Preparation technology and method of high-mixing-amount direct recycled asphalt mixture

Abstract

The invention relates to a preparation technology and a preparation method of a high-mixing-amount direct recycled asphalt mixture, and belongs to the technical field of recycled asphalt mixture production. According to the invention, waste asphalt mixture solid waste is taken as a main raw material, a hard asphalt high modulus design method is adopted, an asphalt regenerant with hardening volatilization characteristics is doped, and the fatigue performance of the regenerated asphalt mixture is taken as a main control index; the mixing amount of the waste asphalt mixture solid waste in the recycled asphalt mixture is increased from about 30% at present to 55%-65%, and the pavement performance of the recycled asphalt mixture is greatly improved (the Marshall stability is improved by 20%-30%, the rebound modulus is improved by 18%-35%, and the rutting stability is improved by 130%-152%). Meanwhile, a direct vat set production process of the recycled asphalt mixture is provided, the production cost and carbon emission of the recycled asphalt mixture are reduced by 50% or above, and the method has excellent economic, environment-friendly and social significance.

Description

Technical Field

[0001] The invention relates to a high-dosage direct-injection recycled asphalt mixture preparation technology and method, belonging to the technical field of recycled asphalt mixture preparation. Background Art

[0002] At present, factory-mixed hot recycling is the best way to recycle solid waste from waste asphalt mixtures, but there are still the following two problems: (1) The current content of solid waste from waste asphalt mixtures in recycled asphalt mixtures is relatively low, generally only about 30%, the absorption capacity is limited, and the practical effect is not obvious; (2) Ordinary asphalt mixture production equipment cannot be directly used for the preparation of recycled asphalt mixtures. It is often necessary to set up two sets of drying drums and vibrating screens at the same time, one set for heating and drying and screening natural aggregates, and the other set for heating and drying and screening recycled aggregates. The production cost, energy consumption and carbon emissions of recycled asphalt mixtures are twice that of ordinary asphalt mixtures. Enterprises cannot afford it and are unwilling to invest, resulting in difficulties in promoting recycled asphalt mixture preparation technology.

[0003] In view of the above two problems, the present invention uses waste asphalt mixture solid waste as the main raw material, adopts the hard asphalt high modulus design method, mixes in asphalt regeneration agent with hardening and volatilization characteristics, takes the fatigue performance of the regenerated asphalt mixture as the main control index, and increases the amount of waste asphalt mixture solid waste in the regenerated asphalt mixture from the current 30% to 55% to 65%, while greatly improving the road performance of the regenerated asphalt mixture. At the same time, it proposes and combines the direct investment production process to reduce the production cost, energy consumption and carbon emissions of the regenerated asphalt mixture by more than 50%, which has excellent economic, environmental and social significance.

[0004] After searching, it was found that the patent "A method for producing factory-mixed hot recycled asphalt concrete" (application number 201510972030.3) replaces part of the ordinary sand and gravel aggregate with crushed solid waste particles of waste asphalt mixture. First, the ordinary sand and gravel aggregate is placed in the drying drum 1# for heating, and the waste asphalt mixture particles are placed in the heating drying drum 2# for heating. This is obviously different from the production process of the present invention which only uses one set of drying drums.

[0005] The patent “An asphalt regeneration agent, its preparation method and application” (application number 201510040028.2) uses plant asphalt, epoxy polyethylene polyamine, epoxy silicone resin, epoxy resin, trichloroethylene and petroleum resin as raw materials to prepare the asphalt regeneration agent, which is completely different from the present invention.

[0006] The patented "Plant-mixed hot recycled asphalt mixture production equipment" (application number 202010451200.4) technology uses three sets of heating, drying and mixing equipment, which is different from the present invention which only uses one set of heating and mixing equipment. The patented "Regenerated Asphalt Mixture Heating Mixing Station" (application number 202110214573.4) requires first heating and stirring the recycled aggregate and the regeneration agent to form an old mixture, then stirring the natural aggregate and the regeneration agent to form a new mixture, and finally heating and stirring the new and old mixtures. A total of three sets of heating and mixing devices are required, which is significantly different from the present invention which only uses one set of heating and mixing equipment.

