CN116376301A - A kind of nano-enzymatic lignin to improve the anti-aging performance of asphalt and its regeneration method - Google Patents

Abstract

The invention provides a method for improving the ageing resistance of asphalt by using nano enzymolysis lignin, belongs to the technical field of durability and regeneration of road materials, and solves the problems of unclear ageing resistance effect, low dispersibility, easiness in segregation, poor regeneration effect and the like of the conventional nano enzymolysis lignin in asphalt. The technical scheme of the invention is as follows: the nano enzymolysis lignin modified asphalt is subjected to short-term and long-term aging tests to prepare long-term aged nano enzymolysis lignin modified asphalt, and a test instrument is used for analyzing an aging resistance improvement mechanism of nano enzymolysis lignin on asphalt; preparing a wood tar-based regenerant from wood tar and five doping agents according to a certain mass ratio; and then pouring a certain amount of wood tar-based regenerant into the nano enzymolysis lignin modified asphalt filled with the aging to prepare regenerated asphalt, and finally, characterizing the action mechanism of the wood tar-based regenerant on the nano enzymolysis lignin modified asphalt by various test instruments to determine the optimal blending amount and preparation process of the wood tar-based regenerant.

Description

A kind of nano-enzymatic lignin to improve the anti-aging performance of asphalt and its regeneration method

technical field

The invention relates to a method for improving the anti-aging performance of asphalt by enzymolysis of nanometer lignin and a regeneration method, belonging to the technical field of road material durability and regeneration.

Background technique

Asphalt is a dark brown complex organic matter with high viscosity solid, semi-solid or viscous, composed of hydrocarbons of different molecular weights and non-metallic derivatives. It is mainly used as road construction and waterproof and anti-corrosion materials in the engineering field. However, due to the rise of the domestic machinery manufacturing industry and the continuous improvement of people's living standards, factors such as the rapid increase in traffic volume, large-scale vehicles, heavy vehicle loads, and temperature differences have placed higher requirements on asphalt pavement. At the same time, the aging phenomenon of asphalt leads to cracks, subsidence, pits and other diseases on the asphalt pavement. service life. As we all know, during the aging process of asphalt, the content of aromatic components and colloids gradually decreases, the content of asphaltene increases, and the original colloidal structure of asphalt gradually gels, which reduces the stability of asphalt colloids and increases the relative molecular weight. Therefore, traditional asphalt can no longer meet the needs of roads, and we have to consider adding modifiers to asphalt to improve road performance, improve the aging resistance and road service life of modified asphalt.

With the advancement of science and technology, nanomaterials are gradually introduced into the field of traffic and roads. Due to the small particle size, large specific surface area, and large number of atoms on the surface, nano-enzymatic lignin shows high activity, so it shows excellent blending, toughening and strengthening properties in asphalt modification. Nano-enzymatic lignin is used as a treatment for enzymatic lignin. It retains some of the physical and chemical properties of enzymatic lignin, such as better retention of rich functional group structures such as phenolic hydroxyl groups and benzene rings, and has good thermal stability and UV aging resistance. At the same time, studies have found that lignin and asphalt have similar functional group structures, which can achieve the goal of improving the compatibility of lignin-modified asphalt, and have good economic and social benefits.

In recent years, some road researchers have found that lignin has strong oxidation resistance, which is mainly due to the active functional groups such as hydroxyl and benzene ring in the lignin structure, which has strong hydrogen atom transfer ability and positive local static electricity. Potential, when oxygen or ultraviolet rays enter the asphalt, the hydrogen bonds in the lignin first oxidize with oxygen, and at the same time, the three-dimensional aromatic network structure of lignin further inhibits the penetration of ultraviolet rays into the asphalt, so lignin itself has excellent anti-aging activity . However, there are few studies on the anti-aging performance of nano-enzymatic lignin modified asphalt. Relevant literature shows that the high-temperature performance of lignin-modified asphalt is significantly improved, but the low-temperature performance is not good, and the fatigue life is reduced. Although lignin itself has excellent aging resistance, when lignin is applied to asphalt roads and put into operation for a period of time Finally, asphalt roads are prone to cracking at low temperatures, which affects the use of lignin in asphalt roads and produces a large amount of waste asphalt, resulting in extreme pollution and waste of resources.

