A method for preparing warm-mix modified rubber asphalt

Abstract

This invention relates to a method for preparing warm-mix modified rubber asphalt, belonging to the technical field of asphalt pavement materials. It solves the problems of reduced road performance, decreased asphalt index, and low overall performance of warm-mix modified rubber asphalt prepared by existing methods. The method includes: preparing pretreated rubber powder; preparing warm-mix agent A; preheating the base asphalt, adding the pretreated rubber powder and copolymer modifier, maintaining the temperature, and stirring to obtain a first modified asphalt; adding warm-mix agent A to the first modified asphalt and stirring to obtain a second modified asphalt; adding warm-mix agent B and a stabilizer to the second modified asphalt, maintaining the temperature, and stirring to obtain a third modified asphalt; repeatedly grinding the third modified asphalt in a colloid mill until the material is homogeneous to obtain the warm-mix modified rubber asphalt; wherein the pretreated rubber powder contains a compensating agent. The warm-mix modified rubber asphalt prepared by this invention effectively reduces the mixing temperature of the mixture while exhibiting good road performance.

Description

Technical Field

[0001] This invention relates to the field of asphalt pavement materials technology, and in particular to a method for preparing warm-mix modified rubber asphalt. Background Technology

[0002] Rubber-modified asphalt, as a new type of environmentally friendly material in the field of road engineering, can not only improve the high-temperature rutting resistance, low-temperature cracking resistance, and aging resistance of asphalt mixtures, but also effectively reduce road noise and resist the effects of heavy traffic and harsh weather. Asphalt pavements with rubber-modified asphalt as the binder have better high-temperature performance and fatigue resistance than ordinary asphalt mixture pavements, and can also reduce noise, prevent slippage, and improve the safety factor. Currently, the preparation of rubber-modified asphalt is a relatively mature technology.

[0003] However, tracking the engineering applications of rubber-modified asphalt reveals that due to its high viscosity, the mixture needs to be heated to very high temperatures (higher than SBS-modified asphalt) during construction. This presents numerous challenges in mixing, transportation, and compaction, leading to increased costs. Furthermore, heating the asphalt and aggregates to such high temperatures not only consumes significant amounts of energy but also generates substantial amounts of waste gas and dust during production and construction, severely impacting the surrounding environment and the health of construction workers. Currently, the production of rubber-modified asphalt mixtures is limited, and under conditions of long transportation distances and low ambient temperatures, the mixture temperature drops too rapidly during mixing, transportation, and compaction, further restricting road construction.

[0004] To reduce the temperature during the mixing, transportation, and compaction of asphalt mixtures, ensure construction quality, extend the construction season, and reduce emissions of exhaust gas and dust, as well as energy consumption, warm mix additives are generally added to hot mix asphalt mixtures. Currently, most warm mix modified rubber asphalts use organic viscosity-reducing methods to lower the high-temperature viscosity of the rubber asphalt. Although this increases the softening point and improves high-temperature performance, the viscosity reduction is not significant, and the road performance of the rubber asphalt mixture decreases, with a noticeable decline in asphalt properties. For example, the ductility and penetration of the rubber asphalt decrease significantly, leading to hardening and brittleness, reduced elasticity, and impaired low-temperature performance, thus affecting the excellent properties of the rubber asphalt. Furthermore, the reduction in mixing temperature also damages the compaction characteristics of the rubber asphalt mixture. Summary of the Invention

[0005] In view of the above analysis, the present invention aims to provide a method for preparing warm-mix modified rubber asphalt, so as to at least solve one of the following problems existing in the preparation methods of warm-mix modified rubber asphalt: 1. The viscosity of existing warm-mix modified rubber asphalt is not significantly reduced; 2. The compaction characteristics of existing warm-mix modified rubber asphalt preparation methods are not improved when the mixing temperature of the mixture is reduced; 3. Although existing warm-mix modified rubber asphalt preparation methods achieve the purpose of reducing the mixing temperature of the mixture, the technical indicators of the original rubber asphalt are also weakened, resulting in varying degrees of reduction in the road performance of the rubber asphalt and its mixture.

[0006] The objective of this invention is mainly achieved through the following technical solutions: This invention provides a method for preparing warm-mix modified rubber asphalt, comprising the following steps: S1: Preparation of pretreated adhesive powder: The pretreated adhesive powder contains a compensating agent; S2: Prepare warm mixing agent A; S3: Preheat the base asphalt, add pretreated rubber powder and copolymer modifier, keep warm, stir, and obtain the first modified asphalt; S4: Add warm mix agent A to the first modified asphalt and stir to obtain the second modified asphalt; S5: Add warm mix agent B and stabilizer to the second modified asphalt, keep it warm, stir, and obtain the third modified asphalt; S6: The third modified asphalt is repeatedly ground in a colloid mill until the material is uniform, thus obtaining warm-mix modified rubber asphalt.

[0007] Further, in step S1, the preparation of the pretreated adhesive powder includes: S11: Add the adhesive powder, interface agent, compensator A, and compensator B to the vertical drum three-dimensional mixer according to the formula weight, premix evenly to obtain a mixture, and set aside; S12: Preparation of adhesive powder activator; S13: Mix the mixture obtained in step S11 and the adhesive powder activator obtained in step S12 according to the mass ratio, knead, press into plate shape, and microwave activate and heat. S14: The product after microwave activation and heating is mechanically crushed to obtain pretreated adhesive powder.

