CN115108762A - Coal ash-based geopolymer material for pouring porous asphalt mixture and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of road building materials, in particular to a fly ash-based polymer material for porous asphalt mixture perfusion and a preparation method. The fly ash-based polymer material for porous asphalt mixture infusion of the present invention comprises, in mass percentage, 16-28% of solid sodium silicate, 1-5% of sodium hydroxide, 44-52% of fly ash, standard sand 10-22%, expansion agent 0.1-4%, coupling agent 0.1-2%, early strength agent 0.1-2%. Advantages: Porous asphalt mixture can be filled with fly ash waste material, energy saving and environmental protection, reducing carbon emissions, and realizing the recycling of solid waste; it can be used directly when mixed with water, which is convenient for storage and transportation, and has good flow after water mixing on site It can quickly form strength and reduce construction time and construction cost; the mixture can effectively take into account high temperature performance, strong water stability, durability and other advantages, and is suitable for popularization and application.

Description

Fly ash-based polymer material and preparation method for porous asphalt mixture pouring

technical field

The invention relates to the technical field of road building materials, in particular to a fly ash-based polymer material for porous asphalt mixture perfusion and a preparation method.

Background technique

Fly ash, as a road construction building material with significant advantages, has been fully developed and utilized in recent years. Fly ash is a lightweight, porous granular material with a similar appearance and finer particles. , is the solid waste produced by the incomplete combustion of coal in the process of thermal power generation and urban heating. The use of fly ash as a road construction building material has very typical advantages. From the perspective of environmental protection, it can effectively avoid the problems of fly ash occupying land resources and polluting the environment; in terms of the nature of the project, it can effectively It can ensure the quality of the project and can effectively reduce the construction cost, but the traditional geopolymer grouting material needs to prepare an alkali activator in advance and then mix it with the cementitious material.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a fly ash-based polymer material and a preparation method for porous asphalt mixture pouring, which effectively overcomes the defects of the prior art.

The technical scheme that the present invention solves the above-mentioned technical problems is as follows:

A fly ash-based polymer material for perfusion of porous asphalt mixtures, in terms of mass percentage, the preparation raw materials include: 16-28% of solid sodium silicate, 1-5% of sodium hydroxide, 44-52% of fly ash, Standard sand 10-22%, expansion agent 0.1-4%, coupling agent 0.1-2%, early strength agent 0.1-2%.

On the basis of the above technical solutions, the present invention can also be improved as follows.

Further, the modulus of the solid sodium silicate is 2.0, the Na ₂ O content is 25.0%, the SiO ₂ content is 49.2%, and the properties are white powder.

Further, the sodium hydroxide is a granular or flaky white solid with a content of ≥96%.

Further, the fineness of the fly ash is 1000-2000 mesh.

Further, the standard sand is quartz sand with a particle size of 0.15 mm or less.

Further, the expansion agent is at least one of UEA expansion agent, magnesium oxide, and HCSA high-efficiency expansion agent.

Further, the coupling agent is at least one of a silane coupling agent, a chromium complex coupling agent, and a titanate coupling agent.

Further, the early strength agent is at least one of nitrite, chromate, triethanolamine, calcium formate, urea, and slag powder.

The beneficial effects are: the use of fly ash waste material to realize the perfusion of porous asphalt mixture, energy saving and environmental protection, reduction of carbon emissions, and realization of recycling of solid waste; The fluidity and permeability of the mixture can quickly form the strength, reducing the construction time and construction cost; the mixture can effectively take into account the high temperature performance, strong water stability, durability and other advantages, suitable for popularization and application.

Also provided is a preparation method of a fly ash-based polymer material for porous asphalt mixture pouring, comprising the following steps:

Step 1. After weighing the solid sodium silicate, sodium hydroxide, fly ash, standard sand, early strength agent and expansion agent of the formula, mix and stir evenly;

In step 2, water and coupling agent are added to the mixture in step 1 for alternating high and low speed stirring, wherein the amount of water added is 22% to 27% of the total mass of the raw materials.

On the basis of the above technical solutions, the present invention can also be improved as follows.

Further, in the low-speed alternating stirring process, the alternating time interval is 3-5 min, and the total mixing time is 10-20 min, wherein the low-speed stirring speed is 1000-1500 rpm and the high-speed stirring speed is 1500-2500 rpm.

The beneficial effects are: the preparation method is simple and efficient.

Detailed ways

The principles and features of the present invention are described below, and the examples are only used to explain the present invention, but not to limit the scope of the present invention.