With the development of highway reconstruction, recycled asphalt pavement has been used as a recycled material in new pavement construction, and the use of old materials helps reduce the demand for virgin asphalt and non-renewable mineral aggregates. At present, the main methods of asphalt regeneration are mixed asphalt regeneration and regenerant regeneration. It is feasible to restore the performance of aged asphalt by adding regenerant to change the chemical composition and colloidal structure. At present, wood tar is the main by-product of biomass thermal cracking. The composition of wood tar is very complex, mainly including aliphatic hydrocarbons, aromatic hydrocarbons and phenolic compounds. It has the characteristics of wide sources, waste utilization, environmental protection and regeneration. In recent years, relevant researchers have found that wood tar as an asphalt modifier can effectively improve the low-temperature performance and fatigue resistance of asphalt. However, there are some differences between wood tar and matrix asphalt in terms of molecular structure, physical and chemical properties, etc. Using a single wood tar as a rejuvenating agent for asphalt may affect the storage stability of modified asphalt, and the fusion mechanism between wood tar and aged asphalt is still unclear. Unclear and limited regeneration recovery of aged asphalt.

Therefore, the present invention provides a nano-enzymatic lignin to improve the anti-aging performance of asphalt and a regeneration method. Firstly, the nano-enzymatic lignin-modified asphalt was prepared by high-temperature melt blending, and then the aged enzymatic lignin-modified asphalt was prepared through short-term and long-term aging tests. Aging effect, using wood tar and five kinds of admixtures to prepare a wood tar-based rejuvenator in a certain proportion, regenerate the aged asphalt, and finally reveal the regeneration mechanism of the wood tar-based rejuvenator on the aged asphalt from the microscopic level through the test instrument, In this way, the optimal dosage of wood tar-based regenerant is determined, and the development of nano-enzymatic lignin and wood tar, two biomass materials, in the road field is promoted.

Contents of the invention

(1) Technical issues

The purpose of the present invention is to provide a nano-enzymatic lignin to improve the anti-aging performance of asphalt and a regeneration method. The nano-enzymatic lignin has uniform size and low molecular weight, and shows excellent similar compatibility in asphalt, which helps to improve the asphalt. Road performance, wood tar can be used as a regenerant of asphalt, which helps to restore the performance of aged asphalt, and solves the problem that the anti-aging mechanism of nano-enzymatic lignin in asphalt is not clear and the dispersion of wood tar in asphalt is low. Easy segregation, poor regeneration effect and other problems.

(2) Technical solution

In order to solve the problems that the anti-aging mechanism of nano-enzymatic lignin in asphalt is not clear and the wood tar has low dispersion, easy segregation and poor regeneration effect in asphalt. The invention provides a method for improving the anti-aging performance of asphalt by enzymatically decomposing lignin with nanometer and regenerating it. The technical scheme of the present invention is as follows: first, nano-enzymolysis lignin-modified asphalt is prepared by high-temperature melt blending, and then the aged enzymolysis lignin-modification asphalt is prepared through short-term and long-term aging tests, and infrared spectroscopy and gel permeation are used Chromatography was used to characterize the functional group changes, molecular weight and distribution characteristics of nano-enzymatic lignin modified asphalt. Wood tar and five different doping agents were used to prepare a wood tar-based rejuvenator in a certain proportion, and the aged asphalt was regenerated. Scanning electron microscopy, Atomic force microscope test was used to characterize the dispersion effect of wood tar-based regenerant on aged nano-enzymatic lignin-modified asphalt, and infrared spectrometer and gel permeation chromatography were used to reveal the functional group changes of nano-enzymatic lignin-modified asphalt before and after aging and regeneration And molecular weight size and distribution characteristics, using differential scanning calorimeter test to reveal the thermal stability mechanism of wood tar-based rejuvenating agent on aging nano-enzymatic lignin modified asphalt, in order to determine the best wood tar-based rejuvenating agent To promote the development of two kinds of biomass materials, nano-enzymatic lignin and wood tar, in the road field.

