A method for rapid pavement repair using crushed stone grouting concrete.

Abstract

This invention relates to a crushed stone grouting concrete for rapid pavement repair and its construction method. The grouting material is composed of a new type of environmentally friendly A and B component dual grout, which has good fluidity, permeability and high mechanical properties, excellent volume stability and crack resistance, etc. The crushed stone grouting concrete construction process is simple, the construction cost is low and the construction efficiency is high, and the overall pavement structural repair can be completed within 2 hours.

Description

Technical Field

[0001] This invention belongs to the field of rapid repair technology for concrete pavement structures, specifically relating to a crushed stone grouting concrete method for rapid pavement repair and its construction method. Background Technology

[0002] Cement concrete pavements have advantages such as high rigidity, high strength, good stability, and no ruts, and are widely used in my country's civil aviation airports and high-speed heavy-load transportation sectors. Currently, the main rapid repair methods for cement concrete pavement structures include precast assembly rapid repair technology and cast-in-place rapid repair technology. Precast assembly technology requires large hoisting equipment and is prone to defects such as misalignment and holes in the bottom of the slab; cast-in-place repair technology involves a large volume of concrete pouring and has high requirements for repair materials and construction.

[0003] Patent application number 202110969723.2 discloses a method for the overall repair of airport pavement, in which the leveling device can also serve as a grouting port, enabling rapid replacement of damaged pavement slabs. Patent CN 114293427 B discloses a method for setting up a prefabricated airport pavement system, which improves the load transfer capacity between panels through joint structure design, and achieves precise control of the flatness of prefabricated slabs through an automatic adjustment device. However, the time required to open traffic for both prefabricated hoisting and integral cast-in-place rapid repair technologies is usually no less than 6 hours, which is difficult to meet the rapid repair requirements during special periods such as disaster relief and wartime repairs.

[0004] The Technical Specification for Grouting-Type Semi-Flexible Pavement of Urban Roads (T / CECS1016-2022) proposes a grouting-type semi-flexible pavement layer. This technology uses large-void asphalt concrete as the matrix and injects cement-based grout to combine the advantages of strong bearing capacity of cement pavement and good flexibility of asphalt concrete, thereby improving the rutting resistance of asphalt concrete pavement structure. The technical indicators of asphalt concrete grout are also given. This type of grout has good fluidity and permeability, but low strength, poor bonding performance, and high drying shrinkage and free bleeding rate.

[0005] Patent CN 108774044 A discloses a grouting material for the steel reinforcement anchor connection of PC components based on magnesium phosphate material. The initial fluidity is 270±10mm, the setting time is 20~60min, and the compressive strength can reach more than 40MPa after 2.5h of grouting. This type of grouting material has good comprehensive performance, but the viscosity is high and the fluidity and permeability are poor. It is suitable for grouting construction of metal pipes, corrugated pipes and other pipelines, but it cannot effectively fill crushed stone and is not suitable for grouting graded crushed stone with small and many voids. Summary of the Invention

[0006] The purpose of this invention is to provide a crushed stone grouting material for rapid pavement repair. This material has good permeability and fluidity, high mechanical properties and bonding strength, and its volume stability and crack resistance are superior to conventional grouting materials. It also has good anti-segregation and anti-bleeding properties.

[0007] The second objective of this invention is to provide a method for preparing and constructing crushed stone grouting concrete.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A type of crushed stone grouting concrete for rapid repair of airport pavement, wherein the grouting material of the concrete is phosphate cement mortar, composed of component A and component B, both of which are low-viscosity slurries, prepared in advance according to a specified ratio and sealed in packaging. Component A comprises the following raw materials in parts by weight:

[0010] 100 parts phosphate, 10-60 parts fly ash, 5-90 parts ultrafine powder, 0.05-1 part cellulose ether, 15-100 parts quartz sand, and 10-40 parts water.

[0011] The phosphates mentioned include one or more of ammonium dihydrogen phosphate, potassium dihydrogen phosphate, sodium dihydrogen phosphate, dipotassium phosphate, and disodium phosphate.

[0012] Preferably, the phosphate is composed of ammonium dihydrogen phosphate, potassium dihydrogen phosphate, and dipotassium phosphate;

[0013] More preferably, the phosphate is composed of 4 parts ammonium dihydrogen phosphate, 1 part potassium dihydrogen phosphate and 0.5 parts dipotassium phosphate.

[0014] The fly ash is either Grade I or Grade II, with Grade I being preferred.

[0015] The ultrafine powder is composed of silica powder and ultrafine fly ash in a weight ratio of 1:(1-3), and the silica powder has a fineness greater than 1000 mesh.

[0016] The cellulose ether mentioned is hydroxypropyl methylcellulose ether.

[0017] The quartz sand has a purity greater than 97%, and the main particle size range is 0.075mm to 0.15mm, of which particles with a size of 0.15mm to 0.3mm account for less than 5%, and particles with a size smaller than 0.075mm account for less than 5%.

[0018] Component B comprises the following raw materials in parts by weight:

[0019] Mineral powder: 100-500 parts; ultrafine powder: 30-120 parts; water-reducing agent: 0.1-5 parts; defoamer: 0.1-3 parts; air-entraining agent: 0.1-1 parts; quartz sand: 20-300 parts; water: 20-100 parts.