Example 1

A convenient type of fly ash-based polymer material for perfusion of porous asphalt mixture, the preparation raw materials include: solid sodium silicate 24.38%, sodium hydroxide 3.36%, fly ash 49.91%, standard sand 18.08% , expansion agent 2.71%, coupling agent 0.9%, early strength agent 0.67%;

Among them, the fly ash is grade I fly ash, the fineness is not more than 18% (1000-2000 mesh), the density is 2.589g/cm3; the modulus of solid sodium silicate is 2.0, the Na ₂ O content is 25.0%, and the SiO ₂ The content is 49.2%, and the property is white powder; sodium hydroxide is a white uniform flake solid with a content of ≥96%; the coupling agent adopts silane coupling agent model KH-550, which is colorless and transparent liquid; early strength agent adopts The slag, preferably the slag model is S95 grade slag powder; the expansion agent adopts HCSA high-efficiency expansion agent, and the specific preparation method includes the following steps:

First of all, the porous asphalt mixture matrix is made according to the OGFC-25 type of aggregates required by the recommended range of the current technical specifications for highway asphalt pavement construction in my country;

Next, take the solid sodium silicate, sodium hydroxide, fly ash, standard sand, slag powder and expansion agent of the formula amount and mix and stir evenly;

After that, add water and coupling agent (silane coupling agent) to the mixture in step 1 to perform high-low speed alternating stirring, wherein the amount of water added is 25.34% of the total mass of the raw materials, and the low-speed stirring speed is 1000-1500rpm high-speed stirring speed At 1500-2500 rpm, the high and low speeds are alternately stirred for a total of 15 minutes, and finally the filled slurry fly ash base polymer material is obtained;

Then, the obtained base asphalt mixture is tightly packed with a smooth surface waterproof material and the surface is reserved, the base asphalt mixture is placed on a cement vibrating table, and the base asphalt mixture is poured in a volume ratio of 3:1 to the grouting material. Fill the polymer material (slurry) of the fly ash base with the slurry, vibrate on the vibrating table for 1 min, and pour while vibrating during the process until the slurry can not completely penetrate from the remaining surface, and finally scrape off the excess slurry on the surface with a scraper material, exposing the surface of the substrate;

Finally, the specimens were cured; the specimens filled with the slurry were placed in a constant temperature curing box with a temperature of 30°C and a humidity of 90% for 7 days to form, and a semi-flexible asphalt mixture filled with fly ash base polymer was obtained.

The fly ash-based polymer material and semi-flexible asphalt mixture obtained in this example are tested, and their properties are as follows:

Properties of fly ash-based polymer materials:

Mechanical properties

The fly ash base polymer material is first formed in a standard size mold (40mm×40mm×160mm), and then cured for 3 days at a temperature of 30°C and greater than 95% humidity, and then the fly ash base polymer material is removed. The flexural strength and compressive strength of the material were tested, and half of the samples were used for the compressive strength measurement. The results are shown in Table 1.

The mechanical properties data of the geopolymer material obtained in Example 1 of Table 1 are as follows:

Flow properties

The fluidity of geopolymer mortars was measured by the expansion method. The glass plate is placed in a horizontal position. Before the test starts, wipe the glass plate and the cement slurry fluidity test mold (36mm×60mm×60mm) with a wet towel, then pour the slurry into the test mold, and lift the test mold to start timing. After 30s, measure the diameter of the slurry with a ruler, measure the maximum diameter and the minimum diameter of the slurry, and take the average value of the two test results. The fluidity results are shown in Table 2.

The flow performance data of the obtained geopolymer material in Table 2 Example 1 are as follows:

condition mobility initial fluidity 268 30min fluidity 251

Shrinkage performance

For the measurement of dry shrinkage of geopolymer mortar, refer to the requirements of "Standards for Test Methods of Basic Properties of Building Mortars" (JGJ/T 70-2009). , the dry shrinkage rate after 56 days of testing with a vertical mortar shrinkage tester shows that its dry shrinkage value is 0.6%.

Road performance of semi-flexible asphalt mixture:

High temperature performance

The high-temperature stability of semi-flexible asphalt mixtures was tested using dynamic uniaxial tests. Rotary compactor (SGC) was used to prepare porous asphalt mixture matrix specimens, which were poured into geopolymer materials and then placed in a curing box (temperature 30°C, >95% humidity) for 3 days of curing. Then, the UTM-100 universal testing machine was used to test the high temperature performance of the specimens that were kept at 60 °C for more than 4 hours. The test results show that the high-temperature dynamic uniaxial times of the semi-flexible asphalt mixture is 3760 times, while the high-temperature dynamic uniaxial times of the base asphalt mixture is 645 times, and the semi-flexible asphalt mixture is much larger than the dynamic uniaxial data of asphalt materials.

Low temperature performance

Low-temperature crack resistance test: The base asphalt mixture is made into a cylindrical specimen with a diameter of 150mm and a height of 50mm, poured into the fly ash base polymer slurry and formed, and then the cylindrical specimen is cut in half along the radius to make The semi-circular specimen, with a 5mm crack in the middle of the semi-circular specimen, was subjected to SCB test at -10°C. The test results showed that the fracture energy of the semi-flexible asphalt pavement material obtained in this example was 865.6 J/m ² .

