Road-bridge transition section structure with carbon capture function and construction method thereof

Abstract

The application discloses a road-bridge transition section structure with a carbon capture function and a construction method thereof, and the structure comprises a carbon capture core section, a bridge abutment connecting section between the carbon capture core section and a bridge abutment, and a roadbed connecting section between the carbon capture core section and a roadbed, and a basement reinforcing layer is arranged at the bottom of the three sections; the carbon capture core section comprises, from bottom to top, an ecological anti-seepage layer, a carbon capture layer and a surface ecological layer; a road surface structure layer for connecting the road and the bridge is arranged at the top of the bridge abutment connecting section, the middle of the surface ecological layer and the top of the roadbed connecting section; the carbon capture layer is paved by using first composite aggregates; and the first composite aggregates comprise graded gravel, steel slag and fly ash. Compared with the prior art, the transition section structure adopts the steel slag and the fly ash as core materials of fillers, can realize the carbon capture and carbon storage functions, and makes the overall rigidity and strength of the structure meet the driving requirements, so that the environmental protection benefits are significantly quantified, and the economic benefits are outstanding.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of road and bridge engineering, and particularly relates to a road and bridge transition section structure with a carbon capture function and a construction method thereof. BACKGROUND

[0002] The existing road and bridge transition section structure has three core problems: firstly, the dependence on natural sandstone resources is high and the cost is high, and the filler is mostly natural graded gravel or cement stabilized gravel, and about 500 m 3 of natural sandstone is consumed per kilometer of road and bridge transition section construction, which exacerbates the shortage of sandstone resources, and the unit price of natural gravel reaches 80 yuan / m 3 , and the material cost accounts for a high proportion; secondly, the engineering performance and maintenance economy are poor, ordinary gravel filler is easy to be loose under the action of vehicle load and rainwater penetration, the 7d (i.e. 7 days) unconfined compressive strength is only 2.5-2.8 MPa, and maintenance and repair are required every 3-5 years, the maintenance cost accounts for more than 20% of the total cost of the road and bridge transition section, and the stiffness mutation of the road and bridge transition section and the abutment and the roadbed easily causes differential settlement and affects driving comfort; and thirdly, the traditional road and bridge transition section has significant shortcomings, the carbon emission is high (about 80 kg / m 3 of carbon emission in the process of natural sandstone mining and transportation, and about 120 kg / m 3 of carbon emission in the production of cement stabilized gravel), only serves as a "structural member" in the service stage, has no carbon capture function, and cannot participate in the engineering carbon sink system.

[0003] Therefore, it is urgent to propose a new road and bridge transition section structure and a construction method thereof, which has a carbon capture function and also has good engineering performance and economic benefits. SUMMARY

[0004] The present application aims to solve the problems of dependence on natural sandstone, high carbon emission, no carbon capture function, high maintenance cost and stiffness mutation of the existing road and bridge transition section, and proposes a new road and bridge transition section structure with a carbon capture function and a construction method thereof, which has a carbon capture function and also has good engineering performance and economic benefits.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a road-bridge transition section structure with carbon capture function, comprising a carbon capture core section, an abutment connection section between the carbon capture core section and the abutment, and a roadbed connection section between the carbon capture core section and the roadbed. A base reinforcement layer is provided at the bottom of the abutment connection section, the bottom of the carbon capture core section, and the bottom of the roadbed connection section. The carbon capture core section comprises, from bottom to top, an ecological impermeable layer, a carbon capture layer, and a surface ecological layer. A pavement structure layer connecting to the road and bridge is provided at the top of the abutment connection section, the middle of the surface ecological layer, and the top of the roadbed connection section. The carbon capture layer is paved with a first composite aggregate, which comprises 45%-60% by weight of graded crushed stone, 30%-40% by weight of steel slag, and 10%-15% by weight of fly ash. The particle size ranges of the graded crushed stone, steel slag, and fly ash are 20-40 mm, 5-20 mm, and 75-300 μm, respectively.

[0007] Based on the above technical solution, a carbon capture layer is constructed using graded crushed stone (coarse), steel slag (medium), and fly ash (fine) of different particle sizes. This layer serves as a dense skeleton for the road-bridge transition section structure, meeting the road surface bearing capacity requirements. Simultaneously, the carbon capture layer contains numerous micro-voids, providing space for carbon capture and storage. Steel slag and fly ash themselves possess a certain carbon capture capacity, enabling the road-bridge transition section structure described in this invention to both meet road traffic requirements and possess a certain carbon capture function. Further design of the gradation of the first composite aggregate is undertaken to increase the number of voids while maximizing skeleton density.

[0008] Furthermore, the first composite aggregate of the carbon capture layer is also mixed with a carbonization activator.

[0009] Adding carbonization activators to the carbon capture layer allows steel slag and fly ash to continuously absorb carbon dioxide, enabling the carbon capture layer to continuously perform its carbon capture and carbon sequestration functions, making it green, environmentally friendly, and sustainable.

[0010] Furthermore, the carbonization activator is a calcium hydroxide-gypsum-based activator, with a mass content of 2%-3% relative to the first composite aggregate, suitable for conventional carbon capture scenarios in general road and bridge transition sections; or, the carbonization activator is a fly ash-active magnesium oxide-based activator, with a mass content of 5%-8% relative to the first composite aggregate, suitable for solid waste co-utilization scenarios where fly ash and magnesium oxide raw materials are stored nearby; or, the carbonization activator is a steel slag-based composite activator, with a mass content of 2%-4% relative to the first composite aggregate, suitable for... In scenarios where steel slag resources are abundant and carbon capture efficiency needs to be enhanced; or, the carbonization activator is a triethanolamine-based activator, with a mass content of 0.3%-0.8% relative to the first composite aggregate, suitable for heavy-duty roads and high-performance scenarios with high requirements for carbon capture efficiency and structural strength; or, the carbonization activator is a carbonic anhydrase-sodium alginate composite synergist activator, with a mass content of 0.5%-1.2% relative to the first composite aggregate, suitable for ecologically sensitive areas (such as around farmland or near wetlands) or low-intervention scenarios where the use of chemical reagents is restricted.

[0011] Furthermore, it also includes a carbon capture and monitoring module, which comprises several carbon dioxide concentration sensors, several activator injection tubes, a first central control unit, a first data acquisition unit, and an intelligent activator delivery device; the several carbon dioxide concentration sensors are embedded in the carbon capture layer and connected to the first data acquisition unit; the several activator injection tubes are embedded in the carbon capture layer and have several liquid outlet holes arranged along their length direction, and the several activator injection tubes are connected to the intelligent activator delivery device; the input end of the first central control unit is connected to the first data acquisition unit, and the output end is connected to the intelligent activator delivery device;

[0012] The intelligent activator delivery device includes a storage tank and a variable frequency pump. The storage tank stores carbonization activator. The input end of the variable frequency pump is connected to the storage tank, and the output end is connected to several activator injection pipes. The variable frequency pump is also electrically connected to the first central control unit and dynamically adjusts the carbonization activator injection amount under the command of the first central control unit to ensure that it is replenished as needed and to avoid waste. The output end of the variable frequency pump is also equipped with a flow sensor for real-time monitoring of the carbonization activator injection amount.

[0013] A carbon capture monitoring module is set up to continuously monitor the carbon dioxide concentration in the voids of the first composite packing. When the concentration is too high, it indicates that the carbon dioxide capture efficiency of the first composite packing is low, and a carbonization activator needs to be supplied to improve the carbon capture efficiency. When the concentration is too low, it indicates that the carbon dioxide absorption path of the first composite packing is blocked, and the surface ecological vegetation layer needs to be loosened to improve its permeability and thus increase the carbon dioxide concentration in the first composite packing.

[0014] Furthermore, it also includes a moisture content monitoring module, which comprises several moisture content sensors, a water spraying device, a ventilation device, a second data acquisition unit, and a second central control unit. The several moisture content sensors are embedded in the carbon capture layer and are connected to the second data acquisition unit. The water spraying device has a water spraying pipeline that extends and is embedded in the carbon capture layer. The ventilation device has a ventilation duct that extends and is embedded around the carbon capture layer. The input end of the second central control unit is connected to the second data acquisition unit, and the output end is connected to the water spraying device and the ventilation device.

[0015] A moisture content monitoring module is installed to continuously monitor the moisture content of the first composite filler, ensuring that the moisture content in the carbon capture layer remains within the optimal range, thereby maximizing the efficiency of carbon capture.

[0016] Furthermore, the moisture content of the carbon capture layer ranges from 15% to 20%.

[0017] Furthermore, the base reinforcement layer located at the bottom of the carbon capture core section is constructed from a mixture of industrial solid waste-based composite cementitious material, cement-stabilized crushed stone, and waste steel fiber. The mass content of the cement-stabilized crushed stone relative to the industrial solid waste-based composite cementitious material is 3%-4%, and the mass content of the waste steel fiber relative to the base reinforcement layer mixture is 0.8%-1%.

[0018] Setting a base reinforcement layer at the bottom of the carbon capture core section can not only improve the load-bearing capacity of the carbon capture core section, but also enhance the deformation resistance of the base, avoid damage to the upper structure due to base settlement, and prevent the carbon capture layer from failing. For the base reinforcement layer at the bottom of the bridge abutment connection section and the bottom of the roadbed connection section, it can be set in the above manner, or conventional base reinforcement materials can be used as the reinforcement layer.

