A kind of anti-collision fence slip form construction concrete additive and its preparation method

Abstract

The present application relates to a kind of anti-collision fence slip form construction concrete additive and its preparation method, the additive includes by weight parts: rheological modifier, paste regulator, paste release agent, thixotropy enhancer, early hardening agent, borax, water.It is prepared by water, rheological modifier, paste release agent, early hardening agent, borax is put into stirring pool and is stirred to dissolve, then thixotropy enhancer is added, continue to put in paste regulator and obtain after stirring.The anti-collision fence slip form construction concrete additive prepared by using the present application can realize anti-collision fence slip form construction concrete pouring, vibrating, finishing once, and the integrity is good, appearance quality is excellent, effectively improves the construction speed of engineering project, guarantees engineering quality.It can be widely applied to highway anti-collision wall, large shoulder, small shoulder, large cover plate ditch, special-shaped ditch, gap type drainage ditch and other slip form construction concrete.

Description

Technical Field

[0001] This invention belongs to the field of concrete additive technology, specifically an additive for slipform construction of crash barriers and its preparation method. Background Technology

[0002] Slipform concrete additives are special concrete additives used in the construction of cement concrete using multi-functional slipform pavers. They are mainly used to improve the construction performance of slipform concrete, increase slipform construction efficiency, and meet the requirement that slipform concrete pouring, vibration, and finishing can be completed in one go.

[0003] Slipform construction was first used for the construction of high bridge piers. Due to its advantages of saving formwork, fast progress, and simple operation, it has been widely applied to the construction of concrete cable towers. In recent years, with the optimization and upgrading of slipform construction technology, it has been widely used in projects such as large covered ditches, super-large canals, crack-type drainage ditches, sloping riverbanks, dam slopes, and embankment reinforcement. The use of slipform technology for highway concrete crash barrier construction is now widely adopted in most parts of my country. However, achieving rapid concrete forming and continuous rapid construction requires high standards for concrete mix design and construction techniques. The advantages of using slipform pavers for crash barrier construction include high mechanization, high construction efficiency, cost savings, and high overall quality of the barriers. Concrete barriers have a certain vertical height, thus requiring high workability of the concrete, and the paving difficulty is much greater than that of curbs and road surfaces. However, current research in my country on the selection of concrete raw materials, admixtures, mix proportions, and vibration paving processes for slipform construction of crash barriers is still insufficient.

[0004] The concrete used for slipform construction differs from that of pumped concrete. Pumped concrete requires good fluidity, a slump of at least 180mm, good workability and slump retention, and must be suitable for long-distance transport and pipeline delivery via concrete pumps. However, the concrete used for slipform construction of crash barriers requires a slump of 20-60mm, without the need for water reduction or slump retention. It must have a good, soft slurry quality to ensure a construction speed of at least 4m / min, and a shiny, smooth surface after completion, requiring no manual finishing. Currently, there are no manufacturers specializing in additives for slipform construction concrete, and no additives are used on-site. This results in insufficient concrete strength, honeycomb-like pitting, cracks, peeling, chipped edges, and the need for manual finishing, leading to a large workload and inconsistent quality. Summary of the Invention

[0005] The purpose of this invention is to provide an additive for slipform construction concrete of crash barriers and its preparation method. This additive can improve the construction performance and 24-hour strength of slipform construction concrete, improve construction progress and work efficiency, and realize the completion of pouring, vibration and finishing in one step.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] An additive for slipform construction of crash barriers concrete, comprising, by weight: 200-240 parts rheology modifier, 10-24 parts slurry conditioner, 20-30 parts slurry slow-release agent, 0.5-2 parts thixotropic enhancer, 8-10 parts early hardener, 5-12 parts borax, and 682-756 parts water; wherein the rheology modifier includes zinc sulfate, aluminum sulfate, sodium montmorillonite, sodium hydroxide, polycarboxylate superplasticizer, and water; wherein the slurry conditioner includes tridecyl polyoxyethylene ether phosphate, tridecyl polyoxyethylene ether, phenolic polyoxyethylene ether phosphate, phenolic polyoxyethylene ether, fatty alcohol polyoxyethylene ether disodium succinate, phosphoric acid, and water; wherein the slurry slow-release agent is acetic acid; wherein the thixotropic enhancer is gellan gum and coagulating polysaccharide; and wherein the early hardener is one or more of tetrahydroxyethyl ethylenediamine, tetraethylenepentamine, and diethylene glycol butyl ether.

