Tunnel anti-collision wall concrete and preparation method and application thereof

Abstract

This application relates to the technical field of concrete, specifically disclosing a concrete for tunnel crash barriers, its preparation method, and its application. The concrete for tunnel crash barriers of this application comprises the following components: 180-220 parts cement, 70-110 parts carbon mineralized materials, 10-15 parts hollow glass microspheres, 1-1.6 parts foaming agent, 0.4-0.7 parts foam stabilizer, 3-9 parts water-reducing agent, 0.6-2 parts fiber, and 130-180 parts mixing water. The preparation method of the carbon mineralized materials is as follows: take 100-300 parts by weight of the mineral materials and 10-50 parts by weight of water, inject 20%-100% CO2 at a flow rate of 1-3 L / min, grind at 400-600 rpm for 20-60 min; dry to constant weight, finely crush and sieve to obtain the final product. The above-mentioned concrete for tunnel crash barriers exhibits long-term stable collapse energy absorption, and excellent impact toughness and freeze-thaw resistance.

Description

Technical Field

[0001] This application relates to the technical field of concrete, specifically to a type of concrete for tunnel crash barriers, its preparation method, and its application. Background Technology

[0002] Tunnels, as a crucial component of modern transportation infrastructure, play a vital role in highways, railways, and urban transportation networks. With increasing traffic volume and vehicle speeds, traffic safety issues within tunnels are becoming increasingly prominent. The enclosed environment and limited space of tunnels make rescue and evacuation more difficult in the event of a traffic accident. Therefore, preventing vehicles from colliding with tunnel walls and reducing traffic accidents has become a key consideration in tunnel design and construction.

[0003] Currently, common tunnel collision prevention measures mainly include the installation of guardrails, crash barriers, and crash walls. Traditional tunnel crash walls are typically made of concrete, reinforced concrete, or metal, relying on their high strength and durability to withstand the impact of vehicle collisions. However, these crash walls have drawbacks in practical applications, such as excessive rigidity, high construction difficulty, high maintenance costs, and high material costs.

[0004] To address the aforementioned issues, patent CN108004986B provides a tunnel crash barrier formwork reinforcement system and construction method to solve quality problems in existing technologies, such as poor concrete forming quality, non-square corners, and grout leakage. Patent CN217440044U provides a convenient installation and dismantling device for tunnel crash barrier steel formwork. However, these inventions still use rigid materials such as concrete and steel structures as the crash barrier base, which is insufficient to absorb the impact force of accident vehicles, causing damage to the tunnel structure.

[0005] Therefore, there is an urgent need for a new type of tunnel crash barrier and its preparation method to improve the energy absorption capacity of the crash barrier, simplify the construction process, reduce maintenance and material costs, thereby improving the overall safety and economy of the tunnel. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, this application provides concrete for tunnel crash barriers, its preparation method, and its application.

[0007] In a first aspect, this application provides a concrete for a tunnel crash barrier, specifically comprising the following components by weight: 180-220 parts cement, 70-110 parts carbon mineralized materials, 10-15 parts hollow glass microspheres, 1-1.6 parts foaming agent, 0.4-0.7 parts foam stabilizer, 3-9 parts water-reducing agent, 0.6-2 parts fiber, and 130-180 parts mixing water;

[0008] The mixing water is selected from at least one of sodium bicarbonate aqueous solution and carbonated water;

[0009] The preparation method of the carbon mineralized mineral material is as follows:

[0010] Weigh out 100-300 parts by weight of mineral material and 10-50 parts by weight of water, and place them in a grinding jar equipped with grinding balls; inject 20%-100% CO2 at a flow rate of 1-3 L / min, and grind at 400-600 rpm for 20-60 min; then dry to constant weight, crush and sieve to obtain the final product; the mineral material is selected from one or more of the following: carbonized yellow phosphorus slag, carbonized calcium carbide slag, carbonized cement clinker, carbonized steel slag, and carbonized magnesium slag.

[0011] This application utilizes the above-mentioned technical solution to prepare carbon mineralized mineral materials, and by screening and using cement, carbon mineralized mineral materials, hollow glass microspheres, foaming agent, foam stabilizer, water-reducing agent, fiber, and mixing water as raw material components of concrete, the prepared tunnel anti-collision wall concrete has long-term stable collapse energy absorption, and excellent impact toughness and freeze-thaw resistance.

[0012] Preferably, the hollow glass microspheres have a particle size ≤60μm and an actual density ≤0.6g / cm³. 3 .