[0019] Furthermore, the first composite aggregate of the carbon capture layer is also mixed with functional additives, including at least one of nano-calcium carbonate and a bio-enzyme stabilizer. The mass content of the nano-calcium carbonate relative to the first composite aggregate is 0.1%-0.3%, preferably 0.2%, and the mass content of the bio-enzyme stabilizer relative to the first composite aggregate is 0.02%-0.1%, preferably 0.05%.

[0020] Nano-calcium carbonate can promote the early strength formation of the carbon capture layer through the micro-aggregate effect and crystal nucleation effect, thereby increasing its early strength by 10%-15%. Bio-enzyme stabilizers can optimize the adhesion and dispersion between filler particles, reduce the shrinkage and deformation of the structure after compaction, and keep the filler compaction degree stable at over 97%, indirectly ensuring the uniformity of the carbon capture reaction.

[0021] Furthermore, the roadbed connection section is paved with a second composite aggregate, which includes graded crushed stone, steel slag, and fly ash. The proportion of the second composite aggregate at the section closest to the carbon capture core is the same as that of the first composite aggregate. As the section extends from the section closest to the carbon capture core to the roadbed, the content of steel slag and fly ash decreases until it reaches the section closest to the roadbed, where the mass content of steel slag, fly ash, and graded crushed stone is 30%, 10%, and 60%, respectively. Preferably, a linear decreasing method is adopted, wherein the content of steel slag decreases by a gradient of 3%-5% per meter, and the content of fly ash decreases by a gradient of 1.5%-2.5% per meter.

[0022] By setting a second composite aggregate with decreasing gradation, the stiffness of the subgrade connection section gradually changes from the carbon capture core section to the road subgrade, thus meeting the requirements for road driving comfort.

[0023] Furthermore, the bridge abutment connection section is uniformly paved with the first composite aggregate, and a shear-resistant member is provided at the connection between the bridge abutment connection section and the bridge abutment; the shear-resistant member can be one of shear studs, steel bars, or steel pipes; by setting the shear-resistant member, the stiffness between the bridge abutment and the bridge abutment connection section is gradually changed, avoiding the phenomenon of vehicle bouncing at the bridge abutment position.

[0024] Furthermore, the ecological seepage barrier layer adopts one of the following: recycled plastic modified geomembrane, bentonite waterproof blanket, and tailings sand-bentonite mixed seepage barrier material; the surface ecological vegetation layer includes planting soil and ecological vegetation blanket laid on the surface of the planting soil, and the ecological vegetation blanket is planted with permeable perennial herbaceous plants of the Poaceae family and the Leguminosae family; setting up the ecological seepage barrier layer can prevent groundwater from seeping back into the carbon capture layer and affecting the carbon capture efficiency; setting up the ecological vegetation layer ensures the permeability of the surface ecological vegetation layer, provides a feasible path for the carbon capture layer to continuously absorb carbon dioxide from the atmosphere, and helps to control the moisture content of the carbon capture layer.

[0025] Furthermore, the bridge abutment connection section, carbon capture core section, and roadbed connection section are constructed by layered integrated casting, or by layered independent paving and step-like splicing.

[0026] Furthermore, the length of the bridge abutment connection section is 1.5-2m, the length of the carbon capture core section is 3-5m, and the length of the roadbed connection section is 2-3m.

[0027] Secondly, the present invention provides a construction method for a road-bridge transition section structure with carbon capture function, comprising the following steps:

[0028] Clear debris from the transition section between the road and bridge and compact the foundation.

[0029] Lay a base reinforcement layer, and lay an ecological seepage-proof layer on the base reinforcement layer located in the carbon capture core section; use the first composite aggregate to lay the carbon capture layer; during the laying of the carbon capture layer, use the first composite aggregate to lay the bridge abutment connection section in layers and simultaneously; lay the roadbed connection section in layers and simultaneously.

[0030] The pavement structure layer connecting the road and bridge is laid, and the surface ecological layer is laid on both sides of the pavement structure layer to form the carbon capture core section; the bridge abutment connection section and the roadbed connection section are laid simultaneously until they are flush with the carbon capture core section to form the road-bridge transition section structure.

[0031] Compared with the prior art, the present invention has the following beneficial technical effects:

[0032] (1) The bridge-road transition section of the present invention adopts a three-section design of bridge abutment connection section, carbon capture core section and roadbed connection section, and sets carbon capture layer and other functional layers for carbon capture core section, which improves the engineering performance of bridge-road transition section structure, stiffness and strength meet traffic requirements, environmental protection benefits are significantly quantified, and economic benefits are outstanding.

[0033] (2) The bridge transition section of this invention uses steel slag and fly ash from industrial solid waste as the core materials for carbon capture. It not only has good carbon capture and carbon sequestration effects, but also consumes a large amount of industrial solid waste, and can even consume waste plastics, realizing the synergistic utilization of multiple types of solid waste; and also improves carbon capture efficiency by supplementing carbonization activators and monitoring the moisture content in composite fillers; carbon emissions during construction are lower than those of conventional transition sections; carbon absorption and carbon capture are higher during service, making it green and environmentally friendly.

[0034] (3) The bridge abutment connection section adopts shear stud design to improve the shear strength of the connection. The composite filler has sufficient strength and stiffness, which can effectively avoid the bridge abutment jumping phenomenon and meet the driving requirements. The roadbed connection section adopts stiffness gradient design, which can reduce the differential settlement between the road-bridge transition section and the roadbed and meet the driving comfort requirements of highways and municipal roads.

[0035] (4) The unit price of industrial solid waste composite aggregate is relatively low, which reduces material costs; the maintenance cycle of road and bridge transition sections is extended, the maintenance cost throughout the entire life cycle is reduced, and the maintenance cost per kilometer of transition section throughout the entire life cycle is significantly reduced, resulting in obvious economic benefits. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the overall structure of the road-bridge transition section.

[0037] Figure 2 This is a schematic diagram of the cross-section of the carbon capture core segment.

[0038] Figure 3 This is a schematic diagram of the carbon capture and monitoring module.

[0039] Figure 4 This is a schematic diagram of the moisture content monitoring module.

[0040] In the diagram: 1. Bridge abutment connection section; 101. First base reinforcement layer; 2. Carbon capture core section; 201. Second base reinforcement layer; 202. Ecological seepage prevention layer; 203. Carbon capture layer; 204. Surface ecological layer; 3. Roadbed connection section; 301. Third base reinforcement layer; 401. Carbon dioxide concentration sensor; 402. Activator injection pipe; 403. First central control unit; 404. First data acquisition unit; 405. Activator intelligent delivery device; 501. Moisture content sensor; 502. Sprinkler equipment; 503. Ventilation equipment; 504. Second data acquisition unit; 505. Second central control unit; 5021. Sprinkler pipeline; 5031. Ventilation pipeline; 6. Road surface structure layer. Detailed Implementation

[0041] The technical solution of the present invention will be clearly and completely described below.

[0042] Implementation method one;

[0043] Please see Figure 1 This embodiment provides a road-bridge transition section structure with carbon capture function, including a carbon capture core section 2, an abutment connection section 1 between the carbon capture core section 2 and the abutment, and a roadbed connection section 3 between the carbon capture core section 2 and the roadbed. A base reinforcement layer is provided at the bottom of the abutment connection section 1, the bottom of the carbon capture core section 2, and the bottom of the roadbed connection section 3. The carbon capture core section 2 includes, from bottom to top, an ecological impermeable layer 202, a carbon capture layer 203, and a surface ecological layer 204. The top of the bridge abutment connection section 1, the middle of the surface ecological layer 204, and the top of the roadbed connection section 3 are provided with a pavement structure layer 6 that connects with the road and bridge. The carbon capture layer 203 is paved with a first composite aggregate, which includes 45%-60% by weight of graded crushed stone, 30%-40% by weight of steel slag, and 10%-15% by weight of fly ash. The particle size ranges of the graded crushed stone, steel slag, and fly ash are 20-40mm, 5-20mm, and 75-300μm, respectively.

[0044] The abutment connection section 1, the carbon capture core section 2, and the roadbed connection section 3 are constructed using integrated casting or by paving independently and then splicing them together in a stepped manner. For ease of explanation, the base reinforcement layer at the bottom of the carbon capture core section 2 is marked as the second base reinforcement layer 201, the base reinforcement layer at the bottom of the abutment connection section 1 is marked as the first base reinforcement layer 101, and the base reinforcement layer at the bottom of the roadbed connection section 3 is marked as the third base reinforcement layer 301.

[0045] First, the specific composition and technical principle of the carbon capture layer in the carbon capture core segment will be explained.

[0046] The length of the middle carbon capture core section is generally 3-5m. From bottom to top, it consists of ecological seepage prevention layer 202, carbon capture layer 203, and surface ecological layer 204, which is the core functional area of ​​the road-bridge transition section. The bottom is the second base reinforcement layer 201. The carbon capture layer 203 is the core area of ​​the carbon capture core section 2.

[0047] The carbon capture layer is laid on top of the ecological seepage prevention layer, with a thickness of 500-600mm (spread in 2-3 layers, each layer 200-300mm thick). It is mainly composed of the first composite aggregate made from industrial solid waste, with the following specific proportions: steel slag (particle size 5-20mm, crushing value ≤12%) 30%-40%, fly ash (Grade I or II, particle size 75-300μm) 10%-15%, and graded crushed stone (particle size 20-40mm) 45%-60%. Adding steel slag and fly ash to the graded crushed stone as composite fillers has the following advantages: ① Steel slag (crushing value ≤12%) provides a high-strength skeleton, and fly ash fills the voids and optimizes the gradation (density increased by 15%); ② The free CaO contained in steel slag and the pozzolanic activity of fly ash provide a chemical basis for subsequent carbon capture.

