An early-strength, ultra-tough geopolymer material based on slag and calcined coal gangue

Abstract

This invention discloses an early-strength, ultra-tough geopolymer material based on slag and calcined coal gangue, belonging to the field of building materials technology. It comprises slag, calcined coal gangue, fine sand, sodium silicate solution, solid sodium hydroxide, water, and polyethylene fiber. The components are calculated by mass ratio as follows: slag: calcined coal gangue: fine sand: sodium silicate solution: sodium hydroxide: water = 0.6–1.0: 0–0.4: 0.1–0.3: 0.29–0.43: 0.07–0.11: 0.11–0.20. Based on the total volume after uniform mixing of all components, the polyethylene fiber content is 19.4 kg / m³. 3 This ultra-high toughness geopolymer material is an early-strength building material made from solid waste, possessing both high strength and high toughness. While ensuring compressive strength, this material exhibits high ductility and high toughness, with a tensile deformation capacity comparable to that of metals such as aluminum and steel.

Description

Technical Field

[0001] This invention relates to an early-strength, ultra-tough geopolymer material based on slag and calcined coal gangue, belonging to the field of building materials technology. Background Technology

[0002] Cement, while widely used in the current construction industry, is neither energy-efficient nor environmentally friendly. In my country, the cement industry accounts for approximately 10% of the country's total CO2 emissions annually. Therefore, exploring and developing green building materials is imperative. Geopolymers are novel inorganic cementitious materials with a three-dimensional network structure, formed by activating silica-alumina minerals or industrial by-product powders with alkali activators. The carbon emissions during the preparation of 1 kg of geopolymer are only 0.18 kg, just 24% of those of ordinary Portland cement, and its energy consumption can be reduced to 10% of cement production. Therefore, geopolymers are considered one of the most promising new green cementitious materials. Furthermore, geopolymers are inexpensive, widely available, and possess high strength, high corrosion resistance, and good thermal stability. Therefore, geopolymers are currently widely used in civil engineering materials, rapid repair materials, protective coatings, and the solidification of chemical pollution and radioactive waste, and are considered a third-generation cement material.

[0003] Despite these advantages, geopolymers are inherently brittle and prone to cracking during use, providing easy pathways for moisture and harmful media to penetrate, thus accelerating material failure and deteriorating durability. Adding fibers to geopolymers is a crucial technical measure to improve their toughness. Polyethylene fibers possess advantages such as high strength, high modulus, and wear resistance. Their high bonding strength with geopolymers significantly enhances their deformability, fundamentally solving the brittleness problem and greatly improving the durability and safety of the structure, making them of significant value. Summary of the Invention

[0004] To address the shortcomings of the existing technology, this invention provides an early-strength, ultra-tough geopolymer material based on slag and calcined coal gangue. This material has the advantages of high strength, ultra-high toughness, fine crack formation upon failure, and good durability.

[0005] The technical solution adopted by this invention to solve its technical problem is: an early-strength, ultra-tough geopolymer material based on slag and calcined coal gangue, comprising slag, calcined coal gangue, fine sand, sodium silicate solution, solid sodium hydroxide, water, and polyethylene fiber; the components are calculated by mass ratio as follows: slag: calcined coal gangue: fine sand: sodium silicate solution: sodium hydroxide: water = 0.6-1.0: 0-0.4: 0.1-0.3: 0.29-0.43: 0.07-0.11: 0.11-0.20, with the total volume after all components are mixed evenly as the base, and the polyethylene fiber content is 19.4 kg / m³. 3 .

[0006] Furthermore, the slag is selected from S95 grade granulated blast furnace slag powder conforming to the standard GB / T 18046-2008. In addition, the content of each chemical component in the slag, by mass ratio, should meet the following requirements: 1.0≤CaO / SiO2≤2.0, 0.1≤Al2O3 / SiO2≤0.3, (CaO+MgO+Al2O3) / SiO2≥1.4.

[0007] Furthermore, the calcined coal gangue is prepared as follows: the coal gangue is calcined at 700℃ for 2 hours and then ball-milled into powder, with a specific surface area ≥450m². 2 / kg, its chemical composition is more than 90% Al2O3 and SiO2.