[0020] The mineral powder includes one or more of metal oxides, brucite powder, and borosilicate powder, preferably a mixture of the three, wherein the metal oxide is calcined magnesium oxide, and the brucite powder and borosilicate powder are natural mineral powders. The preparation method is as follows:

[0021] Blocky reburned magnesium oxide, brucite and borosilicate are mixed in a weight ratio of (0-10):(1-10):(0.1-5), with none of them being 0. Triethanolamine and organosilane are used as grinding aids for grinding until 100-300 mesh powder is obtained.

[0022] The water-reducing agent is a combination of one or more of polycarboxylate superplasticizers, melamine superplasticizers, and naphthalene-based superplasticizers. Preferably, the water-reducing agent is a composite of polycarboxylate superplasticizer and melamine superplasticizer.

[0023] More preferably, the water-reducing agent is a mixture of ester-based polycarboxylate water-reducing agent and melamine-based water-reducing agent in a mass ratio of 1:2.

[0024] The defoamer is one or more of polyether defoamers and silicone defoamers, and more preferably, it is a modified polyether defoamer.

[0025] The air-entraining agent is one or more of the following: saponins, fatty alcohols, rosin resins, and alkylbenzene sulfonates.

[0026] Preferably, the air-entraining agent is a saponin, with triterpenoid saponins as the main component.

[0027] The types of quartz sand and ultrafine powder in component B are the same as those in component A.

[0028] This invention provides a method for preparing and using the grouting material. The method for preparing the A and B component dual grout is as follows:

[0029] 1) Preparation method of component A slurry: First, dry mix all raw materials except water evenly, then add all water and continue stirring until a uniform, low-viscosity, and well-flowing slurry is obtained. Finally, pour it into a plastic bucket and seal it for storage.

[0030] 2) Preparation method of component B slurry: First, divide the water into two equal parts, and put the water-reducing agent, defoamer and air-entraining agent into one part of the water, stir evenly to obtain a solution for later use; then mix the remaining powder materials evenly, pour them into the obtained solution and stir for 1 to 2 minutes, then add the remaining part of water, continue stirring for 2 to 3 minutes to obtain component B, and finally seal and store component B in a plastic bucket.

[0031] The usage method for the A and B component dual-slurry is as follows:

[0032] 1) Before use, components A and B should be stirred to restore their good fluidity to avoid water seepage or peeling at the bottom if left to stand for a long time.

[0033] 2) Component A and Component B are simultaneously pumped into the grouting equipment in proportion, and then the mixed slurry is discharged from the grouting equipment to the grouting pipe opening. The mass ratio of Component A to Component B is 1:2. The proportion of the two components pumped into the grouting equipment is adjusted by the pipe diameter of the Component A and Component B conveying pipes.

[0034] This invention also provides a construction method for crushed stone grouting concrete, comprising the following steps:

[0035] Step 1: Backfill with graded crushed stone. Graded crushed stone is used to backfill the pavement foundation. When the pit depth is ≤50cm, backfill to a depth of 5-15cm below the pavement surface. When the pit depth is >50cm, backfill in layers and compact to a depth of 50cm below the pavement surface, then lay a layer of geotextile or geomembrane, and continue backfilling with graded crushed stone to a depth of 5-15cm below the pavement surface. The surface of the crushed stone is then spread and leveled.

[0036] Step two, pre-embed grouting pipes. Connect the grouting pipe ends to the longitudinal grouting perforated pipes, and use positive and negative threaded connecting sleeves to connect the longitudinal and transverse grouting perforated pipes, forming a crisscrossing longitudinal and transverse grouting pipe network laid flat, with the grouting pipe openings slightly higher than the pavement surface. The spacing between two adjacent longitudinal and transverse grouting perforated pipes should be 30-80cm. After completing the pre-embedding of grouting pipes, continue backfilling with graded crushed stone, and scrape it flat, ensuring the crushed stone surface is flush with the original pavement surface.

[0037] Step 3: Inject grouting material. Prepare the grouting concrete as described above, connect the grouting pipe head to the grouting equipment, and carry out the grouting operation. When grouting material overflows from the surface of the crushed stone, control the grouting efficiency appropriately until the grouting material is flush with the original pavement surface. Then, stop grouting and remove the sleeve in the grouting pipe head.

[0038] Step 4: Surface treatment. Use a clean trowel to continuously work the surface, eliminating air bubbles and protrusions. In areas where the grouting material layer is too thick, a small amount of fine stones can be pressed in, and the surface should continue to be smoothed. The surface should be smoothed at least 3 times.

[0039] Step 5: Open to traffic. Use a 3-meter straightedge to test the flatness of the crushed stone grouting concrete surface, and use a rebound hammer to test the compressive strength of the concrete. Once the strength meets the requirements, the road can be opened to traffic.

[0040] The geotextile or geomembrane can serve as an isolation layer to effectively prevent the grouting material from continuously seeping down and can also mitigate the impact of reflective cracks or uneven settlement of the base on the crushed stone grouting concrete.