[0048] The carbon absorption and capture principle of the carbon capture layer in this invention is as follows.

[0049] (1) Steel slag is rich in free calcium oxide (f-CaO, content 10%-20%) and calcium hydroxide (Ca(OH)2). These two components are the core substances that react with CO2 at room temperature and pressure. The reaction principle is as follows:

[0050] a) First step: Free calcium oxide reacts with water (moisture in the air or rainwater) to produce calcium hydroxide, providing an "active alkali source" for subsequent carbonization: CaO + H2O → Ca(OH)2 (exothermic reaction; the generated Ca(OH)2 dissolves in water, releasing Ca2+). 2+ );

[0051] b) Second step: Calcium hydroxide reacts with CO2 in the air to produce calcium carbonate crystals (CaCO3) that are insoluble in water, thus permanently sealing CO2: Ca(OH)2 + CO2 → CaCO3↓ + H2O;

[0052] c) Additional contribution: The generated calcium carbonate crystals can fill the pores of the composite filler (reducing the porosity by 15%-20%), and at the same time bond with the composite filler particles, increasing the 7-day unconfined compressive strength of the carbon capture layer to ≥3.5MPa, achieving the dual effects of "carbon fixation" and "structural strengthening".

[0053] (2) Although fly ash (especially Grade I / II high-calcium fly ash with CaO content ≥8%) has a weaker carbon capture capacity than steel slag, its overall carbon fixation efficiency can be enhanced through "structural assistance" and "activation". The specific principle is as follows:

[0054] a) Porous structure adsorption: The honeycomb porous structure of fly ash (specific surface area 300-500 m² / kg) can adsorb CO2 molecules, prolonging their residence time in the packing layer and increasing their interaction with Ca. 2+ The probability of the reaction;

[0055] b) Replenishment of active ingredients: The active calcium silicate (2CaO·SiO2) in high-calcium fly ash, after being activated by a carbonization activator (such as calcium hydroxide), can slowly release Ca. 2+ It replenishes the alkali source consumed by the steel slag reaction and extends the carbon capture cycle (from the conventional 3-5 years to 8-10 years).

[0056] Although the composite filler with steel slag and fly ash already has the function of carbon capture, the carbon capture rate is slow by relying solely on the natural reaction of steel slag and fly ash (natural carbonization takes 6-12 months to reach saturation). Therefore, carbonization activators are added, and the carbon capture efficiency is further improved through "chemical adjustment" and "reaction kinetic optimization".

[0057] Furthermore, the carbon capture layer also contains carbonization activators.

[0058] Specifically, the carbonization activator is a mixture of calcium hydroxide and gypsum in a mass ratio of 7:3, and its mass content relative to the first composite aggregate is 2%-3%.

[0059] The principle behind the aforementioned carbonization activator's ability to enhance carbon capture efficiency is as follows:

[0060] (1) Adjust the pH value of the system to activate Ca 2+ Leaching:

[0061] Ca in steel slag 2+ The dissolution efficiency depends on an alkaline environment (optimal pH = 11-13). Calcium hydroxide in the carbonization activator can rapidly increase the pH of the pore water in the composite packing. Without the addition of the carbonization activator, the packing pH is approximately 9-10. 2+ The dissolution rate is only 0.01 mol / (kg·min); after adding 2%-3% carbonization activator, the pH rises to 12-13, and the Ca... 2+ The dissolution rate was increased to 0.035 mol / (kg·min), providing sufficient "reactants" for the CO2 reaction;

[0062] (2) Although gypsum (CaSO4·2H2O) does not react directly with CO2, it can assist in carbon capture through two pathways:

[0063] a) Formation of ettringite: SO4 in gypsum 2- With Ca 2+ Aluminate reaction produces ettringite (3CaO·Al2O3·3CaSO4·32H2O), which can fill pores and reduce CO2 escape. At the same time, its expansion properties can offset the shrinkage of the filler and prevent cracking.

[0064] b) Delaying calcium carbonate crystallization: Gypsum can slow down the growth rate of CaCO3 crystals, causing them to form finer crystals (50-100nm in diameter), increasing the bonding area between the crystals and filler particles, and further improving the strength.

[0065] Besides the calcium hydroxide and gypsum system, carbonization activators also exist in other material systems.

[0066] 1) Substitute materials for industrial by-products; for example, fly ash and active MgO composite system, where the aluminosilicates in fly ash and active MgO undergo a synergistic reaction in a CO2 environment to generate magnesium carbonate (such as spheroidal magnesia and hydrous magnesia) and magnesium aluminosilicate gel (MSH); for example, steel slag-based composite activators, which activate the carbonation activity of free CaO in steel slag by adding admixtures (such as Na2SiO3 and CaCl2) to generate calcium carbonate and calcium silicate gel.

[0067] 2) Bio-based and natural mineral alternative materials; for example, bio-based and natural mineral alternative materials, the porous structure of biochar adsorbs CO2 and provides a reaction interface, MgO carbonizes on the surface of biochar to generate magnesium carbonate, and the organic matter in biochar promotes the migration of calcium and magnesium ions; such as vermiculite-starch carbide composite materials, starch carbide is loaded onto the surface of vermiculite through hydrothermal carbonization to form a dual action site of "physical adsorption-chemical catalysis".

[0068] 3) Chemically synthesized alternative materials; for example, the triethanolamine (TEA) synergistic system, where TEA molecules react with Ca... 2+ Al 3+ Complexes are formed, promoting the deagglomeration of fly ash glass and releasing active silica and alumina components. CO2 and the released Ca... 2+ Amorphous calcium carbonate (ACC) is generated and forms a "bridging structure" with CASH gel, increasing strength by 20%.

[0069] 4) Microbial-polymer synergistic system; for example, carbonic anhydrase bacteria-sodium alginate composite synergist, in which carbonic anhydrase bacteria catalyze the hydration of CO2 to produce HCO3. - Accelerate Ca 2+ Carbonization; sodium alginate forms a three-dimensional network structure, immobilizing Ca. 2+ It also promotes calcium carbonate crystallization.

[0070] The dosage and application of the above-mentioned carbonization activators are as follows.

[0071] 1) Industrial by-product substitution system: The fly ash-active magnesium oxide (MgO) system is added at 5%-8% relative to the first composite aggregate, and the steel slag-based composite activator (containing Na2SiO3 and CaCl2) is added at 2%-4%; it is suitable for cost-priority or resource recycling scenarios, such as road and bridge projects with steel slag and fly ash stockpiles nearby. It can significantly reduce material costs and dispose of industrial solid waste, meet the carbon capture and carrying capacity requirements of general road and bridge transition sections, and does not need to pursue extreme carbonization efficiency or strength.

[0072] 2) Bio-based and natural mineral alternative systems: Biochar-MgO system with a dosage of 3%-5%, vermiculite-starch carbide composite material with a dosage of 1.5%-3%; suitable for ecological restoration or environmentally sensitive scenarios, such as roads and bridges around phosphate mines and in ecological protection areas. Bio-based materials can help improve the surrounding soil microenvironment, while natural mineral components are environmentally friendly and pollution-free, taking into account both carbon capture and ecological compatibility.

[0073] 3) Chemically synthesized alternative systems: The dosage of triethanolamine (TEA) synergistic system is 0.3%-0.8%; it is suitable for high-performance demand scenarios, such as heavy-duty roads and road and bridge transition sections with high requirements for carbon capture efficiency and structural strength. TEA can quickly improve the strength of composite aggregates (increase by 20%) and accelerate the carbonization reaction, meeting the dual requirements of high strength load-bearing capacity and efficient carbon fixation.

[0074] 4) Microbial-polymer synergistic system: The dosage of carbonic anhydrase bacteria-sodium alginate composite synergist is 0.5%-1.2%; suitable for low-intervention ecological areas or mild carbonization needs, such as roads and bridges near farmland and wetlands. The microbial action is mild and does not damage the surrounding ecology. The three-dimensional network of sodium alginate can stabilize the carbonization process, which is suitable for areas where the use of chemical reagents is restricted.

[0075] For cost-priority scenarios, industrial by-product carbonization activators are preferred. These activators are composed of 30%-50% industrial by-products (such as fly ash and steel slag) and 50%-70% active ingredients (such as active MgO and Na2SiO3). The total dosage of the carbonization activator relative to the first composite aggregate is 3%-6%, which can significantly reduce the cost of carbonization activators and meet the carbon capture requirements of general engineering projects. For high-performance scenarios, triethanolamine synergistic systems or acidic activators (phosphogypsum-MgSO4) are used, which are suitable for high-strength concrete or structures with high durability requirements. For ecological restoration scenarios, biochar-MgO or microbial-polymer systems are preferred, which can simultaneously achieve carbon sequestration and pollution control. For resource recycling scenarios, the application of industrial by-products such as steel slag and phosphogypsum can maximize the amount of solid waste disposed of, which meets the requirements of the circular economy.

[0076] Calcium hydroxide and gypsum systems, industrial by-product substitutes, chemically synthesized substitutes, and microbial-polymer synergistic systems can be injected into composite fillers via intelligent activator delivery devices and activator injection pipes. Bio-based and natural mineral substitutes can be directly mixed into the composite fillers. The aforementioned carbonization activators are existing technologies and will not be elaborated upon here.