[0013] Preferably, the foaming agent is hydrogen peroxide with a mass concentration of 10-35%.

[0014] In some specific implementations, the mass concentration of the hydrogen peroxide can be 10-20% or 20-35%.

[0015] In one specific implementation, the mass concentration of the hydrogen peroxide can also be 10%, 20%, or 35%.

[0016] Experimental analysis shows that selecting hydrogen peroxide of the above-mentioned mass concentration as a foaming agent in this application can further improve the performance of concrete.

[0017] Preferably, the foam stabilizer is selected from one or more of methyl cellulose ether (MC), hydroxyethyl cellulose ether (HEC), hydroxyethyl methyl cellulose ether (HEMC), hydroxypropyl methyl cellulose ether (HPMC), stearate series foam stabilizers, styrene-butadiene emulsion, and ethylene-vinyl acetate emulsion.

[0018] Furthermore, the foam stabilizer is composed of a mixture of hydroxypropyl methylcellulose ether and styrene-butadiene emulsion in a weight ratio of 7:0.5-1.5.

[0019] Experimental analysis shows that the foam stabilizer composed of the above-mentioned weight ratio of hydroxypropyl methylcellulose ether and styrene-butadiene emulsion can further improve the performance of concrete.

[0020] Preferably, the water-reducing agent is selected from one or more of polycarboxylate-based water-reducing agents and naphthalene-based water-reducing agents.

[0021] Preferably, the fiber is selected from one or more of polypropylene fiber, polyvinyl alcohol fiber, and carbon fiber.

[0022] Preferably, the mixing water is an aqueous solution of sodium bicarbonate with a molar concentration of 0.10 to 0.75 mol / L.

[0023] In some specific embodiments, the molar concentration of the sodium bicarbonate aqueous solution can be 0.10–0.25 mol / L, 0.10–0.4 mol / L, 0.10–0.55 mol / L, 0.25–0.4 mol / L, 0.25–0.55 mol / L, 0.25–0.75 mol / L, 0.4–0.55 mol / L, 0.4–0.75 mol / L, or 0.55–0.75 mol / L.

[0024] In one specific embodiment, the molar concentration of the sodium bicarbonate aqueous solution may also be 0.10 mol / L, 0.25 mol / L, 0.4 mol / L, 0.55 mol / L, or 0.75 mol / L.

[0025] Experimental analysis shows that selecting the above-mentioned molar concentration of sodium bicarbonate aqueous solution as mixing water in this application can further improve the performance of concrete.

[0026] Based on the above, the inventors of this application have discovered that in the formulation system for preparing concrete for tunnel crash barriers, there is mutual selectivity among foaming agents, foam stabilizers, mixing water, and carbon mineral materials. Different types and specifications of raw materials have a significant impact on the impact toughness and freeze-thaw resistance of concrete. This application further improves the performance of concrete by further screening the types and specifications of foaming agents, foam stabilizers, and mixing water.

[0027] Secondly, this application provides a method for preparing the concrete for the aforementioned tunnel crash barrier, specifically including the following steps in sequence:

[0028] First, weigh out the cement, carbon mineral materials, hollow glass microspheres and fibers, then pour them into a mixer and mix for 10-60 seconds until uniform.

[0029] Add mixing water, foam stabilizer, and water-reducing agent. Stir at 200-600 rpm for 60-600 seconds, then stir at 1000-3000 rpm for 10-60 seconds.

[0030] Add foaming agent and stir at 1000-3000 rpm for 10-60 seconds to obtain slurry;

[0031] The slurry is poured into a mold with a tenon and mortise structure and left to stand for 0.5 to 2 hours to allow it to foam.

[0032] After curing in a curing room for 24–48 hours, demold and continue curing for 28–180 days to obtain the product.

[0033] Thirdly, this application provides a tunnel crash barrier, which is prepared using the aforementioned tunnel crash barrier made of concrete.

[0034] Fourthly, this application provides a method for preparing the above-mentioned tunnel crash barrier, which specifically includes the following steps: transporting the cured tunnel crash barrier to the pre-paving position of the tunnel crash barrier with concrete, assembling modular bodies with mortise and tenon structures, and installing panels on the modular bodies to obtain the tunnel crash barrier.