[0008] Further, in step S12, the preparation of the adhesive powder activator includes: S121: Prepare a liquid mixture of 4006 naphthenic oil and anhydrous ethanol according to the mass ratio; S122: At room temperature, the organic solution of zinc compound is stirred with the liquid mixture obtained in step S1 according to the mass ratio. During the stirring process, zinc dialkyl dithiophosphate is added in three batches to obtain the adhesive powder activator.

[0009] Further, in step S2, the preparation of warm mixing agent A includes: mixing dihydroviscosinate, polyether polyol and esterification catalyst according to the component ratio, heating to the first esterification temperature, stirring for the first time, slowly adding triisopropanolamine, heating to the second esterification temperature, stirring for the second time, and cooling to room temperature to prepare warm mixing agent A.

[0010] Furthermore, in step S3, the preheating temperature of the base asphalt is 170~190℃.

[0011] Furthermore, in step S3, the stirring rate is 500~800 r / min and the stirring time is 65~90 min.

[0012] Furthermore, in step S4, the stirring rate is 200~300 r / min and the stirring time is 60~90 min.

[0013] Furthermore, in step S5, the heat preservation temperature is 145~160℃.

[0014] Furthermore, in step S5, the stirring rate is 500~800 r / min, and the stirring time is 20~45 min.

[0015] The present invention also provides a warm-mix modified rubber asphalt, which is prepared by the above preparation method.

[0016] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: 1. The preparation method of the warm-mix modified rubber asphalt of the present invention introduces a compensating agent into the pretreated rubber powder. During the preparation process, as the pretreated rubber powder swells and develops in the base asphalt, the compensating agent embedded inside or on the surface of the pretreated rubber powder is slowly released simultaneously. The compensating agent can continuously react with the esterification residues or active chemical bonds of warm-mix agent A and warm-mix agent B to produce a mixture, further reducing the viscosity of the rubber asphalt while synergistically exerting the warm-mix effect. It has the advantage of long storage stability. The new products generated by the reaction have good compatibility with the asphalt and can also combine well with the polar groups on the surface of the aggregate. This effectively compensates for the problem of the decline in asphalt technical indicators and the reduction in the road performance of warm-mix modified rubber asphalt and its mixture caused by the introduction of warm-mix agents, ensuring that the warm-mix modified rubber asphalt effectively reduces the mixing temperature while having good road performance.

[0017] 2. The warm-mix modified rubber asphalt prepared by the method of the present invention has reliable long-term storage stability for 72 hours; the mixture prepared by the warm-mix modified rubber asphalt of the present invention exhibits good high and low temperature performance, and the freeze-thaw splitting residual strength ratio, which characterizes water stability, can be stably maintained above 83%. Under the condition of reducing the mixing and compaction temperature by 25°C, it can still achieve the same compaction effect as traditional rubber asphalt at 185°C.

[0018] 3. The warm-mix modified rubber asphalt mixture prepared by the method of the present invention achieves the warm-mix effect while significantly improving high-temperature performance and water stability. The high-temperature dynamic stability (dynamic stability at 60℃) reaches more than 4400 times / mm, and the low-temperature bending failure strain is ≥2900 / με.

[0019] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0020] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0021] Figure 1 is a schematic diagram of the preparation method of the warm-mix modified rubber asphalt of the present invention. Detailed Implementation

[0022] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0023] This invention provides a method for preparing warm-mix modified rubber asphalt, comprising the following steps: S1: Preparation of pretreated adhesive powder: The pretreated adhesive powder contains a compensating agent.

[0024] S2: Prepare warm mixing agent A; S3: Preheat the base asphalt, add pretreated rubber powder and copolymer modifier, keep warm, stir, and obtain the first modified asphalt; S4: Add warm mix agent A to the first modified asphalt and stir to obtain the second modified asphalt; S5: Add warm mix agent B and stabilizer to the second modified asphalt, keep it warm, stir, and obtain the third modified asphalt; S6: The third modified asphalt is repeatedly ground in a colloid mill until the material is uniform, thus obtaining warm-mix modified rubber asphalt.

[0025] Specifically, in step S1, the preparation of the pretreated adhesive powder includes the following steps: S11: Add the adhesive powder, interface agent, compensator A, and compensator B to the vertical drum three-dimensional mixer according to the formula weight, premix evenly to obtain a mixture, and set aside; S12: Preparation of adhesive powder activator; S13: Mix the mixture obtained in step S11 and the adhesive powder activator obtained in step S12 according to the mass ratio, knead, press into plate shape, and microwave activate and heat. S14: The product after microwave activation and heating is mechanically crushed to obtain pretreated adhesive powder.

[0026] Specifically, in step S11, the adhesive powder, interface agent, compensator A, and compensator B are added to a vertical drum three-dimensional mixer according to the formula weight, and premixed evenly to obtain a mixture for later use; wherein, in the formula, the weight ratio of adhesive powder, interface agent, compensator A, and compensator B is 100:3-5:0.5-2:1-4, for example, according to the weight parts: 100 parts adhesive powder, 3-5 parts interface agent, 0.5-2 parts compensator A, and 1-4 parts compensator B.

[0027] Among them, the interface agent is palm oil diethanolamide, which has good compatibility with surface-active warm mix agents. At the same time, its own polar and non-polar groups can enhance the coating of warm mix modified rubber asphalt and stone.

[0028] Among them, compensator A is an organic amine compound intermediate, which can be one or more of triethylenediamine, diethylenetriamine, and 2-methylpentanediamine. Through substitution reaction, it can combine with the warm mix agent in the warm mix modified rubber asphalt to play a synergistic role and jointly achieve the warm mix effect. Through chemical bond interaction, it is distributed on the surface of the stone to improve the coating effect of the warm mix modified rubber asphalt on the stone.

