Environment-friendly high-performance concrete pavement patching material and preparation and construction method thereof

Abstract

The invention discloses an environment-friendly high-performance concrete pavement patching material and a preparation and construction method thereof. The material comprises sulphoaluminate cement, ordinary Portland cement, silica fume, metakaolin, aggregate, a magnesium oxide expanding agent, an ettringite expanding agent, a polycarboxylate superplasticizer, fibers, a sodium gluconate retarder, polymer rubber powder and water. A sulphoaluminate cement-ordinary Portland cement compound system is taken as a core, and a double-expansion-source magnesium oxide, ettringite and acrylate rubber powder enhancement technology is combined, so that a layer with the thickness of 30-120mm is repaired, the 28d compressive strength is greater than or equal to 55MPa, the bonding strength is greater than or equal to 5.0 MPa, the impermeability grade is greater than or equal to P15, the 28d expansion rate is 0.03-0.06%, and the strength loss rate is less than or equal to 8% after soaking in a 5% sodium sulfate solution for 180d. And a base surface treatment and layered vibration technology is adopted, and the environment temperature of 5-40 DEG C is adapted. The concrete pavement repairing agent is widely applied to concrete pavement repairing under harsh working conditions such as airport runways and expressways.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, specifically relating to an environmentally friendly repair material for high-load (aircraft take-off and landing weight ≥ 300 tons, vehicle speed ≥ 80 km / h) concrete pavements such as airport runways and highways, as well as its preparation and construction methods; in particular, it proposes an environmentally friendly high-performance concrete pavement repair material and its preparation and construction methods. Background Technology

[0002] Concrete pavements, due to their superior load-bearing capacity and durability, have become the mainstream paving form for national and provincial highways, airport runways, and bridge surfaces worldwide. By the end of 2024, cement concrete runways accounted for 80.9% of the runways used in transport airports in my country, making it the most prevalent form of airport pavement in the country. However, with increasing service life and a surge in traffic load, a large number of concrete pavements have approached or exceeded their design life. While some runways have not yet reached their design life, the unexpectedly high passenger and cargo traffic, coupled with frequent takeoffs and landings of heavy aircraft (such as the A380), has led to structural defects such as cracks, corner breaks, and joint damage. This damage not only reduces pavement smoothness but also seriously affects aircraft takeoff and landing safety, potentially causing major accidents such as turbulence and tire blowouts. Therefore, efficient repair technologies for aging concrete pavements have become a core issue in airport operation and maintenance.

[0003] Existing repair materials generally suffer from performance shortcomings and insufficient environmental adaptability. Traditional fiber-reinforced concrete or micro-expansion concrete, due to their poor environmental adaptability and insufficient durability, are unable to completely eliminate secondary damage caused by freeze-thaw cycles and salt erosion. While epoxy concrete, widely used abroad, has high bond strength, it relies on isocyanate curing agents, releases harmful gases during construction, and is expensive (approximately 3-5 times more expensive than cement-based materials). Furthermore, its coefficient of thermal expansion differs significantly from that of the concrete matrix (epoxy resin α = 60 × 10⁻⁻⁴). 6 / ℃ vs. concrete α=10×10⁻ 6 = / ℃), which is prone to interfacial delamination due to temperature stress. In addition, most repair materials have insufficient understanding of the compatibility between new and old concrete. For example, sulfoaluminate cement-based repair mortar has high early strength, but its impermeability is only P8 grade, which cannot meet the stringent freeze-thaw resistance (≥F300) and chloride erosion resistance requirements of airport runways; polymer-modified mortar improves flexibility, but the mismatch in shrinkage rate (0.15%~0.20%) causes the repair layer to warp. Therefore, developing environmentally friendly repair materials that combine rapid hardening, high bond strength (≥3MPa), micro-expansion to compensate for shrinkage (28-day expansion rate 0.02%~0.05%), and durability has become a technical bottleneck that the industry urgently needs to overcome. Summary of the Invention

[0004] This invention addresses the shortcomings of traditional repair materials in terms of performance and poor environmental adaptability. It employs a sulfoaluminate cement-ordinary silicate cement composite system as its core, combined with dual expansion sources (magnesium oxide and ettringite) and acrylate adhesive powder reinforcement technology. The aim is to eliminate the risks associated with toxic and flammable components in traditional materials, improve interfacial adhesion and crack resistance in thick-layer repairs (30mm-120mm), achieve synergistic optimization of impermeability, freeze-thaw resistance, and chemical corrosion resistance, and expand the adaptability of construction parameters to cover environmental temperatures from 5 to 40℃. Furthermore, it proposes an environmentally friendly, high-performance concrete pavement repair material and its preparation and construction method.

[0005] The technical solution of the present invention is as follows:

[0006] The environmentally friendly, high-performance concrete pavement repair material of the present invention comprises the following components and parts by weight:

[0007] 30~50 sulfoaluminate cement

[0008] Ordinary Portland cement 10~20

[0009] Silica fume 5~10

[0010] Metakaolin 3~8

[0011] Aggregate 40~60

[0012] Magnesium oxide expanding agent 1.5~3

[0013] Calcium sulfate expander 1.5~3

[0014] Polycarboxylate superplasticizer 0.5~1.5

[0015] Fiber 0.8~1.5

[0016] Sodium gluconate retarder 0~0.15

[0017] Polymer powder 1%~3% (by mass of cementitious material)

[0018] Water: Its amount is controlled by the water-to-binder ratio, which is 0.30~0.38.

[0019] The cementitious material refers to the sum of the masses of sulfoaluminate cement, ordinary silicate cement, silica fume, and metakaolin.