[0035] In summary, the technical solution of this application has the following effects:

[0036] The technical solution of this application will overcome the shortcomings of low resource utilization efficiency and high environmental pollution of yellow phosphorus slag and calcium carbide slag, as well as the high dust, low efficiency, and high energy consumption of cement clinker, steel slag, and magnesium slag in traditional grinding processes. By employing a wet grinding method with an appropriate water-to-solid ratio and carbon dioxide injection, under the effect of mechanochemical coupling, the particle size of yellow phosphorus slag and calcium carbide slag decreases, and the ion dissolution rate accelerates. During the carbon mineralization reaction, calcite, aragonite, and spheroidal CaCO3 are generated. These products overlap and, with their larger specific surface area, act as reactants, nucleating agents, and inert fillers during hydration. The mechanochemical coupling will destroy the passivation layer on the material surface, forming new surfaces available for carbon mineralization, further increasing the carbon dioxide absorption from the raw material end and reducing carbon emissions in the building materials industry, which has significant environmental protection implications. Furthermore, the incompletely carbon-mineralized Ca(OH)2 present in the calcium carbide slag will improve further cement hydration and stabilize the mechanical properties of the matrix.

[0037] The technical solution of this application utilizes sodium bicarbonate aqueous solution and carbonated water as mixing water, which enhances the carbon dioxide absorption effect and increases the amount of carbon dioxide absorbed. Furthermore, it is rich in HCO3-. - / CO3 2- It can accelerate the hydration of the slurry, acting as a quick-setting agent, without the need to add additional accelerators. It ensures early strength growth while improving mold utilization efficiency and production efficiency.

[0038] The concrete used for tunnel crash barriers prepared by the technical solution of this application has a crush strength of 0.5 to 0.6, a crushing strength of 0.30 to 0.40 MPa, and an impact toughness greater than 6000 J. It can withstand long-term and stable crushing and energy absorption according to design standards, providing the buffering effect required for emergency avoidance of various types of accident vehicles and ensuring the safety of vehicles and personnel.

[0039] The technical solution of this application, by specifically selecting the types and specifications of foaming agents, foam stabilizers and mixing water, works synergistically with carbon mineral materials to produce a more superior technical effect, thereby further improving the freeze-thaw resistance of the prepared concrete.

[0040] The technical solution of this application features mortise and tenon structure blocks that facilitate quick splicing and installation, and can be tightly fixed together without the need for additional surface adhesives, reducing engineering costs, improving construction efficiency and overall structural stability. After the tunnel crash barrier has been used, it can be directly replaced or repaired, significantly reducing usage costs. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the tunnel crash barrier of this application; the attached diagram is labeled as follows: 1-road surface; 2-crash barrier; 3-side wall; 4-roof slab. Detailed Implementation

[0042] The present application will be further described in detail below with reference to embodiments, comparative examples and performance test results. These embodiments should not be construed as limiting the scope of protection claimed in this application.

[0043] Yellow phosphorus slag was purchased from Guizhou Phosphate Plant; calcium carbide slag was purchased from Henan Wuhu Environmental Protection Technology Co., Ltd.; polycarboxylate superplasticizer was purchased from Jiangsu Subote New Material Co., Ltd.; polyvinyl alcohol fiber was purchased from Anhui Wanwei Group Co., Ltd.; hydroxyethyl cellulose ether was purchased from Shandong Feicheng Yutian Chemical Co., Ltd.; styrene-butadiene emulsion was purchased from Shandong Shengkai Chemical Co., Ltd.; hydroxypropyl methyl cellulose ether was purchased from Shijiazhuang Wenyu Wood Cellulose Trading Co., Ltd.; and ethylene-vinyl acetate emulsion was purchased from Guangzhou Zhonggao Chemical Co., Ltd.

[0044] Example

[0045] Examples 1-5

[0046] Examples 1-5 provide concrete for tunnel crash barriers and their preparation methods.

[0047] The difference in the above embodiments is that the amount of each component in the concrete for the tunnel crash barrier is different, as shown in Table 1.

[0048] The method for preparing concrete for tunnel crash barriers in the above embodiments is as follows:

[0049] Preparation of carbon mineralized mineral materials: Weigh a total of 2000g of mineral materials (1500g of carbon mineralized yellow phosphorus slag and 500g of carbon mineralized carbide slag) and 250g of water, and put them into a grinding jar equipped with ball milling beads; inject 50% CO2 at a flow rate of 2L / min, and grind at 200rpm for 40min; then dry to constant weight, grind finely and pass through a 75μm sieve to obtain the final product;

[0050] First, weigh out ordinary silicate cement, carbonaceous mineral materials, and hollow glass microspheres (particle size 50μm, actual density 0.5g / cm³). 3 ), polyvinyl alcohol fiber, then pour into a mixer and mix for 40 seconds until uniform;

[0051] Add 0.4 mol / L sodium bicarbonate aqueous solution, water, foam stabilizer (composed of hydroxypropyl methylcellulose ether and styrene-butadiene emulsion in a weight ratio of 7:1), and polycarboxylate superplasticizer. Stir at 400 rpm for 360 seconds, then at 2000 rpm for 30 seconds.