[0029] The compensator B is an inorganic silicon salt, which can be one or more of epoxy silanes, amino silanes, chloropropyl silanes, orthosilicic acids, and hydrosilanes. It can bind the rubber powder particles and the base asphalt more tightly through chemical bonds, and also help the SBS or SBR polymer in step S3 to react, effectively preventing the rubber powder particles from segregating in the asphalt system. It can also play a role in lubrication and deodorization. In summary, this step embeds the compensating material into the rubber powder particles in advance. Because the rubber powder particles undergo a slow swelling reaction during the preparation of modified asphalt, the compensating material plays a slow-release role in the warm-mix modified rubber asphalt system, while also taking into account the synergistic effect with the polymer, so as to jointly achieve the reinforcing effect.

[0030] Specifically, in step S12, the preparation of the adhesive powder activator includes the following steps: S121: Prepare a liquid mixture of 4006 naphthenic oil and anhydrous ethanol according to the mass ratio; S122: At room temperature, the organic solution of zinc compound is stirred with the liquid mixture obtained in step S1 according to the mass ratio. During the stirring process, zinc dialkyl dithiophosphate is added in three batches to obtain the adhesive powder activator.

[0031] The components of the adhesive powder activator, by mass percentage, are: 4006 naphthenic oil 14.88~18.6%, anhydrous ethanol 4.96~6.2%, zinc compound organic solution 74.4~79.36%, and zinc dialkyl dithiophosphate 0.8~1.0%.

[0032] Specifically, the zinc compound organic solution is prepared from cyclohexane and one or more of zinc naphthenate, zinc isooctanoate, and zinc neodecanoate; wherein cyclohexane is the solvent, and one or more of zinc naphthenate, zinc isooctanoate, and zinc neodecanoate are the solutes. The zinc element concentration in the zinc compound organic solution is 8%-15% by mass. One or more of zinc naphthenate, zinc isooctanoate, and zinc neodecanoate are drying components, which can shorten the reaction time of waste adhesive powder after it has been wetted by the activator.

[0033] Specifically, in step S121, the mass ratio of 4006 naphthenic oil to anhydrous ethanol is 3:1 to 4:1; in step S122, the zinc compound organic solution and liquid mixture are mixed at a mass ratio of 1:4 to 1:5 to obtain a mixed solution; the stirring speed is controlled at 2500 to 3000 r / min, the stirring time is 10 to 15 min, and the dialkyl dithiophosphate zinc salt is added to the mixed solution in three parts to finally obtain the adhesive powder activator.

[0034] The prepared rubber powder activator can be dispersed relatively evenly on the surface of waste rubber powder, has a strong penetration effect, and contains a drying component. Compared with existing activators, it can significantly shorten the time required for rubber powder activation process, improve activation efficiency, shorten the action time of waste rubber powder after being wetted by the activator, and improve the extensibility of softened rubber powder.

[0035] Specifically, in step S13, the mixture obtained in step S11 and the rubber powder activator obtained in step S12 are mixed in a mass ratio of 60:1 to 25:1. After the mixture is kneaded by a screw extruder, it is stamped into a sheet shape. Then, it is microwave activated and heated for 5 to 45 minutes under a nitrogen atmosphere and a power range of 300W to 500W.

[0036] Specifically, in step S14, the product after microwave activation and heating is mechanically crushed into pretreated adhesive powder with an average particle size of 40-80 mesh, for later use.

[0037] Specifically, in step S2, the warm-mixing agent A is a liquid diester mixture, obtained by esterification reaction of 30-60 parts by weight of dihydroviscosinate, 4-8 parts by weight of polyether polyol, 8-16 parts by weight of triisopropanolamine, and 1-5 parts by weight of esterification catalyst. The polyether polyol can be one of HSH-204, HSH-210, HSH-220, HSH-230, and HSH-240, and the esterification catalyst is one of phosphotungstic acid, molybdenum acid, and benzenesulfonic acid.

[0038] The specific preparation process of the above-mentioned warm mixing agent A can be as follows: according to the component ratio, dihydroviscosinate, polyether polyol and esterification catalyst are mixed, heated to the first esterification temperature, stirred for the first time, triisopropanolamine is slowly added, heated to the second esterification temperature, stirred for the second time, and cooled to room temperature to obtain warm mixing agent A.

[0039] Taking into account the decomposition volatility of the reactants and the selectivity of the reaction products, the first esterification temperature was set at 125–135 °C. After stirring at 450–550 rpm for 7–7.5 h, triisopropanolamine was slowly added, and the temperature was raised to the second esterification temperature of 140–160 °C. After stirring at 270–330 rpm for 2–2.5 h, the temperature was lowered to room temperature to prepare warm mix agent A. Compared with existing warm mix agents, warm mix agent A exhibits better long-term warm mix retention and causes less damage to the low-temperature technical properties of warm mix modified rubber asphalt.

[0040] Specifically, in step S3, the base asphalt is AH-90 or AH-70 road petroleum asphalt that meets the technical standards; the base asphalt is preheated to 170~190℃, and 18%~33% of the base asphalt mass of pretreated rubber powder and 5‰~1.2% of the base asphalt mass of copolymer modifier are added; then, the mixture is kept at 170~190℃ and stirred for 65~90 min at a stirring rate of 500~800 r / min to obtain the first modified asphalt; wherein the copolymer modifier is styrene-butadiene block copolymer (SBS) or polystyrene-butadiene copolymer (SBR). For example, 100 parts of base asphalt are mixed with 18~33 parts of pretreated rubber powder and 0.5~1.2 parts of copolymer modifier.

