step (2), the mass fraction ratio of the emulsified asphalt to the pure asphalt in the reactive normal-temperature asphalt (hereinafter referred to as the emulsion-normal ratio) is adjusted to vary between 1:1, 2:1 and 1:2, and the specific changes are as follows in Table (Table 3):

[0083] Table 3:

[0084]

[0085] The normal-temperature mixed asphalt mortar of Examples 10-14 is made into test pieces, and the parameters of the mortar fluidity ( / s), 7d compressive strength ( / MPa), 7d bending strength ( / MPa), and compression-bending ratio, etc. are tested. The comparison results are as follows in Table 4 (Table 4):

[0086] Table 4:

[0087]

[0088] From the above table, it can be seen that when the pitch-cement ratio = 0.15, the normal-temperature mixed asphalt mortar of Examples 10 and 11 has the optimal performance of fluidity, compressive strength, and bending strength, but the compressive strength and the bending strength are lower than those of Example 1. This indicates that after the pitch-cement ratio is increased, the fluidity of the normal-temperature mixed asphalt mortar is increased, but the compressive strength and the bending strength are decreased.

[0089] Examples 15-20

[0090] Examples 15-20 are based on Example 1, in which the mixing ratio of the reactive normal-temperature-emulsified mixed asphalt to the cement mortar in step (4) is adjusted, and the ratio of the mass of the pure asphalt to the mass of the silica fume to the sum of the mass of the cement and the mass of the silica fume (i.e., the asphalt-silica fume ratio) is increased to 0.20. That is, the amount of the reactive normal-temperature-emulsified mixed asphalt is continuously increased based on Example 1.

[0091] Then, the water-cement ratio (A) in step (3) is adjusted to vary between 0.25 and 0.30, the silica fume ratio (B) in step (3) is adjusted to vary between 0.03, 0.06 and 0.09, and the mass fraction ratio of the emulsified asphalt to the pure asphalt in the reactive normal-temperature asphalt (hereinafter referred to as the emulsified asphalt-reactive normal-temperature asphalt ratio) in step (2) is adjusted to vary between 1:1, 2:1 and 1:2. The specific variations are shown in Table 5 below:

[0092] Table 5:

[0093]

[0094] The normal-temperature mixed asphalt mortar of Examples 15-20 is made into test pieces, and the flowability ( / s), 7d compressive strength ( / MPa), 7d flexural strength ( / MPa) and the compressive-flexural strength ratio of the mortar are tested. The comparison results are shown in Table 6 below (Table 6):

[0095] Table 6:

[0096]

[0097] As shown in the above tables, when the asphalt-silica fume ratio = 0.20, the normal-temperature mixed asphalt mortar of Examples 18-20 has better comprehensive performance in terms of the compressive strength and the flexural strength, but the compressive strength and the flexural strength are lower than those of Example 10. This indicates that after the asphalt-silica fume ratio is increased, the flowability of the normal-temperature mixed asphalt mortar is increased, but the compressive strength and the flexural strength are decreased.

[0098] Examples 21-24

[0099] Examples 21-24 are based on Example 1, in which the mixing ratio of the reactive normal-temperature-emulsified mixed asphalt to the cement mortar in step (4) is adjusted, and the ratio of the mass of the pure asphalt to the mass of the silica fume to the sum of the mass of the cement and the mass of the silica fume (i.e., the asphalt-silica fume ratio) is increased to 0.25. That is, the amount of the reactive normal-temperature-emulsified mixed asphalt is continuously increased based on Example 1.

[0100] Then, the water-cement ratio (A) of step (3) is adjusted to vary between 0.25 and 0.30, and the silica-cement ratio (B) of step (3) is adjusted to vary between 0.03 and 0.09; in the preparation of the reaction-type normal-temperature-emulsified mixed asphalt in step (2), the mass fraction ratio of the emulsified asphalt to the pure asphalt in the reaction-type normal-temperature asphalt (hereinafter referred to as the emulsion-normal ratio) is adjusted to vary between 1:1, 2:1 and 1:2, and the specific changes are as follows in Table (Table 7):

[0101] Table 7:

[0102]

[0103] The normal-temperature mixed asphalt mortar of Examples 21-24 is made into test pieces, and the mortar fluidity ( / s), 7d compressive strength ( / MPa), 7d flexural strength ( / MPa) and compressive-flexural ratio are tested. The comparison results are as follows in Table 8 (Table 8):

[0104] Table 8:

[0105]

[0106] As can be seen from the above table, when the asphalt-cement ratio is 0.25, the normal-temperature mixed asphalt mortar of Examples 23-24 has relatively optimal comprehensive performance of compressive strength and flexural strength, but the compressive strength and flexural strength are lower than those of Example 15.