[0008] Furthermore, the sodium silicate solution, sodium hydroxide solid, and water need to be mixed to prepare a composite alkali activator, which is prepared as follows: 99% pure sodium hydroxide solid is added to water to prepare a sodium hydroxide solution, which is then added to a sodium silicate solution with an initial modulus of 3.3 and a solid content of 35.5 wt% after cooling, and finally prepared into a sodium silicate solution with a modulus of 1.0.

[0009] Furthermore, the fine sand can be river sand, sea sand, desert sand, or manufactured sand, with a maximum particle size not exceeding 1.0 mm, an average particle size not exceeding 520 μm, and good gradation.

[0010] Furthermore, the polyethylene fiber has a length of 12mm-18mm, a diameter of 15-25μm, an elastic modulus ≥110GPa, and a tensile strength ≥3000MPa.

[0011] Preparation method:

[0012] Step 1: Preparation of the alkali activator by mixing sodium silicate solution, sodium hydroxide, and water. Sodium silicate solution, sodium hydroxide, and water are measured in a mass ratio of 0.29-0.43:0.07-0.11:0.11-0.20. First, solid sodium hydroxide and water are mixed and stirred until fully dissolved. After cooling, the sodium silicate solution is added, and the mixture is stirred again until homogeneous. It can be used only after cooling.

[0013] Step 2: Mixing dry materials of slag, calcined coal gangue, and fine sand. Place the slag, calcined coal gangue, and fine sand into a JJ-5 mixer and mix slowly for 2 minutes at a speed of 145 rad / min to obtain a mixed dry material.

[0014] Step 3: Addition of alkali activator. Add the alkali activator prepared in Step 1 to the mixed dry materials, and stir slowly in a JJ-5 mixer for 2 minutes at a speed of 145 rad / min to obtain a mixed slurry.

[0015] Step 4: Addition of polyethylene fibers and preparation of ultra-high toughness geopolymer material. Add polyethylene fibers to the mixed slurry and stir rapidly for 5 minutes until the fibers are evenly dispersed, thus obtaining the ultra-high toughness geopolymer material.

[0016] The beneficial effects of this invention are:

[0017] This ultra-high toughness geopolymer material is an early-strength building material made from solid waste, possessing both high strength and high toughness. The mechanical properties of this material, measured in 7-day-old specimens, are as follows: compressive strength 70.45 MPa-85.0 MPa, ultimate tensile strain 8.80%-13.63%, and tensile strength 2.50-3.54 MPa. While ensuring compressive strength, this material exhibits high ductility and high toughness, with a tensile deformation capacity comparable to that of metals such as aluminum and steel.

[0018] This material features high compressive strength, ultra-high toughness, large ultimate tensile strain, good deformation resistance, and fine, dense cracks. It can be used as "seamless concrete," significantly extending the service life of building structures, reducing maintenance frequency, and lowering maintenance costs. It is of great significance for preventing harmful substances from corroding structural materials, for corrosion protection, waterproofing, and earthquake resistance of structural components. It can also be widely used as a repair material for large-area repairs of dam slopes, bridges, and road surfaces.

[0019] By eliminating the use of cement and instead employing industrial solid waste as a binder, costs are reduced.

[0020] The incorporation of calcined coal gangue as a raw material significantly enhances the hydration reaction of the geopolymer cementitious material, increases hydration products, and thus increases density, thereby improving early strength. The addition of polyethylene fibers with a large aspect ratio gives the ultra-high toughness geopolymer material the characteristics of multi-crack propagation and strain hardening under tensile loads. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0022] Figure 1 This is a tensile stress-strain curve of the dumbbell-shaped specimen prepared in Example 1 of the present invention.

[0023] Figure 2 This is a tensile stress-strain curve of the dumbbell-shaped specimen prepared in Example 2 of the present invention.

[0024] Figure 3 This is a tensile stress-strain curve of the dumbbell-shaped specimen prepared in Example 3 of the present invention.

[0025] Figure 4This is a tensile stress-strain curve of the dumbbell-shaped specimen prepared in Example 4 of the present invention.

[0026] Figure 5 This is a tensile stress-strain curve of the dumbbell-shaped specimen prepared in Example 5 of the present invention.

