Soil stabilizer for road surface layer pouring and preparation method thereof

Abstract

The invention discloses a soil stabilizer for road surface layer pouring and a preparation method thereof. The self-repairing concrete comprises the following components in percentage by weight: 30-40% of cement, 10-15% of lime, 5-10% of sodium silicate, 10-15% of bentonite, 2-5% of a polymer additive, 1-3% of a fiber reinforced material, 1-3% of nano calcium carbonate, 0.5-1% of biological enzyme, 2-4% of self-repairing microcapsules and a proper amount of water. According to the soil stabilizer, the nano calcium carbonate, the biological enzyme and the self-repairing microcapsule are added, so that the compressive strength and the water stability of the material are remarkably improved. Firstly, due to the ultrahigh specific surface area and the nanoscale particle size of nano calcium carbonate, a tighter filling effect can be formed in soil, the binding force among soil particles is enhanced, and therefore the overall compressive strength is improved. In an experiment, the compressive strength of the embodiment added with the nano calcium carbonate reaches 4.0 MPa after 28 days, the strength is doubled compared with 2.0 MPa of a reference example 1, and the remarkable effect of the nano material on the aspect of enhancing the soil structure is shown.

Description

Technical Field

[0001] The invention belongs to the field of curing agents, and in particular relates to a soil curing agent for pouring a road surface layer and a preparation method thereof. Background Art

[0002] The soil stabilizers currently available on the market are mainly used for applications such as silt solidification, roadbed stabilization, and fluidized solidification backfill, which have high requirements for the mechanical properties and durability of the materials. However, existing soil stabilizers show obvious deficiencies in these aspects. First, the early strength of these stabilizers is low. Usually within 7 days, its compressive strength can only reach 0.1 to 0.7 MPa, which is far below the standard required for engineering applications. This means that in the initial stage after construction, the soil stabilizer cannot provide sufficient support and stability, and is prone to settlement and deformation problems.

[0003] Secondly, the surface water stability of these curing agents is also poor, usually only reaching about 50%. Water stability refers to the ability of the cured soil to maintain its structure and strength after being eroded by water. Due to the low water stability of existing curing agents, when the cured soil is exposed to a humid or rainy environment for a long time, its internal structure will be eroded by water, resulting in a decrease in the bonding force between soil particles, and ultimately causing a significant decrease in strength. Especially in road and infrastructure projects, this lack of water stability can lead to cracking of the road surface, potholes and failure of the overall structure, increasing the cost of maintenance and repair.

[0004] In addition, existing soil stabilizers are susceptible to mechanical stress during long-term use. Vehicle rolling, earthquakes and other dynamic loads will generate dynamic stress on the stabilized soil, which will gradually destroy the bond between soil particles, leading to the generation and expansion of cracks. Due to the insufficient strength and toughness of the stabilizer itself, these cracks cannot be effectively repaired, thus accelerating the destruction of the structure.

[0005] These performance deficiencies limit the application scope and service life of existing soil stabilizers. Especially in engineering projects with high strength and high durability requirements, these stabilizers cannot meet the needs, making it difficult to ensure construction quality and engineering safety.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art, provide a soil solidifying agent for road surface pouring and a preparation method, and solve the problems raised in the above-mentioned background technology.

[0008] In order to solve the above technical problems, the basic idea of ​​the technical solution adopted by the present invention is

[0009] A soil solidifying agent for pouring a road surface layer comprises the following components in weight percentage: 30-40% cement, 10-15% lime, 5-10% sodium silicate, 10-15% bentonite, 2-5% polymer additive, 1-3% fiber reinforcement material, 1-3% nano calcium carbonate, 0.5-1% biological enzyme, 2-4% self-repairing microcapsule and an appropriate amount of water.

[0010] Optionally, the polymer additive is polyvinyl alcohol (PVA), the molecular weight of the polyvinyl alcohol is between 20,000 and 50,000, the elongation at break is between 10-15%, and the glass transition temperature is between 85-90°C.

[0011] Optionally, the fiber reinforcement material is glass fiber, the elastic modulus of glass fiber is 70-85GPa, and the density is 2.5-2.6g / cm 3 .

[0012] Optionally, the specific gravity of the lime is 2.24-2.35 g / cm 3 , bulk density is 0.6-1.2g / cm 3 , the specific surface area is usually 300-500m 2 / kg.

