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CN-122011790-A - Method for synergistically modifying asphalt by nitrogen-doped biomass carbon point and SBS and modified asphalt

CN122011790ACN 122011790 ACN122011790 ACN 122011790ACN-122011790-A

Abstract

The invention discloses a method for synergistically modifying asphalt by nitrogen-doped biomass carbon points and SBS and modified asphalt, and relates to the technical field of asphalt preparation for road engineering. The method comprises the steps of preparing a carbon dot precursor by taking biomass waste as a raw material, adding a nitrogen-containing micromolecular dopant for hydrothermal reaction to prepare a nitrogen-doped biomass carbon dot, and introducing the carbon dot and SBS to a matrix asphalt to mix and modify the matrix asphalt to prepare modified asphalt. The invention inhibits asphalt oxidation and SBS degradation through excellent free radical capturing and ultraviolet shielding capability of carbon points, utilizes the chemical reaction or pi-pi action and hydrogen bonding action of polar functional groups such as polyphenol/hydroxyl/carboxyl on the surfaces of the carbon points and SBS styrene blocks and asphalt aromatic components to construct a multi-interpenetrating network, promotes compatibility and dispersion, and realizes the synergistic promotion of three aspects of high temperature performance, aging resistance and storage stability through the technical path of biomass carbon point preparation, nitrogen doping, SBS composite master batch method and asphalt synergistic modification.

Inventors

  • LV SONGTAO
  • ZHAO PEIQI
  • XIA CHENGDONG
  • HUANG BIN
  • Ling Yumeng
  • WANG YUCHEN
  • YANG YI
  • LU WEIWEI

Assignees

  • 长沙理工大学
  • 湖南省高速公路集团有限公司

Dates

Publication Date
20260512
Application Date
20251229

Claims (10)

  1. 1. The method for synergistically modifying asphalt by nitrogen-doped biomass carbon points and SBS is characterized by comprising the following steps of: S1, preparing a biomass carbon dot precursor, namely crushing biomass waste, mixing the crushed biomass waste with deionized water, stirring and extracting, and collecting filtrate as the biomass carbon dot precursor; S2, nitrogen doping and premixing, namely adding a nitrogen-containing micromolecular dopant into the filtrate of the S1, and uniformly stirring; s3, performing hydrothermal reaction to prepare a nitrogen-doped biomass carbon dot, namely transferring the solution of S2 into a reaction kettle, performing hydrothermal reaction at 160-220 ℃ for 4-12 hours, cooling, filtering, collecting filtrate, concentrating and purifying to obtain the nitrogen-doped biomass carbon dot; s4, preparing composite master batches, namely shearing and mixing the biomass carbon points of S3, SBS and rubber auxiliary agent uniformly according to a proportion, and granulating the mixed materials to obtain the composite master batches, wherein the mass ratio of the biomass carbon points to SBS is 1 (4-10), and the consumption of the rubber auxiliary agent is 10-30wt% of the mass of SBS; S5, asphalt modification, namely adding the composite master batch of the S4 into matrix asphalt, controlling the temperature to be 160-180 ℃, and shearing for 15-30 min at the rotating speed of 3000-5000rpm to enable the modifier to be uniformly dispersed, so as to obtain the modified asphalt.
  2. 2. The method for synergistically modifying asphalt by nitrogen-doped biomass carbon dots and SBS, which is characterized in that the mass-volume ratio of biomass waste to deionized water in S1 is (1-5) g (20-100) mL, and the condition of stirring and extracting is that the temperature is 60-100 ℃ and the stirring and extracting is 10-60 min.
  3. 3. The method of co-modifying pitch with SBS and nitrogen doped biomass carbon dots according to claim 1, wherein the biomass waste in S1 comprises at least one of tea grounds, straw, coffee grounds, and fruit shells.
  4. 4. The method of co-modifying pitch with SBS and nitrogen-doped biomass carbon dots according to claim 1, wherein the small nitrogen-containing dopant in S2 comprises at least one of DETA and TETA.
  5. 5. The method for synergistically modifying asphalt with nitrogen-doped biomass carbon dots and SBS according to claim 1, wherein the addition amount of the nitrogen-containing small molecular dopant in S2 is 0.5-5vol% relative to the volume of the solution of the biomass carbon dot precursor.
  6. 6. The method for synergistically modifying asphalt by nitrogen-doped biomass carbon dots and SBS according to claim 1, wherein the rubber auxiliary agent in S4 comprises silica as a reinforcing filler of rubber, and is mixed with sulfur, BR-g-MAH and a silane coupling agent Si69, wherein the rubber auxiliary agent comprises 8-15 parts of SiO 2 , 0.5-2 parts of sulfur, 1-5 parts of BR-g-MAH and 1-5 parts of Si69 by 100 parts of SBS.
  7. 7. The method for synergistically modifying asphalt by nitrogen-doped biomass carbon dots and SBS, which is characterized in that the concentration and purification process in S3 is specifically characterized in that the collected filtrate is concentrated by a rotary evaporator, a NWCO =1000 Da dialysis membrane is adopted, and dialysis is carried out for 24-72 h, so that small molecular impurities are removed, and a purified biomass carbon dot solution is obtained.
  8. 8. The method for synergistically modifying asphalt by nitrogen-doped biomass carbon dots and SBS, which is disclosed in claim 1, is characterized in that the shearing and mixing conditions in S4 are that the shearing and mixing are carried out for 5-15 min under the conditions of 160-190 ℃ and 3000-5000 rpm, the granulating process is carried out in a double-screw extruder, the extrusion temperature is controlled to be 160-200 ℃, and the particle size of the composite master batch is controlled to be 1-5 nm.
  9. 9. The method for synergistically modifying asphalt with nitrogen-doped biomass carbon dots and SBS according to claim 1, wherein the addition amount of the composite master batch in S5 is 2-6wt% of the matrix asphalt.
  10. 10. The modified asphalt prepared by the method for synergistically modifying asphalt with SBS and nitrogen-doped biomass carbon points according to any one of claims 1-9.