[0077] Furthermore, functional additives can be further incorporated into the carbon capture layer. These functional additives include at least one of nano-calcium carbonate and a bio-enzyme stabilizer. The amount of nano-calcium carbonate relative to the first composite aggregate is 0.1%-0.3%, preferably 0.2%, and the amount of the bio-enzyme stabilizer relative to the first composite aggregate is 0.02%-0.1%, preferably 0.05%. The nano-calcium carbonate has a particle size of 50-100 nm and is incorporated at a concentration of 0.1%-0.3%, which can improve the early strength of the carbon capture layer. The bio-enzyme stabilizer, at a concentration of 0.05%, can improve the compaction performance of the filler, achieving a compaction degree ≥97%.

[0078] Secondly, the specific composition and technical principles of the ecological impermeable layer and the surface ecological layer in the base reinforcement layer and carbon capture core section are explained in detail.

[0079] Furthermore, the second base reinforcement layer 201 is constructed by paving a mixture of industrial solid waste-based composite cementitious material, cement-stabilized crushed stone, and waste steel fiber. The mass content of cement-stabilized crushed stone relative to the industrial solid waste-based composite cementitious material is 3%-4%, and the mass content of waste steel fiber relative to the base reinforcement layer mixture is 0.8%-1%. For the first base reinforcement layer 101 at the bottom of the abutment connection section 1 and the third base reinforcement layer 301 at the bottom of the roadbed connection section 3, they can be set in the above manner, or conventional base reinforcement materials can be used as reinforcement layers.

[0080] Furthermore, the ecological seepage barrier layer 202 is made of one of the following: recycled plastic modified geomembrane, bentonite waterproof blanket, or tailings sand-bentonite mixed seepage barrier material; the surface ecological layer 204 is made of ecological vegetation blanket, which is planted with permeable grass and leguminous perennial herbaceous plants.

[0081] Modified geomembranes made from recycled plastics use waste PE plastic as raw material. They have a thickness ≥1.5mm, tensile strength ≥18MPa, and permeability coefficient ≤1×10⁻⁶. -10 cm / s; Bentonite waterproof blanket (GCL), sodium bentonite expands to 10-15 times its original volume when exposed to water, forming a dense gel layer (permeability coefficient ≤5×10 cm / s); -10 (m / s), effectively blocking water migration paths; tailings sand-bentonite mixed impermeable material, after tailings sand (industrial solid waste) and bentonite are mixed in a 10:1 ratio, the permeability coefficient can reach 5.61×10 m / s. -10m / s, meeting the requirements for impermeable layers (≤1×10 m / s). -9 m / s).

[0082] The applicable scenarios for the above-mentioned ecological seepage-proof layer materials are as follows.

[0083] 1) Recycled plastic modified geomembrane: Suitable for geological conditions with high groundwater levels (requiring strong blocking of groundwater seepage) and sandy or silty soil types; due to its extremely low permeability coefficient (≤1×10⁻⁶). -10 (cm / s), can withstand seepage pressure under high water levels, and the flexible material can adapt to slight settlement deformation of sandy soil / silt; construction requires ensuring that the base is compacted and flat (to avoid the geomembrane being punctured by sharp particles), suitable for scenarios with extremely high requirements for seepage prevention efficiency.

[0084] 2) Bentonite waterproofing blanket (GCL): Suitable for geological conditions with low to medium groundwater levels (no need for extreme seepage resistance) and soil types such as cohesive soil or soil containing a small amount of gravel; sodium-based bentonite expands when it comes into contact with water (volume increases to 10-15 times), can self-repair tiny cracks, can adapt to the weak permeability of cohesive soil (supplementing the seepage prevention shortcomings), and has lower requirements for the flatness of the base than geomembrane, can cope with local unevenness of gravelly soil, and has higher construction flexibility.

[0085] 3) Tailings sand-bentonite mixed impermeable material: Suitable for geological conditions with moderate groundwater levels and soil types of red or yellow soil (acidic soil); the mixture (tailings sand: bentonite = 10:1) can be sourced locally (using local tailings sand), and the permeability coefficient after compaction is ≤5.61×10 -10 With a speed of m / s, it can adapt to the physical and chemical properties of acidic soils and has good compatibility with surrounding red / yellow soils, reducing the risk of interface leakage. It is suitable for projects with surrounding tailings sand storage and the need to take into account solid waste utilization.

[0086] The commonly used planting schemes for plants in ecological vegetation blankets are as follows: plant alfalfa + bermudagrass (3:7), plant alfalfa + bermudagrass (3:7) in arid areas, plant white clover + zoysia grass (4:6) in humid areas, and plant indigo + bahia grass (5:5) in acidic soils.

[0087] Alfalfa is suitable for mild, semi-arid / semi-humid regions in the north and slope protection areas. Alternative materials include: alfalfa, suitable for arid and semi-arid regions and saline-alkali land; indigofera tinctoria, suitable for acidic red soil and phosphate mine restoration; and white clover, suitable for humid regions and shady environments under forests. Alfalfa, alfalfa, indigofera tinctoria, and white clover are all perennial herbaceous plants belonging to the legume family.

[0088] Bermuda grass is suitable for tropical, subtropical, and temperate regions, as well as slopes / lawn areas. Alternative materials include: Zoysia japonica, suitable for coastal areas and sports field lawns; and Bahia grass, suitable for acidic soils and southern slopes. Bermuda grass, Zoysia japonica, and Bahia grass are all perennial herbaceous plants belonging to the Poaceae family.

[0089] The above-mentioned herbaceous plants share the following common characteristics.

[0090] 1) All are perennial herbs with a lifespan of 3-10 years. They can continuously absorb CO2 through photosynthesis, avoiding the "gap period" of carbon fixation and matching the carbon capture cycle of the carbon capture layer of 8-10 years.

[0091] 2) High photosynthetic efficiency (C3 plants: 15-20 μmol CO2 / (m 2 •s), C4 plants 25-30μmolCO2 / (m 2 •s)), and 30%-50% of the fixed carbon is allocated to the well-developed root system, which decomposes or forms soil aggregates, thus enhancing soil carbon sequestration.

[0092] 3) It has resistance to all scenarios (salt, alkali, acid, high temperature, etc.), low maintenance requirements, and can grow stably in the transition sections of roads and bridges in different areas, ensuring continuous carbon capture.

[0093] 4) Root diameter ≤ 2mm (does not damage the pores of the carbon capture layer), litter can decompose in 3-6 months (does not block CO2 penetration), and can also help to channel CO2, ensuring the supply of raw materials for the carbon capture layer.

[0094] 5) Breathability is a structural function of ecological vegetation blankets (porosity ≥40%). The core role of plants is to maintain the stability of the vegetation blankets and actively absorb CO2, rather than to transmit CO2 through their own breathability.

[0095] For different regions, appropriate plants can be selected for planting according to the actual situation, so that the ecological vegetation blanket can meet the carbon capture function of the composite filler. This invention will not elaborate further.

[0096] The detailed design of the other functional layers of the carbon capture core segment is as follows.

[0097] (1) Second substrate reinforcement layer:

[0098] Located at the bottom of the carbon capture core section, with a thickness of 200-250mm, it uses a mixture of cement-stabilized crushed stone and waste steel fiber (cement-stabilized crushed stone content of 3%-4% by mass, waste steel fiber content of 0.8%-1% by mass, length of 15-20mm), with a compaction degree of ≥96%. Its function is to enhance the bearing capacity of the base and avoid uneven settlement in the later stage. The fiber-reinforced composite mechanical effect: cement-stabilized crushed stone provides the foundation bearing capacity (compaction degree ≥96%), and waste steel fiber (length 15-20mm) is three-dimensionally randomly distributed, which can block the propagation of microcracks (crack resistance is improved by 40%), while enhancing the deformation resistance of the base and avoiding damage to the upper structure due to base settlement.

[0099] (2) Ecological seepage barrier layer:

[0100] Lay on top of the base reinforcement layer, retaining only the seepage prevention function, using recycled plastic modified geomembrane (made from waste PE plastic, thickness ≥1.5mm, tensile strength ≥18MPa, permeability coefficient ≤1×10). -10 (cm / s), the geomembrane overlap width is ≥100mm, and hot-melt welding is used to ensure the continuity of seepage prevention and avoid rainwater seepage and erosion of the foundation.

[0101] (3) Surface ecological layer:

[0102] Laying in the core section of carbon capture, using ecological vegetation blankets (with drought-resistant grass seeds such as alfalfa and bermudagrass, with a seed density of ≥200 seeds / m²), the vegetation blanket is 10-15mm thick and covered with 50-80mm thick planting soil after laying. Its function is to achieve ecological restoration and enhance the slope's anti-sliding stability (the slope ratio can be relaxed to 1:1.5, while the conventional ratio is 1:1.75).

[0103] Ecological soil stabilization + anti-sliding reinforcement: The roots of grass species (alfalfa, bermudagrass) in the vegetation blanket penetrate deep into the filler layer to form a "biological root network", which enhances the slope's anti-sliding force (the slope's anti-sliding stability coefficient is increased to over 1.3); at the same time, covering with planting soil achieves ecological restoration, meeting the needs of green engineering.