[0013] Optionally, the specific gravity of bentonite is 2.4-2.8g / cm 3 , water absorption is 200-300%, and cation exchange capacity is 70-120meq / 100g.

[0014] Optionally, the particle size of nano calcium carbonate is 20-100 nanometers and the specific surface area is 20-50m 2 / g, density is 2.7-2.9g / cm 3 , the decomposition temperature is 825-896℃.

[0015] Optionally, the particle size of the self-healing microcapsule is 5-200 microns, the capsule shell material is polyurethane, and the capsule core is an adhesive.

[0016] A method for preparing a soil solidifying agent for road surface pouring, comprising the following steps

[0017] Step (1), adding cement, lime, sodium silicate and bentonite into a stirring tank in order according to weight percentage, starting a stirring device to mix and stir, and obtaining product ① after the products are evenly mixed;

[0018] Step (2), adding nano silicon dioxide and nano calcium carbonate to product ① in sequence and continuing stirring to obtain product ②;

[0019] Step (3), adding a polymer additive and a fiber reinforcement material to the product ②, and continuing stirring to obtain a product ③;

[0020] Step (4), adding biological enzymes and self-repairing microcapsules to product ③ to ensure that they are evenly distributed in the mixture;

[0021] Step (6), according to the consistency of the mixture, add water in an appropriate amount to adjust the water-to-binder ratio of the curing agent to 1.3;

[0022] Step (7), after all the raw materials are completely uniform, continue stirring for 2-5 minutes to ensure that the various raw materials are evenly mixed to obtain the curing agent.

[0023] Optionally, when cement, lime, sodium silicate and bentonite are added to the mixing tank in sequence, the initial stirring speed is recommended to be 100-200RPM (revolutions per minute). After adding nano-silicon dioxide and nano-calcium carbonate, adjust the stirring speed to 200-300RPM, and keep the stirring speed at 150-250RPM when adding polymer additives, fiber reinforcement materials, bio-enzymes and self-healing microcapsules. After all the raw materials are completely mixed, continue stirring for 2-5 minutes, maintaining the stirring speed at 100-150RPM. If a large amount of accumulation occurs during the stirring process, the speed should be reduced to 50-100RPM. Stir for 2-5 minutes after each addition of new raw materials.

[0024] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art. Of course, any product implementing the present invention does not necessarily need to achieve all the advantages described below at the same time.

[0025] The soil solidifier of the present invention significantly improves the compressive strength and water stability of the material by adding nano calcium carbonate, biological enzymes and self-repairing microcapsules. First, due to its ultra-high specific surface area and nanometer-scale particle size, nano calcium carbonate can form a tighter filling effect in the soil, enhance the binding force between soil particles, and thus improve the overall compressive strength. In the experiment, the compressive strength of the embodiment with the addition of nano calcium carbonate reached 4.0MPa after 28 days, which doubled the strength compared to 2.0MPa of reference example 1, showing the significant effect of nanomaterials in enhancing soil structure. Secondly, the introduction of biological enzymes promotes the reaction between organic matter and inorganic matter in the soil, forming more stable chemical bonds and structures, further improving the long-term strength and stability of the soil solidifier.

[0026] The specific embodiments of the present invention are described in further detail below. DETAILED DESCRIPTION

[0027] The present embodiment provides a soil solidifying agent for road surface pouring, comprising the following components in weight percentage: 30-40% cement, 10-15% lime, 5-10% sodium silicate, 10-15% bentonite, 2-5% polymer additive, 1-3% fiber reinforcement material, 1-3% nano calcium carbonate, 0.5-1% biological enzyme, 2-4% self-repairing microcapsule and an appropriate amount of water.

[0028] In this embodiment, the polymer additive is polyvinyl alcohol (PVA), the molecular weight of the polyvinyl alcohol is between 20,000 and 50,000, the elongation at break is 10-15%, and the glass transition temperature is 85-90°C.

[0029] In this embodiment, the fiber reinforcement material is glass fiber, the elastic modulus of the glass fiber is 70-85GPa, and the density is 2.5-2.6g / cm 3 .

[0030] In this embodiment, the specific gravity of the lime is 2.24-2.35 g / cm 3 , bulk density is 0.6-1.2g / cm 3 , the specific surface area is usually 300-500m 2 / kg.