[0041] Furthermore, the maximum particle size of the graded crushed stone is 37.5 mm, the mud content should be less than 0.5%, and it should not contain mud lumps.

[0042] Furthermore, the grouting pipe head consists of a sleeve, a straight pipe, and an elbow. The grouting perforated pipe and the straight pipe are hollow threaded thick-walled steel pipes. Grout outlets are set at intervals in the horizontal and vertical directions on the grouting perforated pipe. The distance between two adjacent grout outlets should not be greater than 15cm. Preferably, the spacing between the longitudinal and transverse grouting perforated pipes is 30-50cm.

[0043] Furthermore, the conveying efficiency of each grouting device is greater than 5m. 3 / h, a flow meter and ball valve switch are installed on the delivery pipe to count the amount of grouting material used and to adjust and control the grouting flow rate.

[0044] Furthermore, the grouting operation can be carried out simultaneously with the backfilling of graded crushed stone above the grouting pipe.

[0045] The present invention provides a method for rapid repair of airport pavement using crushed stone grouting concrete and its construction, which has the following advantages and effects:

[0046] 1. The crushed stone grouting material proposed in this invention is a two-component grout (A and B components), which can be stored for a long time. When using it, the two components are simply mixed. Construction is simple, and there is no dry mixing of powder materials on the construction site, which can effectively avoid dust. The mixed grout stays in the grouting equipment for a very short time, which can effectively prevent the material from hardening and damaging the grouting equipment, and will not cause unnecessary waste due to the material not being used up in time. It is a new type of environmentally friendly grouting material.

[0047] 2. Crushed stone grouting material has excellent comprehensive performance, including its own mechanical properties, bonding performance, volume stability performance, and crack resistance performance. Its initial setting time can be adjusted on site, and it has good fluidity. The fluidity test using the inverted cone method is less than 30 seconds, and the fluidity loss over time is small. It can maintain good fluidity before initial setting. The grouting material has strong bonding ability and can bond with crushed stone and metal grouting pipes to form a whole. The strength of crushed stone grouting concrete can reach more than 20MPa in 1 hour, more than 40MPa in 7 days, and more than 5.0MPa in 7 days, which can meet the requirements of conventional repairs. Its volume stability is very good, shrinkage is minimal, no special curing is required, and its crack resistance performance is significantly better than that of repair materials formulated by conventional systems such as silicate cement, sulfoaluminate cement, and fluoroaluminate cement.

[0048] 3. The grouting pipes of the crushed stone grouting concrete are composed of crisscrossing hollow threaded thick-walled steel pipes. The longitudinal and transverse grouting pipes are connected into a whole by positive and negative threaded connecting sleeves. The grouting pipe network is embedded in the crushed stone concrete, which can play the role of steel mesh reinforcement and increase the bending and tensile resistance of the crushed stone grouting concrete. At the same time, the depth of the crushed stone grouting concrete structure can reach 50cm, which is significantly greater than the thickness of conventional cement concrete slabs. Therefore, the load-bearing capacity of this concrete structure can meet the relevant requirements of airport pavement.

[0049] 4. The construction process of crushed stone grouting concrete is simple, requiring no large machinery or a large amount of manpower. It has low construction costs and high construction efficiency, and can complete the overall structural repair of the airport pavement in a very short time. The total time from construction to opening to traffic can be controlled within 2 hours.

[0050] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0051] Figure 1 This is a cross-sectional schematic diagram of the graded crushed stone grouting concrete in this invention.

[0052] Figure 2 This is a schematic diagram of the grouting pipe structure in this invention;

[0053] Figure 3 This is a diagram showing the grouting pipeline layout in this invention.

[0054] Among them: 1-Graded crushed stone base course, 2-Isolation layer, 3-Graded crushed stone grouting concrete, 4.1-Longitudinal grouting pipe, 4.2-Transverse grouting pipe, 4.3-Grouting pipe head, 4.1.1-Horizontal grout outlet, 4.1.2-Vertical grout outlet, 4.2.1-Positive and negative thread connecting sleeve, 4.3.1-Sleeve, 4.3.2-Straight pipe, 4.3.3-Elbow. Detailed Implementation

[0055] Example 1

[0056] A type of crushed stone grouting concrete for rapid repair of airport pavement, wherein the grouting material is composed of two components, A and B. Component A includes the following raw materials in parts by weight: 100 parts phosphate, 20 parts fly ash, 21 parts ultrafine powder, 0.15 parts cellulose ether, 34 parts quartz sand, and 19 parts water; Component B includes the following raw materials in parts by weight: 220 parts mineral stone powder, 65 parts ultrafine powder, 1 part water-reducing agent, 0.3 parts defoamer, 0.15 parts air-entraining agent, 57 parts quartz sand, and 45 parts water.