[0007] The recycled asphalt preparation method mentioned in the patent "A large-volume high-modulus recycled asphalt mixture and its preparation method and application" (application number 202110907436.9) technology is different from the present invention in the following three points. First, the patented preparation technology requires that the road milling waste material (that is, the recycled coarse and fine aggregates in the present invention) be heated to 120°C, and the mineral material (and the natural aggregate in the present invention) be heated to 190-200°C at the same time, that is, this technology requires two sets of heating equipment, while the present invention only requires one set of heating equipment, and the heating temperature of the present invention is only 165-175°C, and the energy consumption and carbon emissions are lower; secondly, the dosage of waste milling waste materials (that is, the solid waste of waste asphalt mixture in the present invention) in the patented preparation technology is 50%-55%, while the present invention The blending ratio is 55% to 65%, and the resource utilization rate of the waste asphalt mixture of the present invention is higher; finally, the patent increases the blending amount of waste asphalt mixture by forming a smaller skeleton gap rate and a denser skeleton structure through grading design, while the present invention adopts a high modulus design method of hard asphalt, blends in an asphalt regeneration agent with hardening and volatile characteristics, and takes the fatigue performance of the recycled asphalt mixture as the main control indicator to increase the blending amount of waste asphalt mixture and the road performance of the recycled asphalt mixture. The technical principles of the two are completely different.

[0008] By comparison, it is found that the existing technologies for preparing recycled asphalt mixture using solid waste of waste asphalt mixture as raw materials are all different from the present invention, and the technology for preparing recycled asphalt mixture similar to the present invention has not been reported in the literature. Therefore, the present invention designs a high-dosage direct-injection recycled asphalt mixture preparation technology and method. Summary of the invention

[0009] The present invention provides a high-dosage direct-throw type recycled asphalt mixture preparation technology. The present invention uses waste asphalt mixture solid waste as the main raw material, adopts a hard asphalt high modulus design method, mixes an asphalt regeneration agent with hardening and volatilization characteristics, and takes the fatigue performance of the recycled asphalt mixture as the main control index to achieve the increase of the dosage of waste asphalt mixture solid waste in the recycled asphalt mixture from the current 30% to 55% to 65%, and at the same time greatly improves the road performance of the recycled asphalt mixture (Marshall stability is increased by 20% to 30%, rebound modulus is increased by 18% to 35%, and rutting stability is increased by 130% to 152%). At the same time, a direct-throw type production process for recycled asphalt mixture is proposed and combined, which reduces production costs and carbon emissions by more than 50%, and has excellent economic, environmental and social significance.

[0010] The direct-injection production process of recycled asphalt mixture proposed and adopted by the present invention is based on the ordinary asphalt mixture production equipment, by adding a cold aggregate storage bin, a cold aggregate belt conveyor and a hoist, directly transporting the recycled fine aggregate with a high content of waste asphalt to the mixing pot. This production process does not require the addition of special recycled fine aggregate heating, drying and screening equipment. By mixing the recycled fine aggregate with other heated aggregates to obtain heat, the activity of the waste asphalt in the recycled fine aggregate is activated to prepare a recycled asphalt mixture with excellent road performance, reducing the production cost and carbon emissions of the recycled asphalt mixture by more than 50%, and has excellent economic, environmental and social significance.

[0011] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a high-dosage direct-injection recycled asphalt mixture preparation technology, which adopts the hard asphalt high modulus design method to determine the basic mix ratio of the high modulus asphalt mixture, adds asphalt regeneration agent, takes the fatigue performance of the recycled asphalt mixture as the main control index, and further adjusts and optimizes the mix ratio according to the fatigue performance test results of the recycled asphalt mixture, so that the fatigue life of the recycled asphalt mixture under the micro-strain condition of 100με is not less than 1.1 to 1.8 million times, and finally obtains a recycled asphalt mixture with high dosage and high road performance.

[0012] Preferably, it is prepared by mixing one or more of dicyclopentadiene, trivinyltrimethylcyclotrisilazane, conjugated cyclodiolefins, isopropylcyclohexane and trimethylethylamine hydroxide reagents, and its characteristics are that it can significantly stimulate and improve the performance of waste asphalt. At the same time, after the regenerated asphalt mixture hardens, the solvent evaporates naturally and will not remain in the regenerated asphalt mixture, thereby avoiding the influence of solvent residue on the road performance of the regenerated asphalt mixture.

[0013] Preferably, the raw materials used to prepare the recycled asphalt mixture include natural aggregate (including natural fine aggregate and natural coarse aggregate), recycled aggregate (including recycled fine aggregate and recycled coarse aggregate), asphalt regeneration agent and ordinary asphalt.