[0008] The rheology modifier of the present invention comprises the following components by weight: 48-52 parts zinc sulfate, 24-26 parts aluminum sulfate, 12-16 parts sodium montmorillonite, 4-6 parts sodium hydroxide, 5-10 parts polycarboxylate superplasticizer, and 890-907 parts water. The polycarboxylate superplasticizer has a solid content ≥26%, a water reduction rate ≥31%, and a slump change ≤40mm after 1 hour.

[0009] The additive for slipform construction of anti-collision barriers concrete of the present invention comprises the following components by weight: 16-21 parts of tridecyl polyoxyethylene ether phosphate, 2-4 parts of tridecyl polyoxyethylene ether, 12-18 parts of phenol polyoxyethylene ether phosphate, 2-4 parts of phenol polyoxyethylene ether, 6-9 parts of disodium fatty alcohol polyoxyethylene ether succinate, 2-4 parts of phosphoric acid, and 44-60 parts of water.

[0010] The additive for slipform construction of anti-collision barriers in this invention is a slurry slow-release agent of 0.1 mol / L acetic acid.

[0011] The additive for slipform construction of anti-collision barriers of the present invention has a thixotropic reinforcing agent in which the weight ratio of gellan gum and gel polysaccharide is 1:0.2-1.

[0012] A method for preparing an additive for slipform construction concrete of crash barriers, comprising the following steps:

[0013] (1) Preparation of rheology modifiers

[0014] S1. Dissolve zinc sulfate and aluminum sulfate in water to form a solution A with a mass fraction of 8-12%; dissolve sodium hydroxide in water to form a solution B with a mass fraction of 10%.

[0015] S2. Under the condition of 600 r / min, solution A was added dropwise to a three-necked flask at a constant rate of 3 g / min using a peristaltic pump, while solution B was added dropwise at the same time, so that the pH of the mixed solution was stabilized at 10.0±0.2; after the addition was completed, the temperature was raised to 80℃, and the reaction was continued for 48 h under the condition of 280 r / min. After natural cooling to room temperature, solution C was obtained.

[0016] S3. At a rotation speed of 300 r / min, sodium montmorillonite was dispersed in water and stirred for 24 h to form a suspension D with a mass fraction of 6%; then solution C was slowly added to suspension D at a constant rate of 10 g / min and stirred for 12 h; then polycarboxylate superplasticizer was slowly added to the above solution at a constant rate of 0.1 g / min and stirred for another 1 h to obtain a rheology modifier.

[0017] (2) Preparation of slurry conditioner

[0018] At a rotation speed of 80 r / min, tridecyl polyoxyethylene ether phosphate, tridecyl polyoxyethylene ether, phenol polyoxyethylene ether phosphate, phenol polyoxyethylene ether, and fatty alcohol polyoxyethylene ether disodium succinate were mixed in proportion to weight, and then phosphoric acid and water were slowly added and stirred for 30 min to obtain a slurry conditioner.

[0019] (3) Preparation of concrete additives for slipform construction of crash barriers:

[0020] At room temperature, water, rheology modifier, slurry slow-release agent, early hardener, and borax are first added to the mixing tank and stirred until dissolved. Then, thixotropic enhancer is added and stirred for 30 minutes. After stirring for 2 hours, slurry conditioner is added to obtain the additive for slipform construction concrete of crash barriers.

[0021] Mechanism of the invention:

[0022] Rheology modifiers were used to prepare positively charged layered nanostructures using zinc sulfate and aluminum sulfate. Sodium-based montmorillonite, a layered silicate mineral consisting of two verticeally connected silicon-oxygen tetrahedra sandwiching an edge-connected aluminum-oxygen octahedron, exhibits a negative charge due to the random substitution of silicon and magnesium by aluminum. Therefore, negatively charged sodium-based montmorillonite can integrate into the positively charged layered nanostructures. Polycarboxylate superplasticizers, due to their steric hindrance and size effects, cannot embed into the positively charged layered nanostructures and can only interact with the surface of the layered nanostructures electrostatically. Simultaneously, the introduction of polycarboxylate superplasticizers can regulate the size of the layered nanostructures, preventing their continued stacking. Polycarboxylate superplasticizers not acting on the surface of the layered nanostructures exert their dispersing effect, promoting the dispersion of cement particles. Water-reducing agents acting on the surface of layered stacked nanostructures bind tightly to these structures through electrostatic interactions, working together to affect cement particles. The surface of the layered stacked nanostructures contains numerous hydroxyl groups, which also contribute to the dispersibility of cement. Furthermore, the positively charged layered stacked nanostructures readily adsorb onto the surfaces of negatively charged cement minerals such as tricalcium silicate and dicalcium silicate, promoting the dispersion of cement particles and thus enhancing the fluidity of the slurry. Sodium-based montmorillonite embedded in the layered structure further increases the fluidity of the slurry through its combination with polycarboxylate superplasticizers.