[0027] Figure 6 This is a tensile stress-strain curve of the dumbbell-shaped specimen prepared in Example 6 of the present invention. Detailed Implementation

[0028] An early-strength, ultra-tough geopolymer material based on slag and calcined coal gangue comprises slag, calcined coal gangue, fine sand, sodium silicate solution, solid sodium hydroxide, water, and polyethylene fiber. The components, calculated by mass ratio, are slag, calcined coal gangue, fine sand, sodium silicate solution, sodium hydroxide, and water in the following proportions: 0.6-1.0 : 0-0.4 : 0.1-0.3 : 0.29-0.43 : 0.07-0.11 : 0.11-0.20. Based on the total volume after homogeneous mixing of all components, the polyethylene fiber content is 19.4 kg / m³. 3 .

[0029] The raw materials and equipment used in the following examples all meet the following requirements:

[0030] The slag used is S95 grade granulated blast furnace slag powder conforming to the GB / T 18046-2008 standard. Furthermore, the content of each chemical component in the slag, by mass ratio, should meet the following requirements: 0≤CaO / SiO2≤2.0, 0.1≤Al2O3 / SiO2≤0.3, (CaO+MgO+Al2O3) / SiO2≥1.4. As a calcium source material, a higher Ca / Si ratio in the slag promotes calcium absorption during the early stages of the reaction. 2+ with Na + The exchange of NASH gels transforms the product from NASH gels to C-(A)-SH gels, generating C-(A)-SH gels with a higher Ca / Si ratio, thus resulting in higher mechanical strength. Maintaining a suitable Al2O3 / SiO2 ratio and a large (CaO+MgO+Al2O3) / SiO2 ratio can increase the degree of alkali-activated reaction and reduce the chain length of the (N,C)-(A)-SH phase, thus ensuring a faster early strength growth.

[0031] The calcined coal gangue is prepared as follows: the coal gangue is calcined at 700℃ for 2 hours and then ball-milled into powder, with a specific surface area ≥450m². 2The chemical composition of this coal gangue is over 90% Al2O3 and SiO2, per kg. Calcination at 700℃ yields the highest reactivity of the coal gangue compared to other temperatures. Furthermore, the high Al2O3 and SiO2 content ensures the dissolution of active SiO2 and Al2O3 under strong alkali conditions, promoting the early and rapid occurrence of the condensation reaction in the slag-coal gangue depolymerization process. This generates more hydrated calcium aluminosilicate gel (CASH) and sodium aluminosilicate gel (NASH) products, which cross-link to form a stable three-dimensional structure, increasing density and thus improving early strength.

[0032] The sodium silicate solution, sodium hydroxide solid, and water are mixed to prepare a composite alkali activator, which is prepared as follows: 99% pure sodium hydroxide solid is dissolved in water to prepare a sodium hydroxide solution. After cooling, this solution is added to a sodium silicate solution with an initial modulus of 3.3 and a solid content of 35.5 wt%, ultimately preparing a sodium silicate solution with a modulus of 1.0, which serves as the alkali activator. A lower modulus of the alkali activator results in a higher mass proportion of sodium oxide in the activator, leading to a smaller amount of activator required for the same alkali equivalent of silicon-aluminum raw material, affecting workability and mechanical strength. Conversely, an excessively high modulus results in insufficient alkalinity in the environmental system, also affecting strength. Therefore, this invention determines the modulus of the alkali activator to be 1.0.

[0033] The fine sand can be river sand, sea sand, desert sand, or manufactured sand; the maximum particle size of the fine sand does not exceed 1 mm, the average particle size does not exceed 520 μm, and the gradation is good. This invention abandons the current reliance on ground quartz sand (maximum particle size 250 μm, average particle size 110 μm) and selects large-particle-size fine sand as aggregate, which can achieve local material sourcing while ensuring mechanical properties, making it more economical and environmentally friendly.

[0034] The polyethylene fibers have a length of 12mm-18mm, a diameter of 15-25μm, an elastic modulus ≥110GPa, and a tensile strength ≥3000MPa. The polyethylene fibers determine the toughness of the geopolymer material: when subjected to tensile loads, the geopolymer relies on the friction and bonding forces between the aggregates to dissipate energy; once a crack appears in the specimen, it will rapidly break down. However, with the addition of polyethylene fibers to the geopolymer, under tensile stress, the fibers dispersed within the matrix, due to their better tensile deformation capacity, exert their high strength and high elastic modulus properties, achieving energy dissipation through both fiber pull-out work and fiber fracture work, thereby improving the fiber-matrix interface properties and achieving the tough behavior of the geopolymer. Furthermore, a larger fiber aspect ratio results in a greater number of fine fibers per unit volume, leading to tighter fiber dispersion and preventing more cracks, thus achieving higher fracture toughness.