[0041] Specifically, in step S4, 3‰~1% of the mass of the base asphalt is added to the first modified asphalt and stirred for 60~90 minutes at a stirring rate of 200~300 r / min to obtain the second modified asphalt; for example, 100 parts of base asphalt and 0.3~1 parts of warm mix agent A.

[0042] Specifically, in step S5, the warm mix agent B is oxidized polyethylene wax, and the stabilizer is a silane coupling agent. 3%–8% of the base asphalt mass of warm mix agent B and 3‰–1% of the base asphalt mass of stabilizer are added to the second modified asphalt. The mixture is kept at 145–160°C and stirred for 20–45 minutes at a stirring rate of 500–800 r / min to obtain the third modified asphalt. The third modified asphalt is then repeatedly ground in a colloid mill until the material is homogeneous, yielding the warm mix modified rubber asphalt. For example, the base asphalt is 100 parts, the warm mix agent B is 3–8 parts, and the stabilizer is 0.3–1 part.

[0043] The warm-mix modified rubber asphalt prepared by the above preparation method includes base asphalt, pretreated rubber powder, warm-mix agent A, warm-mix agent B, copolymer modifier, and stabilizer; the weight ratio of the base asphalt, pretreated rubber powder, warm-mix agent A, warm-mix agent B, copolymer modifier, and stabilizer is 100:18~33:0.3~1:3~8:0.5~1.2:0.3-1; for example, by weight fraction, it includes: 100 parts of base asphalt, 18~33 parts of pretreated rubber powder, 0.3~1 parts of warm-mix agent A, 3~8 parts of warm-mix agent B, 0.5~1.2 parts of copolymer modifier, and 0.3~1 parts of stabilizer.

[0044] It should be noted that, in the preparation of warm-mix modified rubber asphalt using the method of this invention, as the pretreated rubber powder swells and develops in the base asphalt during the preparation process, the compensator embedded inside or on the surface of the pretreated rubber powder is slowly released simultaneously. The compensator can continuously interact with the esterification residues or active chemical bonds of warm-mix agent A and warm-mix agent B to produce a mixture, further reducing the viscosity of the rubber asphalt while synergistically exerting the warm-mix effect. This results in a longer storage stability advantage, and the newly produced product has good compatibility with asphalt and can also bind well to the polar groups on the surface of aggregates, effectively compensating for... The introduction of warm-mix additives has addressed the issues of reduced road performance and decreased asphalt properties in warm-mix modified rubber asphalt, ensuring that the mixing temperature is effectively reduced while maintaining good road performance. Specifically, the difference between the rotational viscosity (72h) / Pa.s at 180℃ and the rotational viscosity / Pa.s at 180℃ is ≤0.6, indicating improved long-term storage stability of the warm-mix rubber modified asphalt over 72 hours. Other characteristics include: penetration ≥50 (0.1mm) at 25℃, softening point ≥74℃, ductility ≥10cm at 5℃, ductility force ≥40N at 5℃, and elastic recovery ≥78%.

[0045] The warm-mix rubber-modified asphalt mixture prepared in this invention exhibits excellent high and low temperature performance. The freeze-thaw splitting residual strength ratio, a characterization of water stability, can be stably maintained above 83%. Even with a 25°C reduction in mixing and compaction temperature, it still achieves the same compaction effect as traditional rubber asphalt at 185°C. The warm-mix rubber-modified asphalt mixture prepared in this application achieves the warm-mix effect while significantly improving high-temperature performance and water stability. Specifically, the high-temperature dynamic stability (dynamic stability at 60°C) reaches over 4400 cycles / mm, and the low-temperature flexural failure strain is ≥2900 / με.

[0046] Example 1 A warm-mix modified rubber asphalt comprises 100 parts base asphalt, 30 parts pretreated rubber powder, 0.3 parts warm-mix agent A, 3 parts warm-mix agent B, 0.8 parts SBS, and 0.5 parts stabilizer. The preparation steps include: S1: Preparation of pretreated adhesive powder: S11: Add 100 parts of adhesive powder, 3 parts of interface agent, 1 part of compensator A, and 2 parts of compensator B to a vertical drum three-dimensional mixer according to the formula weight, premix evenly to obtain a mixture, and set aside; the interface agent is palm oil diethanolamide, the compensator A is triethylenediamine, and the compensator B is epoxy silane. S12: Preparation of adhesive powder activator: The components of the adhesive powder activator, by mass fraction, are: 15.6% naphthenic oil 4006, 5.2% anhydrous ethanol, 78.4% zinc compound organic solution, and 0.8% zinc dialkyl dithiophosphate.

[0047] S121: Prepare a liquid mixture of 4006 naphthenic oil and anhydrous ethanol at a mass ratio of 3:1; S122: At room temperature, the organic solution of zinc compound is stirred with the liquid mixture obtained in step S1 at a mass ratio of 1:4. During the stirring process, zinc dialkyl dithiophosphate is added in three portions to obtain the adhesive powder activator. The zinc compound organic solution is prepared by cyclohexane (solvent) and zinc naphthenate (solute), and the mass concentration of zinc element in the zinc compound organic solution is 8%; the stirring speed is 2500 rpm and the stirring time is 15 min.