[0057] The phosphate is composed of 4 parts ammonium dihydrogen phosphate, 1 part potassium dihydrogen phosphate, and 0.5 parts dipotassium phosphate; the fly ash is grade I ash; the ultrafine powder is composed of silica powder and ultrafine fly ash in a weight ratio of 1:2.5, with the silica powder having a fineness greater than 1250 mesh; the cellulose ether is hydroxypropyl methylcellulose ether with a viscosity of 200,000; the water-reducing agent is a mixture of ester-based polycarboxylate water-reducing agent and melamine-based water-reducing agent in a mass ratio of 1:2; the defoamer is a polyether-based defoamer; the air-entraining agent is a saponin, with triterpenoid saponins as the main component. The quartz sand has a purity greater than 97%, with the main particle size range being 0.075 mm to 0.15 mm, of which particles between 0.15 mm and 0.3 mm account for less than 5%, and particles smaller than 0.075 mm account for less than 5%; the water is tap water.

[0058] The mineral powders mentioned are metal oxides, brucite powder, and borosilicate powder. The metal oxides are reburned magnesium oxide, and the brucite and borosilicate powders are natural mineral powders.

[0059] The preparation method is as follows: blocky reburned magnesium oxide, brucite and borosilicate are mixed in a weight ratio of 1:3:0.5, and then ground with triethanolamine and organosilane as grinding aids to obtain mineral powder with a fineness of about 150 mesh.

[0060] The preparation method of the A and B component dual slurry is as follows:

[0061] 1) Preparation method of component A: First, dry mix all raw materials except water evenly, then add all the water and continue stirring until a uniform, low-viscosity, and well-flowing slurry is obtained. Finally, pour it into a plastic bucket and seal it for storage.

[0062] 2) Preparation method of component B: First, divide the water into two equal parts, and put the water-reducing agent, defoamer and air-entraining agent into one part of the water, stir evenly to obtain a solution for later use; then mix the remaining powder materials evenly, pour them into the solution and stir for 1 to 2 minutes, then add the remaining part of water, continue stirring for 2 to 3 minutes to obtain component B, and finally seal and store component B in a plastic bucket.

[0063] The method of using the grouting material is as follows:

[0064] 1) Before use, components A and B should be stirred to restore their good fluidity to prevent water seepage or bottoming out due to prolonged standing.

[0065] 2) Component A and Component B are simultaneously injected into the grouting equipment in proportion, and then the mixed grout is discharged from the grouting equipment to the grouting pipe opening. The mass ratio of Component A to Component B is 1:2.

[0066] The mass ratio of the two components pumped into the grouting equipment is controlled by the diameter of the conveying pipes for components A and B.

[0067] The construction method for the crushed stone grouting concrete includes the following steps (see schematic diagram). Figures 1-3 ):

[0068] Step 1: Backfill with graded crushed stone. Graded crushed stone is used to backfill the roadbed. The pit depth is 80cm. First, backfill with 30cm of graded crushed stone 1 in layers and compact it. Lay the isolation layer 2, which is made of geotextile. Then continue to backfill with graded crushed stone to 10cm below the pavement surface and spread the crushed stone surface flat.

[0069] Step 2: Pre-embed grouting pipes. Connect the grouting pipe head 4.3 to the longitudinal grouting perforated pipe 4.1, and use a double-threaded connecting sleeve 4.2.1 to connect the longitudinal grouting perforated pipe 4.1 and the transverse grouting perforated pipe 4.2, forming a longitudinal and transverse crisscrossing grouting pipe network. The grouting pipe openings should be slightly higher than the pavement surface, and the spacing between two adjacent longitudinal and transverse grouting perforated pipes should be 50cm. After completing the pre-embedding of grouting pipes, continue backfilling with graded crushed stone and scrape it flat, ensuring the crushed stone surface is flush with the original pavement surface.

[0070] Step 3, Inject grouting material. Prepare the grouting material, connect the grouting equipment, and carry out the grouting operation. When grouting material overflows from the surface of the crushed stone, control the grouting efficiency appropriately until the grouting material is flush with the original pavement surface. Then stop grouting and remove the grouting sleeve 4.3.1.

[0071] Step 4: Surface treatment. Use a clean trowel to continuously work the surface, eliminating air bubbles and protrusions. In areas where the grouting material layer is too thick, a small amount of fine stones can be pressed in, and the surface should continue to be smoothed. The surface should be smoothed at least 3 times.

[0072] Step 5: Open to traffic. Use a 3-meter straightedge to test the flatness of the crushed stone grouting concrete surface, and use a rebound hammer to test the compressive strength of the concrete. Once the strength meets the requirements, the road can be opened to traffic.

[0073] The grouting pipe head 4.3 consists of a sleeve 4.3.1, a straight pipe 4.3.2, and an elbow 4.3.3. The grouting perforated pipe and the straight pipe are hollow threaded thick-walled steel pipes. A horizontal grout outlet 4.1.1 and a vertical grout outlet 4.1.2 are provided on the grouting perforated pipe. The distance between two adjacent horizontal grout outlets or two adjacent vertical grout outlets is 15cm.

[0074] The conveying efficiency of each grouting device is 5m. 3 The grouting pipe is equipped with a flow meter and ball valve switch at a rate of / h to monitor the amount of grouting material used and to regulate the grouting flow rate. The grouting operation is carried out simultaneously with the backfilling of graded crushed stone above the grouting pipe.