[0023] Furthermore, the pozzolanic effect and layered nanostructure of sodium-based montmorillonite can serve as nucleation sites for CSH, promoting the hydration rate of cement within 48 hours. Under the influence of double-layer repulsion, adsorption forces generated by positive and negative charge attraction, and van der Waals forces, cement, sodium-based montmorillonite, and the layered nanostructure interact more easily, forming a dynamically reversible spatial network structure. This improves the density and mechanical properties of the concrete matrix in slipform construction of crash barriers. The layered nanostructure exhibits good stability, unaffected by temperature conditions. During the service life of concrete, it can insert and solidify harmful ions such as chloride ions and sulfates into its layered structure, effectively improving the durability of concrete.

[0024] The slurry modifier ensures the workability of the concrete during slipform construction of the crash barrier, improves the concrete's softness, promotes the longitudinal dispersion of the cement paste, increases water retention, encapsulation, cohesion, thixotropy, and homogeneity. Simultaneously, it can reduce the shrinkage deformation of the concrete during slipform construction of the crash barrier, preventing cracking.

[0025] Slurry release agents play a role in concentrating concrete during pre-mixing to prevent excessive slurry from hindering concrete accumulation and shaping. However, under the vibration of slipform construction, they can quickly release the slurry, improving the adhesion of the concrete.

[0026] Thixotropic enhancers provide strong thixotropic properties to the system. Gellan gum is a high-molecular-weight linear polysaccharide that exists as a transparent solution during the exothermic hydration of cement, forming a transparent and solid gel after the concrete hydration is complete. The gelling polysaccharide gradually forms a high-strength gel during the exothermic hydration of cement. Combining gellan gum with gelling polysaccharides and borax can reduce the gel's hardness and enhance its elasticity, thereby improving the mechanical properties and durability of the slipform concrete used for crash barriers.

[0027] Early hardeners can rapidly increase the strength of concrete used in slipform construction of crash barriers in a short period of time, ensuring vertical molding of the concrete and preventing chipped edges and corners.

[0028] The beneficial effects of this invention are:

[0029] (1) The additive for anti-collision railing slipform construction concrete prepared by the present invention ensures the smoothness and linearity of the railing during the slipform construction of concrete. It can realize the concrete pouring, vibration and finishing of anti-collision railing slipform construction in one go, with good integrity and excellent appearance quality.

[0030] (2) The additives for slipform construction concrete of crash barriers prepared by the present invention can be widely used in slipform construction concrete for highway crash barriers, large road shoulders, small road shoulders, large covered ditches, irregular ditches, and slotted drainage ditches.

[0031] (3) The anti-collision barrier slipform construction concrete additive prepared by the present invention can complete the relevant work in a short time, and the concrete strength within 24 hours can reach about 20% of the design strength, which effectively improves the construction speed of the project and ensures the quality of the project. Detailed Implementation

[0032] The technical solution of the present invention will be further described in detail below with reference to specific embodiments, but the present invention is not limited to the following technical solutions.

[0033] Example 1

[0034] An additive for slipform construction of crash barriers concrete, prepared by the following method:

[0035] 1. Dissolve 52g of zinc sulfate and 26g of aluminum sulfate in 675g of water to obtain solution A; dissolve 4g of sodium hydroxide in 36g of water to obtain solution B;

[0036] 2. Under a rotation speed of 600 r / min, solution A was added dropwise to a three-necked flask at a constant rate of 3 g / min using a peristaltic pump, while solution B was added dropwise simultaneously, stabilizing the pH of the mixed solution at 10.0 ± 0.2. After the addition was complete, the temperature was raised to 80℃, and the reaction was continued for 48 hours at a rotation speed of 280 r / min. The mixture was then allowed to cool naturally to room temperature to obtain solution C.

