CN115353746B - A kind of ion exchange resin modified emulsified asphalt and its preparation method - Google Patents

Abstract

The purpose of the present invention is to provide an ion exchange resin modified emulsified asphalt and its preparation method, belonging to the technical field of road paving materials, prepared from ion exchange resin and emulsified asphalt, wherein the ion exchange resin modified emulsified asphalt is obtained by ion exchange Composed of resin, emulsified asphalt and additives, the ion exchange resin is a basic anion exchange resin, the emulsified asphalt is a cationic emulsified asphalt, and the additive is polyvinyl alcohol. The ion-exchange resin-modified emulsified asphalt prepared by the invention has the advantages of simple preparation process, strong storage stability, and high-temperature resistance, and is suitable for high-temperature areas in summer. At the same time, the invention utilizes ion-exchange resin solid waste in an environmentally friendly manner , and obtain modified emulsified asphalt with excellent performance, which is of great significance to environmental protection.

Description

A kind of ion exchange resin modified emulsified asphalt and its preparation method

technical field

The invention belongs to the technical field of road paving materials, in particular to an ion exchange resin modified emulsified asphalt and a preparation method thereof, in particular to an ion exchange resin modified emulsified asphalt especially suitable for cold recycled asphalt pavement and a preparation method thereof.

Background technique

In recent years, the problems of energy and resource consumption and environmental pollution in the road construction industry have attracted more and more attention. Cold mix asphalt (CMA) technology using emulsified asphalt has significant advantages over hot mix asphalt (HMA) technology. The study pointed out that compared with HMA technology, CMA technology reduces the heating process of asphalt and aggregate during the entire pavement construction process, can save more than 50% of energy, and only produces 33% of carbon dioxide and 17% of volatile organic compound emissions. However, due to the addition of water and emulsifiers, the mechanical properties of emulsified asphalt and its mixture have declined. and fatigue life have a direct impact.

Improving the performance of emulsified asphalt is still a widely concerned issue in the field of road construction. The modification of emulsified asphalt mainly focuses on the use of physical modification methods such as elastomers, plastomers, and polymer materials, while relatively few studies have been conducted on the modification of emulsified asphalt from the perspective of ions and reactive groups. As a typical electric double layer structure substance, emulsified asphalt is different from hot mix asphalt due to its special ionic properties. Studies have shown that the chemical reaction will only occur when the ions of the emulsified asphalt are opposite to the reactant ions. The type of emulsifier ions has a significant impact on the stability of the emulsified asphalt binder. Adding salt or small solid particles can accelerate the coalescence of the asphalt emulsion . The cohesion and stability of emulsified asphalt are also related to the solid wettability and electrical interaction between asphalt droplets and minerals, and the wettability depends on the interaction between hydrophobic solid clusters and asphalt molecules. Surfactant concentration must be set to create a balance between bitumen emulsion properties and adhesion between bitumen and aggregate. At the same time, the pH of emulsified asphalt also has a great influence on its stability. According to the theory of suspension rheology, a reasonable pH can control the water amount in the asphalt droplet, making its cohesiveness and stability better.

The ion exchange resin will dissociate into lipophilic groups and hydrophilic groups in the solution, wherein the lipophilic groups can adsorb each other with the oily asphalt droplets, and the hydrophilic groups are opposite to the ionic properties of the emulsified asphalt itself. With the conditions for chemical reactions to occur, interface properties can be exhibited. Therefore, the present invention adopts the basic anion exchange resin to modify the emulsified asphalt, and provides a modified material with excellent performance for the cold recycled asphalt pavement.

Contents of the invention

The purpose of the present invention is to provide an ion exchange resin modified emulsified asphalt and its preparation method, which is composed of emulsified asphalt, ion exchange resin and additives, and finally forms an emulsified asphalt with excellent performance under normal temperature conditions. The invention can provide a modified emulsified asphalt with simple preparation, low cost, strong storage stability, high viscosity and strong stability against high temperature.

The present invention adopts following technical scheme:

An ion exchange resin modified emulsified asphalt comprises the following components in parts by weight: 100 parts of emulsified asphalt, 10-40 parts of ion exchange resin, and 0.2-1 part of additives.

Further, the emulsified asphalt is a slow-cracking cationic emulsified asphalt, which is a dark brown emulsion, and its evaporation residue technical index is not lower than the following characteristics.