[0020] In the aforementioned environmentally friendly high-performance concrete pavement repair material, the total amount of sulfoaluminate cement and ordinary silicate cement accounts for 50% to 70% of all cementitious materials (i.e., the sum of the mass of sulfoaluminate cement, ordinary silicate cement, silica fume, and metakaolin). In the aforementioned environmentally friendly high-performance concrete pavement repair material, the polymer powder is acrylate powder or ethylene-vinyl acetate (EVA) powder.

[0021] In the aforementioned environmentally friendly high-performance concrete pavement repair material, the fiber is basalt fiber with a length of 6-12 mm; or, the fiber is steel fiber with an aspect ratio of 50-80; or, the fiber is carbon fiber with an aspect ratio of 600-1200; or, the fiber is amorphous alloy fiber with an aspect ratio of 300-800; or, the fiber is polymer fiber with an aspect ratio of 200-500.

[0022] In the aforementioned environmentally friendly high-performance concrete pavement repair material, when the retarder is not included, the dosage of the water-reducing agent should be increased to 1.2% to 1.5% of the mass of the cementitious material; when the retarder is included, the dosage of the water-reducing agent is 0.5% to 1.5%.

[0023] In the aforementioned environmentally friendly high-performance concrete pavement repair material, the aggregate is one or a mixture of two of quartz sand and corundum, with a particle size range of 0.15~2.36mm.

[0024] The preparation method of the environmentally friendly high-performance concrete pavement repair material of the present invention includes the following steps:

[0025] S1. Dry material premixing: Add sulfoaluminate cement, ordinary silicate cement, silica fume, metakaolin, aggregate, magnesium oxide expansion agent, and ettringite expansion agent into a mixer and mix at a speed of 600~800r / min for 3-4 minutes.

[0026] S2. Dry and wet mixing: Dissolve the water-reducing agent, polymer powder and retarder in water, then add the solution to the dry mixture and stir for 5 to 7 minutes until the fluidity of the mixture reaches 220±10mm.

[0027] S3. Fiber dispersion: Add the fiber in two batches and stir at a low speed of 600~800r / min for 1-2 minutes to ensure uniform fiber dispersion.

[0028] S4. Let the mixture stand for 10-15 minutes in a sealed container.

[0029] In the preparation method of the environmentally friendly high-performance concrete pavement repair material, in the fiber dispersion step, when the fiber used is steel fiber, carbon fiber, amorphous alloy fiber or polymer fiber, whether it is used alone (single admixture) or mixed (multiple admixture), the stirring speed must be increased to 1000 r / min to ensure uniform fiber dispersion.

[0030] The construction steps of the environmentally friendly high-performance concrete pavement repair material of the present invention are as follows: Figure 1 This includes the following steps:

[0031] S1. Surface preparation: The concrete surface is mechanically milled or roughened to make its average roughness Ra≥0.5mm, then cleaned and coated with interface agent.

[0032] S2. Material Mixing and Temperature Control: The repair material is mixed on-site, and the outlet temperature is controlled to be ≤35℃. When the ambient temperature is <10℃, an early-strength agent of 0.5%~1.5% of the mass of the cementitious material is added. The early-strength agent is an inorganic salt early-strength agent, including at least one of calcium nitrate, calcium nitrite, and sodium sulfate, preferably calcium nitrate. When the ambient temperature is >30℃, cooling water is circulated through the mixer to control the material temperature.

[0033] S3. Layered spreading and vibration: Spread the repair material in layers, each layer being 40-80mm thick, with an interval of no more than 45 minutes between layers; spray the interface between layers with a cement paste with a water-cement ratio of 0.3-0.4; use a plate vibrator for vibration, with the vibration time controlled at 1.5-3.0 min / m² depending on the layer thickness.

[0034] S4. Curing: After spreading and leveling, immediately cover with a water-retaining film for no less than 72 hours.

[0035] The construction method described above requires watering for at least 7 days after curing.

[0036] The preparation method of the present invention adopts

[0037] Segmented mixing: dry mixing → wet mixing (including adhesive powder) → stepwise fiber dispersion;

[0038] Film curing: Covering with a water-retaining film for curing effectively prevents moisture evaporation, avoids early cracking, and ensures the development of strength in the later stage.

[0039] This invention uses silica fume and metakaolin composite to fill pores and reduce permeability; it uses magnesium oxide expansion agent and ettringite expansion agent to compensate for shrinkage in stages, with ettringite expansion rate of 0.02%~0.04% in 1~7 days and magnesium oxide expansion rate of 0.01%~0.02% in 7~28 days.

[0040] Fiber reinforcement is used to inhibit crack propagation. Acrylic adhesive powder is used to improve interfacial chemical bonding and enhance adhesion.

[0041] Sulfoaluminate cement (C4A3Š≥60%) provides early strength (1-day compressive strength ≥20MPa);

[0042] Ordinary Portland cement (C3S≥50%) ensures the stability of strength in the later stage.

[0043] Among the alternative technical solutions:

[0044] Acrylic powder replacement: Acrylic ester adhesive powder can be replaced with EVA adhesive powder (dosage 1%~2%), and the water-to-binder ratio should be reduced to 0.30~0.33;

[0045] Fiber replacement: Basalt fiber can be replaced with steel fiber (1.5~2.5 parts, aspect ratio 50~80), carbon fiber (0.5~1.2 parts, aspect ratio 600~1200), amorphous alloy fiber (1.0~2.0 parts, aspect ratio 300~800), polymer fiber (0.5~1.5 parts, aspect ratio 200~500), etc., which can be used alone or in combination. When using the above rigid fibers, the stirring speed needs to be adjusted to 1000 r / min. Retarder-free scheme: When removing sodium gluconate, the water-cement ratio is adjusted to 0.32~0.38, and the water-reducing agent dosage is increased to 1.2%~1.5%.

[0046] Quartz sand replacement solution: Use corundum or a mixture of quartz sand and corundum.