[0075] Example 2

[0076] A type of crushed stone grouting concrete for rapid repair of airport pavement, wherein the grouting material is composed of two components, A and B. Component A includes the following raw materials in parts by weight: 100 parts phosphate, 29 parts fly ash, 30 parts ultrafine powder, 0.25 parts cellulose ether, 40 parts quartz sand, and 22 parts water; Component B includes the following raw materials in parts by weight: 274 parts mineral stone powder, 64 parts ultrafine powder, 1.5 parts water-reducing agent, 0.5 parts defoamer, 0.17 parts air-entraining agent, 55 parts quartz sand, and 46 parts water.

[0077] The raw material requirements, preparation method, and application method of the grouting material are the same as in Example 1. The difference is:

[0078] The depth of the foundation pit for the crushed stone grouting concrete repair is 30cm. The construction steps for backfilling graded crushed stone are as follows: backfill graded crushed stone directly to a position 10cm below the pavement surface, and spread the crushed stone surface flat. After the pre-embedded grouting pipe process is completed, continue to backfill graded crushed stone and scrape it flat. The crushed stone surface is flush with the original pavement surface. The remaining construction steps are the same as in Example 1.

[0079] Example 3

[0080] A type of crushed stone grouting concrete for rapid repair of airport pavement, wherein the grouting material is composed of two components, A and B. Component A includes the following raw materials in parts by weight: 100 parts phosphate, 11 parts fly ash, 57 parts ultrafine powder, 0.3 parts cellulose ether, 46 parts quartz sand, and 23 parts water; Component B includes the following raw materials in parts by weight: 315 parts mineral stone powder, 58 parts ultrafine powder, 1.7 parts water-reducing agent, 0.6 parts defoamer, 0.2 parts air-entraining agent, 50 parts quartz sand, and 48 parts water.

[0081] The raw material requirements, preparation method, and usage method of the grouting material are the same as in Example 1.

[0082] Example 4

[0083] A type of crushed stone grouting concrete for rapid repair of airport pavement, wherein the grouting material is composed of two components, A and B. Component A includes the following raw materials in parts by weight: 100 parts phosphate, 56 parts fly ash, 27 parts ultrafine powder, 0.5 parts cellulose ether, 53 parts quartz sand, and 24 parts water; Component B includes the following raw materials in parts by weight: 370 parts mineral stone powder, 54 parts ultrafine powder, 2.1 parts water-reducing agent, 0.7 parts defoamer, 0.22 parts air-entraining agent, 48 parts quartz sand, and 46 parts water.

[0084] The raw material requirements, preparation method, and usage method of the grouting material are the same as in Example 1.

[0085] Example 5

[0086] A type of crushed stone grouting concrete for rapid repair of airport pavement, wherein the grouting material is composed of two components, A and B. Component A includes the following raw materials in parts by weight: 100 parts phosphate, 11 parts fly ash, 57 parts ultrafine powder, 0.3 parts cellulose ether, 46 parts quartz sand, and 23 parts water; Component B includes the following raw materials in parts by weight: 175 parts mineral stone powder, 72 parts ultrafine powder, 0.8 parts water-reducing agent, 0.25 parts defoamer, 0.13 parts air-entraining agent, 59 parts quartz sand, and 44 parts water.

[0087] The raw material requirements, preparation method, and usage method of the grouting material are the same as in Example 1.

[0088] Example 6

[0089] A crushed stone grouting concrete for rapid repair of airport pavement, wherein the phosphate is ammonium dihydrogen phosphate, and the mixing ratio, preparation method and application method of the grouting material are the same as in Example 1.

[0090] Example 7

[0091] A crushed stone grouting concrete for rapid repair of airport pavement, wherein the phosphate is potassium dihydrogen phosphate, and the mixing ratio, preparation method and application method of the grouting material are the same as in Example 1.

[0092] Example 8

[0093] A type of crushed stone grouting concrete for rapid repair of airport pavement, wherein the phosphate is composed of ammonium dihydrogen phosphate and potassium dihydrogen phosphate mixed in a weight ratio of 1:1, and the mixing ratio, preparation method and application method of the grouting material are the same as in Example 1.

[0094] Example 9

[0095] A type of crushed stone grouting concrete for rapid repair of airport pavement, wherein the phosphate is composed of ammonium dihydrogen phosphate, potassium dihydrogen phosphate and potassium monohydrogen phosphate mixed in a weight ratio of 2:1:0.3. The mixing ratio, preparation method and application method of the grouting material are the same as in Example 1.

[0096] Example 10

[0097] A type of crushed stone grouting concrete for rapid repair of airport pavement, wherein the phosphate is composed of ammonium dihydrogen phosphate, potassium dihydrogen phosphate and potassium monohydrogen phosphate mixed in a weight ratio of 3:1:0.4. The mixing ratio, preparation method and application method of the grouting material are the same as in Example 1.

[0098] Example 11

[0099] A type of crushed stone grouting concrete for rapid repair of airport pavement, wherein the phosphate is composed of ammonium dihydrogen phosphate and potassium dihydrogen phosphate mixed in a weight ratio of 4:1, and the mixing ratio, preparation method and application method of the grouting material are the same as in Example 1.