[0052] Add 20% hydrogen peroxide foaming agent and stir at 2000 rpm for 30 seconds to obtain a slurry;

[0053] The slurry was poured into a 1500mm×500mm×900mm mold with a tenon and mortise structure and allowed to stand for 1 hour to foam.

[0054] After curing in the curing room for 36 hours, the product is demolded and then cured for another 36 hours.

[0055] Table 1. Dosage of each component in the concrete used for tunnel crash barriers in Examples 1-5

[0056]

[0057] Examples 6-9

[0058] Examples 6-9 provide concrete for tunnel crash barriers and their preparation methods.

[0059] The difference between the above embodiments and Embodiment 1 is that the type of mixing water is different, as shown below.

[0060] In Example 6: the mixing water was a 0.10 mol / L sodium bicarbonate aqueous solution.

[0061] In Example 7: the mixing water was a 0.25 mol / L sodium bicarbonate aqueous solution.

[0062] In Example 8: the mixing water was a 0.55 mol / L sodium bicarbonate aqueous solution.

[0063] In Example 9: the mixing water was a 0.75 mol / L sodium bicarbonate aqueous solution.

[0064] All other process parameters in the above embodiments are the same as those in Embodiment 1.

[0065] Examples 10-14

[0066] Examples 10-14 respectively provide concrete for tunnel crash barriers and its preparation method.

[0067] The difference between the above embodiments and Embodiment 1 is that the types of foam stabilizers are different, as detailed below.

[0068] In Example 10: The foam stabilizer is composed of a mixture of hydroxyethyl cellulose ether and styrene-butadiene emulsion in a weight ratio of 7:1.

[0069] In Example 11: The foam stabilizer is composed of a mixture of hydroxypropyl methylcellulose ether and ethylene-vinyl acetate emulsion in a weight ratio of 7:1.

[0070] In Example 12: The foam stabilizer is composed of a mixture of hydroxypropyl methylcellulose ether and styrene-butadiene emulsion in a weight ratio of 1:7.

[0071] In Example 13: The foam stabilizer is composed of hydroxypropyl methylcellulose ether and styrene-butadiene emulsion in a weight ratio of 7:0.5.

[0072] In Example 14: The foam stabilizer is composed of a mixture of hydroxypropyl methylcellulose ether and styrene-butadiene emulsion in a weight ratio of 7:1.5.

[0073] All other process parameters in the above embodiments are the same as those in Embodiment 1.

[0074] Comparative Example

[0075] Comparative Examples 1-5

[0076] Comparative Examples 1-5 each provide a type of concrete and a method for its preparation.

[0077] The difference between the above comparative example and Example 1 is that the amount of each component in the concrete for the tunnel crash barrier is different, as shown in Table 1.

[0078] All other process parameters in the above comparative examples are the same as those in Example 1.

[0079] Comparative Example 6

[0080] Comparative Example 6 provides a type of concrete and a method for its preparation.

[0081] The difference between Comparative Example 6 and Example 1 is that the preparation methods of the carbon mineralized mineral materials are different, as detailed below.

[0082] In Comparative Example 6: Preparation of carbon mineralized mineral materials: Weigh a total of 2000g of mineral materials (1500g of carbon mineralized yellow phosphorus slag and 500g of carbon mineralized carbide slag), 250g of water, put them into a grinding jar equipped with ball milling beads, and grind them at 200rpm for 40min; then dry them to constant weight, crush them and pass them through a 75μm sieve to obtain the final product;

[0083] All other process parameters in Comparative Example 6 are the same as those in Example 1.

[0084] Performance testing

[0085] The concrete prepared in the examples and comparative examples was cured for 28 days, and then the compressibility, shrinkage strength and impact toughness were tested.

[0086] The method for testing the crushability is as follows: testing and calculation shall be carried out in accordance with the requirements of MH / T 5111-2015.

[0087] The method for testing collapse strength is as follows: A 100mm × 100mm × 100mm specimen is cut from the test block. Following the requirements of MH / T5111-2015, the specimen is dried to constant weight. Then, the specimen is placed within a cubic constraint frame and positioned below the compression rod of a universal testing machine, ensuring the specimen's centerline coincides with the axis of the compression rod. The universal testing machine is started, and the stress and collapse depth during compression are recorded. Collapse curves at various ages are plotted. In this application, the average stress data from 15 to 45mm along the plateau segment of the collapse curve is taken as the collapse strength.