[0031] In this embodiment, the specific gravity of bentonite is 2.4-2.8 g / cm 3 , water absorption is 200-300%, and cation exchange capacity is 70-120meq / 100g.

[0032] In this embodiment, the particle size of nano calcium carbonate is 20-100 nanometers, and the specific surface area is 20-50m 2 / g, density is 2.7-2.9g / cm 3 , the decomposition temperature is 825-896℃.

[0033] In this embodiment, the particle size of the self-repairing microcapsule is 5-200 microns, the capsule shell material is polyurethane, and the capsule core is an adhesive.

[0034] A method for preparing a soil solidifying agent for road surface pouring, comprising the following steps

[0035] Step (1), adding cement, lime, sodium silicate and bentonite into a stirring tank in order according to weight percentage, starting a stirring device to mix and stir, and obtaining product ① after the products are evenly mixed;

[0036] Step (2), adding nano silicon dioxide and nano calcium carbonate to product ① in sequence and continuing stirring to obtain product ②;

[0037] Step (3), adding a polymer additive and a fiber reinforcement material to the product ②, and continuing stirring to obtain a product ③;

[0038] Step (4), adding biological enzymes and self-repairing microcapsules to product ③ to ensure that they are evenly distributed in the mixture;

[0039] Step (6), according to the consistency of the mixture, add water in an appropriate amount to adjust the water-to-binder ratio of the curing agent to 1.3;

[0040] Step (7), after all the raw materials are completely uniform, continue stirring for 2-5 minutes to ensure that the various raw materials are evenly mixed to obtain the curing agent.

[0041] In this embodiment, when cement, lime, sodium silicate and bentonite are added to the mixing tank in sequence, it is recommended that the initial stirring speed is 100-200RPM (revolutions per minute). After adding nano-silicon dioxide and nano-calcium carbonate, the stirring speed is adjusted to 200-300RPM. When adding polymer additives, fiber reinforcement materials, biological enzymes and self-repairing microcapsules, the stirring speed is maintained at 150-250RPM. After all the raw materials are completely mixed, continue to stir for 2-5 minutes, maintaining the stirring speed at 100-150RPM. If a large amount of accumulation occurs during the stirring process, the speed should be reduced to 50-100RPM. Stir for 2-5 minutes after each addition of new raw materials.

[0042] The present invention will now be described in further detail.

[0043] Example 1 In this example, a soil solidifying agent for road surface pouring is provided, which includes the following components in weight percentage: cement 35%, lime 12%, sodium silicate 7%, bentonite 12%, polyvinyl alcohol (PVA) 4%, molecular weight 30000, elongation at break 12%, glass transition temperature 87°C, glass fiber 2%, elastic modulus 75GPa, density 2.55g / cm 3 , nano calcium carbonate 2%, particle size 50 nanometers, specific surface area 35m 2 / g, density is 2.8g / cm 3 , decomposition temperature is 860℃, biological enzyme is 0.7%, self-repairing microcapsule is 3%, particle size is 100 microns, capsule shell material is polyurethane, capsule core is adhesive, water is appropriate

[0044] Example 2: In this example, a soil solidifying agent for road surface pouring is provided, comprising the following components in weight percentage: 30% cement, 10% lime, 6% sodium silicate, 14% bentonite, 3% polyvinyl alcohol (PVA), with a molecular weight of 25,000, an elongation at break of 11%, a glass transition temperature of 86°C, 3% glass fiber, an elastic modulus of 72 GPa, and a density of 2.53 g / cm3 , nano calcium carbonate 3%, particle size 40 nanometers, specific surface area 30m 2 / g, density is 2.75g / cm 3 , decomposition temperature is 850℃, biological enzyme 1%, self-repairing microcapsule 2%, particle size is 80 microns, capsule shell material is polyurethane, capsule core is adhesive, water is appropriate

[0045] Example 3: In this example, a soil solidifying agent for road surface pouring is provided, comprising the following components in weight percentage: 38% cement, 13% lime, 8% sodium silicate, 11% bentonite, 5% polyvinyl alcohol (PVA), molecular weight of 45,000, elongation at break of 13%, glass transition temperature of 88°C, 1.5% glass fiber, elastic modulus of 80 GPa, density of 2.6 g / cm 3 , nano calcium carbonate 2%, particle size is 60 nanometers, specific surface area is 40m 2 / g, density is 2.78g / cm 3 The decomposition temperature is 870℃, the biological enzyme is 0.6%, the self-repairing microcapsule is 4%, the particle size is 120 microns, the capsule shell material is polyurethane, the capsule core is adhesive, and the balance is water.