[0047] Technical advantages of the environmentally friendly high-performance concrete pavement repair material of this invention:

[0048] Mechanical properties: 28d compressive strength ≥55MPa (GB / T 17671-2021), bond strength ≥5.0MPa (JTG / T3364-2022);

[0049] Durability: Impermeability grade ≥ P15 (GB / T 50082-2009), freeze-thaw cycle resistance ≥ F300 (mass loss rate < 0.5%, relative dynamic elastic modulus retention rate ≥ 85%).

[0050] Volume stability: 28-day expansion rate of 0.03%~0.06%, with phased compensation for shrinkage;

[0051] Chemical corrosion resistance: Strength loss rate ≤8% after immersion in 5% sodium sulfate solution for 180 days;

[0052] Application adaptability: The standard formula (including retarder) can be applied in ambient temperatures of 5~40℃, with an open time of ≥40min. By adjusting the formula (omitting the retarder), it can be adapted for rapid application scenarios, and the open time can be shortened accordingly.

[0053] This invention discloses an environmentally friendly, high-performance concrete pavement repair material and its preparation and construction method. The material uses a sulfoaluminate cement-ordinary silicate cement composite system as its core, combined with dual expansion sources (magnesium oxide and ettringite) and acrylate adhesive powder reinforcement technology, to achieve repairs of 30mm-120mm thick layers. Its 28-day compressive strength is ≥55MPa, bond strength is ≥5.0MPa, impermeability grade is ≥P15, 28-day expansion rate is 0.03%~0.06%, and the strength loss rate after soaking in 5% sodium sulfate solution for 180 days is ≤8%. During construction, surface treatment and layered vibration techniques are employed, adaptable to ambient temperatures of 5~40℃. This invention eliminates toxic and flammable components such as isocyanates and amines. Through open-ended formulation and process parameter design, it features interchangeable cement and adhesive powder types, adaptable to different climatic conditions and engineering requirements. It can be widely used in the repair of concrete pavements under harsh conditions such as airport runways and highways. The preparation and construction method of this environmentally friendly, high-performance concrete pavement repair material are specifically presented. Attached Figure Description

[0054] Figure 1 Construction process flow chart Detailed Implementation

[0055] Example 1:

[0056] Material formula (parts by weight)

[0057] Sulfoaluminate cement: 40

[0058] Ordinary Portland cement: 15

[0059] Silica fume: 7

[0060] Metakaolin: 5

[0061] Quartz sand (0.15~2.36mm): 50

[0062] Magnesium oxide expanding agent: 2

[0063] Calcium sulfate expander: 2

[0064] Acrylic ester adhesive powder: 1% (accounting for 67 parts of the total cementitious material, with an actual usage of 0.67 parts).

[0065] Polycarboxylate superplasticizer: 1.0

[0066] Basalt fiber: 1.2

[0067] Sodium gluconate: 0.1

[0068] Water-to-binder ratio: 0.34

[0069] Preparation process:

[0070] S1. Dry material premixing: Add sulfoaluminate cement, ordinary silicate cement, silica fume, metakaolin, quartz sand, magnesium oxide expansion agent, and ettringite expansion agent into a forced mixer and mix at a speed of 600 r / min for 4 minutes.

[0071] S2. Dry and wet mixing: Dissolve the water-reducing agent, retarder, and acrylic ester powder in water, slowly add them to the dry mixture, and stir for 6 minutes until the fluidity of the mixture reaches 220±10mm.

[0072] S3. Fiber dispersion: Basalt fiber is sprinkled in twice, and stirred at 800r / min for 1 minute twice to ensure uniform fiber dispersion.

[0073] S4. Let the mixture stand for 12 minutes in a sealed container.

[0074] Construction steps:

[0075] The construction steps of the environmentally friendly high-performance concrete pavement repair material of the present invention are as follows: Figure 1 :

[0076] Step 1: Surface preparation: Machine mill the surface to an average roughness Ra≥0.5mm, or roughen it to form a groove with a depth of 1~3mm; after rinsing with a high-pressure water gun (≥20MPa), apply an interface agent.

[0077] Step 2: Material Mixing and Temperature Control: Mix on-site, controlling the outlet temperature to ≤35℃. When the ambient temperature is <10℃, add calcium nitrate early strength agent (0.5%~1.5%); when the ambient temperature is >30℃, circulate cooling water through the mixer to control the material temperature to ≤35℃.

[0078] Step 3: Layered spreading and vibration: Each layer is 40~80mm thick, with an interval of ≤45 minutes between layers; spray the interface between layers with a cement paste with a water-cement ratio of 0.3~0.4. Use a plate vibrator for compaction, and control the compaction time according to the layer thickness (30~50mm: 1.5~2.0min / m²; 50~80mm: 2.0~3.0min / m²).

[0079] Step 4: Surface leveling and curing: After laser leveling, immediately cover with polyethylene film for curing for no less than 72 hours, followed by water curing for no less than 7 days.

[0080] Performance test results:

[0081] The overall performance of this embodiment is significantly superior to that of traditional repair materials, as shown in the test results below:

[0082] Mechanical properties: 28-day compressive strength 58.5 MPa, bond strength 5.3 MPa.

[0083] Durability: Impermeability grade P16, freeze-thaw cycle resistance F325 (mass loss rate 0.3%, relative dynamic elastic modulus retention rate 88%).

[0084] Volume stability: 28-day expansion rate of 0.045%, effectively compensating for shrinkage, with no cracking.

[0085] Chemical corrosion resistance: The strength loss rate is 5.2% after immersion in 5% sodium sulfate solution for 180 days.

[0086] Workability: At an ambient temperature of 25℃, the initial flowability is 225mm and the opening time is 45 minutes.

[0087] Example 2:

[0088] This embodiment uses the minimum value of the dosage range of each component to verify the lower limit performance of the formulation.