[0048] S13: Mix the mixture in step S11 and the rubber powder activator in step S12 at a mass ratio of 53:1 (i.e., add 2 parts of rubber powder activator and mix with the mixture in S11). After the mixture is kneaded by a screw extruder, it is stamped into a sheet shape. Then, it is microwave activated and heated for 20 minutes under nitrogen atmosphere and 300W power range. S14: The product after microwave activation and heating is mechanically crushed into pretreated adhesive powder with an average particle size of 40-80 mesh, and weighed in 30 parts by weight.

[0049] S2: Preparation of warm mixing agent A: 40 parts of dihydromucoacinic acid, 6 parts of polyether polyol (HSH-204) and 2 parts of esterification catalyst (phosphotungstic acid) are heated to 125°C and stirred at 500 r / min for 7 h. 10 parts of triisopropanolamine are slowly added, the temperature is raised to 140°C, and stirred at 300 r / min for 2 h before being cooled to room temperature to prepare the agent. S3: Preheat the base asphalt (AH-90 road petroleum asphalt) to 170℃, add pretreated rubber powder and SBS by metering, keep warm and stir for 70 minutes at a stirring rate of 800 r / min to obtain the first modified asphalt; S4: Add warm mix agent A to the first modified asphalt and stir at 250 r / min for 1 h to obtain the second modified asphalt; S5: Add warm mix agent B (oxidized polyethylene wax) and stabilizer (silane coupling agent) to the second modified asphalt, keep it at 145℃, and stir at 500r / min for 45min to obtain the third modified asphalt; S6: The third modified asphalt is repeatedly ground in a colloid mill until the material is uniform, thus obtaining warm-mix modified rubber asphalt.

[0050] Example 2 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the rubber powder activator in this embodiment has the following components by mass percentage: 14.88% 4006 naphthenic oil, 4.96% anhydrous ethanol, 79.36% zinc compound organic solution, and 0.8% zinc dialkyl dithiophosphate. Prepared by the following steps: S1: Prepare a liquid mixture of 4006 naphthenic oil and anhydrous ethanol at a mass ratio of 3:1; S2: At room temperature, the organic solution of zinc compound is stirred with the liquid mixture obtained in step S1 at a mass ratio of 1:5. During the stirring process, zinc dialkyl dithiophosphate is added in three batches to obtain the adhesive powder activator. The zinc compound organic solution is prepared by cyclohexane (solvent) and zinc naphthenate (solute), and the mass concentration of zinc element in the zinc compound organic solution is 10%; the stirring speed is 2800 rpm and the stirring time is 12 min.

[0051] The remaining processes and parameters are the same as in Example 1.

[0052] Example 3 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the rubber powder activator in this embodiment has the following components by mass percentage: 18.6% 4006 naphthenic oil, 6.2% anhydrous ethanol, 74.4% zinc compound organic solution, and 0.8% zinc dialkyl dithiophosphate. Prepared by the following steps: S1: Prepare a liquid mixture of 4006 naphthenic oil and anhydrous ethanol at a mass ratio of 4:1; S2: At room temperature, the organic solution of zinc compound is stirred with the liquid mixture obtained in step S121 at a mass ratio of 1:4. During the stirring process, zinc dialkyl dithiophosphate is added in three batches to obtain the adhesive powder activator. The zinc compound organic solution is prepared by cyclohexane (solvent) and zinc naphthenate (solute), and the mass concentration of zinc in the zinc compound organic solution is 8%; the stirring speed is 3000 rpm and the stirring time is 10 min.

[0053] The remaining processes and parameters are the same as in Example 1.

[0054] Example 4 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the composition of the pretreated rubber powder in this embodiment is: 100 parts rubber powder, 3 parts interface agent, 0.5 parts compensator A, 2 parts compensator B, and 2 parts rubber powder activator. The remaining processes and parameters are the same as in Example 1.

[0055] Example 5 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the composition of the pretreated rubber powder in this embodiment is: 100 parts rubber powder, 3 parts interface agent, 1.5 parts compensator A, 2 parts compensator B, and 2 parts rubber powder activator. The remaining processes and parameters are the same as in Example 1.

[0056] Example 6 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the composition of the pretreatment rubber powder in this embodiment is: 100 parts rubber powder, 3 parts interface agent, 2 parts compensator A, 2 parts compensator B, and 2 parts rubber powder activator. The remaining processes and parameters are the same as in Example 1.

[0057] Example 7 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the composition of the pretreated rubber powder in this embodiment is: 100 parts rubber powder, 3 parts interface agent, 1 part compensator A, 3 parts compensator B, and 2 parts rubber powder activator. The remaining processes and parameters are the same as in Example 1.

[0058] Example 8 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the composition of the pretreated rubber powder in this embodiment is: 100 parts rubber powder, 3 parts interface agent, 0.5 parts compensator A, 4 parts compensator B, and 2 parts rubber powder activator. The remaining processes and parameters are the same as in Example 1.

[0059] Example 9 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the composition of the pretreatment rubber powder in this embodiment is: 100 parts rubber powder, 5 parts interface agent, 1 part compensator A, 2 parts compensator B, and 2 parts rubber powder activator. The remaining processes and parameters are the same as in Example 1.

[0060] Example 10 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that in the preparation process of the pretreated rubber powder in this embodiment: the zinc compound organic solution is prepared by cyclohexane (solvent) and zinc isooctanoate (solute), and the mass concentration of zinc element in the zinc compound organic solution is 15%; the stirring speed is 2500 rpm and the stirring time is 15 min. The microwave activation parameters are: under nitrogen atmosphere and 500W power range, microwave activation heating is performed for 40 min.