[0107] By comparing the 7d compressive strength, flexural strength and compressive-flexural ratio of the reaction-type normal-temperature-emulsified asphalt mortar at different asphalt-cement ratios, it can be found that the addition of the reaction-type normal-temperature-asphalt can significantly improve the flexural performance of the mortar, and when the asphalt-cement ratio is 0.10 or 0.15, the overall mechanical strength of the asphalt mortar decreases more obviously with the increase of the water-cement ratio, and when the water-cement ratio is 0.25, the overall target performance is relatively excellent. Therefore, when preparing the normal-temperature mixed asphalt mortar, the asphalt-cement ratio is preferably set to 0.10-0.15, and the water-cement ratio is 0.25.

[0108] The scanning electron microscope (SEM) is used to present different state morphological substances in the asphalt mortar, so as to analyze and infer the cement hydration degree. The scanning results are shown in A, B, C, D and E of Figure 1 . In A of Figure 1 , the calcium aluminate in the middle red dashed line box is in a relatively sharp columnar shape, the hydrated calcium silicate gel in the blue dashed line box is in a cluster shape, and the calcium hydroxide in the white dashed line box is in a cluster shape. In the pure cement mortar, more calcium aluminate, calcium hydroxide and cluster-shaped hydrated calcium silicate gel (C-S-H) can be seen, and the cement hydration is relatively complete. By comparing the pure cement mortar (Comparative Example 1), it can be seen that the calcium aluminate content in the asphalt mortar at the asphalt-cement ratio of 0.10 is relatively small, the shape is relatively flat, and there is an asphalt film (A) on the surface of the calcium aluminate. Figure 1B). It shows that the addition of a small amount of asphalt can alleviate the hydration rate of cement to a certain extent. With the continuous increase of asphalt ratio, the content of asphalt increases, and the asphalt is distributed in the mortar paste in the form of dots, and does not form a continuous phase. The sharp columnar ettringite is partially wrapped by the asphalt film, and the shape is further slowed down, and the length is also shortened. When the asphalt ratio is 0.15, the addition of asphalt has affected the generation of cement hydration products to a certain extent Figure 1 C). When the asphalt ratio reaches 0.20, the ettringite is almost completely wrapped by the asphalt film, which hinders its further contact with water and hinders the continuation of hydration Figure 1 D). At an asphalt ratio of 0.25, the asphalt film has formed a continuous phase, and the ettringite has been completely wrapped in the asphalt film, and the length has almost shortened to be difficult to see Figure 1 E).

[0109] Therefore, with the increase of the proportion of asphalt in the mortar, a certain amount of asphalt film is formed, and more asphalt film hinders the further hydration of the asphalt mortar, resulting in a continuous decrease in the proportion of the hard cement paste formed by hydration, and ultimately leading to a decrease in compressive strength. The asphalt phase increases from the flaky distribution to the continuous phase, which increases the bending performance to a certain extent. In order to meet the comprehensive performance of pavement materials, the asphalt ratio should be controlled to be ≤0.25.

[0110] When the mass ratio of reactive asphalt increases in the same asphalt ratio, the fluidity of the mortar will be significantly reduced. This is mainly due to the addition of reactive asphalt which is acidic, which will quickly react with the alkaline cement mortar, consuming a certain amount of cement paste while gradually solidifying itself, thereby reducing the flow performance of the paste. Therefore, the preferred ratio of asphalt to cement is 1:2, 1:1 or 2:1.

[0111] Example 25

[0112] The present embodiment provides a one-piece semi-flexible pavement material made of asphalt mortar at room temperature, limestone aggregate and RAP (waste asphalt mixture), and the preparation method is as follows:

[0113] (1) Preparation of reactive asphalt at room temperature: 60 parts of base asphalt (70# asphalt is used as base asphalt) is heated to 135°C, and 28 parts of reactive liquidizing agent is added under the condition of 50 rpm shear stirring, and stirred for 20 min until completely dispersed and uniform, to prepare reactive asphalt at room temperature. The reactive liquidizing agent is prepared by stirring and mixing castor oil, dodecyl dimethyl betaine and tri- (dimethylaminomethyl) phenol polymer in a mass ratio of 20:7:3.