[0089] Material formula (parts by weight):

[0090] Sulfoaluminate cement: 30

[0091] Ordinary Portland cement: 10

[0092] Silica fume: 5

[0093] Metakaolin: 3

[0094] Quartz sand: 40

[0095] Magnesium oxide expanding agent: 1.5

[0096] Calcium sulfate expander: 1.5

[0097] Acrylic ester adhesive powder: 1% (as a percentage of the mass of the cementitious material; the total mass of the cementitious material is 48 parts, and the actual amount used is 0.48 parts).

[0098] Polycarboxylate superplasticizer: 0.5

[0099] Basalt fiber: 0.8

[0100] Sodium gluconate: 0.05

[0101] Water-to-binder ratio: 0.30

[0102] Preparation process:

[0103] S1. Dry material premixing: Add sulfoaluminate cement, ordinary silicate cement, silica fume, metakaolin, quartz sand, magnesium oxide expansion agent, and ettringite expansion agent into a forced mixer and mix at 600 r / min for 4 minutes.

[0104] S2. Dry and wet mixing: Dissolve the water-reducing agent, retarder, and acrylic powder in water, slowly add them to the dry mixture, and stir for 7 minutes until the fluidity reaches 220±10mm.

[0105] S3. Fiber dispersion: Basalt fiber is sprinkled in twice, and stirred at 600 r / min for 2 minutes twice to ensure uniform fiber dispersion.

[0106] S4. Let the mixture stand for 15 minutes in a sealed container.

[0107] Construction steps:

[0108] Step 1: Surface preparation: Machine mill the surface to an average roughness Ra≥0.5mm, or roughen it to form a groove with a depth of 1~3mm; after rinsing with a high-pressure water gun (≥20MPa), apply an interface agent.

[0109] Step 2: Material Mixing and Temperature Control: Mix on-site, controlling the outlet temperature to ≤35℃. When the ambient temperature is <10℃, add calcium nitrate early strength agent (0.5%~1.5%); when the ambient temperature is >30℃, circulate cooling water through the mixer to control the material temperature to ≤35℃.

[0110] Step 3: Layered Spreading and Vibration: Each layer should be 40-80mm thick, with an interval of ≤45 minutes between layers; spray a neat cement paste with a water-cement ratio of 0.3-0.4 onto the interlayer interface. Use a plate vibrator for compaction, controlling the vibration time according to the layer thickness (30-50mm: 1.5-2.0min / m²; 50-80mm: 2.0-3.0min / m²). Due to the low water-cement ratio (0.30) of this formula, the material is slightly viscous; therefore, the plate vibration time should be taken at the upper limit of the above range to ensure compaction.

[0111] Step 4: Surface leveling and curing: After laser leveling, immediately cover with polyethylene film for curing for no less than 72 hours, followed by water curing for no less than 7 days.

[0112] Performance test results:

[0113] Mechanical properties: 28-day compressive strength 55.8 MPa, bond strength 5.1 MPa.

[0114] Durability: Impermeability grade P15, freeze-thaw cycle resistance F300 (mass loss rate 0.4%, relative dynamic elastic modulus retention rate 86%).

[0115] Volume stability: 28-day expansion rate 0.032%.

[0116] Chemical corrosion resistance: The strength loss rate is 7.5% after immersion in 5% sodium sulfate solution for 180 days.

[0117] Construction adaptability: Opening time 42 minutes.

[0118] Results: It was verified that even at the minimum mixing ratio, the material's performance fully meets and slightly exceeds the preset technical indicators, making it suitable for thin-layer repairs or mild climatic conditions, demonstrating the lower limit of the formulation's economic efficiency.

[0119] Example 3:

[0120] This embodiment uses the maximum value of the dosage range of each component to verify the upper limit performance of the formulation.

[0121] Material formula (parts by weight):

[0122] Sulfoaluminate cement: 50

[0123] Ordinary Portland cement: 20

[0124] Silica fume: 10

[0125] Metakaolin: 8

[0126] Quartz sand: 60

[0127] Magnesium oxide expander: 3

[0128] Calcium alum expander: 3

[0129] Acrylic ester adhesive powder: 3% (accounting for 88 parts of the total cementitious material, with an actual usage of 2.64 parts).

[0130] Polycarboxylate superplasticizer: 1.5

[0131] Basalt fiber: 1.5

[0132] Sodium gluconate: 0.15

[0133] Water-to-binder ratio: 0.38

[0134] Preparation process:

[0135] S1. Dry material premixing: Add sulfoaluminate cement, ordinary silicate cement, silica fume, metakaolin, quartz sand, magnesium oxide expansion agent, and ettringite expansion agent into a forced mixer and mix at 800 r / min for 3 minutes.

[0136] S2. Dry and wet mixing: Dissolve the water-reducing agent, retarder, and acrylic ester powder in water, slowly add them to the dry mixture, and stir for 5 minutes until the fluidity of the mixture reaches 220±10mm.

[0137] S3. Fiber dispersion: Basalt fiber is sprinkled in twice, and stirred at 800r / min for 1 minute twice to ensure uniform fiber dispersion.

[0138] S4. Let the mixture stand for 10 minutes in a sealed container.

[0139] Construction steps:

[0140] Step 1: Surface preparation: Machine mill the surface to an average roughness Ra≥0.5mm, or roughen it to form a groove with a depth of 1~3mm; after rinsing with a high-pressure water gun (≥20MPa), apply an interface agent.

[0141] Step Two: Material Mixing and Temperature Control: Mix on-site, controlling the outlet temperature to ≤35℃. When the ambient temperature is <10℃, add calcium nitrate early-strength agent (0.5%~1.5%); when the ambient temperature is >30℃, circulate cooling water through the mixer to control the material temperature to ≤35℃. Due to the high content of cementitious materials in the formula, the hydration heat release is relatively fast, so it is necessary to strengthen the monitoring of outlet temperature and material temperature.