[0088] The impact toughness test method is as follows: the impact energy dissipation is tested and calculated according to the drop hammer impact method of ACI-544-2R-89.

[0089] Freeze-thaw resistance: According to the provisions of MH / T 5111-2015, the impact toughness of concrete is tested after 25 freeze-thaw cycles.

[0090] Test results are shown in Table 2.

[0091] Table 2. Performance test results of concrete in the examples and comparative examples.

[0092]

[0093] Based on Table 2, by comparing the performance test results of concrete in the examples and comparative examples, it can be seen that the concrete prepared using the technical solution provided in this application has a crush strength of 0.5 to 0.6, a shrinkage strength of 0.30 to 0.40 MPa, an impact toughness greater than 6100 J, and a freeze-thaw resistance coefficient greater than 0.855 after the freeze-thaw test.

[0094] By comparing the performance test results of concrete in Examples 1 and 6-9, this application selects sodium bicarbonate aqueous solution with a molar concentration of 0.10-0.75 mol / L as mixing water, which can further improve the impact toughness and freeze-thaw resistance of concrete.

[0095] By comparing the performance test results of concrete in Examples 1 and 10-14, this application selects a foam stabilizer composed of a mixture of hydroxypropyl methylcellulose ether and styrene-butadiene emulsion in a weight ratio of 7:0.5-1.5, which can further improve the impact toughness and freeze-thaw resistance of concrete.

[0096] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A type of concrete for tunnel crash barriers, characterized in that, Specifically, it includes the following components in parts by weight: 180-220 parts cement, 70-110 parts carbon mineralized materials, 10-15 parts hollow glass microspheres, 1-1.6 parts foaming agent, 0.4-0.7 parts foam stabilizer, 3-9 parts water-reducing agent, 0.6-2 parts fiber, and 130-180 parts mixing water; The preparation method of the carbon mineralized mineral material is as follows: Weigh out 100-300 parts by weight of mineral material and 10-50 parts by weight of water, and place them in a grinding jar equipped with grinding balls; inject 20%-100% CO2 at a flow rate of 1-3 L / min, and grind at 400-600 rpm for 20-60 min; then dry to constant weight, grind finely and sieve to obtain the final product; the mineral material is selected from one or more of the following: carbonized yellow phosphorus slag, carbonized calcium carbide slag, carbonized cement clinker, carbonized steel slag, and carbonized magnesium slag; The foam stabilizer is composed of a mixture of hydroxypropyl methylcellulose ether and styrene-butadiene emulsion in a weight ratio of 7:0.5-1.

5. The mixing water is an aqueous solution of sodium bicarbonate with a molar concentration of 0.10~0.75 mol / L.

2. The concrete for tunnel crash barriers according to claim 1, characterized in that, The hollow glass microspheres have a particle size ≤60μm and an actual density ≤0.6g / cm3.

3. The concrete for tunnel crash barriers according to claim 1, characterized in that, The foaming agent is hydrogen peroxide with a mass concentration of 10-35%.

4. The concrete for tunnel crash barriers according to claim 1, characterized in that, The fiber is selected from one or more of polypropylene fiber, polyvinyl alcohol fiber, and carbon fiber.

5. The method for preparing concrete for tunnel crash barriers according to any one of claims 1-4, characterized in that, Specifically, the following steps are performed sequentially: First, weigh out the cement, carbon mineral materials, hollow glass microspheres and fibers, then pour them into a mixer and mix for 10-60 seconds until uniform. Add mixing water, foam stabilizer, and water-reducing agent. Stir at 200-600 rpm for 60-600 seconds, then stir at 1000-3000 rpm for 10-60 seconds. Add foaming agent and stir at 1000~3000 rpm for 10~60s to obtain slurry; The slurry is poured into a mold with a tenon and mortise structure and left to stand for 0.5 to 2 hours to allow it to foam. After curing in a curing room for 24-48 hours, demold and continue curing for 28-180 days to obtain the product.

6. A tunnel crash barrier, characterized in that, It is prepared using the concrete for the tunnel crash barrier as described in any one of claims 1-4.

7. The method for preparing the tunnel crash barrier according to claim 6, characterized in that, Specifically, the following steps are performed sequentially: The cured tunnel crash barrier is transported to the pre-installation location using concrete. Modular sections with mortise and tenon joints are then assembled, and panels are installed on the modules to obtain the tunnel crash barrier.

Images