[0035] Example 1

[0036] The following raw material components are prepared according to the following mass ratio: slag, fine sand, sodium silicate solution, sodium hydroxide, and water, in a ratio of 1.0:0.2:0.361:0.0895:0.157. Based on the total volume after all components are thoroughly mixed, the polyethylene fiber content is 19.4 kg / m³. 3 The polyethylene fiber is 12mm long, 25μm in diameter, and has an aspect ratio of 480.

[0037] Step 1: Preparation of the alkali activator by mixing sodium silicate solution, sodium hydroxide, and water. Sodium silicate solution, sodium hydroxide, and water are measured in a mass ratio of 0.361:0.0895:0.157. First, solid sodium hydroxide and water are mixed and stirred until fully dissolved. After cooling, the sodium silicate solution is added, and the mixture is stirred again until homogeneous. It can be used only after cooling.

[0038] Step 2: Mixing dry materials of slag and fine sand. Put the slag and fine sand into a JJ-5 mixer and mix slowly for 2 minutes at a speed of 145 rad / min to obtain a mixed dry material.

[0039] Step 3: Addition of alkali activator. Add the alkali activator prepared in Step 1 to the mixed dry materials, and stir slowly in a JJ-5 mixer for 2 minutes at a speed of 145 rad / min to obtain a mixed slurry.

[0040] Step 4: Addition of polyethylene fibers and preparation of ultra-high toughness geopolymer material. Add polyethylene fibers to the mixed slurry in small amounts and multiple times, and stir rapidly for 5 minutes until the fibers are evenly dispersed to obtain the ultra-high toughness geopolymer material.

[0041] Example 2

[0042] The following raw material components are prepared according to the following mass ratio: slag: calcined coal gangue: fine sand: sodium silicate solution: sodium hydroxide: water = 0.9:0.1:0.2:0.361:0.0895:0.157. Based on the total volume after all components are mixed evenly, the polyethylene fiber content is 19.4 kg / m³. 3 The polyethylene fiber is 12mm long, 25μm in diameter, and has an aspect ratio of 480.

[0043] Step 1: Preparation of the alkali activator by mixing sodium silicate solution, sodium hydroxide, and water. Sodium silicate solution, sodium hydroxide, and water are measured in a mass ratio of 0.361:0.0895:0.157. First, solid sodium hydroxide and water are mixed and stirred until fully dissolved. After cooling, the sodium silicate solution is added, and the mixture is stirred again until homogeneous. It can be used only after cooling.

[0044] Step 2: Mixing dry materials of slag, calcined coal gangue, and fine sand. Place the slag, calcined coal gangue, and fine sand into a JJ-5 mixer and mix slowly for 2 minutes at a speed of 145 rad / min to obtain a mixed dry material.

[0045] Step 3: Addition of alkali activator. Add the alkali activator prepared in Step 1 to the mixed dry materials, and stir slowly in a JJ-5 mixer for 2 minutes at a speed of 145 rad / min to obtain a mixed slurry.

[0046] Step 4: Addition of polyethylene fibers and preparation of ultra-high toughness geopolymer material. Add polyethylene fibers to the mixed slurry in small amounts and multiple times, and stir rapidly for 5 minutes until the fibers are evenly dispersed to obtain the ultra-high toughness geopolymer material.

[0047] Example 3

[0048] The following raw material components are prepared according to the following mass ratio: slag: calcined coal gangue: fine sand: sodium silicate solution: sodium hydroxide: water = 0.8:0.2:0.2:0.361:0.0895:0.157. Based on the total volume after all components are mixed evenly, the polyethylene fiber content is 19.4 kg / m³. 3 The polyethylene fiber is 12mm long, 25μm in diameter, and has an aspect ratio of 480.

[0049] Step 1: Preparation of the alkali activator by mixing sodium silicate solution, sodium hydroxide, and water. Sodium silicate solution, sodium hydroxide, and water are measured in a mass ratio of 0.361:0.0895:0.157. First, solid sodium hydroxide and water are mixed and stirred until fully dissolved. After cooling, the sodium silicate solution is added, and the mixture is stirred again until homogeneous. It can be used only after cooling.

[0050] Step 2: Mixing dry materials of slag, calcined coal gangue, and fine sand. Place the slag, calcined coal gangue, and fine sand into a JJ-5 mixer and mix slowly for 2 minutes at a speed of 145 rad / min to obtain a mixed dry material.