[0114] (2) Preparation of reactive normal temperature-emulsified mixed asphalt: Select BC-1 type cationic emulsified asphalt for mixing and mix with reactive normal temperature asphalt, so that the mass fraction ratio of emulsified asphalt to reactive normal temperature asphalt (hereinafter referred to as the emulsion ratio) is 1:1.

[0115] Mix the reactive normal temperature asphalt and the emulsified asphalt using a shear instrument, and add 0.5% of the defoaming agent by mass before the start of shearing. The shearing speed is 1500 rpm, and the shearing stirring is carried out at room temperature for 20 min to prepare the reactive normal temperature-emulsified asphalt.

[0116] (3) Preparation of cement mortar: P.Ⅰ62.5 grade Portland cement, 80 mesh diamond sand, silica fume, defoaming agent, expanding agent and water reducing agent are mixed to prepare cement mortar. The water-cement ratio (the ratio of water quantity to the sum of cement and silica fume mass) is 0.25, the silica fume ratio (the ratio of silica fume mass to the sum of cement and silica fume mass) is 0.09, and the ratio of diamond sand and silica fume mass to the sum of cement and silica fume mass is 0.1. The defoaming agent is 0.5% of the total mass of silica fume and cement, the expanding agent is 0.5% of the total mass of silica fume and cement, and the polycarboxylic acid water reducing agent is 1% of the total mass of silica fume and cement.

[0117] (4) Mix and stir the reactive normal temperature-emulsified mixed asphalt of step (2) and the cement mortar of step (3) uniformly to prepare normal temperature mixed asphalt mortar. When mixing, the ratio of pure asphalt mass to the sum of silica fume mass and cement plus silica fume mass (i.e. the asphalt-cement ratio) is 0.15, calculated based on the amount of pure asphalt in the reactive normal temperature-emulsified mixed asphalt.

[0118] (5) Screen the RAP milled from the original AC-13 asphalt pavement, and compare it with the graded AC-13. Through preliminary screening and pretreatment of the RAP used, combined with the screening result analysis, it is found that the original pavement has a fine aggregate due to the effect of traffic load, but most of the aggregate is still within the upper limit of the grading, which indicates that the RAP still retains the structural characteristics of the original grading (see Figure 2 ). Therefore, the RAP of the original AC-13 asphalt pavement can be directly replaced with the corresponding graded limestone aggregate according to the mass percentage.

[0119] Since there is an aging asphalt film on the surface of the RAP, the adhesion of the aging asphalt film to the asphalt mortar is significantly lower than that of ordinary limestone aggregate. Therefore, before using the RAP, the reactive normal temperature-emulsified mixed asphalt (emulsion ratio 1:1) prepared in step (2) is used for surface pretreatment to improve the adhesion of the RAP. For example, Figure 3As shown in A and B of FIG. 1, after the RAP material is wrapped by the reactive normal-temperature-emulsified asphalt pretreatment, the aged asphalt film on the surface of the RAP will be combined with the hydrophilic emulsifier molecules in the emulsified asphalt, which will make the emulsified asphalt quickly wrap the surface of the RAP and completely wrap the RAP in the emulsified asphalt. On the other hand, after the reactive normal-temperature asphalt contacts the RAP, the phenomenon of asphalt colloid aggregation will occur, and the colloid aggregation of the reactive normal-temperature asphalt will form a new asphalt film, which will further wrap the RAP therein to improve the adhesion of the RAP. Even after the water boiling test, the asphalt film is still firmly wrapped on the surface of the RAP.

[0120] Meanwhile, the experiment also tests the pure emulsified asphalt, the reactive normal-temperature-emulsified mixed asphalt with a milk-to-normal ratio of 2:1, 1:1 and 1:2 for wrapping pretreatment of the RAP, and the results show that the wrapping rate of the RAP using the reactive normal-temperature-emulsified mixed asphalt with a milk-to-normal ratio of 2:1, 1:1 and 1:2 is increased by 12%, 18% and 16% respectively compared with the pure emulsified asphalt slurry. Especially, the wrapping rate of the RAP using the reactive normal-temperature-emulsified mixed asphalt with a milk-to-normal ratio of 1:1 can reach 94%.