(3) Beneficial effect

Due to the continuous development of the national economy and the continuous improvement of people's living standards, factors such as rapid increase in traffic volume, large-scale vehicles, heavy vehicles and temperature differences have put forward higher requirements for asphalt pavement. At the same time, the aging phenomenon of asphalt leads to cracks, subsidence, potholes and other diseases on the asphalt pavement. service life. Due to the small particle size, large specific surface area, and large number of atoms on the surface, nano-enzymatic lignin shows high activity, so it shows excellent blending, toughening and strengthening properties in asphalt modification. Nano-enzymatic lignin is used as a treatment for enzymatic lignin. It retains some of the physical and chemical properties of enzymatic lignin, such as better retention of rich functional group structures such as phenolic hydroxyl groups and benzene rings, and has good thermal stability and UV aging resistance. Wood tar is the main by-product of biomass pyrolysis, mainly including aliphatic hydrocarbons, aromatic hydrocarbons and phenolic compounds. It has the characteristics of wide sources, waste utilization, environmental protection and regeneration. However, the anti-aging mechanism of nano-enzymatic lignin in asphalt is not clear, and wood tar has low dispersion, easy segregation, and general regeneration effect in asphalt. The invention provides a nano-enzymatic lignin to improve the anti-aging performance of asphalt and a regeneration method. The mechanism of the anti-aging effect of nano-enzymatic lignin on asphalt is revealed through related equipment, and a wood tar-based regeneration agent is developed at the same time, which is beneficial to reduce The segregation phenomenon of wood tar during asphalt production or storage improves the regeneration effect of wood tar. According to the present invention, actively cooperate with relevant biotechnology enterprises, rationally utilize the biomass materials such as corn stalk enzymolysis lignin and wood tar, develop and industrialize the production of nano-enzymolysis lignin and wood tar-based regenerant products, reduce production costs, Protecting the ecological environment has practical significance for improving the aging resistance of asphalt pavement and rationally developing biomass energy.

Detailed ways

The present invention provides a nano-enzymolysis lignin to improve the anti-aging performance of asphalt and a regeneration method. The specific implementation steps are as follows:

(1) Put 400 grams of base asphalt in a beaker, heat it to 165 ° C to completely melt the base asphalt, place the beaker under a high-speed shearing machine to shear and stir at a shear rate of 5000 rpm, and simultaneously mix 32 grams of Slowly add the nano-enzymatic lignin powder into the molten asphalt, shear and stir for 50 minutes, and then continue to stir with a glass rod until no bubbles are generated in the asphalt, and place it in an oven at 120°C for 50 minutes to develop the nanozyme Lignin-modified asphalt;

(2) Carry out the aging test according to the aging method in the "Test Regulations for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20-2011). The temperature of the oven is 163°C for 85 minutes, and then the nano-enzymatic lignin modified asphalt after short-term aging is subjected to long-term aging through the pressure aging test. Long-term aging nano-enzymatic lignin-modified asphalt, using infrared spectroscopy and gel permeation chromatography to characterize the functional group changes, molecular weight and distribution characteristics of matrix asphalt and nano-enzymatic lignin-modified asphalt, and analyze nano-enzymatic lignin Improve the anti-aging performance of asphalt;

(3) Place the beaker on an insulation cover with a temperature of 80°C, and put a certain amount of wood tar, dioctyl phthalate, polymer resin, compatibilizer, stabilizer, diethyldithiocarbamate Zinc is slowly poured into a beaker, wherein the mass ratio of wood tar, dioctyl phthalate, polymer resin, compatibilizer, stabilizer, and zinc diethyldithiocarbamate is 70:5:1:5 : 4: 15, and stir with a glass rod until evenly mixed to obtain a wood tar-based regenerant;

(4) Place the beaker with long-term aging asphalt on the insulation cover at 145°C, slowly pour a certain amount of wood tar-based regenerant into the beaker, and use an electric mixer with a stirring speed of 1000 rpm to stir for 10 minutes , and then put the beaker in an oven at 120°C for 30 minutes to insulate and develop it to obtain aged nano-enzymatic lignin-modified asphalt regenerated by wood tar-based regenerant;

(5) Scanning electron microscopy and atomic force microscopy were used to characterize the dispersion effect of wood tar-based regenerants in long-term aging nano-enzymatic lignin-modified asphalt, and infrared spectroscopy and gel permeation chromatography tests were used to reveal nano-enzymatic lignin modification. The functional group changes, molecular weight and distribution characteristics of asphalt before and after aging and after regeneration, and the thermal stability of wood tar-based regenerant to long-term aging nano-enzymatic lignin modified asphalt was studied by differential scanning calorimeter test;

(6) Explore the regeneration effect of different dosages of wood tar-based regenerants on the road performance of long-term aging nano-enzymatic lignin modified asphalt, and reveal the effect of wood tar-based rejuvenators on long-term aging nano-enzymatic lignin modified asphalt. The regeneration mechanism of permanent asphalt, determine the optimal dosage of wood tar-based rejuvenator, prepare wood tar-based rejuvenator to regenerate nano-enzymatic lignin modified asphalt, and improve the regeneration effect of long-term aging asphalt.