[0051] Step 3: Addition of alkali activator. Add the alkali activator prepared in Step 1 to the mixed dry materials, and stir slowly in a JJ-5 mixer for 2 minutes at a speed of 145 rad / min to obtain a mixed slurry.

[0052] Step 4: Addition of polyethylene fibers and preparation of ultra-high toughness geopolymer material. Add polyethylene fibers to the mixed slurry in small amounts and multiple times, and stir rapidly for 5 minutes until the fibers are evenly dispersed to obtain the ultra-high toughness geopolymer material.

[0053] Example 4

[0054] The following raw material components are prepared according to the following mass ratio: slag: calcined coal gangue: fine sand: sodium silicate solution: sodium hydroxide: water = 0.7:0.3:0.2:0.361:0.0895:0.157. Based on the total volume after all components are mixed evenly, the polyethylene fiber content is 19.4 kg / m³. 3 The polyethylene fiber is 12mm long, 25μm in diameter, and has an aspect ratio of 480.

[0055] Step 1: Preparation of the alkali activator by mixing sodium silicate solution, sodium hydroxide, and water. Sodium silicate solution, sodium hydroxide, and water are measured in a mass ratio of 0.361:0.0895:0.157. First, solid sodium hydroxide and water are mixed and stirred until fully dissolved. After cooling, the sodium silicate solution is added, and the mixture is stirred again until homogeneous. It can be used only after cooling.

[0056] Step 2: Mixing dry materials of slag, calcined coal gangue, and fine sand. Place the slag, calcined coal gangue, and fine sand into a JJ-5 mixer and mix slowly for 2 minutes at a speed of 145 rad / min to obtain a mixed dry material.

[0057] Step 3: Addition of alkali activator. Add the alkali activator prepared in Step 1 to the mixed dry materials, and stir slowly in a JJ-5 mixer for 2 minutes at a speed of 145 rad / min to obtain a mixed slurry.

[0058] Step 4: Addition of polyethylene fibers and preparation of ultra-high toughness geopolymer material. Add polyethylene fibers to the mixed slurry in small amounts and multiple times, and stir rapidly for 5 minutes until the fibers are evenly dispersed to obtain the ultra-high toughness geopolymer material.

[0059] Example 5

[0060] The following raw material components are prepared according to the following mass ratio: slag: calcined coal gangue: fine sand: sodium silicate solution: sodium hydroxide: water = 0.6:0.4:0.2:0.361:0.0895:0.157. Based on the total volume after all components are mixed evenly, the polyethylene fiber content is 19.4 kg / m³. 3 The polyethylene fiber is 12mm long, 25μm in diameter, and has an aspect ratio of 480.

[0061] Step 1: Preparation of the alkali activator by mixing sodium silicate solution, sodium hydroxide, and water. Sodium silicate solution, sodium hydroxide, and water are measured in a mass ratio of 0.361:0.0895:0.157. First, solid sodium hydroxide and water are mixed and stirred until fully dissolved. After cooling, the sodium silicate solution is added, and the mixture is stirred again until homogeneous. It can be used only after cooling.

[0062] Step 2: Mixing dry materials of slag, calcined coal gangue, and fine sand. Place the slag, calcined coal gangue, and fine sand into a JJ-5 mixer and mix slowly for 2 minutes at a speed of 145 rad / min to obtain a mixed dry material.

[0063] Step 3: Addition of alkali activator. Add the alkali activator prepared in Step 1 to the mixed dry materials, and stir slowly in a JJ-5 mixer for 2 minutes at a speed of 145 rad / min to obtain a mixed slurry.

[0064] Step 4: Addition of polyethylene fibers and preparation of ultra-high toughness geopolymer material. Add polyethylene fibers to the mixed slurry in small amounts and multiple times, and stir rapidly for 5 minutes until the fibers are evenly dispersed to obtain the ultra-high toughness geopolymer material.

[0065] Example 6

[0066] The following raw material components are prepared according to the following mass ratio: slag: calcined coal gangue: fine sand: sodium silicate solution: sodium hydroxide: water = 0.7:0.3:0.2:0.361:0.0895:0.157. Based on the total volume after all components are mixed evenly, the polyethylene fiber content is 19.4 kg / m³. 3 The polyethylene fiber is 12mm long, 15μm in diameter, and has an aspect ratio of 800.