[0037] 3. At a rotation speed of 300 r / min, 12 g of sodium montmorillonite was dispersed in 188 g of deionized water and stirred for 24 h to form a suspension D with a mass fraction of 6%. Then, solution C was slowly added to suspension D at a constant rate of 10 g / min and stirred for 12 h. After that, 7 g of polycarboxylate superplasticizer was slowly added to the above solution at a constant rate of 0.1 g / min and stirred for another 1 h to obtain the rheology modifier.

[0038] 4. At a rotation speed of 80 r / min, mix 16 g of tridecyl polyoxyethylene ether phosphate, 2 g of tridecyl polyoxyethylene ether, 18 g of phenol polyoxyethylene ether phosphate, 4 g of phenol polyoxyethylene ether, and 8 g of fatty alcohol polyoxyethylene ether disodium succinate. Then slowly add 4 g of phosphoric acid and 48 g of water and stir for 30 min to obtain a slurry conditioner.

[0039] 5. At room temperature, first add 703g of water, 240g of rheology modifier, 25g of 0.1mol / L acetic acid, 8g of tetrahydroxyethyl ethylenediamine, and 5g of borax to a mixing tank and stir until dissolved. Then add 0.8g of cold-setting adhesive and 0.4g of coagulating polysaccharide, stir for 30 minutes, and then add 17g of slurry conditioner. After stirring for 2 hours, the additive for slipform construction concrete of crash barriers is obtained.

[0040] Example 2

[0041] An additive for slipform construction of crash barriers concrete, prepared by the following method:

[0042] 1. Dissolve 48g of zinc sulfate and 24g of aluminum sulfate in 606g of water to obtain solution A; dissolve 5g of sodium hydroxide in 45g of water to obtain solution B;

[0043] 2. Under a rotation speed of 600 r / min, solution A was added dropwise to a three-necked flask at a constant rate of 3 g / min using a peristaltic pump, while solution B was added dropwise simultaneously, stabilizing the pH of the mixed solution at 10.0 ± 0.2. After the addition was complete, the temperature was raised to 80℃, and the reaction was continued for 48 hours at a rotation speed of 280 r / min. The mixture was then allowed to cool naturally to room temperature to obtain solution C.

[0044] 3. At a rotation speed of 300 r / min, 16 g of sodium montmorillonite was dispersed in 251 g of deionized water and stirred for 24 h to form a suspension D with a mass fraction of 6%. Then, solution C was slowly added to suspension D at a constant rate of 10 g / min and stirred for 12 h. After that, 5 g of polycarboxylate superplasticizer was slowly added to the above solution at a constant rate of 0.1 g / min and stirred for another 1 h to obtain the rheology modifier.

[0045] 4. At a rotation speed of 80 r / min, mix 21 g of tridecyl polyoxyethylene ether phosphate, 4 g of tridecyl polyoxyethylene ether, 12 g of phenol polyoxyethylene ether phosphate, 2 g of phenol polyoxyethylene ether, and 9 g of fatty alcohol polyoxyethylene ether disodium succinate. Then slowly add 3 g of phosphoric acid and 49 g of water and stir for 30 min to obtain a slurry conditioner.

[0046] 5. At room temperature, first add 732g of water, 200g of rheology modifier, 20g of 0.1mol / L acetic acid, 10g of tetraethylenepentamine, and 12g of borax to a mixing tank and stir until dissolved. Then add 1.5g of cold-setting adhesive and 0.5g of gelling polysaccharide, stir for 30 minutes, and then add 24g of slurry conditioner. After stirring for 2 hours, the additive for slipform construction concrete of crash barriers is obtained.

[0047] Example 3

[0048] An additive for slipform construction of crash barriers concrete, prepared by the following method:

[0049] 1. Dissolve 50g of zinc sulfate and 25g of aluminum sulfate in 622g of water to obtain solution A; dissolve 6g of sodium hydroxide in 54g of water to obtain solution B;

[0050] 2. Under a rotation speed of 600 r / min, solution A was added dropwise to a three-necked flask at a constant rate of 3 g / min using a peristaltic pump, while solution B was added dropwise simultaneously, stabilizing the pH of the mixed solution at 10.0 ± 0.2. After the addition was complete, the temperature was raised to 80℃, and the reaction was continued for 48 hours at a rotation speed of 280 r / min. The mixture was then allowed to cool naturally to room temperature to obtain solution C.