Further, the ion exchange resin is a strongly basic anion exchange resin, solid brown to golden yellow spherical particles at room temperature, with a quaternary ammonium group [-N(CH ₃ ) ₃ OH], and a cross-linking degree of not less than 7%. The styrene-divinylbenzene copolymer will dissociate in solution to form anion and lipophilic groups.

Further, the additive is an additive for m-phenylene type unsaturated polyester long afterglow aggregate, which is polyvinyl alcohol, and its appearance is white flake, flocculent or powdery solid, slightly soluble in dimethyl sulfoxide, insoluble in Gasoline, kerosene, vegetable oil, benzene, toluene, dichloroethane, carbon tetrachloride, acetone, ethyl acetate, methanol, ethylene glycol, etc., viscosity 3-70, pH 4.5-6.5, loss on drying ≤ 5.0, Acid value ≤ 3.0%, alcoholysis degree 85-89.

A preparation method of ion exchange resin modified emulsified asphalt, comprising the following steps:

Step 1: At room temperature, add the additive to the emulsified asphalt in an amount of 0.2-1.0 parts of the emulsified asphalt mass, and stir at a stirring speed of 100-500 rpm for 1-3 minutes to form a mixture A.

Step 2: At room temperature, add the strongly basic anion exchange resin to the above mixture A in an amount of 10-40 parts of the emulsified asphalt mass and stir at a stirring speed of 100-500 rpm for 2-4 minutes , the ion exchange resin modified emulsified asphalt is prepared.

The beneficial effects of the present invention are as follows:

1. The preparation of ion exchange resin modified emulsified asphalt is simple;

2. Ion exchange resin modified emulsified asphalt can be modified at room temperature, and the prepared modified emulsified asphalt has strong storage stability;

3. The prepared ion exchange resin modified emulsified asphalt has high viscosity;

4. The prepared ion exchange resin modified emulsified asphalt has strong high temperature stability.

Detailed ways

The present invention discovers an ion exchange resin modified emulsified asphalt and its optimal preparation method through a large number of experimental studies and repeated verifications. The implementation of the present invention will be specifically described below in conjunction with several representative examples, but the following examples do not constitute a limitation to the present invention.

Example 1

At room temperature, add 0.2 parts of polyvinyl alcohol to 100 parts of cationic emulsified asphalt, stir for 3 minutes under the condition of a mixer with a rotation speed of 500 rpm, and store the obtained mixture A in a sealed manner;

At room temperature, add 10 parts of strong basic anion exchange resin to the mixture A, and stir for 2 minutes under the condition of a mixer with a rotation speed of 500 rpm to obtain ion exchange resin modified emulsified asphalt.

Put the ion exchange resin modified emulsified asphalt in the aluminum cylinder, then place it on the electric furnace or gas furnace (with asbestos pad) and heat it slowly until the moisture in the sample has completely evaporated, and then heat it at 163℃±3.0℃ Heating at low temperature for 1 min to obtain the evaporation residue of ion exchange resin modified emulsified asphalt.

Example 2

At room temperature, add 0.4 parts of polyvinyl alcohol to 100 parts of cationic emulsified asphalt, stir for 3 minutes under the condition of a mixer with a rotating speed of 500 rpm, and seal the obtained mixture A for storage;

At room temperature, add 20 parts of strong basic anion exchange resin to the mixture A, and stir for 2 minutes under the condition of a mixer with a rotation speed of 500 rpm to obtain ion exchange resin modified emulsified asphalt.

The ion exchange resin modified emulsified asphalt evaporation residue is the same as in Example 1.

Example 3

At room temperature, add 0.6 parts of polyvinyl alcohol to 100 parts of cationic emulsified asphalt, stir for 3 minutes under the condition of a mixer with a rotation speed of 500 rpm, and seal the obtained mixture A for storage;

At room temperature, add 30 parts of strongly basic anion exchange resin to the mixture A, and stir for 2 minutes under the condition of a mixer with a rotation speed of 500 rpm to obtain ion exchange resin modified emulsified asphalt.

The ion exchange resin modified emulsified asphalt evaporation residue is the same as in Example 1.

