CN115057660A - Water-blended quick-hardening metakaolin-based geopolymer material for pouring porous asphalt mixture and preparation method thereof - Google Patents

Abstract

The invention discloses a water-blended quick-hardening metakaolin-based geopolymer material for pouring a porous asphalt mixture, which is mainly prepared by compounding 15-25% of solid sodium silicate, 20-28% of metakaolin, 6-12% of fly ash, 2-4% of sodium hydroxide, 25-35% of water, 5-15% of fine sand, 0.1-5% of an expanding agent and 0.1-2% of a coupling agent in percentage by mass.

Description

Water-increasing fast-hardening metakaolin-based polymer material for porous asphalt mixture perfusion and its preparation method

technical field

The invention relates to the technical field of road building materials, in particular to a water-increasing fast-hardening metakaolin-based polymer material for perfusion of porous asphalt mixture and a preparation method thereof.

Background technique

In a long period of time in the future, due to the continuous increase in the penetration rate and proportion of asphalt pavement, road maintenance has become the focus of the transportation industry, and rutting and cracks, as the main diseases of asphalt pavement, are the main problems of road maintenance work. The key issue. The use of cement-based grouting material for semi-flexible asphalt mixture pouring has excellent performance in improving the high temperature rutting resistance of asphalt mixture, but inevitably there are problems such as poor volume stability, high porosity, poor fluidity and insufficient strength, and the cement production process damage and pollution of the ecological environment. Gel materials using geopolymers such as metakaolin or fly ash have the advantages of high temperature resistance, high early strength, and low reaction heat, which can reduce production energy consumption and carbon emissions and realize solid waste recycling. The polymer grouting material needs to prepare an alkali activator liquid in advance before it can be mixed with the cementitious material. This kind of geopolymer material is cumbersome to prepare, has a long maintenance period, and has a slow strength formation. In practical engineering applications, it is not convenient for long-term stable storage and long-distance storage. transportation. Therefore, the development of a water-increasing fast-hardening metakaolin-based polymer material for porous asphalt mixture filling can greatly improve the early strength and fluidity of the geopolymer material, reduce the early cracking tendency of the slurry, and can be stored for a long time. It is of great significance for the promotion and application of geopolymer grouting materials in asphalt concrete.

SUMMARY OF THE INVENTION

In view of this, the present invention aims to provide a water-increasing fast-hardening metakaolin-based polymer material for porous asphalt mixture infusion, which can ensure the early strength and fluidity of the geopolymer material and reduce the early cracking tendency of the slurry. At the same time, it can effectively take into account the high temperature rutting resistance and durability, effectively solve the tedious steps and time and transportation problems of traditional geopolymer grouting materials that need to prepare alkali activator liquid in advance, and has important economic and time benefits.

In order to achieve the above object, the technical scheme of the present invention is achieved in this way:

A water-converting fast-hardening metakaolin-based polymer material for perfusion of porous asphalt mixtures, in terms of mass percentage, comprising the following components: 15-25% of solid sodium silicate, 20-28% of metakaolin, and 6% of fly ash ~12%, sodium hydroxide 2~4%, water 25~35%, fine sand 5~15%, expansion agent 0.1~5%, coupling agent 0.1~2%.

Optionally, 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 property is white powder.

Optionally, the fineness of the metakaolin and fly ash are both 1000-2000 mesh.

Optionally, the fine sand is one or more of machine-made sand, quartz sand, and river sand with a particle size of less than 0.15 mm.

Optionally, the expansion agent is one or more of UEA expansion agent and HCSA expansion agent.

Optionally, the coupling agent is one of monoalkoxy pyrophosphate type coupling agent, KH-550 silane coupling agent, KH-560 silane coupling agent, KH-570 silane coupling agent or variety.

The second object of the present invention is to provide a method for preparing the above-mentioned porous asphalt mixture perfusion fast-hardening metakaolin-based polymer material, the preparation method comprising the following steps:

First, the solid sodium silicate, the metakaolin, the fly ash, the fine sand and the expansion agent are mixed and stirred evenly, and then the water and the silane coupling agent are added for high and low speed. Alternate stirring, wherein, the medium and low speed stirring speed of the high and low speed alternating stirring is 1000-1500 rpm, and the high-speed stirring speed is 1500-2500 rpm, so as to obtain a water-conversion fast-hardening metakaolin-based polymer material for porous asphalt mixture perfusion.

Optionally, in the high and low speed alternating stirring, the high and low speed alternating time interval is 3-5 minutes, and the total mixing time is 10-20 minutes.