[0142] Step 3: Layered spreading and vibration: Each layer is 40~80mm thick, with an interval of ≤45 minutes between layers; spray the interface between layers with a cement paste with a water-cement ratio of 0.3~0.4. Use a plate vibrator for compaction, and control the compaction time according to the layer thickness (30~50mm: 1.5~2.0min / m²; 50~80mm: 2.0~3.0min / m²).

[0143] Step 4: Surface leveling and curing: After laser leveling, immediately cover with polyethylene film for curing for no less than 72 hours, followed by water curing for no less than 7 days.

[0144] Performance test results:

[0145] Mechanical properties: 28-day compressive strength 65.2 MPa, bond strength 5.8 MPa.

[0146] Durability: Impermeability grade P18, freeze-thaw cycle resistance F350 (mass loss rate 0.2%, relative dynamic elastic modulus retention rate 91%).

[0147] Volume stability: 28-day expansion rate 0.058%.

[0148] Chemical corrosion resistance: The strength loss rate is 4.8% after immersion in 5% sodium sulfate solution for 180 days.

[0149] Construction adaptability: Opening time 48 minutes.

[0150] Results: The results demonstrate that at the maximum formulation ratio, the material exhibits superior mechanical properties and durability, with a significant increase in compressive strength. It is suitable for thick-layer repairs (120mm) or extreme climatic conditions, showcasing the upper limit of the formulation's performance.

[0151] Example 4:

[0152] This embodiment aims to verify the technical effect of using EVA (vinyl acetate-ethylene copolymer) powder to replace acrylate powder. EVA powder provides better water resistance and flexibility, making it suitable for engineering environments with high requirements for hydrolysis resistance.

[0153] Material formula (parts by weight):

[0154] Sulfoaluminate cement: 35

[0155] Ordinary Portland cement: 15

[0156] Silica fume: 8

[0157] Metakaolin: 4

[0158] Quartz sand: 55

[0159] Magnesium oxide expanding agent: 2

[0160] Calcium sulfate expander: 2.5

[0161] EVA adhesive powder: 1.5% (accounting for 62 parts of the total cementitious material, with an actual usage of 0.93 parts).

[0162] Polycarboxylate superplasticizer: 1.2

[0163] Basalt fiber: 1.0

[0164] Sodium gluconate: 0.08

[0165] Water-to-adhesive ratio: 0.31 (This ratio is adjusted appropriately because the water requirement of EVA adhesive powder differs from that of acrylic ester).

[0166] Preparation process:

[0167] S1. Dry material premixing: Add sulfoaluminate cement, ordinary silicate cement, silica fume, metakaolin, quartz sand, magnesium oxide expansion agent, and ettringite expansion agent into a forced mixer and mix at a speed of 600 r / min for 4 minutes.

[0168] S2. Dry and wet mixing: Dissolve the water-reducing agent, retarder, and EVA powder in water, slowly add them to the dry mixture, and stir for 6 minutes until the fluidity of the mixture reaches 220±10mm.

[0169] S3. Fiber dispersion: Basalt fiber is sprinkled in twice, and stirred at 800r / min for 1 minute twice to ensure uniform fiber dispersion.

[0170] S4. Let the mixture stand for 12 minutes in a sealed container.

[0171] Construction steps:

[0172] Step 1: Surface preparation: Machine mill the surface to an average roughness Ra≥0.5mm, or roughen it to form a groove with a depth of 1~3mm; after rinsing with a high-pressure water gun (≥20MPa), apply an interface agent.

[0173] Step 2: Material Mixing and Temperature Control: Mix on-site, controlling the outlet temperature to ≤35℃. When the ambient temperature is <10℃, add calcium nitrate early strength agent (0.5%~1.5%); when the ambient temperature is >30℃, circulate cooling water through the mixer to control the material temperature to ≤35℃.

[0174] Step 3: Layered spreading and vibration: Each layer is 40~80mm thick, with an interval of ≤45 minutes between layers; spray the interface between layers with a cement paste with a water-cement ratio of 0.3~0.4. Use a plate vibrator for compaction, and control the compaction time according to the layer thickness (30~50mm: 1.5~2.0min / m²; 50~80mm: 2.0~3.0min / m²).

[0175] Step 4: Surface Leveling and Curing: After laser leveling, immediately cover with polyethylene film for curing for no less than 72 hours, followed by water curing for no less than 7 days. Special Note: Because EVA adhesive powder has a low film-forming temperature, if the ambient temperature is below 10℃, an insulating curing film should be applied immediately after paving and leveling to ensure that the surface temperature of the repair layer is not lower than 10℃ during the initial curing period (within 24 hours).

[0176] Performance test results:

[0177] In this embodiment, EVA powder is used instead of acrylic powder, which maintains excellent performance while exhibiting better water resistance and economy.

[0178] Mechanical properties: 28-day compressive strength 55.8 MPa, bond strength 4.9 MPa (slightly lower than Example 1, but still far exceeding the industry high standard of ≥3 MPa).

[0179] Durability: Impermeability grade P15, freeze-thaw cycle resistance F310 (mass loss rate 0.4%, relative dynamic modulus retention rate 86%). After immersion in water for 48 hours, the bond strength retention rate is as high as 95%, which is significantly better than the 90% of the acrylic system, demonstrating the excellent water resistance of EVA powder.

[0180] Volume stability: 28-day expansion rate 0.041%.

[0181] Chemical corrosion resistance: The strength loss rate after immersion in 5% sodium sulfate solution for 180 days is 6.9%.

[0182] Construction adaptability: The opening time is 50 minutes, which is longer than that of Example 1, making it suitable for construction in summer.