Freeze-thaw split test

The freeze-thaw splitting test was used to test the water stability of the semi-flexible asphalt pavement material obtained in this example. The results show that the freeze-thaw splitting ratio of the semi-flexible asphalt mixture filled with fly ash base polymer is 79.5%, which is greater than the standard requirement. 75%.

The freeze-thaw splitting test data of the semi-flexible asphalt mixture obtained in Example 1 of Table 3 are as follows:

immersion marshall test

The water stability performance of the semi-flexible asphalt pavement material obtained in this example was tested by the immersion Marshall test. The results show that the residual stability of the semi-flexible asphalt mixture filled with fly ash base polymer is 95.8%, far exceeding the 80% required by the specification. .

The immersion Marshall test data of the semi-flexible asphalt mixture obtained in Example 1 of table 4 is as follows:

Example 2

A fly ash-based polymer material for perfusion of porous asphalt mixtures, by mass percentage, comprising: solid sodium silicate 24.88%, sodium hydroxide 3.43%, fly ash 48.2%, standard sand 18.45%, expansion agent 2.76% %, coupling agent 0.92%, early strength agent 1.37%;

Among them, the fly ash is grade I fly ash, the fineness is not more than 18% (1000-2000 mesh), the density is 2.589g/cm3; the modulus of solid sodium silicate is 2.0, the Na ₂ O content is 25.0%, and the SiO ₂ The content is 49.2%, and the property is white powder; sodium hydroxide is a white uniform flake solid with a content of ≥96%; the coupling agent adopts silane coupling agent model KH-550, which is colorless and transparent liquid; early strength agent adopts The slag, preferably the slag model is S95 grade slag powder; the expansion agent adopts HCSA high-efficiency expansion agent, and the specific preparation method is roughly the same as that of Example 1.

The fly ash-based polymer material and semi-flexible asphalt mixture obtained in this example are tested, and their properties are as follows:

Properties of fly ash-based polymer materials:

Mechanical properties

The fly ash base polymer material is first formed in a standard size mold (40mm×40mm×160mm), and then cured for 3 days at a temperature of 30°C and greater than 95% humidity, and then the fly ash base polymer material is removed. The flexural strength and compressive strength of the material were tested, and half of the samples were used for the compressive strength measurement. The results are shown in Table 1.

Table 5 embodiment 2 gained geopolymer material mechanical property data, as follows:

Flow properties

The fluidity of geopolymer mortars was measured by the expansion method. The glass plate is placed in a horizontal position. Before the test starts, wipe the glass plate and the cement slurry fluidity test mold (36mm×60mm×60mm) with a wet towel, then pour the slurry into the test mold, and lift the test mold to start timing. After 30s, measure the diameter of the slurry with a ruler, measure the maximum diameter and the minimum diameter of the slurry, and take the average value of the two test results. The fluidity results are shown in Table 2.

The flow properties data of the obtained geopolymer material in Example 2 of Table 6 are as follows:

condition mobility initial fluidity 273 30min fluidity 258

Shrinkage performance

For the measurement of dry shrinkage of geopolymer mortar, refer to the requirements of "Standards for Test Methods of Basic Properties of Building Mortars" (JGJ/T 70-2009). , the dry shrinkage rate after 56 days of testing with a vertical mortar shrinkage tester shows that the dry shrinkage value is 0.62%.

Road performance of semi-flexible asphalt mixture:

High temperature performance

The high-temperature stability of semi-flexible asphalt mixtures was tested using dynamic uniaxial tests. Rotary compactor (SGC) was used to prepare porous asphalt mixture matrix specimens, which were poured into geopolymer materials and then placed in a curing box (temperature 30°C, >95% humidity) for 3 days of curing. Then, the UTM-100 universal testing machine was used to test the high temperature performance of the specimens that were kept at 60 °C for more than 4 hours. The test results show that the high-temperature dynamic uniaxial times of the semi-flexible asphalt mixture is 3960 times, while the high-temperature dynamic uniaxial times of the base asphalt mixture is 645 times. The semi-flexible asphalt mixture is much larger than the dynamic uniaxial data of asphalt materials.

Low temperature performance

Low-temperature crack resistance test: The base asphalt mixture is made into a cylindrical specimen with a diameter of 150mm and a height of 50mm, poured into the fly ash base polymer slurry and formed, and then the cylindrical specimen is cut in half along the radius to make The semi-circular specimen, with a 5mm crack in the middle of the semi-circular specimen, was subjected to SCB test at -10°C. The test results showed that the fracture energy of the semi-flexible asphalt pavement material obtained in this example was 964.8 J/m ² .