[0046] Example 4: In this example, a soil solidifying agent for road surface pouring is provided, comprising the following components in weight percentage: 32% cement, 11% lime, 9% sodium silicate, 13% bentonite, 2.5% polyvinyl alcohol (PVA), with a molecular weight of 20,000, an elongation at break of 10%, a glass transition temperature of 85°C, 2.5% glass fiber, an elastic modulus of 70 GPa, and a density of 2.5 g / cm 3 , nano calcium carbonate 1.5%, particle size 30 nanometers, specific surface area 25m 2 / g, density is 2.73g / cm 3 The decomposition temperature is 830℃, the biological enzyme is 0.8%, the self-repairing microcapsule is 3%, the particle size is 90 microns, the capsule shell material is polyurethane, the capsule core is adhesive, and the balance is water.

[0047] Comparative Example 1: In this embodiment, a soil solidifying agent for road surface pouring is provided, which includes the following components in weight percentage: cement 35%, lime 12%, sodium silicate 7%, bentonite 12%, polyvinyl alcohol 4%, molecular weight 30000, elongation at break 12%, glass transition temperature 87°C, glass fiber 2%, elastic modulus 75GPa, density 2.55g / cm 3 , water

[0048] Experimental Example 1: Compressive Strength Test

[0049] Mix the soil stabilizer with the soil in proportion to prepare a cubic specimen with a size of 100mm×100mm×100mm. Place the specimen in a standard curing room at a temperature of 20±2℃ and a relative humidity of more than 95% for 7 days, 14 days, and 28 days of curing, respectively. Take out the cured specimens and wipe them clean with a damp cloth. Place the specimen on a pressure testing machine and apply pressure evenly at a loading speed of 2.4kN / s. Record the maximum pressure value when the specimen breaks and the compressive strength f c Calculate as follows: Where P is the maximum pressure value at rupture, in Newton (N); A is the pressure area of ​​the sample, in square millimeters (mm 2 ), and the test results are shown in Table 1.

[0050] Table 1 Compressive strength test results Example / time 7-day compressive strength (MPa) 14-day compressive strength (MPa) 28-day compressive strength (MPa)

[0051]

[0052] From the compressive strength test results in Table 1, it can be seen that the compressive strength values ​​of Example 1 after 7 days, 14 days and 28 days are 1.7 MPa, 2.5 MPa and 4.0 MPa, respectively, which are significantly higher than 0.8 MPa, 1.5 MPa and 2.0 MPa of Control Example 1. The compressive strengths of Example 2 and Example 3 are also significantly higher than those of Control Example 1, with higher strength values ​​after 7 days, 14 days and 28 days, respectively. The results show that the soil curing agent with the addition of nano-calcium carbonate, biological enzymes and self-repairing microcapsules can significantly improve the compressive strength of the material.

[0053] Experimental Example 2: Water Stability Test

[0054] Mix the soil stabilizer with the soil in proportion to prepare a cubic specimen with a size of 100mm×100mm×100mm. Place the specimen in a standard curing room at a temperature of 20±2℃ and a relative humidity of more than 95% for 7 days, 14 days and 28 days of curing respectively. Soak the cured specimen in water for 24 hours at a water temperature of 20±2℃. Take out the soaked specimen and wipe it clean with a damp cloth. Place the specimen on a pressure testing machine and apply pressure evenly at a loading speed of 2.4kN / s. Record the maximum pressure value when the specimen ruptures. The water stability is calculated as follows: The compressive strength before immersion in water refers to the compressive strength after conventional curing, and the compressive strength after immersion in water refers to the compressive strength after immersion treatment. The test results are shown in Table 2:

[0055] Table 2 Water stability test results

[0056] Example / Time 7-day water stability (%) 14-day water stability (%) 28-day water stability (%) Example 1 78 82 87 Example 2 70 75 80 Example 3 75 80 85 Comparative Example 1 45 50 55

[0057] From the water stability test results in Table 2, it can be seen that the water stability of Example 1 after 7 days, 14 days and 28 days is 78%, 82% and 87% respectively, which is significantly better than 45%, 50% and 55% of Control Example 1. The water stability of Example 2 and Example 3 is also significantly higher than that of Control Example 1, showing better water resistance. The results show that the soil solidifier with the addition of nano-calcium carbonate, biological enzymes and self-repairing microcapsules has significantly improved strength retention after water erosion and has better water stability.