[0100] Example 12

[0101] A type of crushed stone grouting concrete for rapid repair of airport pavement, wherein the mineral stone powder is composed of calcined magnesium oxide, brucite powder and borosilicate powder, with a weight ratio of calcined magnesium oxide, brucite powder and borosilicate powder of 1:2:0.4. The remaining raw materials and preparation methods are the same as in Example 1, and the on-site application method is the same as in Example 2.

[0102] Example 13

[0103] A type of crushed stone grouting concrete for rapid repair of airport pavement, wherein the mineral stone powder is composed of calcined magnesium oxide, brucite powder and borosilicate powder, with a weight ratio of calcined magnesium oxide, brucite powder and borosilicate powder of 1:1:0.3. The remaining raw materials and preparation methods are the same as in Example 1, and the on-site application method is the same as in Example 2.

[0104] Example 14

[0105] A type of crushed stone grouting concrete for rapid repair of airport pavement, wherein the mineral stone powder is composed of calcined magnesium oxide, brucite powder and borosilicate powder, with a weight ratio of calcined magnesium oxide, brucite powder and borosilicate powder of 3:1:0.5. The remaining raw materials and preparation methods are the same as in Example 1, and the on-site application method is the same as in Example 2.

[0106] Example 15

[0107] A type of crushed stone grouting concrete for rapid repair of airport pavement, wherein the mineral stone powder is a mixture of magnesia powder and borosilicate powder in a weight ratio of 1:0.2, the remaining raw materials and preparation methods are the same as in Example 1, and the on-site application method is the same as in Example 2.

[0108] Example 16

[0109] A type of crushed stone grouting concrete for rapid repair of airport pavement, wherein the grouting material is prepared in the same way as in Example 1, with components A and B prepared separately, sealed in plastic buckets and stored for 3 months before use, and the usage and construction methods are the same as in Example 1.

[0110] Comparative Example 1

[0111] A type of crushed stone grouting concrete for rapid repair of airport pavement, wherein the grouting material is sulfoaluminate cement mortar. This grouting material is an improvement on a high-performance self-compacting concrete and its preparation method as described in patent number 202210557220.9, and includes the following raw materials by mass fraction: 85-110 parts of sulfoaluminate cement, 8-12 parts of fly ash, 7-15 parts of ultrafine fly ash, 0.3-0.6 parts of water-reducing agent, 0.02-0.06 parts of early-strength agent, 0.06-0.3 parts of retarder, 0.05-0.1 parts of stabilizer, 0.1-0.3 parts of defoamer, 20-50 parts of quartz sand, and 30-48 parts of water. The sulfoaluminate cement is composed of 80 parts of high-belite sulfoaluminate cement, 15 parts of anhydrous calcium sulfoaluminate clinker, and 5 parts of anhydrous gypsum.

[0112] The preferred sulfoaluminate cement mortar grouting material comprises the following raw materials in parts by weight: 100 parts sulfoaluminate cement, 10 parts fly ash, 10 parts ultrafine fly ash, 0.48 parts water-reducing agent, 0.048 parts early-strength agent, 0.1 parts retarder, 0.072 parts stabilizer, 0.18 parts defoamer, 30 parts quartz sand, and 38 parts water. Among these, the 100 parts sulfoaluminate cement consists of 80 parts high-belite sulfoaluminate cement, 15 parts anhydrous calcium sulfoaluminate clinker, and 5 parts anhydrous gypsum.

[0113] The preparation and use method of the sulfoaluminate cement mortar grouting material is as follows: All raw materials except water are thoroughly mixed and sealed in a woven bag or metal can with an inner bag to obtain the sulfoaluminate cement mortar product. When using, weigh a certain amount of the product and a corresponding proportion of water, and pour them separately into a high-speed mixing device. To ensure that there is no powder flocculation or agglomeration during mixing, 2 / 3 of the water can be added first. After the powder is basically dispersed evenly, the remaining water is added and mixing continues until the slurry has good fluidity. Each mixing time is 1-2 minutes.

[0114] The construction steps for the sulfoaluminate cement mortar grouting material are the same as in Example 1.

[0115] Comparative Example 2

[0116] A type of crushed stone grouting concrete for rapid repair of airport pavement, wherein the grouting material is composed of two grouts, A and B, and the material ratio and preparation method of components A and B are the same as in Example 1.

[0117] The construction steps in this case differ from those in Example 1 in that: no horizontal grouting pipes are installed, and the spacing of the longitudinal grouting pipes is increased to 1m; the remaining construction steps are the same as in Example 1.

[0118] The A component of the grouting material proposed in this invention has good storage performance. However, when the water-reducing agent in the B component is a single polycarboxylate water-reducing agent, it is prone to bleeding and bottom caking after standing. When a single melamine-based or naphthalene-based water-reducing agent is used, the flowability of the B component is poor. When a combination of naphthalene-based and polycarboxylate water-reducing agents is used, the flowability is still poor. When a combination of melamine-based and polycarboxylate water-reducing agents is used, the effect is better. Among them, the effect of using ester-based polycarboxylate water-reducing agents and melamine is better. Furthermore, by compounding air-entraining agents, defoamers, and ultrafine powders, and by continuously optimizing the formulation of mineral stone powder, the bottom caking phenomenon of the B component during storage is solved.