Freeze-thaw split test

The freeze-thaw splitting test was used to test the water stability performance of the semi-flexible asphalt pavement material obtained in this example. The results show that the freeze-thaw splitting ratio of the semi-flexible asphalt mixture filled with fly ash base polymer is 80.4%, which is greater than the standard requirement. 75%.

The freeze-thaw splitting test data of the semi-flexible asphalt mixture obtained in Example 2 of table 7 are as follows:

immersion marshall test

The water stability performance of the semi-flexible asphalt pavement material obtained in this example was tested by the immersion Marshall test. The results show that the residual stability of the semi-flexible asphalt mixture filled with fly ash base polymer is 97.6%, far exceeding the 80% required by the specification. .

The immersion Marshall test data of the semi-flexible asphalt mixture obtained in Example 2 of table 8 are as follows:

It should be noted that the principle of the present invention is as follows:

Sodium silicate can dissolve silicon and aluminum in fly ash after adding water, and then polymerize to form aluminosilicate gel, and then polycondensate into inorganic polymers such as calcium aluminosilicate, and solidify to generate strength; active substances in slag and fly ash are dissolved out After that, the product of sodium silicate and water is consolidated, and the fly ash and slag particles are wrapped in it to form a frozen body, and the powder particles are tightly bonded to the surrounding frozen body. Complete, there is no disintegration phenomenon like Portland cement particles; the introduction of silane coupling agent can greatly improve the adhesion and strength between the matrix and the grout; at the same time, the hydrolysis of silicon functional groups in the silane coupling agent requires the participation of water, Makes the slurry bleeding rate reduced, thereby reducing the slurry shrinkage.

Compared with the prior art, the beneficial effects of the present invention are:

(1) It is proposed to develop a fly ash-based polymer material for the perfusion of porous asphalt mixture, which can realize the perfusion of porous asphalt mixture by using fly ash waste material, which can save energy and protect the environment, reduce carbon emissions, and realize the recycling of solid waste.

(2) It can be used directly after mixing with water, which is convenient for storage and transportation. After mixing with water on site, it has good fluidity and permeability, which can quickly form strength and reduce construction time and construction cost.

(3) After the obtained geopolymer material is poured into the porous asphalt mixture, it can effectively take into account the high temperature performance, strong water stability, durability and other advantages, and is suitable for popularization and application.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (10)

1. A fly ash-based polymer material for porous asphalt mixture perfusion is characterized in that, by mass percentage, the preparation raw materials comprise: 16-28% of solid sodium silicate, 1-5% of sodium hydroxide, pulverized coal Ash 44-52%, standard sand 10-22%, expansion agent 0.1-4%, coupling agent 0.1-2%, early strength agent 0.1-2%. 2 . The fly ash-based polymer material for porous asphalt mixture perfusion according to claim 1 , wherein the modulus of the solid sodium silicate is 2.0, the Na ₂ O content is 25.0%, and the SiO ₂ The content is 49.2%, and the character is white powder. 3 . The fly ash-based polymer material for porous asphalt mixture perfusion according to claim 1 , wherein the sodium hydroxide is a granular or flaky white solid with a content of ≥96%. 4 . 4 . The fly ash-based polymer material according to claim 1 , wherein the fineness of the fly ash is 1000-2000 mesh. 5 . 5 . The fly ash-based polymer material for porous asphalt mixture perfusion according to claim 1 , wherein the standard sand is quartz sand with a particle size of less than 0.15 mm. 6 . 6 . The fly ash-based polymer material for porous asphalt mixture perfusion according to claim 1 , wherein the expansion agent is at least one of UEA expansion agent, magnesium oxide, and HCSA high-efficiency expansion agent. 7 . 7. The fly ash-based polymer material for porous asphalt mixture perfusion according to claim 1, wherein the coupling agent is a silane coupling agent, a chromium complex coupling agent, a titanic acid At least one of the ester coupling agents. 8. The fly ash-based polymer material for porous asphalt mixture perfusion according to claim 1, wherein the early strength agent is nitrite, chromate, triethanolamine, calcium formate, urea , at least one of slag powder. 9. A preparation method of fly ash-based polymer material for porous asphalt mixture perfusion, characterized in that, comprising the steps: Step 1. After weighing the solid sodium silicate, sodium hydroxide, fly ash, standard sand, early strength agent and expansion agent of the formula, mix and stir evenly; In step 2, water and coupling agent are added to the mixture in step 1 for alternating high and low speed stirring, wherein the amount of water added is 22% to 27% of the total mass of the raw materials. 10 . The method for preparing a fly ash-based polymer material for porous asphalt mixture perfusion according to claim 9 , wherein in the low-speed alternating stirring process, the alternating time interval is 3-5 min, and the total time interval is 3-5 min. 11 . The mixing time is 10-20 minutes, wherein the low-speed stirring speed is 1000-1500 rpm and the high-speed stirring speed is 1500-2500 rpm.