[0058] The present invention is not limited to the above-mentioned embodiments. Anyone should be aware that any structural changes made under the enlightenment of the present invention, and any technical solutions that are the same or similar to the present invention, fall within the protection scope of the present invention. The technology, shape, and structural parts not described in detail in the present invention are all well-known technologies.

Claims

1. A soil solidifying agent for road surface pouring, characterized in that: The invention comprises the following components in weight percentage: 30-40% cement, 10-15% lime, 5-10% sodium silicate, 10-15% bentonite, 2-5% polymer additive, 1-3% fiber reinforcement material, 1-3% nano calcium carbonate, 0.5-1% biological enzyme, 2-4% self-repairing microcapsule and appropriate amount of water.

2. A soil solidifying agent for road surface pouring according to claim 1, characterized in that: The polymer additive is polyvinyl alcohol (PVA), the molecular weight of the polyvinyl alcohol is between 20,000 and 50,000, the elongation at break is between 10-15%, and the glass transition temperature is between 85-90°C.

3. A soil solidifying agent for road surface pouring according to claim 1, characterized in that: The fiber reinforcement material is glass fiber, the elastic modulus of glass fiber is 70-85GPa, and the density is 2.5-2.6g / cm 3 .

4. The soil solidifying agent for road surface pouring according to claim 1, characterized in that: The specific gravity of the lime is 2.24-2.35 g / cm 3 , bulk density is 0.6-1.2g / cm 3 , the specific surface area is usually 300-500m 2 / kg.

5. The soil solidifying agent for road surface pouring according to claim 1, characterized in that: The specific gravity of bentonite is 2.4-2.8g / cm 3 , water absorption is 200-300%, and cation exchange capacity is 70-120meq / 100g.

6. The soil solidifying agent for road surface pouring according to claim 1, characterized in that: The particle size of nano calcium carbonate is 20-100 nanometers and the specific surface area is 20-50m 2 / g, density is 2.7-2.9g / cm 3 , the decomposition temperature is 825-896℃.

7. The soil solidifying agent for road surface pouring according to claim 1, characterized in that: The particle size of the self-repairing microcapsule is 5-200 microns, the capsule shell material is polyurethane, and the capsule core is an adhesive.

8. A method for preparing a soil solidifying agent for road surface pouring, characterized in that: The following steps are included Step (1), adding cement, lime, sodium silicate and bentonite into a stirring tank in order according to weight percentage, starting a stirring device to mix and stir, and obtaining product ① after the products are evenly mixed; Step (2), adding nano silicon dioxide and nano calcium carbonate to product ① in sequence and continuing stirring to obtain product ②; Step (3), adding a polymer additive and a fiber reinforcement material to the product ②, and continuing stirring to obtain a product ③; Step (4), adding biological enzymes and self-repairing microcapsules to product ③ to ensure that they are evenly distributed in the mixture; Step (6), according to the consistency of the mixture, add water in an appropriate amount to adjust the water-to-binder ratio of the curing agent to 1.3; Step (7), after all the raw materials are completely uniform, continue stirring for 2-5 minutes to ensure that the various raw materials are evenly mixed to obtain the curing agent.

9. The method for preparing a soil solidifying agent for road surface pouring according to claim 1, characterized in that: When cement, lime, sodium silicate and bentonite are added to the mixing tank in sequence, the initial stirring speed is recommended to be 100-200RPM (revolutions per minute). After adding nano-silicon dioxide and nano-calcium carbonate, adjust the stirring speed to 200-300RPM. When adding polymer additives, fiber reinforcement materials, bio-enzymes and self-healing microcapsules, keep the stirring speed at 150-250RPM. After all the raw materials are completely mixed, continue stirring for 2-5 minutes, keeping the stirring speed at 100-150RPM. If a large amount of accumulation occurs during the stirring process, the speed should be reduced to 50-100RPM. Stir for 2-5 minutes after each addition of new raw materials.

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