The working principle of the present invention is:

Incorporating fly ash into the polymer grouting material of metakaolin base can improve the fluidity of the grouting material at a lower water-cement ratio. ”, and the fly ash has a large mesh number, and it is not easy to cause “agglomeration” during stirring, thus increasing the fluidity of the slurry; on the one hand, the selection of quartz sand with a particle size of 0.15mm or less is convenient for the quartz sand of this particle size to enter. On the other hand, the geopolymer grouting material can significantly reduce the water loss shrinkage of the geopolymer material after adding the sand; but after adding the quartz sand, the effect of regulating the shrinkage is limited, and the To reduce the fluidity of the geopolymer grouting material, it is necessary to consider adding an expansion agent to the geopolymer material. After the expansion agent reacts with water, the expansion source ettringite is formed. On the one hand, ettringite can improve the resistance of the geopolymer grouting material. On the other hand, after the geopolymer material is poured into the porous asphalt mixture, under the action of temperature and load, ettringite is less affected by temperature and can absorb part of the stress to resist low temperature cracking; the introduction of silane coupling agent can greatly improve the porous Adhesion and strength of asphalt mixture and grouting material; at the same time, the hydrolysis of silicon functional groups in silane coupling agent requires the participation of water, and part of the water can be provided by water molecules escaping from metakaolin, which reduces the bleeding rate of the slurry , thereby reducing the shrinkage of the slurry; the above components work together to make the obtained slurry have the advantages of good volume stability, high early strength, etc., and then show good road performance, and can further ensure that it is compatible with the semi-flexible asphalt mixture matrix. binding and stability properties.

Compared with the prior art, the water-converting fast-hardening metakaolin-based polymer material for porous asphalt mixture perfusion has the following advantages:

1. For the first time, the present invention proposes to develop a water-increasing fast-hardening metakaolin-based polymer material for porous asphalt mixture infusion, which can greatly improve the early strength and fluidity of the geopolymer material while adding water for immediate use. And reduce the early cracking tendency of the slurry, its 1d can form a specific strength of 15-25MPa, and the 56d drying shrinkage control range is between -0.1% and 0.1%.

2. Except for water and coupling agent, other substances in the present invention are solid materials, which are convenient for storage and transportation, and have important economic and time benefits.

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

Detailed ways

It should be noted that the embodiments of the present invention and the features of the embodiments may be combined with each other under the condition of no conflict.

The present invention will be described in detail below with reference to the embodiments.

In each embodiment of the present invention, in order to test the performance of the water-increasing fast-hardening metakaolin-based polymer material for the convenient porous asphalt mixture pouring and its performance after pouring the porous asphalt mixture, the selected porous asphalt mixture is composed of mineral aggregates. The gradation is the OGFC _- 25 class grading that meets the requirements of the current technical specifications for highway asphalt pavement construction in China; the fineness of metakaolin and fly ash is 1000-2000 mesh; It is 25.0%, the content of SiO ₂ is 49.2%, and the property is white powder; sodium hydroxide is a white uniform flaky solid with a content of ≥96%; the silane coupling agent used is added after the grouting material is evenly mixed and continues to be mixed evenly , the silane coupling agent is provided by Shandong Yousuo Chemical Technology Co., Ltd., the model is KH-550, it is a colorless and transparent liquid; the fine sand is quartz sand with a particle size of less than 0.15mm; the expansion agent is HCSA high-efficiency expansion agent, gray In powder form, the fineness is ≥200μm, the specific surface area is ≤280m ² /kg, and the sieve residue of 1.18mm sieve is ≤0.5%.

Example 1

A quick-hardening metakaolin-based polymer material used for perfusion of porous asphalt mixture, comprising the following components by mass percentage: 20% of solid sodium silicate, 2.8% of sodium hydroxide, 30% of water, 24% of metakaolin %, fly ash 9%, fine sand 14%, expansion agent 2%, coupling agent 0.5%.

The specific preparation method of the water-increasing fast-hardening metakaolin-based polymer material for the perfusion of porous asphalt mixture of the present embodiment includes the following steps:

According to the above-mentioned raw material formula, weigh the solid sodium silicate, metakaolin, fly ash, fine sand and expansion agent, mix and stir evenly, then add water and silane coupling agent to stir alternately at high and low speeds. The specific process is as follows: firstly stir at a low speed of 1000 rpm for 5 minutes, and then stir at a high speed of 2000 rpm for 5 minutes, so as to alternately cycle and stir, and the stirring time is 20 minutes in total to obtain a water-increasing fast-hardening metakaolin-based polymer material for porous asphalt mixture perfusion . .