[0104] In addition to the carbon capture core section, surface ecological layers can be installed on the top surface of the subgrade connection section and the bridge abutment connection section, as well as on both sides of the pavement structure layer. The subgrade connection section and the bridge abutment connection section also have certain carbon capture and carbon sequestration functions. However, their main function is to connect with the subgrade and bridge abutment in terms of stiffness and strength.

[0105] Then, the specific composition and technical principles of the bridge abutment connection section and the roadbed connection section are explained in detail.

[0106] Furthermore, the subgrade connection section is paved with a second composite aggregate, which includes graded crushed stone, steel slag, and fly ash. Its proportions closest to the carbon capture core section are the same as the first composite aggregate. As it extends from the carbon capture core section to the roadbed, the amounts of steel slag and fly ash decrease, reaching 30% steel slag and 10% fly ash at its closest point to the roadbed. The abutment connection section is paved uniformly with the first composite aggregate. Shear studs are installed at the connection between the abutment and the bridge abutment.

[0107] The length of the bridge abutment connection section is generally 1.5-2m. It adopts a design of "low-carbon filler layer (with the same proportion as the first composite filler of the carbon capture layer) + pre-embedded shear nails". One end of the shear nail is embedded in the bridge abutment concrete (embedding depth ≥100mm), and the other end is embedded in the low-carbon filler layer to solve the problem of weak shear resistance between the transition section and the bridge abutment. The spacing of the shear nails is generally 300-400mm, and the diameter is generally 16-18mm. The bridge abutment is a rigid concrete structure (elastic modulus of about 30GPa), and the filler in the road-bridge transition section structure is a semi-rigid material (elastic modulus of about 1-3GPa). The short section length of 1.5-2m can shorten the stiffness change distance of "rigid-semi-rigid" and avoid the concentration of load in a short distance. At the same time, it is suitable for the construction space near the bridge abutment (usually the working range around the bridge abutment is limited).

[0108] Material aspect: Continuous paving with the same mix proportion;

[0109] During construction, the low-carbon first composite filler of the intermediate carbon capture section is first laid to the interface of the bridge abutment connection section. Then, the same proportion filler of the bridge abutment connection section and the second composite filler are laid simultaneously on the roadbed connection section. The mixing and paving interval shall not exceed 2 hours, and the overlap width shall be ≥500mm. The "material fusion layer" is formed by rolling with an intelligent road roller (compaction degree ≥97%) to eliminate interface gaps.

[0110] Structural level: Shear studs anchor and transmit force;

[0111] The "pre-embedded shear studs" in the bridge abutment connection section are the key to the transition: one end of the shear stud is implanted into the bridge abutment concrete (implantation depth ≥100mm, anchoring force ≥50kN / stud), and the other end is embedded in the low-carbon filler layer, forming a shear-resistant system of "mechanical interlocking + material bonding" - which not only transfers the rigid load of the bridge abutment to the filler layer, but also prevents horizontal sliding between the connection section and the bridge abutment, solving the core pain point of "weak shear resistance" in traditional transition sections, and ultimately achieving mechanical integration of "bridge abutment-connection section-intermediate section".

[0112] Subgrade connection section: 2-3m in length, adopts "low-carbon filler stiffness gradient design" ("based on the actual formula of the middle section, to achieve no sudden change in interface", 40% is only the upper limit of the middle section. When the middle section takes any value in the range of 30%-40%, the gradient starting point of the subgrade connection section will be aligned with it, and then gradually reduced to 30%, finally achieving the design goal of "smooth stiffness transition + functional continuity"), to achieve a smooth stiffness transition with the subgrade and reduce differential settlement.

[0113] The technical principle of the overall design of the road-bridge transition section structure of this invention is as follows: By coordinating the segmented functions of the abutment connection section, the intermediate carbon capture core section, and the roadbed connection section, combined with the connection method of integrated casting or stepped splicing (with shear studs on the splicing surface), the unity of "continuous mechanical transmission + smooth stiffness transition + integrated carbon capture function" is achieved: The abutment connection section solves the problem of weak shear resistance between the road-bridge transition section and the abutment by means of the mechanical interlocking of the shear studs and the bearing capacity of the low-carbon filler; The intermediate carbon capture core section utilizes the alkaline components of industrial solid waste composite aggregate and the mineralization reaction with CO2 to achieve carbon capture and carbon sequestration while meeting the load-bearing requirements; The roadbed connection section gradually changes the ratio of steel slag and graded crushed stone, so that the stiffness transitions linearly from the intermediate carbon capture core section to the roadbed, reducing differential settlement; The three-segment connection method ensures that vehicle load and roadbed stress are continuously transmitted along the transition section, avoiding interface stress concentration, and finally forming an integrated structure with engineering performance, solid waste resource utilization and carbon emission reduction functions.

[0114] Next, we will discuss in detail the reasons and principles behind the carbon capture and carbon sequestration functions, as well as other functions, achieved by the materials used in the carbon capture core section of this invention.

[0115] (1) Steel slag:

[0116] In existing technologies, steel slag is mostly processed through hot quenching, drum grinding, and other processes. After processing, it is used either as a cement admixture (its usage has decreased due to new standards and specifications), as an aggregate for asphalt pavement (utilizing its hardness and wear resistance), or as a compound with fly ash and blast furnace slag to prepare wall materials (40%-50% admixture). The core function is to achieve solid waste disposal as a "substitute raw material," focusing on single mechanical properties (such as strength and wear resistance) without linking carbon capture function. Some of it requires ultrafine grinding to improve activity, resulting in high energy consumption. In this invention, steel slag is mixed into low-carbon composite filler at a dosage of 30%-40%, with a particle size controlled at 5-20mm (crushing value ≤12%). Ultrafine grinding is not required. It serves as structural aggregate to provide load-bearing capacity (7-day unconfined compressive strength ≥3.5Mpa, 7-day unconfined compressive strength is the test result under standard curing conditions), and achieves carbon capture through the reaction of free CaO and CO2 (carbon absorption during service life ≥6kg / m³). 3 The carbon absorption capacity is ≥6kg / m³ (the measured value after one year of service under normal temperature and pressure). It also achieves a smooth transition in stiffness by gradually increasing the admixture from 40% to 30% in the subgrade connection section, taking into account the triple functions of "structural bearing capacity + carbon capture + mechanical adaptation".

[0117] (2) Fly ash:

[0118] In existing technologies, fly ash is either crudely mixed as a cheap filler, or graded and purified (e.g., cenospheres, silica fume) to be used as a high-value building material raw material, or prepared into color-changing silica gel, aluminum-iron flocculants, etc. through microwave activation and centrifugal separation. The core is "single high-value utilization," focusing on improving the material's own performance (such as fluidity and adsorption), without combining it with the structural functions of road and bridge (such as carbon capture and stiffness synergy). In this invention, fly ash (Grade I or II) is mixed into the low-carbon composite filler at a dosage of 10%-15%. It does not rely on graded purification or microwave activation. It mainly adsorbs CO2 through its porous structure, prolongs its reaction time with steel slag, and fills the pores of steel slag and graded crushed stone, improving the compaction degree of the filler (≥97%), assisting steel slag in achieving carbon capture, and serving the "environmental protection function + engineering compaction stability" of the road and bridge transition section, rather than simply high-value utilization.

[0119] (3) Other key materials (activators, impermeable materials, etc.):

[0120] In existing technologies, carbonization / activation activators (such as calcium hydroxide and gypsum) are mostly added once to enhance the cementitious activity of the steel slag-fly ash system without dynamic control. In this invention, the carbonization activator uses a 7:3 ratio of calcium hydroxide and gypsum (with a dosage of 2%-3%) or other systems. It can be linked with the carbon concentration sensor through the activator injection pipe, automatically replenishing the carbon when the carbon absorption is insufficient, forming a closed loop for carbon capture. The ecological seepage prevention layer uses recycled PE modified geomembrane (thickness ≥1.5mm), which not only blocks rainwater infiltration to ensure the carbon capture microenvironment, but also realizes the resource utilization of waste PE. The monitoring materials (carbon concentration / moisture content sensor, PE injection pipe) adopt a minimally invasive embedded design, which does not damage the filler voids and realizes "real-time monitoring-dynamic control", which is completely different from the "single function, single use" logic of existing technologies.

[0121] Next, the ingenuity and innovation of the structure and material design of this invention will be discussed in detail.

[0122] (1) Design of "permeable entrance" for CO2 in the surface vegetation layer:

[0123] The surface layer needs to achieve a balance between "efficient CO2 introduction and anti-clogging" through a porous design. A needle-punched ecological vegetation blanket (porosity ≥40%) is used, with 1-3mm mesh-like gaps between fibers allowing CO2 to penetrate quickly while intercepting debris. The covering granular planting soil, with 5% decomposed straw added, forms 25%-30% porosity, preventing compaction after watering (compacted clay soil will reduce porosity from 20% to below 5%, directly blocking CO2 penetration). Furthermore, controlling the vegetation pruning height (10-15cm) prevents excessive foliage from forming a "closed layer," ensuring smooth airflow between the surface and the lower layers.

[0124] (2) "Permeability-strength balance" void design in low-carbon composite fillers:

[0125] By controlling gradation and compaction, a two-layer structure of "large void mass transfer + small void reaction" is created. Steel slag (5-20mm) and graded crushed stone (20-40mm) form large voids of 2-5mm (accounting for 60% in total), serving as the main channel for rapid CO2 infiltration; fly ash filling forms small voids of 0.1-0.5mm (accounting for 40%), facilitating the exchange of CO2 and Ca. 2+ The reaction provides microspaces, with the overall porosity controlled at 18%-22%. The compaction degree is intentionally left to be 97%-98% (lower than conventional roadbeds), which ensures a 7-day compressive strength of ≥3.5MPa while preventing large voids from being squeezed out, and ensuring that CO2 can penetrate to the bottom of the layer within 24 hours.