[0061] Example 11 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the warm-mix agent A in this embodiment includes: 45 parts of dihydroviscosinate, 8 parts of polyether polyol (HSH-204), 12 parts of triisopropanolamine, and 2 parts of esterification catalyst (phosphotungstic acid). The remaining processes and parameters are the same as in Example 1.

[0062] Example 12 The preparation method of the warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the preparation process of the warm-mix agent A in this embodiment is as follows: dihydroviscosinate, polyether polyol (HSH-204) and esterification catalyst (phosphotungstic acid) are heated to 130°C, stirred at 450 r / min for 7.5 h, triisopropanolamine is slowly added, the temperature is raised to 150°C, stirred at 270 r / min for 2.5 h, and then cooled to room temperature to obtain the warm-mix agent. The remaining processes and parameters are the same as in Example 1.

[0063] Example 13 The preparation method of the warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the preparation process of the warm-mix agent A in this embodiment is as follows: dihydroviscosinate, polyether polyol (HSH-204) and esterification catalyst (phosphotungstic acid) are heated to 135°C, stirred at 550 r / min for 7 h, triisopropanolamine is slowly added, the temperature is raised to 160°C, stirred at 330 r / min for 2 h, and then cooled to room temperature to prepare the warm-mix agent. The remaining processes and parameters are the same as in Example 1.

[0064] Example 14 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the components of the warm-mix modified asphalt in this embodiment are: 100 parts asphalt, 30 parts pretreatment rubber powder, 0.6 parts warm-mix agent A, 3 parts warm-mix agent B, 0.8 parts SBS, and 0.5 parts stabilizer. The remaining processes and parameters are the same as in Example 1.

[0065] Example 15 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the components of the warm-mix modified asphalt in this embodiment are: 100 parts asphalt, 30 parts pretreatment rubber powder, 0.9 parts warm-mix agent A, 3 parts warm-mix agent B, 0.8 parts SBS, and 0.5 parts stabilizer. The remaining processes and parameters are the same as in Example 1.

[0066] Example 16 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the components of the warm-mix modified asphalt in this embodiment are: 100 parts asphalt, 30 parts pretreatment rubber powder, 0.3 parts warm-mix agent A, 5 parts warm-mix agent B, 0.8 parts SBS, and 0.5 parts stabilizer. The remaining processes and parameters are the same as in Example 1.

[0067] Example 17 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the components of the warm-mix modified asphalt in this embodiment are: 100 parts asphalt, 30 parts pretreatment rubber powder, 0.3 parts warm-mix agent A, 7 parts warm-mix agent B, 0.8 parts SBS, and 0.5 parts stabilizer. The remaining processes and parameters are the same as in Example 1.

[0068] Example 18 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the preparation process of warm-mix modified asphalt in this embodiment is as follows: S1: Preparation of pretreated adhesive powder: Same as in Example 1.

[0069] S2: Preparation of warm mixing agent A: Same as in Example 1; S3: Preheat the base asphalt to 180℃, add pretreated rubber powder, styrene-butadiene block copolymer (SBS) or polystyrene-butadiene copolymer (SBR) by metering, keep warm and stir for 80 min at a stirring speed of 600 r / min to obtain the first modified asphalt; S4: Add warm mix agent A to the first modified asphalt and stir at 200 r / min for 1.5 h to obtain the second modified asphalt; S5: Add warm mix agent B and stabilizer to the second modified asphalt, keep it at 150℃, and stir at 600r / min for 30min to obtain the third modified asphalt; S6: The third modified asphalt is repeatedly ground in a colloid mill until the material is uniform, thus obtaining warm-mix modified rubber asphalt.

[0070] Example 19 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the preparation process of warm-mix modified asphalt in this embodiment is as follows: S1: Preparation of pretreated adhesive powder: Same as in Example 1.

[0071] S2: Preparation of warm mixing agent A: Same as in Example 1; S3: Preheat the base asphalt to 190℃, add pretreated rubber powder, styrene-butadiene block copolymer (SBS) or polystyrene-butadiene copolymer (SBR) by metering, keep warm and stir for 90 min at a stirring rate of 500 r / min to obtain the first modified asphalt; S4: Add warm mix agent A to the first modified asphalt and stir at 300 r / min for 1 h to obtain the second modified asphalt; S5: Add warm mix agent B and stabilizer to the second modified asphalt, keep it at 160℃, and stir at 800r / min for 20min to obtain the third modified asphalt; S6: The third modified asphalt is repeatedly ground in a colloid mill until the material is uniform, thus obtaining warm-mix modified rubber asphalt.

[0072] Example 20 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1. The difference lies in the rubber powder activator in this embodiment, while the rest of the process and parameters are the same as in Example 1.

[0073] The components of the adhesive powder activator in this embodiment, by mass percentage, are: 15.6% 4006 naphthenic oil, 5.2% anhydrous ethanol, 78.4% zinc compound organic solution, and 0.8% dialkyl dithiophosphate zinc salt.

[0074] Prepared by the following steps: S1: Prepare a liquid mixture of 4006 naphthenic oil and anhydrous ethanol at a mass ratio of 3:1; S2: At room temperature, the organic solution of zinc compound and the liquid mixture obtained in step S1 are stirred at a mass ratio of 1:5. During the stirring process, zinc dialkyl dithiophosphate salt is added at one time to prepare the adhesive powder activator. The zinc compound organic solution is prepared by cyclohexane (solvent) and zinc naphthenate (solute), and the mass concentration of zinc element in the zinc compound organic solution is 20%; the stirring speed is 2500 rpm and the stirring time is 5 min.