Using the water-increasing fast-hardening metakaolin-based polymer material for the perfusion of the porous asphalt mixture of the present embodiment is used to perfuse the porous asphalt mixture, which specifically includes the following steps:

1) The porous asphalt mixture matrix is made in accordance with the OGFC-25 class set up according to the recommended range of the current technical specifications for highway asphalt pavement construction in my country;

2) The obtained porous asphalt mixture matrix is tightly packed with a waterproof material with a smooth surface and the surface is reserved, and the porous asphalt mixture matrix and the porous asphalt mixture are poured with a water-converted fast-hardening metakaolin-based polymer material (below). The volume ratio of the above-mentioned “metakaolin-based polymer slurry”) is 1:0.24, and the metakaolin-based polymer slurry is poured into the porous asphalt mixture matrix, and then placed on a vibrating table for 1 min. until the slurry can not completely penetrate from the surface of the porous asphalt mixture matrix, and finally scrape off the excess slurry on the surface with a scraper to expose the surface of the porous asphalt mixture matrix;

3) Curing the specimen: The specimen grouted in step 2) is placed in a constant temperature curing box with a temperature of 30° C. and a humidity of 90% for 7 days to form, to obtain a semi-flexible asphalt mixture filled with metakaolin base polymer.

The porous asphalt mixture perfusion obtained in this example is tested with a water-increasing fast-hardening metakaolin-based polymer material and a semi-flexible asphalt mixture filled with a metakaolin-based polymer, and its properties are as follows:

Material properties of water-increasing fast-hardening metakaolin-based polymer for porous asphalt mixture pouring:

(1) Mechanical properties

The above-mentioned metakaolin-based polymer materials are first molded in a standard size mold (40mm×40mm×160mm), and then cured for 1 day and 3 days at a temperature of 30°C and greater than 95% humidity. The flexural strength and compressive strength of the base polymer material were tested, and half of the sample was used for the compressive strength measurement in the compressive test of the sample. The loading speeds for bending and compression tests were 50N/s±10N/s and 2400N/s±200N/s, respectively. The results are shown in Table 1.

Table 1 Mechanical property data of geopolymer material obtained in Example 1

(2) Flow performance

The fluidity of the above metakaolin based polymer materials 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.

Table 2 Flow property data of the geopolymer material obtained in Example 1

condition Fluidity(mm) initial fluidity 243 30min fluidity 238

(3) Shrinkage performance

The dry shrinkage measurement of the above metakaolin based polymer materials refers to the requirements of "Standards for Test Methods for Basic Properties of Building Mortars" (JGJ/T 70-2009). After curing in the box, take it out after reaching the predetermined age (1d, 3d, 5d, 7d, 14d, 21d, 28d), and then use a vertical mortar shrinkage instrument to measure its dry shrinkage value, as shown in Table 3, calculate the dry shrinkage rate.

Table 3 Shrinkage performance data of the geopolymer material obtained in Example 1

time 1d 3d 5d 7d 14d 21d 28d Dry shrinkage (×10⁶) 150 210 234 251 255 254 256

Road performance of semi-flexible asphalt mixture filled with metakaolin base polymer:

(1) High temperature performance

The high temperature stability of the above semi-flexible asphalt mixture was tested by dynamic uniaxial test. 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 3200 times, while the high-temperature dynamic uniaxial times of the base asphalt mixture is generally about 600 times. The semi-flexible asphalt mixture is much larger than the dynamic uniaxial data of asphalt materials. .

(2) Low temperature performance

Low-temperature crack resistance test: The base asphalt mixture is made into cylindrical specimens with a diameter of 150mm and a height of 50mm, which are poured into the metakaolin base polymer slurry and formed, and then the cylindrical specimens are cut in half along the radius to form a semicircle The test piece, a 5mm crack in the middle of the semicircular test piece, was subjected to the SCB test at -10°C. The test results showed that the fracture energy of the semi-flexible asphalt mixture obtained in this example was 632.6N/m.

(3) Freeze-thaw splitting test

The freeze-thaw splitting test was used to test the water stability performance of the semi-flexible asphalt mixture obtained in this example, and the results are shown in Table 4.

It can be seen from Table 4 that the freeze-thaw splitting ratio of the semi-flexible asphalt mixture filled with metakaolin base polymer is 78.80%, which is greater than the 75% freeze-thaw splitting ratio requirement of the base asphalt mixture.

Table 4 Freeze-thaw splitting test data of semi-flexible asphalt mixture obtained in Example 1

(4) Water immersion Marshall test

The water stability performance of the semi-flexible asphalt mixture obtained in this example was tested by the water immersion Marshall test, and the results are shown in Table 5.

It can be seen from Table 5 that the residual stability of semi-flexible asphalt mixture filled with metakaolin base polymer is 129.8%, which is far greater than the 80% residual stability requirement of base asphalt mixture.