[0014] Preferably, the recycled aggregate used in the recycled asphalt mixture is the waste asphalt mixture milled out during the asphalt pavement reconstruction process, which is crushed and screened into granular material. The recycled aggregate is divided into two types: recycled fine aggregate and recycled coarse aggregate, wherein the particle size of the recycled fine aggregate is 0-5 mm, and the particle size of the recycled coarse aggregate is 5-10 mm, 10-25 mm.

[0015] Preferably, the equipment includes cold aggregate storage bin 1#, cold aggregate storage bin 2#, a belt conveyor, a drying drum, an elevator, a vibrating screen, a hot aggregate storage bin, a mixing pot and a finished product bin.

[0016] Preferably, the recycled fine aggregate is not heated and dried, but is directly sent to the mixing pot via a belt conveyor for mixing.

[0017] Preferably, the mixing pot productivity calculation formula is:

[0018] Q=G 0 ×K t ×t 0

[0019] Where: G 0 Indicates the mass of material in the mixing pot (kg);

[0020] t 0 Indicates the stirring time (the time the mixture stays in the stirring pot) (min);

[0021] K t It represents the time utilization coefficient, which is between 0.85 and 0.90.

[0022] A method for preparing a high-dosage direct-injection recycled asphalt mixture comprises the following steps:

[0023] (1) First, the recycled waste asphalt mixture is crushed and screened into three grades, namely, recycled fine aggregate (particle size 0-5 mm), recycled coarse aggregate 1# (particle size 5-10 mm) and recycled coarse aggregate 2# (particle size 10-25 mm);

[0024] (2) Adopt the high modulus design method of hard asphalt, add asphalt regeneration agent with hardening and volatilization characteristics, take the fatigue performance of recycled asphalt mixture as the main control index, increase the amount of waste asphalt in the recycled asphalt mixture from the current about 30% to 55%~65%, and determine the production mix ratio;

[0025] (3) Loading recycled coarse aggregate and natural aggregate into cold aggregate storage bin 1#, and loading recycled fine aggregate into cold aggregate storage bin 2#;

[0026] (4) The recycled coarse aggregate and natural aggregate in the cold aggregate storage bin 1# are sent to the drying drum via a belt conveyor, and the temperature is controlled at 165-175°C. After drying, the heated recycled coarse aggregate and natural aggregate are sent to the vibrating screen via an elevator, and sent to the hot aggregate storage bin after screening;

[0027] (5) According to the production mix ratio, the heated aggregates in the hot aggregate storage bin and the recycled fine aggregates in the cold aggregate storage bin 2# are weighed and sent to the mixing pot. At the same time, the asphalt and asphalt regeneration agent are weighed and added to the mixing pot. After being mixed evenly, they are sent to the finished product bin to complete the preparation process.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] It overcomes the problems of low waste asphalt content, poor road performance, high production cost and large carbon emissions in the existing recycled asphalt mixture production technology, and increases the use of waste asphalt mixture from 30% in the current technology to 55%-65%, greatly improving the road performance of the Marshall stability, rebound modulus and rutting stability of the recycled asphalt mixture. At the same time, it simplifies the production process and reduces the production cost and carbon emissions of the recycled asphalt mixture by more than 50%. It is of great significance to increase the utilization rate of waste asphalt mixture, reduce enterprise production costs, promote energy conservation and save resources, strengthen the quality control of the mixture, and set up standardized testing methods and equipment to ensure that the quality of the mixture meets the requirements. DETAILED DESCRIPTION

[0030] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] Embodiment 1

[0032] (1) First, the recycled waste asphalt mixture is crushed and screened into three grades, namely, recycled fine aggregate (particle size 0-5 mm), recycled coarse aggregate 1# (particle size 5-10 mm) and recycled coarse aggregate 2# (particle size 10-25 mm);

[0033] (2) Adopting the high modulus design method of hard asphalt, adding asphalt regeneration agent with hardening and volatile characteristics, taking the fatigue performance of recycled asphalt mixture as the main control index, increasing the amount of waste asphalt in the recycled asphalt mixture from the current about 30% to 55%-65%, and finally determining the production mix ratio (mass ratio) as 22 parts of natural coarse aggregate, 15 parts of natural fine aggregate, 33 parts of recycled coarse aggregate, 30 parts of recycled fine aggregate, 3.5 parts of oil-stone ratio, and 1.8 parts of asphalt regeneration agent;

[0034] (3) Loading recycled coarse aggregate and natural aggregate into cold aggregate storage bin 1#, and loading recycled fine aggregate into cold aggregate storage bin 2#;