[0126] (3) Ensuring interlayer connectivity (a key measure to avoid "mass transfer gaps"):

[0127] The gaps between each layer must form continuous channels; otherwise, the problem of "permeable surface but blocked lower layers" will occur. During construction, the interval between the carbon capture layer and the surface ecological vegetation layer should not exceed 2 hours. If the interval exceeds this time, the surface layer of the carbon capture layer should be milled to expose fresh gaps by 5mm. The surface ecological vegetation layer should be compacted using a light roller (≤5t), with the compaction degree controlled at 85%-90% to prevent the compression of large gaps in the lower low-carbon layer. In the later stages, debris on the vegetation carpet should be cleaned every quarter, and the soil should be loosened every spring to avoid the decrease in connectivity caused by soil compaction, ensuring "unimpeded transmission" of CO2 from the air to the bottom of the low-carbon layer.

[0128] The above-described embodiments already enable the road-bridge transition section structure to have good carbon capture capabilities. However, due to the lack of real-time monitoring, the carbon capture and carbon sequestration functions are prone to lack of continuity, and the carbon capture and carbon sequestration effects are not optimal. Therefore, the present invention makes the following improvements based on the above-described embodiments.

[0129] Furthermore, it also includes a carbon capture monitoring module, which comprises several carbon dioxide concentration sensors 401, several activator injection pipes 402, a first central control unit 403, a first data acquisition unit 404, and an activator intelligent delivery device 405. The several carbon dioxide concentration sensors 401 are embedded within the carbon capture layer 203 to detect CO2 concentration, and are connected to the first data acquisition unit 404. The activator injection pipes 402 are embedded at the bottom of the carbon capture layer 203, and have several outlet holes arranged along their length on their walls. The several activator injection pipes 402 are connected to the activator intelligent delivery device 405. The intelligent delivery device 405 is connected to the first data acquisition unit 404 at its input end and the intelligent delivery device 405 at its output end. Specifically, the intelligent delivery device 405 includes a storage tank and a frequency converter pump. The storage tank stores carbonization activator. The input end of the frequency converter pump is connected to the storage tank, and the output end is connected to several activator injection pipes. The frequency converter pump is also electrically connected to the first control unit 403 and dynamically adjusts the amount of carbonization activator injected under the command of the first control unit 403 to ensure that it is replenished as needed and to avoid waste. The output end of the frequency converter pump is also equipped with a flow sensor for real-time monitoring of the amount of carbonization activator injected.

[0130] Employs a high-precision carbon dioxide concentration sensor (e.g., per 1m). 3 One unit is deployed, with a sampling frequency of once per hour. The carbon absorption is calculated by detecting changes in CO2 concentration in the packing layer. When the carbon absorption is ≥6 kg / m³, the reaction is normal, and the first central control unit does not activate. When the carbon absorption is <3 kg / m³ (e.g., Ca...), the carbon absorption is significantly reduced. 2+ (Excessive consumption, insufficient CO2 supply) triggers the "replenishment" command in the first central control unit. Upon triggering, the first central control unit automatically opens the activator injection pipe (PE pipe, 2-3mm orifice diameter, for example, each pipe controlling a radial range of 1.5-2.0m within the packing material), replenishing the composite packing with carbonization activator. The injected activator permeates evenly along the outlet holes (distributed in a quincunx pattern, with a hole spacing of 100-150mm), specifically replenishing Ca. 2+ Restart the carbon capture reaction; the injection rate is automatically adjusted according to the carbon absorption gap (e.g., a gap of 2 kg / m³). 3 (Correspondingly, 0.5% activator is injected) to avoid waste.

[0131] In a specific embodiment, the first central control unit may be a Siemens S7-1200 G2 series PLC (a new generation of compact controller) or a Zhejiang University Control AR7000 series touch screen paperless recorder (integrating data monitoring and control), and the first data acquisition unit may be an Advantech ADAM-4017+ multi-channel analog acquisition unit (industrial-grade RS485 bus type) or a DataTaker DT85G geotechnical engineering dedicated data acquisition unit (supporting remote wireless transmission).

[0132] It is important to note that CO2 and Ca... 2+ The reaction requires a certain level of humidity (optimal moisture content 15%-20%): when the moisture content is <12%, Ca... 2+ Dissolution is hindered, and the reaction stagnates; when the moisture content is >25%, CO2 is difficult to penetrate and easily leads to softening of the packing material. Therefore, this invention monitors the moisture content of the carbon capture section to achieve optimal capture efficiency.

[0133] Furthermore, it also includes a moisture content monitoring module, which comprises several moisture content sensors 501, a watering device 502, a ventilation device 503, a second data acquisition unit 504, and a second central control unit 505. The several moisture content sensors 501 are embedded in the carbon capture layer 203, and the second data acquisition unit 504 is connected to the several moisture content sensors 501. The watering device 502 is provided with a watering pipe 5021, which extends and is embedded in the carbon capture layer 203. The ventilation device 503 is provided with a ventilation duct 5031, which extends and is embedded around the carbon capture layer 203. The input end of the second central control unit 505 is connected to the second data acquisition unit 504, and the output end is connected to the watering device 502 and the ventilation device 503.

[0134] In a specific embodiment, the moisture content sensor is used every 2m. 3 One unit can be installed, with 1-3 layers, to monitor the moisture content of the packing material and prevent excessive moisture from affecting carbonization efficiency. The sprinkler pipe 5021 is mainly installed above the carbon capture layer 203. The second central control unit can use a Mitsubishi FX5U series PLC or a Delta DVP-ES2 series PLC, and the second data acquisition unit can use an Omron CP1W-AD041 analog acquisition unit or an Advantech ADAM-4017.

[0135] The sprinkler system is shallowly buried, with micro-spray / drip irrigation pipelines laid out along the shallow layer inside the carbon capture layer according to the sensor monitoring misalignment area, avoiding the root system of ecological vegetation; the ventilation system uses pre-reserved ventilation pipelines at bridge abutments and road connection sections, combined with pre-buried ventilation pipelines on the side of the carbon capture layer, to connect small low-noise pipe fans, forming airflow circulation using the gaps in the connection sections. All of these are linked to the second central control unit to respond to moisture content data. When the moisture content is off, the ventilation system is activated to reduce the moisture content of the carbon capture section.

[0136] Before rainwater penetrates the surface vegetation blanket / protective layer, most of the accumulated water is drained horizontally (the surface ecological layer, which serves as a road shoulder, is usually sloped), reducing the amount of rainwater infiltrating into the filler layer. For the small amount of rainwater that has already infiltrated into the low-carbon composite filler, ventilation ducts can be used to allow the rainwater to evaporate quickly to reach a suitable moisture content range, preventing rainwater from stagnating in the filler layer (especially after the geomembrane blocks downward drainage).

[0137] In addition, settlement sensors (one every 5m) can be installed on the surface of the road-bridge transition section along the length of the transition section to monitor differential settlement.

[0138] The moisture content of the carbon capture layer is crucial for the carbon capture and storage capabilities of the composite packing. Both excessively high and low moisture content will reduce the carbon capture efficiency of the composite packing. Typically, the optimal moisture content range for the aforementioned composite packing is 15%-20%. Therefore, this invention employs various measures to control water content and ensure carbon capture efficiency.

[0139] (1) First layer: Structural water control - blocking external water intrusion and locking in internal water stability;

[0140] By designing the functional layers of the carbon capture core section, external rainwater and groundwater are reduced from a physical perspective, while internal moisture evaporation or loss is also reduced. This is the basis for water control.

[0141] 1) Ecological seepage barrier layer: blocks the infiltration of external groundwater sources;

[0142] Core function: The ecological seepage-proof layer is set below the low-carbon first composite filler layer. As a "waterproof barrier" in the transition section, it can block groundwater and lateral seepage water from invading the low-carbon filler layer, avoid a sudden increase in water content, and ensure its stable performance.

[0143] Technical details: Uses recycled plastic modified geomembrane (thickness ≥ 1.5mm, permeability coefficient ≤ 1×10⁻⁶). -10 cm / s), the overlap is hot-melt welded (welding temperature 180-200℃, pressure holding for 30min with no pressure drop) to form a "seamless waterproof membrane"; the geomembrane is laid on the top surface of the base reinforcement layer, directly covering the low carbon filler layer below, cutting off the path of external water to the filler from the source.

[0144] 2) Surface vegetation layer: regulates surface runoff and evaporation;

[0145] Runoff control: The root system of the ecological vegetation blanket (containing alfalfa and bermudagrass) forms a "surface cover layer" to slow down the rate of rainwater erosion. At the same time, the planting soil (50-80mm thick) can temporarily store rainwater and consume it through vegetation transpiration, preventing rainwater from directly collecting and seeping into the filler layer.

[0146] Moisture retention: The vegetation layer reduces direct evaporation of moisture from the surface of the low-carbon composite filler layer. During the high temperatures of summer, the vegetation blocks sunlight, reducing the rate of moisture loss on the surface of the composite filler layer by 30%, thus maintaining stable internal moisture levels.