[0119] To further evaluate the performance of grouting materials and the construction effect of graded crushed stone grouting concrete, the following experimental methods were adopted to systematically compare and study the performance of each embodiment.

[0120] 1. Test the initial fluidity of the grouting material and the fluidity loss over time after 10 minutes, setting time, and penetration depth. The penetration depth test uses a transparent acrylic tube with a diameter of 10cm and a height of more than 50cm. First, seal the bottom of the acrylic tube with a plastic film, then fill it with 50cm of gravel, and then pour in the grouting material. Observe the penetration of the grouting material and record its final penetration depth.

[0121] 2. Test the 1-hour and 7-day flexural and compressive strength and 28-day shrinkage rate of the crushed stone grouting concrete. When molding the crushed stone grouting concrete, first fill the mold with crushed stone, then pour in the grouting material, allowing the grouting material to penetrate into the pores between the crushed stones and finally fill the gaps between the crushed stones. Then smooth the surface to make the surface of the test block flat.

[0122] 3. Drill core samples on site, observe the density and appearance of the core, and test the 7-day splitting tensile strength of the core. The test results are shown in Table 1.

[0123] As shown in Table 1, compared with the sulfoaluminate system grouting material, the phosphate grouting material has better fluidity and permeability. Under the condition that the initial setting time is not much different, the fluidity of Comparative Example 1 decreases significantly at 10 min, and the final penetration depth of Comparative Example 1 is also lower. This may also be due to the greater loss of fluidity over time. In addition, the shrinkage rate of Comparative Example 1 is slightly larger, and its flexural strength is significantly lower than that of other examples. This may be because the grout content of the grouting material is higher, and conventional system grouting materials have high requirements for moisture retention and curing, and are prone to internal micro-cracks.

[0124] Comparing Examples 1-15, it can be seen that the dual-slurry grouting material has good fluidity and permeability, almost no shrinkage, and high flexural and compressive strength, which can meet general repair requirements. At the same time, the phosphate and mineral powder are formulated using a ternary combination technology, which not only prolongs the setting time of the grouting material and improves its fluidity and permeability, but also increases its early strength, achieving excellent results. Example 16 shows that the performance of the dual-slurry grouting material did not change significantly after 3 months of storage, indicating that the dual-slurry grouting material has good storage performance. This overturns the characteristics of conventional cement-based materials and has obvious advantages, which can provide technical reference for the formulation of inorganic anti-corrosion coatings or inorganic rebar adhesives.

[0125] In addition, the grouting network composed of crisscrossing hollow threaded thick-walled steel pipes proposed in this invention not only improves the grouting effect of the grouting material, but also effectively strengthens the structure of the crushed stone grouting concrete, further improving the integrity and load-bearing capacity of the structure, achieving remarkable results.

[0126] Table 1

[0127]

[0128]

[0129] Note: ① The fluidity and shrinkage tests shall be conducted in accordance with the T0508-2005 Test Method for Flowability of Cement Paste (Inverted Cone Method) and the T0511-2005 Test Method for Dry Shrinkage of Cement Mortar in the "Test Procedures for Cement and Cement Concrete in Highway Engineering" (JTG 3420-2020), respectively.

[0130] ② The test method for initial setting time shall refer to the "Standard for Test Methods of Basic Performance of Building Mortar" (JGJ / T 70-2009);

[0131] ③ The flexural and compressive strength and splitting tensile strength of concrete were tested in accordance with the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GB / T 50081-2019). The concrete flexural strength test block was 100mm×100mm×400mm in size, the concrete compressive strength test block was 150mm×150mm×150mm in size, and the splitting tensile strength test specimen was a φ150mm cylinder.

[0132] ④ In the core samples taken from the boreholes in Comparative Example 2, the core samples taken along the edge of the plate and in the middle area between the two grouting pipes showed signs of not being densely filled, while the core samples taken in the other cases appeared to be relatively dense; no cracks were found on the surface of any of the embodiments.

[0133] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A type of crushed stone grouting concrete for rapid pavement repair, characterized in that, The grouting material for the concrete consists of component A and component B. Both components are low-viscosity slurries, prepared in advance according to a specific ratio, and sealed separately. Component A includes the following raw materials in parts by weight: 100 parts phosphate, 10-60 parts fly ash, 5-90 parts ultrafine powder, 0.05-1 part cellulose ether, 15-100 parts quartz sand, and 10-40 parts water. Component B includes the following raw materials in parts by weight: 100-500 parts mineral powder, 30-120 parts ultrafine powder, 0.1-5 parts water-reducing agent, 0.1-3 parts defoamer, 0.1-1 part air-entraining agent, 20-300 parts quartz sand, and 20-100 parts water. The phosphate is composed of ammonium dihydrogen phosphate, potassium dihydrogen phosphate, and dipotassium phosphate; The mineral powder is a mixture of blocky reburned magnesium oxide, brucite and borosilicate in a weight ratio of (0~10):(1~10):(0.1~5), with none of them being 0. Triethanolamine and organosilane are used as grinding aids for grinding until a powder of 100 mesh to 300 mesh is obtained. The water-reducing agent is a composite of polycarboxylate water-reducing agent and melamine water-reducing agent.