[0075] Example 21 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1. The difference is that the rubber powder activator in this embodiment is the existing rubber activator 480. The rest of the process and parameters are the same as in Example 1.

[0076] Example 22 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the pre-treated rubber powder in this embodiment consists of: 100 parts rubber powder, 3 parts interface agent, 2 parts compensator A, and 2 parts rubber powder activator. The remaining processes and parameters are the same as in Example 1.

[0077] Example 23 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the pre-treated rubber powder in this embodiment consists of: 100 parts rubber powder, 3 parts interface agent, 2 parts compensator B, and 2 parts rubber powder activator. The remaining processes and parameters are the same as in Example 1.

[0078] Example 24 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except for the component ratio of warm-mix agent A. The components of warm-mix agent A in this embodiment are: 25 parts dihydroviscosinate, 15 parts polyether polyol (HSH-204), 8 parts triisopropanolamine, and 2 parts esterification catalyst (phosphotungstic acid). The remaining processes and parameters are the same as in Example 1.

[0079] Example 25 The preparation methods of warm-mix modified asphalt in this embodiment are similar to those in Embodiment 1. The difference lies in the preparation process parameters of warm-mix agent A in this embodiment, while the rest of the process and parameters are the same as in Embodiment 1.

[0080] The specific preparation process is as follows: dihydromucoacin, polyether polyol and esterification catalyst are heated to 150°C, stirred at 500 r / min for 7 h, triisopropanolamine is slowly added, the temperature is raised to 170°C, stirred at 300 r / min for 2 h and then cooled to room temperature to prepare warm mixing agent A.

[0081] Example 26 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the components of the warm-mix modified asphalt in this embodiment are: 100 parts asphalt, 30 parts pretreated rubber powder, 0.8 parts SBS, and 0.5 parts stabilizer. Warm-mix agent A and warm-mix agent B are not added during the preparation process, and the remaining processes and parameters are the same as in Example 1.

[0082] Example 27 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the components of the warm-mix modified asphalt in this embodiment are: 100 parts asphalt, 30 parts pretreated rubber powder, 3 parts warm-mix agent B, 0.8 parts SBS, and 0.5 parts stabilizer. Warm-mix agent A is not added during the preparation process, and the remaining processes and parameters are the same as in Example 1.

[0083] Example 28 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Example 1, except that the components of the warm-mix modified asphalt in this embodiment are: 100 parts asphalt, 30 parts pretreatment rubber powder, 0.3 parts warm-mix agent A, 0.8 parts SBS, and 0.5 parts stabilizer. Warm-mix agent B is not added during the preparation process, and the remaining processes and parameters are the same as in Example 1.

[0084] Example 29 The preparation method of warm-mix modified asphalt in this embodiment is similar to that in Embodiment 1. The difference lies in the preparation parameters of the warm-mix modified asphalt in this embodiment, while the rest of the process and parameters are the same as in Embodiment 1.

[0085] S1: Preparation of pretreated adhesive powder: Same as in Example 1.

[0086] S2: Preparation of warm mixing agent A: Same as in Example 1; S3: Preheat the base asphalt to 160℃, add pretreated rubber powder, styrene-butadiene block copolymer (SBS) or polystyrene-butadiene copolymer (SBR) by metering, keep warm for 80 min, stir at 600 r / min to obtain the first modified asphalt; S4: Add warm mix agent A to the first modified asphalt and stir at 400 r / min for 1 h to obtain the second modified asphalt; S5: Add warm mix agent B and stabilizer to the second modified asphalt, keep it at 130℃, and stir at 600r / min for 30min to obtain the third modified asphalt; S6: The third modified asphalt is repeatedly ground in a colloid mill until the material is uniform, thus obtaining warm-mix modified rubber asphalt.

[0087] Comparative Example 1 The preparation method of the warm-mix modified asphalt in this comparative example is similar to that in Example 1, except for the pretreated rubber powder. The composition of the pretreated rubber powder in this comparative example is: 100 parts rubber powder and 2 parts rubber powder activator. The remaining processes and parameters are the same as in Example 1.

[0088] Comparative Example 2 The preparation method of the warm-mix modified asphalt in this comparative example is similar to that in Example 1, except for the pretreated rubber powder. The composition of the pretreated rubber powder in this comparative example is: 100 parts rubber powder, 3 parts interface agent, and 2 parts rubber powder activator. The remaining processes and parameters are the same as in Example 1.

[0089] The performance of the asphalt prepared in the examples and comparative examples was tested using the test methods and evaluation standards of the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering".

[0090] The mix design of the warm-mix rubber-modified asphalt mixture prepared in this invention was carried out using the dense-grained gradation AR-SAC-13. With a fixed asphalt-aggregate ratio of 5.4%, the asphalt prepared in the examples and comparative examples was molded into mixtures according to the aggregate ratio determined by the gradation design. Compaction characteristics and road performance were then tested. Compaction characteristics included the porosity of Marshall-molded and rotary-compacted specimens at different compaction temperatures. Road performance included dynamic stability at 60°C, freeze-thaw splitting residual strength ratio (representing water stability), low-temperature flexural failure strain, and the more stringent 50°C immersion Hamburg rutting test.

[0091] Table 1. Test results of technical indicators of warm-mix modified asphalt in the examples and comparative examples.

[0092] Table 2. Relevant test results of warm-mix modified asphalt mixtures in the examples and comparative examples.