[0035] (4) The recycled coarse aggregate and natural aggregate in the cold aggregate storage bin 1# are sent to the heating and drying drum via a belt conveyor, and the temperature is controlled at 165-175°C. After drying, the heated aggregate is sent to the vibrating screen via an elevator, and sent to the hot aggregate storage bin after screening;

[0036] (5) According to the production mix ratio, the heated aggregate in the hot aggregate storage bin and the recycled fine aggregate in the cold aggregate storage bin 2# are weighed and sent to the mixing pot. At the same time, the asphalt and asphalt modifier are weighed and added to the mixing pot. After being mixed evenly, they are sent to the finished product bin to complete the preparation process. The Marshall stability of the recycled asphalt mixture is increased by 27%, the rebound modulus is increased by 32%, and the rutting stability is increased by 150%.

[0037] Embodiment 2

[0038] (1) First, the recycled waste asphalt mixture is crushed and screened into three grades, namely, recycled fine aggregate (particle size 0-5 mm), recycled coarse aggregate 1# (particle size 5-10 mm) and recycled coarse aggregate 2# (particle size 10-25 mm);

[0039] (2) Adopting the high modulus design method of hard asphalt, adding asphalt regeneration agent with hardening and volatile characteristics, taking the fatigue performance of recycled asphalt mixture as the main control index, increasing the amount of waste asphalt in the recycled asphalt mixture from the current about 30% to 55%-65%, and finally determining the production mix ratio (mass ratio) as 20 parts of natural coarse aggregate, 24 parts of natural fine aggregate, 27 parts of recycled coarse aggregate, 29 parts of recycled fine aggregate, 3.9 oil-stone ratio, and 1.7 parts of asphalt regeneration agent;

[0040] (3) Loading recycled coarse aggregate and natural aggregate into cold aggregate storage bin 1#, and loading recycled fine aggregate into cold aggregate storage bin 2#;

[0041] (4) The recycled coarse aggregate and natural aggregate in the cold aggregate storage bin 1# are sent to the heating and drying drum via a belt conveyor, and the temperature is controlled at 165-175°C. After drying, the heated aggregate is sent to the vibrating screen via an elevator, and sent to the hot aggregate storage bin after screening;

[0042] (5) According to the production mix ratio, the heated aggregate in the hot aggregate storage bin and the recycled fine aggregate in the cold aggregate storage bin 2# are weighed and sent to the mixing pot. At the same time, the asphalt and asphalt modifier are weighed and added to the mixing pot. After being mixed evenly, they are sent to the finished product bin to complete the preparation process. The Marshall stability of the recycled asphalt mixture is increased by 25%, the rebound modulus is increased by 31%, and the rutting stability is increased by 146%.

[0043] Embodiment 3

[0044] (1) First, the recycled waste asphalt mixture is crushed and screened into three grades, namely, recycled fine aggregate (particle size 0-5 mm), recycled coarse aggregate 1# (particle size 5-10 mm) and recycled coarse aggregate 2# (particle size 10-25 mm);

[0045] (2) Adopting the high modulus design method of hard asphalt, adding asphalt regeneration agent with hardening and volatile characteristics, taking the fatigue performance of recycled asphalt mixture as the main control index, increasing the amount of waste asphalt in the recycled asphalt mixture from the current about 30% to 55%-65%, and finally determining the production mix ratio (mass ratio) as 28 parts of natural coarse aggregate, 27 parts of natural fine aggregate, 21 parts of recycled coarse aggregate, 24 parts of recycled fine aggregate, 3.9 oil-stone ratio, and 1.5 parts of asphalt regeneration agent;

[0046] (3) Loading recycled coarse aggregate and natural aggregate into cold aggregate storage bin 1#, and loading recycled fine aggregate into cold aggregate storage bin 2#;

[0047] (4) The recycled coarse aggregate and natural aggregate in the cold aggregate storage bin 1# are sent to the heating and drying drum via a belt conveyor, and the temperature is controlled at 165-175°C. After drying, the heated aggregate is sent to the vibrating screen via an elevator, and sent to the hot aggregate storage bin after screening;

[0048] (5) According to the production mix ratio, the heated aggregate in the hot aggregate storage bin and the recycled fine aggregate in the cold aggregate storage bin 2# are weighed and sent to the mixing pot. At the same time, the asphalt and asphalt modifier are weighed and added to the mixing pot. After being mixed evenly, they are sent to the finished product bin to complete the preparation process. The Marshall stability of the recycled asphalt mixture is increased by 24%, the rebound modulus is increased by 33%, and the rutting stability is increased by 144%.