[0183] Results: Although the bonding strength was slightly lower than the benchmark after using EVA adhesive powder, it still met the requirement of ≥5.0MPa. At the same time, the material showed better water resistance and flexibility, proving the feasibility of the replacement.

[0184] Example 5:

[0185] This embodiment aims to verify the technical effectiveness of using steel fibers instead of basalt fibers. Steel fibers have higher tensile strength and toughness, making them suitable for areas with extremely high requirements for impact resistance and fatigue resistance.

[0186] Material formula (parts by weight):

[0187] Sulfoaluminate cement: 45

[0188] Ordinary Portland cement: 12

[0189] Silica fume: 6

[0190] Metakaolin: 6

[0191] Quartz sand: 58

[0192] Magnesium oxide expanding agent: 2.5

[0193] Calcium sulfate expander: 1.8

[0194] Acrylic ester adhesive powder: 2% (accounting for 69 parts of the total cementitious material, with an actual usage of 1.38 parts).

[0195] Polycarboxylate superplasticizer: 1.0

[0196] Copper-plated steel fiber: 2.0 (length-to-diameter ratio 60)

[0197] Sodium gluconate: 0.12

[0198] Water-to-binder ratio: 0.35

[0199] Preparation process:

[0200] S1. Dry material premixing: Add sulfoaluminate cement, ordinary silicate cement, silica fume, metakaolin, quartz sand, magnesium oxide expansion agent, and ettringite expansion agent into a forced mixer and mix at a speed of 600 r / min for 4 minutes.

[0201] S2. Dry and wet mixing: Dissolve the water-reducing agent, retarder, and acrylic ester powder in water, slowly add them to the dry mixture, and stir for 6 minutes until the fluidity of the mixture reaches 220±10mm.

[0202] S3. Fiber dispersion: Add copper-plated steel fibers in two batches, increase the speed of the mixer to 1000 r / min, and stir for 2 minutes twice to ensure that the fibers are evenly dispersed and free of clumping.

[0203] S4. Let the mixture stand for 12 minutes in a sealed container.

[0204] Construction steps:

[0205] Step 1: Surface preparation: Machine mill the surface to an average roughness Ra≥0.5mm, or roughen it to form a groove with a depth of 1~3mm; after rinsing with a high-pressure water gun (≥20MPa), apply an interface agent.

[0206] Step 2: Material Mixing and Temperature Control: Mix on-site, controlling the outlet temperature to ≤35℃. When the ambient temperature is <10℃, add calcium nitrate early strength agent (0.5%~1.5%); when the ambient temperature is >30℃, circulate cooling water through the mixer to control the material temperature to ≤35℃.

[0207] Step 3: Layered Spreading and Vibration: Each layer should be 40-80mm thick, with an interval of ≤45 minutes between layers; spray a layer of neat cement slurry with a water-cement ratio of 0.3-0.4 at the interface between layers. Use a plate vibrator for compaction, controlling the vibration time according to the layer thickness (30-50mm: 1.5-2.0min / m²; 50-80mm: 2.0-3.0min / m²). Due to the addition of steel fibers, the workability of the mixture is slightly reduced; avoid excessive turning during spreading, and ensure thorough vibration.

[0208] Step 4: Surface leveling and curing: After laser leveling, immediately cover with polyethylene film for curing for no less than 72 hours, followed by water curing for no less than 7 days.

[0209] Performance test results:

[0210] Mechanical properties: 28-day compressive strength 63.8 MPa, bond strength 5.5 MPa.

[0211] Durability: Impermeability grade P16, freeze-thaw cycle resistance F330 (mass loss rate 0.3%, relative dynamic elastic modulus retention rate 90%).

[0212] Volume stability: 28-day expansion rate 0.049%.

[0213] Chemical corrosion resistance: The strength loss rate is 5.6% after immersion in 5% sodium sulfate solution for 180 days.

[0214] Construction adaptability: Opening time 43 minutes.

[0215] Effect description: After using steel fiber, the compressive strength and impact resistance are significantly enhanced. Although the corrosion resistance is reduced, the core indicators are excellent, making it particularly suitable for parts with stringent requirements for fatigue and impact resistance.

[0216] Example 6:

[0217] This embodiment aims to verify the feasibility of eliminating the retarding component in situations where long open times or low-temperature construction are not required, in order to simplify the formulation and reduce costs.

[0218] Material formula (parts by weight):

[0219] Sulfoaluminate cement: 38

[0220] Ordinary Portland cement: 18

[0221] Silica fume: 7

[0222] Metakaolin: 5

[0223] Quartz sand: 52

[0224] Magnesium oxide expanding agent: 2.2

[0225] Calcium sulfate expander: 2.2

[0226] Acrylic ester adhesive powder: 1.2% (as a percentage of the mass of the cementitious material; the total mass of the cementitious material is 68 parts, and the actual amount used is 0.82 parts).

[0227] Polycarboxylate superplasticizer: 1.3 (Because the retarder is removed, the loss of fluidity is accelerated, so the dosage of superplasticizer is increased to ensure workability)

[0228] Basalt fiber: 1.1

[0229] Water-to-binder ratio: 0.35

[0230] Preparation process:

[0231] S1. Dry material premixing: Add sulfoaluminate cement, ordinary silicate cement, silica fume, metakaolin, quartz sand, magnesium oxide expansion agent, and ettringite expansion agent into a forced mixer and mix at a speed of 600 r / min for 4 minutes.

[0232] S2. Dry-wet mixing: Pre-dissolve the water-reducing agent and acrylic powder in water, and slowly add them to the dry mix. Since there is no retarder, the loss of fluidity is accelerated, so the stirring time should be shortened to 5 minutes. Proceed to the next step immediately after the fluidity is quickly measured to be 220±10mm.