[0121] (6) The 70% aggregate with a gradation of AC-13C limestone aggregate + 30% pretreated RAP (the original gradation of the asphalt pavement is AC-13) is used as the aggregate, and the amount of pure asphalt (the total amount of pure asphalt from the reactive normal-temperature asphalt and the emulsified asphalt) from the reactive normal-temperature-emulsified mixed asphalt is 3.37%.

[0122] The designed air void rate of the aggregate is 25%, the aggregate with a particle size of 13.2-16mm and 9.5-13.2mm is used as the coarse aggregate, the particle size of 4.75-9.5mm is omitted, the maximum particle size of the fine aggregate gradation design is selected as 2.36, and the mineral powder content is 3%. The proportion of coarse aggregate is 88.11%, and the proportion of fine aggregate is 8.89%.

[0123] (7) The aggregate of step (6) is uniformly stirred with the normal-temperature mixed asphalt slurry of step (4) at normal temperature to obtain an integrated semi-flexible pavement material.

[0124] (8) Integrated semi-flexible pavement material filling rate determination: according to JTG E20-2011 Highway Engineering Asphalt and Asphalt Mixture Test Regulations T 0702-2011, T 0703-2011, an integrated semi-flexible material Marshall test piece with a size of Φ101.6mm x 63.5mm is prepared, and the test piece is placed in a curing room with a humidity of not less than 90% and a temperature of 20℃±5℃ for a standard time.

[0125] The ratio of the actual use amount of the reactive normal temperature-emulsified asphalt mortar used herein to the calculated amount of the mortar required is used to characterize the filling rate, and the test results are shown in the following table (Table 9):

[0126] Table 9:

[0127]

[0128] In summary, from the above table, compared with the traditional cast-in-place semi-flexible pavement, the actual mortar amount of the integrated semi-flexible pavement material is very close to the theoretical mortar amount calculated by the volume of the standard Marshall test specimen. The overall mortar filling rate of the integrated semi-flexible pavement material of the present application is as high as 98.95%. Therefore, the direct mixing integrated semi-flexible pavement has a higher mortar filling rate than the traditional cast-in-place semi-flexible pavement material, which indicates the feasibility of the process of the integrated semi-flexible pavement material of the present application.

[0129] Example 26

[0130] On the basis of Example 25, the asphalt-aggregate ratio of the normal temperature mixed asphalt mortar and the RAP content are changed. Specifically, the asphalt-aggregate ratio of the normal temperature mixed asphalt mortar prepared in step (4) is adjusted to 0.1, 0.15, 0, 20 and 0.25; the RAP content in step (6) is adjusted to 30%, 40% and 50%. Meanwhile, when the RAP content is 40%, the amount of pure asphalt (total amount of pure asphalt from the reactive normal temperature-emulsified asphalt) is 3.34%; when the RAP content is 50%, the amount of pure asphalt is 3.31%. Twelve kinds of integrated semi-flexible pavement material test specimens are obtained, and each of the test specimens is subjected to the following performance tests:

[0131] ① High temperature stability of the integrated semi-flexible pavement material

[0132] The high temperature stability of the material is evaluated by using the asphalt mixture rutting test in the “JTG E20-2011 Highway Engineering Asphalt and Asphalt Mixture Test Procedures”

[74] . The rutting test is performed on the test specimen after curing for 7 days to determine the dynamic stability, the test temperature is 60℃, the wheel pressure is 0.7MPa, and the dynamic stability is calculated.

[0133] The calculation formula is: ;

[0134] In the formula, DS is the dynamic stability of the semi-flexible pavement material (times / mm), d1 is the deformation amount of the test specimen when the loading time is 45min (mm), d2 is the deformation amount of the test specimen when the loading time is 60min (mm), C1 is the type correction coefficient of the testing machine, which is taken as 1.0 according to the equipment situation of this test, C2 is the test specimen coefficient, which is taken as 1.0 according to the test specimen situation of this test, and N is the speed of the test wheel when rolling, which is taken as 42 times / min. The calculation results are shown in the following table (Table 10):

[0135] Table 10:

[0136]