[0093] As shown in Tables 1 and 2, the warm-mix rubber-modified asphalt prepared by the method of this invention, by introducing a compensating agent into the pretreated rubber powder, effectively compensates for the problems of reduced road performance and attenuation of asphalt indicators caused by the introduction of the warm-mix agent. This ensures that the warm-mix rubber-modified asphalt effectively reduces the mixing temperature while maintaining good road performance. The warm-mix rubber-modified asphalt exhibits good performance in terms of ductility, elastic recovery, and softening point; specifically, penetration at 25℃ ≥ 50 (0.1 mm), softening point ≥ 74℃, ductility at 5℃ ≥ 10 cm, ductility at 5℃ ≥ 40 N, and elastic recovery ≥ 78%. Simultaneously, the long-term storage stability of the warm-mix rubber-modified asphalt is improved after 72 hours (i.e., the difference between the rotational viscosity at 180℃ (72h) / Pa.s and the rotational viscosity at 180℃ / Pa.s is ≤ 0.6, showing little change; while the difference in the comparative example is > 0.6).

[0094] The warm-mix rubber-modified asphalt mixture prepared by the method of this invention exhibits excellent high and low temperature performance. The freeze-thaw splitting residual strength ratio, a characterization of water stability, can be stably maintained above 83%. Even with a 25°C reduction in mixing and compaction temperature, it still achieves the same compaction effect as at 185°C. The high-temperature dynamic stability (60°C dynamic stability) reaches over 4400 cycles / mm, and the low-temperature flexural failure strain is ≥2900 / με. This allows the warm-mix modified rubber asphalt prepared by this invention to achieve the effects of warm mixing while ensuring the road performance of the mixture, while also reducing asphalt fume emissions, effectively improving the construction environment, and extending the construction period.

[0095] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing warm-mix modified rubber asphalt, characterized in that, Includes the following steps: S1: Preparation of pretreated adhesive powder: The pretreated adhesive powder contains a compensating agent; S2: Prepare warm mixing agent A; S3: Preheat the base asphalt, add pretreated rubber powder and copolymer modifier, keep warm, stir, and obtain the first modified asphalt; S4: Add warm mix agent A to the first modified asphalt and stir to obtain the second modified asphalt; S5: Add warm mix agent B and stabilizer to the second modified asphalt, keep it warm, stir, and obtain the third modified asphalt; S6: The third modified asphalt is repeatedly ground in a colloid mill until the material is uniform, to obtain warm-mix modified rubber asphalt; The pretreated adhesive powder is prepared by the following method: S11: Add the adhesive powder, interface agent, compensator A, and compensator B to a vertical drum three-dimensional mixer according to the formula weight ratio of 100:3~5:0.5~2:1~4, premix evenly to obtain a mixture, and set aside; The interface agent is palm oil diethanolamide; S12: Preparation of a rubber powder activator, wherein the components of the rubber powder activator, by mass fraction, are: 14.88–18.6% 4006 naphthenic oil, 4.96–6.2% anhydrous ethanol, 74.4–79.36% zinc compound organic solution, and 0.8–1.0% zinc dialkyl dithiophosphate; wherein the zinc compound organic solution is prepared by cyclohexane with one or more of zinc naphthenate, zinc isooctanoate, and zinc neodecanoate, and the mass concentration of zinc element is 8%. 15%; S13: Mix the mixture obtained in step S11 and the adhesive powder activator obtained in step S12 according to a mass ratio of 60:1 to 25:1, knead, press into sheet form, and microwave activate and heat. S14: The product after microwave activation and heating is mechanically crushed to obtain pretreated adhesive powder; The compensator is compensator A and compensator B, wherein compensator A is one or more of triethylenediamine, diethylenetriamine, and 2-methylpentanediamine; and compensator B is an epoxysilane. The warm mixing agent A is a liquid dicarboxylic acid ester mixture, which is obtained by esterification reaction between dihydromucoacinic acid, polyether polyol, triisopropanolamine and esterification catalyst. By weight, the dihydromucoacinic acid is 30-60 parts, the polyether polyol is 4-8 parts, the triisopropanolamine is 8-16 parts and the esterification catalyst is 1-5 parts. The warm mixing agent B is oxidized polyethylene wax; The copolymer modifier is a styrene-butadiene block copolymer or a polystyrene-butadiene copolymer; The stabilizer is a silane coupling agent; The warm-mix modified rubber asphalt prepared by the aforementioned method comprises base asphalt, pretreated rubber powder, warm-mix agent A, warm-mix agent B, copolymer modifier, and stabilizer; the weight ratio of the base asphalt, pretreated rubber powder, warm-mix agent A, warm-mix agent B, copolymer modifier, and stabilizer is 100:18-33:0.3-1:3-8:0.5-1.2:0.3 1.

2. The preparation method according to claim 1, characterized in that, In step S3, the preheating temperature of the base asphalt is 170~190℃.

3. The preparation method according to claim 2, characterized in that, In step S3, the stirring rate is 500~800 r / min and the stirring time is 65~90 min.

4. The preparation method according to claim 1, characterized in that, In step S4, the stirring rate is 200~300 r / min and the stirring time is 60~90 min.

5. The preparation method according to claim 1, characterized in that, In step S5, the heat preservation temperature is 145~160℃.

6. The preparation method according to claim 5, characterized in that, In step S5, the stirring rate is 500~800 r / min and the stirring time is 20~45 min.

7. A warm-mix modified rubber asphalt, characterized in that, It is prepared by the preparation method according to any one of claims 1-6.

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