[0147] 3) Base reinforcement layer: to prevent groundwater backflow;

[0148] Compacted seepage prevention: The base reinforcement layer adopts "cement-stabilized crushed stone + waste steel fiber" (compaction degree ≥96%). The high-density structure can block the rise of underground capillary water to the low-carbon filler layer. If the groundwater level at the project site is high, a 100mm thick graded crushed stone blind ditch can be added below the base reinforcement layer to quickly drain groundwater and avoid back seepage.

[0149] (2) Second layer: Active monitoring - real-time monitoring of moisture content dynamics;

[0150] By collecting data in real time using a moisture content sensor, the moisture status of the low-carbon composite filler can be accurately determined, providing a basis for regulation and avoiding "blindly adding or draining water".

[0151] 1) Sensor deployment and monitoring logic;

[0152] Deployment density: One moisture content sensor is deployed every 2m², embedded in the upper part of the low-carbon composite packing layer (200-300mm deep, avoiding the surface evaporation zone and the bottom seepage prevention zone) to ensure that the monitoring data reflects the moisture status of the core reaction zone of the packing.

[0153] Monitoring frequency: In conjunction with the central control unit, data is collected every 30 minutes, and the moisture content value is transmitted in real time. When the data is below 15% (water shortage in the reaction) or above 20% (water accumulation in the reaction), the central control unit is triggered to issue an adjustment command.

[0154] 2) Data calibration and anomaly warning;

[0155] On-site calibration: The sensor data is calibrated quarterly using the "alcohol combustion method" (weighing a filler sample → burning to remove water → weighing again) to avoid misjudgment due to sensor drift;

[0156] Abnormal warning: If the moisture content rises suddenly in a short period of time (e.g., from 18% to 22% in 1 hour), it may be due to damage to the seepage prevention layer. The central control unit will immediately trigger an audible and visual warning to prompt on-site inspection and repair.

[0157] (3) Third layer: dynamic regulation - replenishing water when water is scarce and draining water when water is plentiful, precisely maintaining the optimal range;

[0158] According to monitoring data, the moisture content is stabilized at 15%-20% through "targeted water replenishment" or "assisted drainage" measures to ensure the efficiency of carbon capture reaction.

[0159] 1) In case of water shortage: replenish water in a targeted manner (moisture content <15%).

[0160] Hydration method: Hydration is achieved through two pathways to prevent localized areas from becoming too dry or too wet:

[0161] Surface watering: Use the watering system of the surface ecological vegetation layer (automatic sprinkler heads can be set up at 5m intervals) to water the planting soil. The water slowly seeps into the low carbon filler layer through the vegetation roots. The watering rate is controlled at 0.5L / m²·h to avoid rapid infiltration that could cause a sudden increase in local moisture content.

[0162] Deep water replenishment: If the lower part of the packing layer is short of water, a mixture of "carbonization activator + water" (water content 95%) can be slowly injected through the activator injection tube of the carbon capture monitoring module. This replenishes the water without affecting the function of the activator. After replenishing the water, let it stand for 24 hours until the water is evenly diffused before monitoring and adjustment.

[0163] 2) In case of water accumulation: assist with drainage (moisture content > 20%).

[0164] Surface drainage: Set a drainage slope for the ecological vegetation layer for surface drainage. Alternatively, lay a 50mm thick gravel blind ditch under the surface vegetation blanket in the waterlogged area to guide the water to drain laterally to the drainage ditches on both sides of the road-bridge transition section.

[0165] Deep drainage: If water accumulates inside the filler layer (such as when the impermeable layer temporarily fails after a rainstorm), a hole (50mm in diameter, to the bottom of the filler layer) can be drilled in the waterlogged area. A gravel filter pipe wrapped with permeable geotextile can be inserted to drain the water through gravity. Once the moisture content drops to about 18%, the filter pipe can be pulled out and the hole can be backfilled with filler of the same proportion.

[0166] (4) Water control during construction: Locking in the initial moisture content in advance;

[0167] In addition to water control during service life, moisture content control during construction is also crucial. Ensuring that the low-carbon composite filler layer reaches the optimal state of 15%-20% during paving lays the foundation for subsequent adjustments.

[0168] 1) Pretreatment of filler: When mixing industrial solid waste composite aggregate, add an appropriate amount of water in advance according to the weather conditions (such as dry and windy days), and use a "rapid moisture analyzer" to detect it in real time to ensure that the initial moisture content of the filler after mixing is 17%-18% (leaving room for slight evaporation).

[0169] 2) Covering after spreading: If compaction is not completed on the same day after the low-carbon composite filler layer is spread in layers, it is necessary to cover it with waterproof geotextile to avoid rainwater erosion or water evaporation causing fluctuations in moisture content.

[0170] 3) Activator injection pipe: PE pipe (diameter 25-30mm) is used, which is laid along the length of the transition section at a spacing of 1.5-2m. The pipe body is opened with liquid outlet holes with a diameter of 2-3mm (hole spacing 100-150mm, plum blossom distribution) to replenish carbonization activator to the low carbon filler layer.

[0171] 4) Second Central Control Unit: Electrically connected to each moisture content sensor, integrating data acquisition, analysis, and control functions, and can be connected to a remote operation and maintenance platform. When the carbon dioxide concentration sensor detects that the carbon absorption is below 3 kg / m³... 3 At that time, the activator injection tube is automatically opened and closed to replenish the carbonization activator;

[0172] ① A carbon dioxide concentration sensor monitors the reaction progress of CO2 with the packing material in real time (sampling frequency: once per hour).

[0173] ② The activator injection pipe replenishes the carbonization activator (calcium hydroxide + gypsum), and by adjusting the pH value of the system (maintaining an alkaline environment of 10-12), the carbonization activator in the steel slag is accelerated. 2+ The carbonization reaction with CO2 (to produce CaCO3) ensures a carbon capture efficiency of ≥6 kg / m³. 3 .

[0174] In summary, the road-bridge transition section structure with carbon capture function described in this invention has the following advantages:

[0175] (1) Improved engineering performance:

[0176] a) Strength and stability: The 7-day unconfined compressive strength of the low-carbon composite filler (carbon capture layer) is ≥3.5MPa, which is 25%-36% higher than that of conventional crushed stone filler, and its resistance to loosening is enhanced; the shear stud design of the bridge abutment connection section increases the shear strength of the connection by more than 40%, and the gradual stiffness design of the roadbed connection section ensures that the differential settlement is ≤5mm, which meets the requirements of driving comfort on highways;

[0177] b) Impermeability: The permeability coefficient of the recycled plastic modified geomembrane is ≤1×10⁻⁶. -10 cm / s, effectively blocking the intrusion of groundwater from the top and sides; combined with the surface gravel blind ditch and other drainage systems, it quickly discharges the small amount of rainwater that seeps into the filler layer, avoiding foundation erosion and excessive moisture content in the filler layer.

[0178] c) Maintenance cycle: The overall damage resistance of the road-bridge transition section is improved, and the maintenance cycle is extended from 3-5 years to 10-12 years or even longer, with significantly enhanced stability throughout the entire life cycle.

[0179] (2) Significant environmental benefits:

[0180] a) Solid waste resource utilization: Each kilometer of transition section can dispose of approximately 150 m³ of steel slag and approximately 50 m³ of fly ash, reducing the solid waste storage area by approximately 200 m³, while consuming approximately 0.8 t / km of waste PE plastic, thus achieving the synergistic utilization of multiple types of solid waste.

[0181] b) Carbon emission reduction and carbon capture: Carbon emissions during the construction phase are reduced by 45%-50% compared to the conventional transition phase (carbon emissions from industrial solid waste transportation are only 1 / 3 of those from natural sand and gravel); carbon absorption during service phase is ≥6kg / m³. 3 Each kilometer of transition section can capture approximately 3 tons of carbon annually. Based on the current carbon price of 60 yuan / ton, the annual carbon credit revenue is approximately 180 yuan / kilometer, which can be incorporated into the engineering carbon sink system.

[0182] (3) Outstanding economic benefits:

[0183] a) Reduced material costs: The unit price of industrial solid waste composite aggregate is approximately 50 yuan / m³. 3 Compared to natural crushed stone (80 yuan / m³) 3 This reduces costs by 37.5%, saving approximately 15,000 yuan per kilometer in material costs for the transition section.

[0184] b) Reduced maintenance costs: The maintenance cycle is extended to 10-12 years, and the total life cycle maintenance cost is reduced by more than 65%. The total maintenance cost per kilometer of transition section can be reduced by about 80,000 to 100,000 yuan.

[0185] Traditional technologies focus only on single engineering functions such as gradual stiffness change, seepage prevention, and anti-slip properties, failing to achieve an integrated design encompassing "industrial solid waste resource utilization, carbon capture, intelligent monitoring, and stiffness coordination." However, this invention can achieve this.

[0186] Implementation method two;

[0187] Please see Figure 1 This embodiment provides a construction method for a road-bridge transition section structure with carbon capture function, including the following steps:

[0188] Clear debris from the transition section between the road and bridge and compact the foundation.

[0189] Lay a base reinforcement layer, and lay an ecological seepage-proof layer on the base reinforcement layer located in the carbon capture core section; use the first composite aggregate to lay the carbon capture layer; during the laying of the carbon capture layer, use the first composite aggregate to lay the bridge abutment connection section in layers and simultaneously; lay the roadbed connection section in layers and simultaneously.

[0190] The pavement structure layer connecting the road and bridge is laid, and the surface ecological layer is laid on both sides of the pavement structure layer to form the carbon capture core section; the bridge abutment connection section and the roadbed connection section are continued to be laid until they are flush with the carbon capture core section to form the road-bridge transition section structure.