[0067] Step 1: Preparation of the alkali activator by mixing sodium silicate solution, sodium hydroxide, and water. Sodium silicate solution, sodium hydroxide, and water are measured in a mass ratio of 0.361:0.0895:0.157. First, solid sodium hydroxide and water are mixed and stirred until fully dissolved. After cooling, the sodium silicate solution is added, and the mixture is stirred again until homogeneous. It can be used only after cooling.

[0068] Step 2: Mixing dry materials of slag, calcined coal gangue, and fine sand. Place the slag, calcined coal gangue, and fine sand into a JJ-5 mixer and mix slowly for 2 minutes at a speed of 145 rad / min to obtain a mixed dry material.

[0069] Step 3: Addition of alkali activator. Add the alkali activator prepared in Step 1 to the mixed dry materials, and stir slowly in a JJ-5 mixer for 2 minutes at a speed of 145 rad / min to obtain a mixed slurry.

[0070] Step 4: Addition of polyethylene fibers and preparation of ultra-high toughness geopolymer material. Add polyethylene fibers to the mixed slurry in small amounts and multiple times, and stir rapidly for 5 minutes until the fibers are evenly dispersed to obtain the ultra-high toughness geopolymer material.

[0071] The performance of the ultra-high toughness geopolymer material prepared by this invention was tested, and the test results are shown in Tables 1-2 and 2. Figure 1-6 As shown.

[0072] Tests and trials

[0073] 1. Uniaxial tensile test: Dumbbell-shaped specimens of 13mm × 60mm (30mm in the middle section) × 240mm were used. Three specimens were molded for each example. After being placed at room temperature for 24 hours, the specimens were demolded and cured in an 80℃ high-temperature curing chamber for 2 hours. After removal, they were subjected to standard curing for 6 days at a curing temperature of 20±2℃ and a relative humidity of ≥95%. The test indicators were tensile strength and ultimate tensile strain.

[0074] 2. Axial compression test: Three 50mm×50mm×50mm specimens were molded for each example. After being placed at room temperature for 24 hours, the specimens were demolded and cured in an 80℃ high-temperature curing chamber for 2 hours. After removal, they were cured for 6 days under standard conditions at a temperature of 20±2℃ and a relative humidity of ≥95%. The test index was compressive strength.

[0075] 3. Single fiber pull-out test: Ten matrix specimens (excluding fiber) with a single polyethylene fiber vertically embedded were molded for each example. The specimens were cured in an 80℃ high-temperature curing chamber for 2 hours, then standard cured for 6 days at a temperature of 20±2℃ and a relative humidity ≥95%. The test indicators were friction bond strength and slip hardening coefficient.

[0076] The specimens prepared in Examples 1-6 were subjected to performance tests, and the test results are shown in Tables 1-2.

[0077] Table 1 shows the mechanical performance test results.

[0078]

[0079] Table 2 shows the test results of the fiber-matrix interface properties.

[0080]

[0081] As shown in Table 1, Examples 1-5 improved the performance of the composite material by changing the ratio of slag and calcined coal gangue. This is because increasing the amount of calcined coal gangue promotes the early and rapid occurrence of the condensation reaction of the slag-coal gangue depolymerization, resulting in more calcium aluminosilicate hydrate gel (CASH) and sodium aluminosilicate gel (NASH) products, which increases the matrix density and thus improves the early compressive strength. Example 6 further improved the tensile properties of the composite material by increasing the aspect ratio of the polyethylene fibers without significantly reducing the compressive strength. This is because a larger aspect ratio results in a greater number of fine fibers per unit volume, leading to tighter fiber dispersion, which prevents more cracks and thus achieves higher fracture toughness, thereby improving tensile properties.

[0082] To explain the high toughness mechanism, the properties of ultra-high toughness geopolymer materials were understood from the fiber / matrix interface behavior, and the friction bond strength and slip hardening coefficient were measured. Table 2 shows that Example 4 exhibits a higher friction bond strength and tensile strength than Example 1. This is attributed to the increased production of hydrated calcium aluminosilicate gel (CASH) and sodium aluminosilicate gel (NASH) products with increasing calcined coal gangue content, which crosslink to form a stable three-dimensional structure, increasing density and thus increasing the interfacial contact area around the fiber, resulting in higher friction bond strength and consequently higher tensile strength. Furthermore, a larger slip hardening coefficient indicates greater interfacial wear during fiber pull-out, leading to higher tensile strain hardening capacity.