[0137] From the above table, under the action of 60℃ and wheel pressure of 0.7MPa, the integrated semi-flexible pavement material with different RAP contents under different asphalt-aggregate ratios still maintains a very high dynamic stability. It can be seen from the test results that the dynamic stability of the material decreases continuously with the increasing asphalt-aggregate ratio, and the dynamic stability decreases slowly when the asphalt-aggregate ratio is 0.15-0.20; the dynamic stability decreases greatly when the asphalt-aggregate ratio is 0.10-0.15 and 0.15-0.20. The reason for this phenomenon is that the increasing asphalt content makes the overall material more soft and the high-temperature performance worse. Under the same asphalt-aggregate ratio, the dynamic stability of the material increases continuously with the increasing proportion of RAP in the material, which is related to the aged asphalt remaining in RAP. In summary, the integrated semi-flexible pavement with different RAP contents still retains the excellent high-temperature stability of the traditional poured semi-flexible pavement, and the dynamic stability is greater than 9000 times / mm.

[0138] ②Low-temperature crack resistance of integrated semi-flexible pavement material

[0139] The low-temperature crack resistance of the material was determined and evaluated by small beam bending test. The test conditions were to load the middle section of the small beam at a temperature of 10℃. The test process is shown in Figure 4 , and the calculation method is as follows:

[0140]

[0141] The calculation results are shown in the following table (Table 11):

[0142] Table 11: Small beam bending test results of integrated semi-flexible pavement material with different RAP contents under different asphalt-aggregate ratios

[0143]

[0144] At the same time, it can be calculated that the bending tensile strength of the traditional poured semi-flexible pavement small beam specimen at the time of fracture is 5.92MPa; the maximum bending tensile strain is ; the bending stiffness modulus is 4702.67 MPa. From the data in the above table, the low temperature performance of the integrated semi-flexible pavement material with reactive normal temperature-emulsified asphalt mortar as the mixture is significantly improved compared to the traditional poured semi-flexible pavement material. With the continuous increase of the asphalt content ratio in the integrated semi-flexible pavement, the bending tensile strength and the maximum bending tensile strain of the specimen when it is destroyed are first increased and then decreased. The integrated semi-flexible pavement material under RAP content of 30%, 40% and 50% all shows the maximum bending tensile strain when the asphalt-aggregate ratio is 0.20. Analysis of the test data shows that the low temperature performance of the integrated semi-flexible pavement material with reactive normal temperature-emulsified asphalt mortar as the mixture first increases and then decreases with the continuous increase of the asphalt content ratio. This shows that in the integrated semi-flexible pavement material, the larger the asphalt-aggregate ratio, the better the low temperature performance, and there should be an optimal asphalt-aggregate ratio. This also indirectly proves the excellent low temperature cracking resistance of the reactive normal temperature-emulsified asphalt, which can effectively make up for the disadvantage of the traditional poured semi-flexible pavement material in low temperature environment.

[0145] ③Integrated semi-flexible pavement material immersion Marshall stability

[0146] According to the relevant test procedures in the "Highway Engineering Asphalt and Asphalt Mixture Test Technology Regulations", the Marshall test specimen after curing for 7d is tested. Two groups are set up, one group is immersed in a 60℃ water bath for 30-40min, and the Marshall stability record value is MS; the other group is immersed at the same temperature for 48h, and the Marshall stability record value is MS1, and the residual stability MS0=MS1 / MS*100% is calculated according to formula (5.5). After calculation, the initial stability and molding stability test results of different RAP content recycled asphalt mixture are shown in Table 12:

[0147] Table 12: Immersion residual stability test results of integrated semi-flexible pavement material with different RAP contents under different asphalt-aggregate ratios

[0148]

[0149] From the data in the above table, the residual stability of the integral semi-flexible pavement material as a whole decreases with the increase of the asphalt ratio, especially when the asphalt ratio is between 0.20 and 0.25, the decrease is significantly increased, and the residual stability also decreases with the increase of the asphalt ratio when the asphalt ratio is between 0.10 and 0.20. The reason for this phenomenon is that during the maintenance of the test piece, the appropriate environment can further promote the hydration of cement, so that the strength of the test piece increases. However, with the continuous increase of the asphalt ratio, the asphalt film in the material continuously increases, which isolates the further hydration of cement, resulting in a significant decrease in strength. Under the same asphalt ratio, with the continuous increase of the RAP content, the residual stability also shows a decreasing trend, and with the increase of the RAP content and the increase of the asphalt ratio, this decreasing trend is more obvious. The reason for this phenomenon is that the continuous increase of the RAP content reduces the fusion degree of RAP and asphalt mortar, which reduces the overall water stability of the material. In summary, the integral semi-flexible pavement material with different RAP contents contains cement, which accelerates the hydration of cement during maintenance, resulting in better water stability.