Example 4

At room temperature, add 0.8 parts of polyvinyl alcohol to 100 parts of cationic emulsified asphalt, stir for 3 minutes under the condition of a mixer with a rotation speed of 500 rpm, and seal the obtained mixture A for storage;

At room temperature, add 40 parts of strong basic anion exchange resin to the mixture A, and stir for 2 minutes under the condition of a mixer with a rotation speed of 500 rpm to obtain ion exchange resin modified emulsified asphalt.

The ion exchange resin modified emulsified asphalt evaporation residue is the same as in Example 1.

Example 5

At room temperature, add 1.0 parts of polyvinyl alcohol to 100 parts of cationic emulsified asphalt, stir for 3 minutes under the condition of a mixer with a rotation speed of 500 rpm, and store the obtained mixture A in a sealed manner;

At room temperature, add 50 parts of strong basic anion exchange resin to the mixture A, and stir for 2 minutes under the condition of a mixer with a rotation speed of 500 rpm to obtain ion exchange resin modified emulsified asphalt.

The ion exchange resin modified emulsified asphalt evaporation residue is the same as in Example 1.

comparative example

At room temperature, 100 parts of cationic emulsified asphalt was taken as a comparative example.

The evaporation residue of modified emulsified asphalt is the same as in Example 1.

Carry out conductivity, pH test to embodiment 1～5 and comparative example below, analyze the impact of internal ionic strength and storage stability of modified emulsified asphalt; Simultaneously carry out penetration, softening point, Ductility test to characterize the basic performance of different content resins on the evaporation residue of emulsified asphalt. Various test conditions and test results are as follows:

1. Conductivity and pH test

The prepared ion exchange resin-modified emulsified asphalt was tested with a DDSJ-308A conductivity meter and a PHSJ-4A pH meter to test the conductivity and pH of the examples and comparative examples. The test results are shown in Table 1 below.

Table 1

According to Table 1, compared with the comparative examples, the conductivity of Examples 1-5 were all increased, while the pH values were all decreased. With the increase of resin content, the electrical conductivity of the emulsified asphalt in Example 1-5 showed an increasing trend, from 4.50ms/cm to 19.38ms/cm. After the dosage is 40%, continue to increase the resin, and the rate of increase in electrical conductivity slows down. The ion-exchange resin improves the ability of the modified suspension to release ions. After adding the resin, the conductivity of the modified emulsified asphalt is further improved, and the strength of the released ions is increased, thereby improving the stability of the multi-phase suspension; the resin dosage continues When increasing, the ionization effect of the resin in the asphalt emulsion weakens, and the degree of ion exchange with the emulsified asphalt decreases, resulting in a slowdown in the rate of increase in conductivity. The pH of emulsified asphalt decreases gradually with the increase of resin content, and the acidity increases. Previous studies have shown that cationic emulsified asphalt can promote the reaction of ammonium molecules to produce cationic molecules (ammonium salt molecules) under acidic conditions, and can better exert its stability and bonding performance. At a lower pH, the functional groups of the resin are used more efficiently and have a larger adsorption capacity for ions. The increase of H ⁺ can change the ionization balance of the modified emulsified asphalt, increase the thickness of the electric double layer of the resin-asphalt combined structure, and enhance its stability. However, when the resin content exceeds 30%, the H ⁺ concentration of cationic emulsified asphalt is too high, which will destroy the structure of the electric double layer and cause demulsification, which means that the increase rate of electrical conductivity will slow down. Based on the above analysis, the modified emulsified asphalt with an appropriate amount of recycled resin can enhance the electron intensity released from the asphalt emulsion, increase the thickness of the diffusion layer, enhance the stability of the multiphase suspension, and delay the demulsification of the emulsified asphalt.

2. Three major indicators

Penetration, softening point, and ductility tests were performed on the evaporation residues of modified emulsified asphalt in Examples 1-5 and comparative proportions according to the "Test Regulations for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20-2011) to characterize different Effect of resin content on basic properties of emulsified asphalt evaporation residue. The test results are shown in Table 2.