[0191] The detailed construction process is as follows.

[0192] 1) Foundation treatment: Remove the topsoil of the transition section (removal depth ≥300mm), and compact the foundation with a heavy roller (compaction degree ≥95%).

[0193] 2) Construction of base reinforcement layer: Lay the base reinforcement layer in layers (each layer is 100-125mm thick) and compact it (6-8 times of compaction, compaction speed 2-3km / h).

[0194] 3) Construction of ecological seepage prevention layer: A recycled plastic modified geomembrane is laid on the top surface of the base reinforcement layer. The overlap is welded by hot melt welding (welding temperature 180-200℃, welding speed 1.5-2m / min). After welding, the air tightness test is carried out (air pressure 0.2MPa, pressure holding time ≥30min, no pressure drop is qualified).

[0195] 4) Construction of low-carbon composite filler layer: Mix industrial solid waste composite aggregate, carbonization activator and functional additives according to the ratio (mixing time ≥3min, mixing uniformity ≥95%), and spread in layers (spread in 2-3 layers, each layer 200-300mm), and compact with intelligent road roller (real-time monitoring of compaction degree to ensure ≥97%); bridge abutment connection section, roadbed connection section and carbon capture core section are laid and compacted in layers and simultaneously (the mixing and spreading interval between bridge abutment connection section, roadbed connection section and carbon capture layer shall not exceed 2 hours, the overlap width shall be ≥500mm, compacted with intelligent road roller, compaction degree ≥97%, 6-8 times of compaction, and compaction speed 2-3km / h).

[0196] 5) Installation of carbon capture monitoring module and moisture content monitoring module: During the paving of the first composite filler, install the activator injection pipe, carbon dioxide concentration sensor, moisture content sensor, ventilation pipe and water sprinkler pipe according to the design elevation. Multiple carbon concentration and moisture content sensors are arranged at the design spacing. The sensor leads are run through Φ20mm PVC protective pipe (with reserved expansion section) and connected to the first and second central control units. During installation, avoid drainage components and ensure close contact with the first composite filler. Lay the activator injection pipe (with the pipe body wrapped with reverse filter geotextile) along the length of the transition section. The liquid outlet faces the inside of the filler layer and is fixed with U-shaped buckles. Avoid drainage blind ditches and geogrids. Both ends are exposed and sealed.

[0197] 6) Construction of surface ecological vegetation layer: When the composite filler reaches the bottom elevation of the pavement structure layer, first lay the pavement structure layer on the surface of the road-bridge transition section to connect it with the road-bridge at both ends. Then lay ecological vegetation blankets on the top surface of the low-carbon composite filler layer and on both sides of the pavement structure layer, cover with 50-80mm thick planting soil, and water for maintenance (maintenance cycle 7-10 days, keep soil moisture content 15%-20%).

[0198] 7) During the later operation and maintenance period, carbon absorption and moisture content are collected in real time through the first and second central control units. When the carbon absorption is lower than 3 kg / m³, the system will detect the carbon absorption rate. 3When the activator injection pipe is activated, it will automatically open to replenish the carbonization activator; when the moisture content is insufficient or too high, water will be controlled through ventilation equipment or sprinkler equipment; on-site verification will be carried out every six months to ensure stable operation of the system.

[0199] The above description is only used to illustrate the technical solution of the present invention and is not intended to limit it. Any modifications or substitutions made by other people skilled in the art to the technical solution, as long as they do not depart from the connotation of the technical solution of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A road-bridge transition section structure with carbon capture function, characterized in that, The system includes a carbon capture core section, an abutment connection section between the carbon capture core section and the abutment, and a roadbed connection section between the carbon capture core section and the roadbed. A base reinforcement layer is provided at the bottom of the abutment connection section, the bottom of the carbon capture core section, and the bottom of the roadbed connection section. The carbon capture core section, from bottom to top, includes an ecological impermeable layer, a carbon capture layer, and a surface ecological layer. A pavement structure layer connecting to the road and bridge is provided at the top of the abutment connection section, the middle of the surface ecological layer, and the top of the roadbed connection section. The carbon capture layer is paved with a first composite aggregate, which includes 45%-60% by weight of graded crushed stone, 30%-40% by weight of steel slag, and 10%-15% by weight of fly ash. The particle sizes of the graded crushed stone, steel slag, and fly ash range from 20-40 mm, 5-20 mm, and 75-300 μm, respectively.

2. The road-bridge transition section structure with carbon capture function according to claim 1, characterized in that, The first composite aggregate of the carbon capture layer also contains a carbonization activator.

3. The road-bridge transition section structure with carbon capture function according to claim 2, characterized in that, The carbonization activator is a calcium hydroxide-gypsum activator with a mass content of 2%-3%; or a fly ash-active magnesium oxide activator with a mass content of 5%-8%; or a steel slag-based composite activator with a mass content of 2%-4%; or a triethanolamine activator with a mass content of 0.3%-0.8%; or a carbonic anhydrase-sodium alginate composite synergistic activator with a mass content of 0.5%-1.2%.

4. The road-bridge transition section structure with carbon capture function according to claim 3, characterized in that, It also includes a carbon capture and monitoring module, which comprises several carbon dioxide concentration sensors, several activator injection tubes, a first central control unit, a first data acquisition unit, and an intelligent activator delivery device. The several carbon dioxide concentration sensors are embedded in the carbon capture layer and connected to the first data acquisition unit. The several activator injection tubes are embedded in the carbon capture layer and have several liquid outlet holes arranged along their length. The several activator injection tubes are connected to the intelligent activator delivery device. The input end of the first central control unit is connected to the first data acquisition unit, and the output end is connected to the intelligent activator delivery device.

5. The road-bridge transition section structure with carbon capture function according to claim 4, characterized in that, It also includes a moisture content monitoring module, which comprises several moisture content sensors, a water spraying device, a ventilation device, a second data acquisition unit, and a second central control unit. The several moisture content sensors are embedded in the carbon capture layer and are connected to the second data acquisition unit. The water spraying device has a water spraying pipeline that extends and is embedded in the carbon capture layer. The ventilation device has a ventilation duct that extends and is embedded around the carbon capture layer. The input end of the second central control unit is connected to the second data acquisition unit, and the output end is connected to the water spraying device and the ventilation device.

6. The road-bridge transition section structure with carbon capture function according to claim 5, characterized in that, The moisture content of the carbon capture layer ranges from 15% to 20%.

7. The road-bridge transition section structure with carbon capture function according to claim 6, characterized in that, The base reinforcement layer located at the bottom of the carbon capture core section is constructed from a mixture of industrial solid waste-based composite cementitious material, cement-stabilized crushed stone, and waste steel fiber. The cement-stabilized crushed stone accounts for 3%-4% of the mass of the industrial solid waste-based composite cementitious material, and the waste steel fiber accounts for 0.8%-1% of the mass of the base reinforcement layer mixture.

8. The road-bridge transition section structure with carbon capture function according to claim 7, characterized in that, The first composite aggregate of the carbon capture layer is also mixed with functional additives, including at least one of nano-calcium carbonate and bio-enzyme stabilizer. The mass content of nano-calcium carbonate relative to the first composite aggregate is 0.1%-0.3%, and the mass content of bio-enzyme stabilizer relative to the first composite aggregate is 0.02%-0.1%.

9. The road-bridge transition section structure with carbon capture function according to any one of claims 1-8, characterized in that, The roadbed connection section is paved with a second composite aggregate. The second composite aggregate includes graded crushed stone, steel slag, and fly ash. Its proportion at the point closest to the carbon capture core section is the same as that of the first composite aggregate. As it extends from the point close to the carbon capture core section to the point close to the roadbed, the amount of steel slag and fly ash decreases. When it is closest to the roadbed, the mass content of steel slag, fly ash, and graded crushed stone is 30%, 10%, and 60%, respectively.

10. The road-bridge transition section structure with carbon capture function according to claim 9, characterized in that, The bridge abutment connection section is constructed by uniformly paving with the first composite aggregate, and shear-resistant components are provided at the connection between the bridge abutment connection section and the bridge abutment.

11. The road-bridge transition section structure with carbon capture function according to any one of claims 1-8, characterized in that, The ecological seepage-proof layer adopts one of the following: recycled plastic modified geomembrane, bentonite waterproof blanket, and tailings sand-bentonite mixed seepage-proof material; the surface ecological layer includes planting soil and ecological vegetation blanket laid on the surface of planting soil, and the ecological vegetation blanket is planted with perennial herbaceous plants of the grass family and leguminous family with good air permeability.

12. The construction method of the road-bridge transition section structure with carbon capture function according to any one of claims 1-8, characterized in that, Includes the following steps: Clear debris from the transition section between the road and bridge and compact the foundation. Lay a base reinforcement layer, and lay an ecological seepage-proof layer on the base reinforcement layer located in the carbon capture core section; use the first composite aggregate to lay the carbon capture layer; During the laying of the carbon capture layer, the first composite aggregate is used to lay the bridge abutment connection section in layers and simultaneously, and the roadbed connection section is laid in layers and simultaneously. The pavement structure layer connecting the road and bridge is laid, and the surface ecological layer is laid on both sides of the pavement structure layer to form the carbon capture core section; the bridge abutment connection section and the roadbed connection section are laid simultaneously until they are flush with the carbon capture core section to form the road-bridge transition section structure.

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