[0233] S3. Fiber dispersion: Basalt fiber is sprinkled in twice, and stirred at 800r / min for 1 minute twice to ensure uniform fiber dispersion.

[0234] S4. Settling and aging: The settling time is shortened to 8 minutes, and it should be used for paving as soon as possible.

[0235] Construction steps:

[0236] Step 1: Surface preparation: Machine mill the surface to an average roughness Ra≥0.5mm, or roughen it to form a groove with a depth of 1~3mm; after rinsing with a high-pressure water gun (≥20MPa), apply an interface agent.

[0237] Step 2: Material Mixing and Temperature Control: Mix on-site, controlling the outlet temperature to ≤35℃. When the ambient temperature is <10℃, add calcium nitrate early strength agent (0.5%~1.5%); when the ambient temperature is >30℃, circulate cooling water through the mixer to control the material temperature to ≤35℃.

[0238] Step 3: Layered Paving and Vibration: Each layer should be 40-80mm thick, with an interval of ≤45 minutes between layers; spray a neat cement slurry with a water-cement ratio of 0.3-0.4 onto the interlayer interface. Use a plate vibrator for compaction, controlling the vibration time according to the layer thickness (30-50mm: 1.5-2.0min / m²; 50-80mm: 2.0-3.0min / m²). This plan has a short open time (approximately 20-25 minutes), requiring close coordination between each process.

[0239] Step 4: Surface leveling and curing: After laser leveling, immediately cover with polyethylene film for curing for no less than 72 hours, followed by water curing for no less than 7 days.

[0240] Performance test results:

[0241] Mechanical properties: Early strength: The 1-day compressive strength reaches 28.5 MPa, which is much higher than the 21.0 MPa of Example 1, meeting the requirements for rapid load-bearing. The 28-day compressive strength is 57.0 MPa, and the bond strength is 5.1 MPa, which is comparable to Example 1.

[0242] Durability: Impermeability grade P15, freeze-thaw cycle resistance F305 (mass loss rate 0.4%, relative dynamic elastic modulus retention rate 86%).

[0243] Volume stability: 28-day expansion rate 0.038%.

[0244] Chemical corrosion resistance: The strength loss rate after immersion in 5% sodium sulfate solution for 180 days is 6.3%.

[0245] Construction openness: The opening time is 22 minutes, and the time interval between initial setting and final setting is shortened, which is conducive to opening to light traffic within 4 hours.

[0246] Results: After removing the retarder, the early strength of the material increased by about 15%. Although the open time was shortened, all durability and mechanical properties still met the requirements, providing an effective solution for rapid construction scenarios.

[0247] Example 7:

[0248] This embodiment aims to verify a solution that uses corundum to partially replace quartz sand to significantly improve the wear resistance of repair materials. It is particularly suitable for areas with extremely severe wear, such as airport runway ends and curves.

[0249] Material formula (parts by weight):

[0250] Sulfoaluminate cement: 40

[0251] Ordinary Portland cement: 15

[0252] Silica fume: 9

[0253] Metakaolin: 4

[0254] Quartz sand: 25

[0255] Emery (16-80 mesh): 25

[0256] Magnesium oxide expanding agent: 2

[0257] Calcium sulfate expander: 2

[0258] Acrylic ester adhesive powder: 2.5% (as a percentage of the total mass of the cementitious material, which is 68 parts in total, with an actual usage of 1.7 parts).

[0259] Polycarboxylate superplasticizer: 1.4 (Due to the rough surface of the corundum, the amount of superplasticizer needs to be increased to maintain fluidity)

[0260] Basalt fiber: 1.3

[0261] Sodium gluconate: 0.1

[0262] Water-to-binder ratio: 0.36

[0263] Preparation process:

[0264] S1. Dry material premixing: Add sulfoaluminate cement, ordinary silicate cement, silica fume, metakaolin, mixed aggregate of quartz sand and corundum, magnesium oxide expansion agent, and ettringite expansion agent into the mixer and mix at 700 r / min for 4 minutes to ensure uniform mixing.

[0265] S2. Dry and wet mixing: Dissolve the water-reducing agent, retarder, and acrylic ester powder in water, slowly add them to the dry mixture, and stir for 6 minutes until the fluidity of the mixture reaches 220±10mm.

[0266] S3. Fiber dispersion: Basalt fiber is sprinkled in twice, and stirred at 800r / min for 1 minute twice to ensure uniform fiber dispersion.

[0267] S4. Let the mixture stand for 12 minutes in a sealed container.

[0268] Construction steps:

[0269] Step 1: Surface preparation: Machine mill the surface to an average roughness Ra≥0.5mm, or roughen it to form a groove with a depth of 1~3mm; after rinsing with a high-pressure water gun (≥20MPa), apply an interface agent.

[0270] Step 2: Material Mixing and Temperature Control: Mix on-site, controlling the outlet temperature to ≤35℃. When the ambient temperature is <10℃, add calcium nitrate early strength agent (0.5%~1.5%); when the ambient temperature is >30℃, circulate cooling water through the mixer to control the material temperature to ≤35℃.

[0271] Step 3: Layered spreading and vibration: Each layer is 40~80mm thick, with an interval of ≤45 minutes between layers; spray the interface between layers with a cement paste with a water-cement ratio of 0.3~0.4. Use a plate vibrator for compaction, and control the compaction time according to the layer thickness (30~50mm: 1.5~2.0min / m²; 50~80mm: 2.0~3.0min / m²).

[0272] Step 4: Surface leveling and curing: After laser leveling, immediately cover with polyethylene film for curing for no less than 72 hours, followed by water curing for no less than 7 days.

[0273] Performance test results:

[0274] Mechanical properties: 28-day compressive strength 61.5 MPa, bond strength 5.3 MPa.