Claims (1)

1. A method for improving the ageing resistance of asphalt by using nano enzymolysis lignin is characterized by comprising the following specific steps:

(1) Placing 400 g of matrix asphalt in a beaker, heating to 165 ℃ to enable the matrix asphalt to be completely melted, placing the beaker under a high-speed shearing machine to conduct shearing stirring at a shearing speed of 5000 revolutions per minute, slowly adding 32 g of nano enzymolysis lignin powder into the melted asphalt, conducting shearing stirring for 50 minutes, continuing stirring by using a glass rod until bubbles are not generated in the asphalt, and placing the mixture in a baking oven at 120 ℃ to develop for 50 minutes to obtain nano enzymolysis lignin modified asphalt;

(2) According to an ageing method in highway engineering asphalt and asphalt mixture test procedure (JTG E20-2011), carrying out short-term ageing on the nano enzymolysis lignin modified asphalt through a rotating film oven ageing test, wherein the ageing time is 85 minutes, the oven temperature is 163 ℃, then carrying out long-term ageing on the nano enzymolysis lignin modified asphalt subjected to short-term ageing through a pressure ageing test, the air pressure is 2.1MPa, the temperature is 100 ℃ and the ageing is 20 hours, so as to obtain the nano enzymolysis lignin modified asphalt subjected to long-term ageing, and adopting infrared spectrum and gel permeation chromatography tests to represent the functional group change, the molecular weight and the distribution characteristics of the matrix asphalt and the nano enzymolysis lignin modified asphalt, and analyzing the improvement effect of the nano enzymolysis lignin on the ageing resistance of the asphalt;

(3) Placing a beaker on a heat preservation sleeve with the temperature of 80 ℃, slowly pouring a certain amount of wood tar, dioctyl phthalate, high polymer resin, compatilizer, stabilizer and zinc diethyl dithiocarbamate into the beaker, wherein the mass ratio of the wood tar to the dioctyl phthalate to the high polymer resin to the compatilizer to the stabilizer to the zinc diethyl dithiocarbamate is 70:5:1:5:4:15, and stirring the mixture by using a glass rod until the mixture is uniformly mixed to obtain the wood tar-based regenerant;

(4) Placing a beaker filled with long-term aged asphalt on a heat insulation sleeve at 145 ℃, slowly pouring a certain amount of wood tar-based regenerant into the beaker, stirring for 10 minutes by adopting an electric stirrer with the stirring speed of 1000 revolutions per minute, and then placing the beaker in a baking oven at 120 ℃ for heat insulation and development for 30 minutes to prepare the aged nano enzymatic hydrolysis lignin modified asphalt regenerated by the wood tar-based regenerant;

(5) The dispersion effect of the wood tar-based regenerant in the long-term aged nano enzymolysis lignin modified asphalt is represented by adopting a scanning electron microscope and an atomic force microscope test, the functional group change, the molecular weight and the distribution characteristics of the nano enzymolysis lignin modified asphalt before and after aging and after regeneration are revealed by adopting an infrared spectrometer and a gel permeation chromatography test, and the thermal stability of the wood tar-based regenerant on the long-term aged nano enzymolysis lignin modified asphalt is researched by adopting a differential scanning calorimeter test;

(6) The regeneration effect of the wood tar-based regenerant with different doping amounts on the road performances of the long-term aged nano enzymolysis lignin modified asphalt is explored, the regeneration mechanism of the wood tar-based regenerant on the long-term aged nano enzymolysis lignin modified asphalt is revealed, the optimal doping amount of the wood tar-based regenerant is determined, the wood tar-based regenerant is prepared to regenerate the nano enzymolysis lignin modified asphalt, and the regeneration effect of the long-term aged asphalt is improved.