[0150] (4) Freeze-thaw splitting performance of the integral semi-flexible pavement material

[0151] According to the requirements of the freeze-thaw splitting test, the water damage resistance of the integral semi-flexible pavement material with different RAP contents is detected. According to the "Highway Engineering Asphalt and Asphalt Mixture Test Regulations", the splitting tensile strength test of the material test piece after 7 days of maintenance is carried out. The test results are shown in Table 13.

[0152] Table 13: Freeze-thaw splitting tensile strength test results of the integral semi-flexible pavement with different RAP contents and different asphalt ratios

[0153]

[0154] In summary, low temperature has an adverse effect on the integral semi-flexible pavement material, but with the increase of the asphalt ratio, this deficiency is compensated to a certain extent. According to the requirements of "JTG F40-2004 Highway Asphalt Pavement Construction Technical Specifications", the integral semi-flexible pavement material with an asphalt ratio of 0.1 and a RAP content of 30%, an asphalt ratio of 0.15 and a RAP content of 30% and 40%, an asphalt ratio of 0.20 and a RAP content of 30% and 40%, and an asphalt ratio of 0.25 and a RAP content of 30% and 40% meets the requirements of modified asphalt mixture in semi-dry areas and arid areas (i.e. the freeze-thaw splitting strength ratio TSR is not less than 75%), which indicates that the integral semi-flexible pavement material of the present application can withstand the erosion of rainwater, snow and ice, and has good water stability.

[0155] Anti-skid performance of integral semi-flexible pavement material

[0156] Determined by using a pendulum friction coefficient tester, and characterized by a pendulum value Fb. According to the “T 0964-2008 Test Method for Determining Road Surface Friction Coefficient by Pendulum Tester”, the anti-skid ability of the integral semi-flexible pavement material under different RAP contents in a wet state was determined, and the experimental data are shown in Table 14.

[0157] Table 14: Determination results of friction coefficient of integral semi-flexible pavement material with different RAP contents under different asphalt ratios

[0158]

[0159] From the above data, it can be seen that the BPN test values of the integral semi-flexible pavement material with different RAP contents under different asphalt ratios are not consecutive, and the values of each specimen are floating around 55. This fully demonstrates that the integral semi-flexible pavement material has good anti-skid ability. In summary, the pendulum value Fb (BPN) of the integral semi-flexible pavement material with different RAP contents under different asphalt ratios is greater than or equal to 45. The above anti-skid performance test shows that because the forming process of the integral semi-flexible pavement material is direct mixing, and the proportion of coarse aggregate in the gradation design is relatively high, the high proportion of coarse aggregate improves the anti-skid ability of the pavement to a certain extent.

[0160] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An integral semi-flexible pavement material, characterized in that, It is prepared by mixing and mixing the asphalt mortar at normal temperature and the large-void matrix mixture; The asphalt mortar at normal temperature comprises mixed asphalt and cement mortar, and the mixed asphalt and cement mortar are mixed after being prepared respectively to obtain the asphalt mortar at normal temperature; The mixed asphalt is a reactive asphalt at normal temperature-emulsified asphalt obtained by mixing reactive asphalt at normal temperature and emulsified asphalt, and the mixed asphalt contains a defoaming agent; the emulsified asphalt is anionic emulsified asphalt; The cement mortar comprises Portland cement, water, silica fume and an additive; The mass ratio of pure base asphalt in the emulsified asphalt to pure base asphalt in the reactive asphalt at normal temperature is 2:1-1:2; The ratio of asphalt to cement is the ratio of the total mass of pure base asphalt in the reactive asphalt at normal temperature and the emulsified asphalt to the total mass of cement and silica fume, and the ratio of asphalt to cement is 0.10-0.25; The water-cement ratio of the cement mortar is 0.25-0.35; the silica fume ratio is the ratio of the mass of silica fume to the total mass of cement and silica fume, and the silica fume ratio is 0.01-0.10; fine sand is further added to the cement mortar, and the ratio of the mass of fine sand and silica fume to the total mass of cement and silica fume is ≤0.1; The reactive asphalt at normal temperature is prepared by adding a reactive liquefier and a modifier water-based epoxy resin emulsion to base asphalt in a flowing state and mixing by shearing; the reactive liquefier is prepared by using unsaturated fatty acid as a liquefier base material, and then adding an amphoteric surfactant and a phenol polymer and stirring and mixing; The large-void matrix mixture has a porosity of 20-28% and is composed of limestone aggregate and pretreated RAP, and the pretreatment of RAP is adhesion improvement treatment using reactive asphalt at normal temperature-emulsified asphalt.