Claims

1. A slag and calcined coal gangue based early strength type super ductile geopolymer material, characterized by: The composition comprises slag, calcined coal gangue, fine sand, sodium silicate solution, sodium hydroxide solid, water and polyethylene fiber; the components are mixed uniformly according to the mass ratio of slag: calcined coal gangue: fine sand: sodium silicate solution: sodium hydroxide: water = 0.6-0.9: 0.1-0.4: 0.1-0.3: 0.29-0.43: 0.07-0.11: 0.11-0.20, and the dosage of polyethylene fiber is 19.4 kg / m 3 The polyethylene fiber with a large aspect ratio is mixed, the length of the polyethylene fiber is 12-18 mm, and the diameter is 15-25 μm, so that the super-high toughness polymer material has the characteristics of multi-crack and strain hardening under the action of tensile load; the calcined coal gangue is prepared in the following manner: the coal gangue is calcined at 700 ℃ for 2 hours, then ball milled into powder, and the specific surface area is ≥450 m² / kg; the content of each chemical component of the slag should satisfy the mass ratio of 1.0≤CaO / SiO2≤2.0, 0.1≤Al2O3 / SiO2≤0.3, (CaO+MgO+Al2O3) / SiO2≥1.4; the content of Al2O3 and SiO2 in the calcined coal gangue is more than 90%.

2. A slag and calcined coal gangue based early strength type super ductile geopolymer material according to claim 1, characterized by: The components are mixed uniformly in the mass ratio of slag: calcined coal gangue: river sand: sodium silicate solution: sodium hydroxide: water = 0.8: 0.2: 0.2: 0.361: 0.0895: 0.157, and the total volume after mixing is taken as the base, and the polyethylene fiber content is 19.4 kg / m 3 The length of the polyethylene fiber is 12 mm, the diameter is 25 μm, and the fiber aspect ratio is 480.

3. A slag and calcined coal gangue based early strength type super ductile geopolymer material as claimed in claim 1, wherein: The components are mixed uniformly in the mass ratio of slag: calcined coal gangue: river sand: sodium silicate solution: sodium hydroxide: water = 0.7: 0.3: 0.2: 0.361: 0.0895: 0.157, and the total volume after mixing is taken as the basis, and the polyethylene fiber content is 19.4 kg / m 3 The length of the polyethylene fiber is 12 mm, the diameter is 25 μm, and the fiber aspect ratio is 480.

4. A slag and calcined coal gangue based early strength type super ductile geopolymer material as claimed in claim 1, wherein: The components are mixed uniformly in the mass ratio of slag: calcined coal gangue: river sand: sodium silicate solution: sodium hydroxide: water = 0.7: 0.3: 0.2: 0.361: 0.0895: 0.157, and the total volume after mixing is taken as the basis, and the polyethylene fiber content is 19.4 kg / m 3 The length of the polyethylene fiber is 12 mm, the diameter is 15 μm, and the fiber aspect ratio is 800.

5. A slag and calcined coal gangue based early strength type super ductile geopolymer material according to claim 1, characterized by: The slag is selected from S95 grade granulated blast furnace slag powder according to the standard of GB / T 18046-2008.

6. A slag and calcined coal gangue based early strength type super ductile geopolymer material as claimed in claim 1, wherein: The sodium silicate solution, the sodium hydroxide solid and water are mixed to prepare the composite alkali activator, which is prepared in the following manner: the 99% purity sodium hydroxide solid is prepared into a sodium hydroxide solution by adding water, and after cooling, it is added into a sodium silicate solution with an initial modulus of 3.3 and a solid content of 35.5wt%, and finally configured into a sodium silicate solution with a modulus of 1.

0.

7. A slag and calcined coal gangue based early strength type super ductile geopolymer material as claimed in claim 1, wherein: The fine sand is river sand, sea sand, desert sand or machine-made sand, the maximum particle size of the fine sand is not more than 1.0mm, the average particle size is not more than 520μm, and the grading is good.

8. A slag and calcined coal gangue based early strength type super ductile geopolymer material as claimed in claim 1, wherein: The polyethylene fiber has an elastic modulus of not less than 110GPa and a tensile strength of not less than 3000MPa.

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