Table 5 Water-immersed Marshall test data of the semi-flexible asphalt mixture obtained in Example 1

Example 2

A fast-hardening metakaolin-based polymer material (hereinafter referred to as "metakaolin-based polymer material") for porous asphalt mixture perfusion, comprising the following components in percent by mass: solid sodium silicate 21%, Sodium hydroxide 2.1%, water 27%, metakaolin 27%, fly ash 8.6%, fine sand 12%, expansion agent 1.5%, coupling agent 0.8%. The specific preparation steps are the same as those in Example 1.

Table 6 shows the test results of the mechanical properties of the metakaolin based polymer material in this example, Table 7 shows the flow property test results, and Table 8 shows the shrinkage property test results.

Table 6 Mechanical property data of geopolymer material obtained in Example 2

Table 7 Flow property data of the geopolymer material obtained in Example 2

condition Fluidity(mm) initial fluidity 254 30min fluidity 243

Table 8 Shrinkage performance data of the geopolymer material obtained in Example 2

time 1d 3d 5d 7d 14d 21d 28d Dry shrinkage (×10⁶) 345 362 363 363 367 367 366

The road performance of the semi-flexible asphalt mixture obtained by pouring the metakaolin-based polymer material in this example into the porous asphalt mixture matrix refers to the method described in Example 1, and the performance of the semi-flexible asphalt mixture obtained in this example is tested. The high temperature performance of flexible asphalt mixture, its dynamic uniaxial times is 2890 times, while the high temperature dynamic uniaxial times of matrix asphalt mixture is generally about 600 times, and the semi-flexible asphalt mixture is much larger than the dynamic uniaxial data of asphalt materials; The low-temperature performance of the flexible asphalt mixture, its fracture energy is 712.1N/m; the results of the freeze-thaw splitting test are shown in Table 9, the freeze-thaw splitting ratio of the obtained semi-flexible asphalt mixture is 79.07%, which is greater than 75% of the base asphalt mixture. Freeze-thaw split ratio requirements. See Table 10 for the test results of the Marshall test in water immersion. The measured residual stability in water immersion is 117.6%, which is far greater than the 80% immersion residual stability requirement of the base asphalt mixture.

Table 9 Freeze-thaw splitting test data of semi-flexible asphalt mixture obtained in Example 2

Table 10 The water-immersed Marshall test data of the semi-flexible asphalt mixture obtained in Example 1

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. within.

Claims (8)

1. A water-blended quick-hardening metakaolin-based geopolymer material for pouring a porous asphalt mixture is characterized by comprising the following components in percentage by mass: 15-25% of solid sodium silicate, 20-28% of metakaolin, 6-12% of fly ash, 2-4% of sodium hydroxide, 25-35% of water, 5-15% of fine sand, 0.1-5% of an expanding agent and 0.1-2% of a coupling agent.

2. The metakaolin based geopolymer material blended with water and quickly hardened for porous asphalt mixture injection as claimed in claim 1, wherein the solid sodium silicate has a modulus of 2.0, Na ₂ O content of 25.0% and SiO ₂ The content was 49.2%, and the product was white powder.

3. The metakaolin-based geopolymer material blended with water and hardened quickly for porous asphalt mixture pouring according to claim 1, wherein the fineness of the metakaolin and the fineness of the fly ash are both 1000-2000 meshes.

4. The metakaolin-based geopolymer material blended with water and hardened quickly for porous asphalt mixture injection as claimed in claim 1, wherein the fine sand is one or more of machine-made sand, quartz sand and river sand with a particle size of less than 0.15 mm.

5. The metakaolin-based geopolymer material as recited in claim 1, wherein the swelling agent is one or more of a UEA swelling agent and a HCSA swelling agent.

6. The metakaolin-based geopolymer material as set forth in claim 1, wherein the coupling agent is one or more of monoalkoxy pyrophosphate-type coupling agent, KH-550 silane coupling agent, KH-560 silane coupling agent, and KH-570 silane coupling agent.

7. A method for preparing a water-blended fast-hardening metakaolin-based geopolymer material for porous asphalt mixture injection according to any one of claims 1 to 6, comprising the steps of:

firstly, uniformly mixing and stirring the solid sodium silicate, the metakaolin, the fly ash, the fine sand and the expanding agent, then adding the water and the silane coupling agent, and carrying out high-low speed alternative stirring, wherein the high-low speed alternative stirring is carried out at a medium-low speed stirring rotating speed of 1000-1500 rpm, and the high-speed stirring rotating speed is 1500-2500 rpm, so as to obtain the water-added quick-hardening metakaolin-based geopolymer material for pouring the porous asphalt mixture.

8. The preparation method of the water-blended fast-hardening metakaolin-based geopolymer material for pouring the porous asphalt mixture according to claim 7, wherein the interval of the high-speed and low-speed alternating time in the high-speed and low-speed alternating stirring is 3-5 min, and the total stirring time is 10-20 min.