2. The integral semi-flexible pavement material of claim 1, wherein, When the ratio of asphalt to cement is 0.10: the water-cement ratio is 0.25, the silica fume ratio is 0.03, and the mass ratio of pure base asphalt in the emulsified asphalt to pure base asphalt in the reactive asphalt at normal temperature is 1:2; or, the water-cement ratio is 0.25, the silica fume ratio is 0.09, and the mass ratio of pure base asphalt in the emulsified asphalt to pure base asphalt in the reactive asphalt at normal temperature is 2:1; or, the water-cement ratio is 0.30, the silica fume ratio is 0.06, and the mass ratio of pure base asphalt in the emulsified asphalt to pure base asphalt in the reactive asphalt at normal temperature is 2:1; or, the water-cement ratio is 0.25, the silica fume ratio is 0.06, and the mass ratio of pure base asphalt in the emulsified asphalt to pure base asphalt in the reactive asphalt at normal temperature is 1:1; When the ratio of asphalt to cement is 0.15: the water-cement ratio is 0.25, the silica fume ratio is 0.06, and the mass ratio of pure base asphalt in the emulsified asphalt to pure base asphalt in the reactive asphalt at normal temperature is 1:1; or, the water-cement ratio is 0.25, the silica fume ratio is 0.09, and the mass ratio of pure base asphalt in the emulsified asphalt to pure base asphalt in the reactive asphalt at normal temperature is 2:1; When the ratio of asphalt to cement is 0.20: the water-cement ratio is 0.30, the silica fume ratio is 0.03, and the mass ratio of pure base asphalt in the emulsified asphalt to pure base asphalt in the reactive asphalt at normal temperature is 1:1; Or, the water-cement ratio is 0.30, the silica-cement ratio is 0.06, and the mass ratio of pure base asphalt in the emulsified asphalt to pure base asphalt in the reactive cold asphalt is 2:

1. Or, the water-cement ratio is 0.30, the silica-cement ratio is 0.09, and the mass ratio of pure base asphalt in the emulsified asphalt to pure base asphalt in the reactive cold asphalt is 1:

2. When the cement ratio is 0.25: The water-cement ratio is 0.30, the silica-cement ratio is 0.09, and the mass ratio of pure base asphalt in the emulsified asphalt to pure base asphalt in the reactive cold asphalt is 1:

2. Or, the water-cement ratio is 0.30, the silica-cement ratio is 0.03, and the mass ratio of pure base asphalt in the emulsified asphalt to pure base asphalt in the reactive cold asphalt is 1:

1.

3. The integral semi-flexible pavement material of claim 1, wherein, The reactive cold asphalt is prepared by adding 20-30 parts by mass of a reactive liquefying agent and 10-20 parts by mass of an aqueous epoxy resin emulsion modifier to 50-60 parts by mass of base asphalt that is in a flowable state after being heated at a high temperature, and then mixing and stirring the mixture by shearing; The reactive liquefying agent is prepared by mixing and stirring an unsaturated fatty acid as a liquefying agent base material, alkyl dimethyl betaine, and a phenol polymer, wherein the mass ratio of the unsaturated fatty acid: alkyl dimethyl betaine: phenol polymer is 15-25:5-10:1-5; the unsaturated fatty acid is at least one of myristoleic acid, elaidic acid, oleic acid, linoleic acid, erucic acid, palmitoleic acid, and ricinoleic acid; the alkyl dimethyl betaine is C10-20 alkyl dimethyl betaine; and the phenol polymer is tri-(dimethylaminomethyl) phenol polymer.

4. The integral semi-flexible pavement material of claim 1, wherein, The reactive cold asphalt further comprises 10-20 parts by weight of a coupling agent, and the coupling agent is a silane coupling agent.

5. The integral semi-flexible pavement material of claim 4, wherein, The coupling agent is C10-20 alkyl triethoxysilane.

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