[0049] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-dosage direct-injection recycled asphalt mixture preparation technology, characterized in that: The basic mix ratio of high modulus asphalt mixture is determined by the high modulus design method of hard asphalt, and asphalt regeneration agent is added. The fatigue performance of the recycled asphalt mixture is taken as the main control indicator. According to the fatigue performance test results of the recycled asphalt mixture, the mix ratio is further adjusted and optimized to ensure that the fatigue life of the recycled asphalt mixture under the micro-strain condition of 100με is not less than 1.1 to 1.8 million times, and finally a recycled asphalt mixture with high addition and high road performance is obtained.

2. The asphalt regeneration agent according to claim 1, characterized in that: It is prepared by mixing one or more of dicyclopentadiene, trivinyltrimethylcyclotrisilazane, conjugated cyclodiolefin, isopropylcyclohexane and trimethylethylamine hydroxide reagents. Its characteristics are that it can significantly stimulate and improve the performance of waste asphalt. At the same time, after the recycled asphalt mixture hardens, the solvent will evaporate naturally and will not remain in the recycled asphalt mixture, thus avoiding the influence of solvent residue on the road performance of the recycled asphalt mixture.

3. A high-dosage direct-injection recycled asphalt mixture production technology, characterized by: The raw materials used to prepare the recycled asphalt mixture include natural aggregate (including natural fine aggregate and natural coarse aggregate), recycled aggregate (including recycled fine aggregate and recycled coarse aggregate), asphalt regeneration agent and ordinary asphalt.

4. The direct-investment recycled asphalt mixture production technology according to claim 3 is characterized in that: The recycled aggregate is solid waste of waste asphalt mixture formed by milling damaged asphalt pavement. It is a granular material formed after crushing and screening, and is divided into recycled coarse aggregate (particle size 5-10mm, 10-25mm) and recycled fine aggregate (particle size 0-5mm).

5. A high-dosage direct-injection recycled asphalt mixture preparation technology, characterized by: The equipment includes cold aggregate storage bin 1#, cold aggregate storage bin 2#, belt conveyor, drying drum, elevator, vibrating screen, hot aggregate storage bin, mixing pot and finished product bin.

6. The direct-investment recycled asphalt mixture production technology according to claim 3 is characterized in that: The recycled fine aggregate is not heated or dried, but is directly sent to the mixing pot for mixing via a belt conveyor.

7. The direct-investment recycled asphalt mixture production technology according to claim 6 is characterized in that: The formula for calculating the mixing pot productivity is: Q=G0×K t ×t0 Where: G0 represents the mass of the material in the stirring pot (kg); t0 represents the stirring time (residence time of the mixture in the stirring pot) (min); K t It represents the time utilization coefficient, which is between 0.85 and 0.

90.

8. A method for preparing a high-volume direct-injection recycled asphalt mixture, based on a high-volume direct-injection recycled asphalt mixture preparation technology according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) First, the recycled waste asphalt mixture solid waste is crushed and screened into three grades, namely, recycled fine aggregate (particle size 0-5 mm), recycled coarse aggregate 1# (particle size 5-10 mm) and recycled coarse aggregate 2# (particle size 10-25 mm); (2) Adopting the high modulus design method of hard asphalt, adding asphalt regeneration agent with hardening and volatilization characteristics, taking the fatigue performance of recycled asphalt mixture as the main control index, increasing the content of solid waste of waste asphalt mixture in recycled asphalt mixture from the current about 30% to 55%~65%, and determining the production mix ratio; (3) Loading recycled coarse aggregate and natural aggregate into cold aggregate storage bin 1#, and loading recycled fine aggregate into cold aggregate storage bin 2#; (4) The recycled coarse aggregate and natural aggregate in the cold aggregate storage bin 1# are sent to the drying drum via a belt conveyor, and the temperature is controlled at 165-175°C. After drying, the heated recycled coarse aggregate and natural aggregate are sent to the vibrating screen via an elevator, and sent to the hot aggregate storage bin after screening; (5) According to the production mix ratio, the heated aggregates in the hot aggregate storage bin and the recycled fine aggregates in the cold aggregate storage bin 2# are weighed and sent to the mixing pot. At the same time, the asphalt regeneration agent and ordinary asphalt are weighed and added to the mixing pot. After being mixed evenly, they are sent to the finished product bin to complete the preparation process.