Table 2

It can be seen from Table 2 that, compared with the comparative example, the penetration and ductility of the modified emulsified asphalt of Examples 1-5 showed a downward trend overall, while the softening point gradually increased. The reason for this phenomenon is that when the recycled resin is added to the emulsified asphalt, it will dissociate the lipophilic group and form a macromolecular structure after combining with the asphalt molecule, which increases the agglomeration ability of the evaporation residue; and the resin has high mechanical strength , the combination of the two causes the asphalt to harden as a whole and the needle penetration decreases. When the resin content reaches 30%, the needle penetration increases temporarily, from 42.6mm to 44.4mm, and continues to increase the resin needle penetration and then decreases. It may be because the combination of lipophilic groups of 30% resin and asphalt molecules has reached a state of mutual equilibrium, and when the dosage continues to increase, this balance will be broken. The modified asphalt is destabilized, the excess resin dissociates insufficiently, and the binding effect with asphalt molecules is poor, and there is a phenomenon of mutual agglomeration in the asphalt, resulting in a decrease in penetration. In general, proper resin content will harden the evaporation residue and enhance the high temperature performance of emulsified asphalt.

It can be seen from Table 2 that compared with the comparative example, the ductility of the modified emulsified asphalt residue in Examples 1-5 decreased from 401.30 mm to 214.65 mm, a decrease of 46.5%. The reason is that in the evaporation residue, the plastic deformation of the asphalt plays a decisive role in the ductility. The cohesion between asphalt is weak, and the bonded phase formed by the resin between the asphalt has poor plastic deformation ability, which creates a weak deformation zone with the modified asphalt, so the ductility of the emulsified asphalt is reduced.

It can be seen from Table 2 that compared with the comparative example, the softening point of the modified emulsified asphalt residue in Examples 1-5 increases with the increase of the recycled resin content. When the resin content is 20%, the softening point reaches 57.08°C. Increased by 6.1%; when the content is greater than 20%, the growth rate of softening point slows down. It shows that the use of resin as emulsified asphalt modifier will make the asphalt hard as a whole, and with the continuous increase of resin content, the modified emulsified asphalt is less affected by temperature, and the temperature sensitivity is reduced, which improves the high temperature performance of emulsified asphalt.

Based on the three major indicators of recycled resin-modified emulsified asphalt, it is found that the use of resin-modified emulsified asphalt will thicken and harden the evaporation residue of emulsified asphalt, enhance the high-temperature performance of emulsified asphalt, but reduce the crack resistance. When the resin content is 30%, the bonding state between resin and asphalt is the best, the recycled resin can give full play to its performance, and the resin-modified emulsified asphalt will show relatively good plastic deformation ability and good high temperature performance.

The reagents used in the present invention are all commercially available, and the methods used in the present invention are conventional methods unless otherwise specified.

Finally, it should be noted that: the above-described embodiments are only specific implementations of the present invention, used to illustrate the technical solutions of the present invention, rather than limiting them, and the scope of protection of the present invention is not limited thereto, although referring to the foregoing The embodiment has described the present invention in detail, and those of ordinary skill in the art should understand that any person familiar with the technical field can still modify the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention Changes can be easily thought of, or equivalent replacements are made to some of the technical features; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the scope of the present invention within the scope of protection. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (2)

1. An ion exchange resin modified emulsified asphalt, characterized in that: it comprises the following components in parts by weight: 100 parts of emulsified asphalt, 10-50 parts of ion exchange resin, and 0.2-1 part of additive; The emulsified asphalt is a slow-cracking cationic emulsified asphalt, which is a dark brown emulsion. The penetration of the evaporation residue at 25°C is ≥60·0.1mm, the softening point is 50-55°C, and the ductility at 10°C is ≥40cm ; The ion exchange resin is a strongly basic anion exchange resin with a quaternary ammonium group [-N(CH3)3OH] and a styrene-divinylbenzene copolymer with a crosslinking degree of not less than 7%; The additive is polyvinyl alcohol. 2. a preparation method of ion exchange resin modified emulsified pitch as claimed in claim 1, is characterized in that: comprises the steps: At room temperature, add the additive to the emulsified asphalt in an amount of 0.2-1.0 parts of the emulsified asphalt mass, and then stir. The stirring speed is 100-500 rpm, and the stirring time is 1-3min; Thereafter, the strong basic anion exchange resin is added to the above-mentioned mixture in an amount of 10-40 parts of the emulsified asphalt mass, and the stirring speed is 100-500 rpm, and the stirring time is 2-4min. The permanent emulsified asphalt is prepared.