[0051] 3. At a rotation speed of 300 r / min, 14 g of sodium montmorillonite was dispersed in 219 g of deionized water and stirred for 24 h to form a suspension D with a mass fraction of 6%. Then, solution C was slowly added to suspension D at a constant rate of 10 g / min and stirred for 12 h. After that, 10 g of polycarboxylate superplasticizer was slowly added to the above solution at a constant rate of 0.1 g / min and stirred for another 1 h to obtain the rheology modifier.

[0052] 4. At a rotation speed of 80 r / min, mix 18 g of tridecyl polyoxyethylene ether phosphate, 3 g of tridecyl polyoxyethylene ether, 12 g of phenol polyoxyethylene ether phosphate, 4 g of phenol polyoxyethylene ether, and 9 g of fatty alcohol polyoxyethylene ether disodium succinate. Then slowly add 2 g of phosphoric acid and 52 g of water and stir for 30 min to obtain a slurry conditioner.

[0053] 5. At room temperature, first add 721.5g water, 220g rheology modifier, 30g 0.1mol / L acetic acid, 5g tetrahydroxyethyl ethylenediamine, 5g diethylene glycol butyl ether, and 8g borax to a mixing tank and stir until dissolved. Then add 0.25g cold-setting adhesive and 0.25g coagulating polysaccharide, stir for 30 minutes, and then add 10g slurry conditioner. After stirring for 2 hours, the additive for slipform construction concrete of crash barriers is obtained.

[0054] Comparative Example 1

[0055] Compared with Example 1, no rheology modifier was added, i.e., step 4 was the same as in Example 1. At room temperature, 703g of water, 25g of 0.1mol / L acetic acid, 8g of tetrahydroxyethyl ethylenediamine, and 5g of borax were first added to a mixing tank and stirred until dissolved. Then, 0.8g of cold-setting adhesive and 0.4g of gelling polysaccharide were added, and after stirring for 30 minutes, 17g of slurry conditioner was added. After stirring for 2 hours, the additive for slipform construction concrete of the crash barrier was obtained.

[0056] Comparative Example 2

[0057] Compared with Example 1, no slurry conditioner was added, i.e., steps 1-3 were the same as in Example 1. At room temperature, 703g of water, 240g of rheology modifier, 25g of 0.1mol / L acetic acid, 8g of tetrahydroxyethyl ethylenediamine, and 5g of borax were first added to a mixing tank and stirred until dissolved. Then, 0.8g of cold-setting adhesive and 0.4g of coagulating polysaccharide were added, and the mixture was stirred for 2.5 hours to obtain the additive for slipform construction concrete of crash barriers.

[0058] Comparative Example 3

[0059] Compared to Example 1, no slurry slow-release agent was added; that is, steps 1-4 were the same as in Example 1. At room temperature, 703g of water, 240g of rheology modifier, 8g of tetrahydroxyethyl ethylenediamine, and 5g of borax were first added to a mixing tank and stirred until dissolved. Then, 0.8g of cold-setting adhesive and 0.4g of coagulating polysaccharide were added, and after stirring for 30 minutes, 17g of slurry conditioner was added. After stirring for 2 hours, the additive for slipform construction concrete of the crash barrier was obtained.

[0060] Comparative Example 4

[0061] Compared with Example 1, no thixotropic enhancer was added, that is, steps 1-4 were the same as in Example 1.

[0062] At room temperature, 703g of water, 240g of rheology modifier, 25g of 0.1mol / L acetic acid, 8g of tetrahydroxyethyl ethylenediamine, and 5g of borax are first added to a mixing tank and stirred until dissolved. Then, 17g of slurry conditioner is added and stirred for 2.5 hours to obtain the additive for slipform construction concrete of crash barriers.

[0063] Comparative Example 5

[0064] Compared with Example 1, no early-strength hardener was added, that is, steps 1-4 were the same as in Example 1.

[0065] At room temperature, 703g of water, 240g of rheology modifier, 25g of 0.1mol / L acetic acid, and 5g of borax are first added to a mixing tank and stirred until dissolved. Then, 0.8g of cold-setting adhesive and 0.4g of gelling polysaccharide are added and stirred for 30 minutes. Finally, 17g of slurry conditioner is added and stirred for 2 hours to obtain the additive for slipform construction concrete of crash barriers.

[0066] Comparative Example 6

[0067] Compared with Example 1, steps 1-4 are the same as in Example 1.