2. The crushed stone grouting concrete for rapid pavement repair according to claim 1, characterized in that, The fly ash is either Grade I or Grade II fly ash; the ultrafine powder is composed of silica powder and ultrafine fly ash in a weight ratio of 1:(1~3), wherein the silica powder has a fineness greater than 1000 mesh; the quartz sand has a purity greater than 97%, and the main particle size range is 0.075mm~0.15mm, wherein the proportion of particles with a size of 0.15mm~0.3mm is less than 5%, and the proportion of particles with a size smaller than 0.075mm is less than 5%.

3. The crushed stone grouting concrete for rapid pavement repair according to claim 1, characterized in that, The defoamer is one or more of polyether defoamers and silicone defoamers, and the air-entraining agent is one or more of saponins, fatty alcohols, rosin resins, and alkylbenzene sulfonates.

4. The crushed stone grouting concrete for rapid pavement repair according to claim 1, characterized in that, The preparation method of the A and B component dual slurry is as follows: 1) Preparation method of component A: First, dry mix all raw materials except water evenly, then add all the water and continue stirring to obtain a uniform, low-viscosity, and well-flowing slurry. Finally, pour it into a plastic bucket and seal it for storage. 2) Preparation method of component B: First, divide the water into two equal parts, and put the water-reducing agent, defoamer and air-entraining agent into one part of the water, stir evenly to obtain a solution for later use; then mix the remaining powder materials evenly, pour them into the obtained solution and stir for 1~2 minutes, then add the remaining part of water, continue to stir for 2~3 minutes to obtain component B, and finally seal and store component B in a plastic bucket.

5. The crushed stone grouting concrete for rapid pavement repair according to claim 1, characterized in that, The method of using the grouting material is as follows: 1) Before use, components A and B should be stirred to restore their good fluidity to prevent water seepage or peeling from occurring during prolonged standing. 2) Component A and Component B are simultaneously pumped into the grouting equipment in proportion, and then the mixed slurry is discharged from the grouting equipment to the grouting pipe opening. The mass ratio of Component A to Component B is 1:

2. The proportion of the two components pumped into the grouting equipment is adjusted by the pipe diameter of the Component A and Component B conveying pipes.

6. A method for rapid repair of pavement using crushed stone grouting concrete as described in any one of claims 1-5, comprising the following steps: Step 1: Backfill with graded crushed stone; Use graded crushed stone to backfill the pavement foundation. When the pit depth is ≤50cm, backfill to a depth of 5~15cm below the pavement surface. When the pit depth is >50cm, backfill in layers and compact to a depth of 50cm below the pavement surface, lay a layer of geotextile or geomembrane, and then continue backfilling with graded crushed stone to a depth of 5~15cm below the pavement surface, and smooth the surface of the crushed stone. Step 2: Pre-embed grouting pipes; connect the grouting pipe ends to the longitudinal grouting perforated pipes, and use positive and negative threaded connecting sleeves to connect the longitudinal and transverse grouting perforated pipes to form a longitudinal and transverse grouting pipe network laid flat, with the grouting pipe openings slightly higher than the pavement surface. The spacing between two adjacent longitudinal grouting perforated pipes and two adjacent transverse grouting perforated pipes is 30~80cm; after completing the pre-embedding of grouting pipes, continue backfilling with graded crushed stone and scraping it flat, with the crushed stone surface flush with the original pavement surface; Step 3: Inject grouting material; Prepare the grouting concrete as described in any one of claims 1-5, connect the grouting pipe head to the grouting equipment, and carry out the grouting operation. When grouting material overflows from the surface of the crushed stone, control the grouting efficiency appropriately until the grouting material is flush with the original pavement surface, then stop the grouting and remove the sleeve in the grouting pipe head. Step 4, surface treatment; use a clean trowel to continuously work the surface, eliminating air bubbles and protrusions. In areas where the grouting material layer is too thick, a small amount of fine stones can be pressed in, and the surface should be continued to be smoothed. The surface should be smoothed at least 3 times. Step 5: Open to traffic; test the flatness of the crushed stone grouting concrete surface and test the compressive strength of the concrete. Once the strength meets the requirements, traffic can be opened.

7. The method for rapid pavement repair according to claim 6, characterized in that, The maximum particle size of the graded crushed stone is 37.5 mm, the mud content should be less than 0.5%, and it should not contain mud lumps.

8. A method for rapid pavement repair according to claim 6, characterized in that, The grouting pipe head consists of a sleeve, a straight pipe, and an elbow. The grouting perforated pipe and the straight pipe are hollow threaded thick-walled steel pipes. Grout outlets are set at intervals in the horizontal and vertical directions on the grouting perforated pipe. The distance between two adjacent grout outlets in each direction should not be greater than 15cm.

9. A method for rapid pavement repair according to claim 6, characterized in that, The conveying efficiency of each grouting equipment is greater than 5m. 3 / h, the delivery pipe is equipped with a flow meter and a ball valve switch to count the amount of grouting material used and to adjust and control the grouting flow rate; the grouting operation can be carried out simultaneously with the graded crushed stone backfilling construction above the grouting pipe.

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