[0275] Durability: Impermeability grade P16, freeze-thaw cycle resistance F320 (mass loss rate 0.3%, relative dynamic elastic modulus retention rate 88%).

[0276] Volume stability: 28-day expansion rate 0.042%.

[0277] Chemical corrosion resistance: The strength loss rate is 5.8% after immersion in 5% sodium sulfate solution for 180 days.

[0278] Construction adaptability: Opening time 41 minutes.

[0279] Results: After using corundum aggregate, the wear resistance of the material was improved by more than 50%, while the core mechanical and durability indicators showed no decline, proving its unique advantages in ultra-high wear areas.

[0280] The performance data from the above seven embodiments shows that:

[0281] 1. Full compliance: The core performance indicators (mechanical properties, durability, volume stability, and chemical corrosion resistance) of all embodiments fully meet or exceed the preset technical requirements.

[0282] 2. Robust formulation: Regardless of end-value conditions or the substitution of key components, the technical solution of this invention exhibits excellent stability and reliability.

[0283] 3. Adjustable performance: By adjusting the ratio or components, specific properties (such as early strength, wear resistance, and toughness) can be enhanced in a targeted manner while meeting basic requirements, which reflects the design essence of the "open formulation" of this invention and its strong engineering adaptability.

[0284] The technical solutions disclosed and proposed in this invention can be implemented by those skilled in the art by appropriately modifying the conditions and routes, etc. Although the methods and preparation techniques of this invention have been described through preferred embodiments, those skilled in the art can obviously modify or recombine the methods and technical routes described herein without departing from the content, spirit, and scope of this invention to achieve the final preparation technique. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included within the spirit, scope, and content of this invention.

Claims

1. An environmentally friendly, high-performance concrete pavement repair material, characterized in that, The components and their mass fractions are as follows: 30~50 sulfoaluminate cement Ordinary Portland cement 10~20 Silica fume 5~10 Metakaolin 3~8 Aggregate 40~60 Magnesium oxide expanding agent 1.5~3 Calcium sulfate expander 1.5~3 Polycarboxylate superplasticizer 0.5~1.5 Fiber 0.8~1.5 Sodium gluconate retarder 0~0.15 The polymer powder is added at a rate of 1% to 3% of the total mass of the cementitious material. Water, the amount of which meets the water-to-binder ratio of 0.30~0.38; The cementing material is the sum of the masses of sulfoaluminate cement, ordinary silicate cement, silica fume, and metakaolin.

2. The environmentally friendly high-performance concrete pavement repair material as described in claim 1, characterized in that, The sum of the masses of the sulfoaluminate cement and the ordinary silicate cement accounts for 50% to 70% of the total mass of the cementitious materials.

3. The environmentally friendly high-performance concrete pavement repair material as described in claim 1, characterized in that, The polymer powder is acrylate powder or ethylene-vinyl acetate powder.

4. The environmentally friendly high-performance concrete pavement repair material as described in claim 1, characterized in that, The fiber is selected from at least one of basalt fiber, steel fiber, carbon fiber, amorphous alloy fiber or polymer fiber; wherein the basalt fiber has a length of 6~12mm, the steel fiber has an aspect ratio of 50~80, the carbon fiber has an aspect ratio of 600~1200, the amorphous alloy fiber has an aspect ratio of 300~800, and the polymer fiber has an aspect ratio of 200~500.

5. The environmentally friendly high-performance concrete pavement repair material as described in claim 1, characterized in that, The sodium gluconate retarder has a mass fraction of 0, and the polycarboxylate superplasticizer has a dosage of 1.2% to 1.5% of the total mass of the cementitious material.

6. The environmentally friendly high-performance concrete pavement repair material as described in claim 1, characterized in that, The aggregate is one or a mixture of two of the following: quartz sand and corundum, with a particle size range of 0.15~2.36mm.

7. The method for preparing the environmentally friendly high-performance concrete pavement repair material according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Dry material premixing: Add sulfoaluminate cement, ordinary silicate cement, silica fume, metakaolin, aggregate, magnesium oxide expansion agent, and ettringite expansion agent into a mixer and mix at a speed of 600~800r / min for 3-4 minutes. S2. Dry and wet mixing: Dissolve the water-reducing agent, polymer powder and retarder in water, then add the solution to the dry mixture and stir for 5 to 7 minutes until the fluidity of the mixture reaches 220±10mm. S3. Fiber dispersion: Add the fiber in two batches and stir at 600~800 r / min for 1-2 minutes to ensure uniform fiber dispersion; when the fiber is steel fiber, carbon fiber, amorphous alloy fiber or polymer fiber, increase the stirring speed to 1000 r / min. S4. Let the mixture stand for 10-15 minutes in a sealed container.

8. A construction method using the environmentally friendly high-performance concrete pavement repair material prepared according to claim 7, characterized in that, Includes the following steps: S1. Surface preparation: The concrete surface is mechanically milled or roughened to make its average roughness Ra≥0.5mm, then cleaned and coated with interface agent. S2. Material mixing and temperature control: Mix the repair material on site and control the outlet temperature to ≤35℃; when the ambient temperature is <10℃, add 0.5%~1.5% of the cementitious material mass as an early strength agent; when the ambient temperature is >30℃, circulate cooling water through the mixer to control the material temperature. S3. Layered spreading and vibration: Spread the repair material in layers, each layer being 40-80mm thick, with an interval of no more than 45 minutes between layers. Apply a neat cement paste with a water-cement ratio of 0.3 to 0.4 to the interlayer interface; use a plate vibrator for compaction, and control the compaction time to 1.5 to 3.0 min / m² depending on the layer thickness; S4. Curing: After spreading and leveling, immediately cover with a water-retaining film for curing for no less than 72 hours, and then spray water for curing for no less than 7 days.

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