Description

Method for synergistically modifying asphalt by nitrogen-doped biomass carbon point and SBS and modified asphalt Technical Field The invention relates to the technical field of asphalt materials for road engineering, in particular to a method for modifying asphalt by combining nitrogen-doped biomass carbon points and SBS and modified asphalt. Background In recent years, along with the continuous increase of traffic demands and the continuous expansion of road network scale, asphalt pavements have become a main pavement form of global highway construction by virtue of the advantages of simple construction, good travelling comfort, short maintenance period and the like. According to statistics, the asphalt pavement proportion in China at present is over 90 percent. However, petroleum asphalt as a core material of asphalt pavement, the source of which depends on non-renewable petrochemical resources, and the production process is accompanied by high energy consumption and large pollution discharge, and development of green and sustainable replacement or modification technology is urgently needed. In order to solve the problems that petroleum asphalt is easy to generate rutting under a high-temperature environment, easy to crack under a low-temperature condition, and has insufficient ageing resistance in the service process, a polymer modification technology is generally adopted at home and abroad. Among them, modifiers represented by SBS (styrene-butadiene-styrene block copolymer) are widely used because of their excellent elastic recovery ability and network reinforcing effect. SBS modified asphalt has good performance in high temperature rut resistance and crack resistance, and has been widely used in highways and heavy traffic roads. However, SBS modified asphalt still has a series of problems to be solved in practical engineering application, namely (1) the cost is high, SBS belongs to petrochemical-based high polymer materials, the price is high, the influence of crude oil price fluctuation is remarkable, and the large-scale popularization and application of the SBS modified asphalt are greatly restricted. (2) The storage stability is poor, the compatibility between SBS and asphalt is limited, and the SBS and asphalt are easy to phase-separate or aggregate in the thermal storage process, so that the modifier is unevenly distributed, and the pavement construction quality and long-term performance are affected. (3) The aging resistance is insufficient, under the combined action of ultraviolet radiation, oxidation and thermal environment, the SBS molecular chain segments (especially polybutadiene parts) are easy to break, crosslink or degrade, so that asphalt is hardened and embrittled, and the service life of the asphalt is shortened. Research shows that under 160-180 ℃ storage condition, the mechanical property of SBS modified asphalt is obviously reduced along with time, and the network structure of the SBS modified asphalt is gradually destroyed, so that the existing system still has defects in long-term durability. To overcome the above problems, researchers have proposed various strategies for improvement, including the incorporation of adjuvants, co-polymers or nanoenhancers in SBS-bitumen systems. For example, (1) inorganic nanomaterials such as nanoclay, silica, etc., are used to improve the dispersion and thermal stability of SBS, but have limited compatibility with organic asphalt. (2) The carbon nanomaterial, such as carbon nanotube and graphene, improves the mechanical property and ageing resistance of asphalt by enhancing the interface acting force. However, the preparation process of the material is complex, the price is high, and the material is difficult to popularize in large-scale engineering. (3) Organic auxiliary agents such as plasticizers and compatilizers can delay phase separation to a certain extent, but have the problems of environment unfriendly or unstable effect and the like. Based on the above-described research on modifiers, carbon Dots (CDs) are attracting attention as a novel nanocarbon material. The carbon dots have the characteristics of small particle size (< 10 nm), excellent fluorescence performance, rich polar functional groups (hydroxyl groups, carboxyl groups and polyphenol groups) on the surface, ultraviolet absorption and free radical scavenging capability and the like. These properties make it particularly useful in the fields of photovoltaic materials, sensors, catalysis and polymeric composites. Research has shown that carbon dots can effectively inhibit the degradation process of polymer materials under illumination and oxidation conditions, and improve the interfacial binding force between a polymer matrix and a modifier. In the field of asphalt modification, a small amount of exploratory research and attempts have been made, for example, graphene Quantum Dots (GQDs) or petroleum-based carbon dots (CQDs) are combined with SBS, and the results show that the Gra