[0068] At room temperature, 703g of water, 300g of rheology modifier, 25g of 0.1mol / L acetic acid, 8g of tetrahydroxyethyl ethylenediamine, and 5g of borax are first added to a mixing tank and stirred until dissolved. Then, 0.8g of cold-setting adhesive and 0.4g of coagulating polysaccharide are added and stirred for 30 minutes. Finally, 17g of slurry conditioner is added and stirred for 2 hours to obtain the additive for slipform construction concrete of crash barriers.

[0069] Comparative Example 7

[0070] Compared with Example 1, steps 1-4 are the same as in Example 1.

[0071] At room temperature, 703g of water, 240g of rheology modifier, 25g of 0.1mol / L acetic acid, 8g of tetrahydroxyethyl ethylenediamine, and 5g of borax are first added to a mixing tank and stirred until dissolved. Then, 0.8g of cold-setting adhesive and 0.4g of coagulating polysaccharide are added and stirred for 30 minutes. Finally, 5g of slurry conditioner is added and stirred for 2 hours to obtain the additive for slipform construction concrete of crash barriers.

[0072] Comparative Example 8

[0073] Compared with Example 1, steps 1-4 are the same as in Example 1.

[0074] At room temperature, 703g of water, 240g of rheology modifier, 25g of 0.1mol / L acetic acid, 8g of tetrahydroxyethyl ethylenediamine, and 5g of borax are first added to a mixing tank and stirred until dissolved. Then, 3.2g of cold-setting adhesive and 1.6g of gelling polysaccharide are added and stirred for 30 minutes. Finally, 17g of slurry conditioner is added and stirred for 2 hours to obtain the additive for slipform construction concrete of crash barriers.

[0075] The cement used for the performance verification of concrete additives in the slipform construction of crash barriers was Dongjun PO 425 ordinary Portland cement with a water-cement ratio of 0.46 and a sand ratio of 46%, of which fine yellow sand accounted for 57% and river sand accounted for 43%, and the water consumption was 170 kg / m³.3 The dosage of additives in the concrete for slipform construction of crash barriers is 1.0%.

[0076] Table 1 Comparison of the performance of concrete additives used in slipform construction of crash barriers

[0077]

[0078]

[0079] As can be seen from the data in Table 1, the slipform construction speed of concrete with the additives used in Examples 1-3 of the anti-collision barrier slipform construction is faster than that without the additives, and the surface is smooth and shiny, eliminating the need for manual finishing and improving work efficiency. The 1-day strength and 28-day strength are significantly higher than the benchmark. This is mainly because the benchmark concrete only used water as a lubricant, resulting in less slurry and poor concrete condition. After being vibrated by the slipform machine, the slurry was not dense enough, so the surface was not smooth and air bubbles appeared.

[0080] Compared to Example 1, Comparative Example 1, without the addition of a rheology modifier, exhibited poor concrete cohesion, a smaller slump, and lower 1-day and 28-day strengths. This demonstrates that the rheology modifier significantly improves the overall performance of slipform construction concrete for crash barriers, particularly enhancing its cohesion and mechanical properties. In Comparative Example 6, compared to Example 1, the amount of rheology modifier was increased to 300 parts (200-240 parts rheology modifier), improving the cohesion of the slurry. However, partial collapse occurred during construction, possibly due to an excessively large slump (70mm).

[0081] Compared to Example 1, Comparative Example 2, without the addition of a slurry modifier, exhibited slightly poorer cohesiveness, less slurry on the stone surface, and a 28-day strength 2 MPa lower than Example 1. This indicates that the slurry modifier significantly improves the density of the concrete slurry during slipform construction of the crash barrier. In contrast, Comparative Example 7, compared to Example 1, reduced the amount of slurry modifier to 5 parts (10-24 parts slurry modifier), resulting in a slower construction speed than Example 1 but faster than Comparative Example 2. This suggests that the insufficient amount of slurry modifier led to an insignificant effect.

[0082] Compared to Example 1, Comparative Example 3, without the addition of a slurry retarder, showed increased concrete slump and faster construction speed. However, it also exhibited chipped edges and corners, indicating that the slurry retarder plays a role in consolidation during pre-mixing, slowly releasing the slurry during the vibration of the slipforming agent to ensure the compactness of the slurry and concrete. The rebound strength of Comparative Example 3 was slightly lower than that of Example 1, possibly because abundant slurry during pre-mixing could lead to separation of the slurry from the aggregate during vibration, thus affecting the surface strength of the concrete.

[0083] Compared to Example 1, Comparative Example 4, without the addition of thixotropic enhancer, showed slightly poorer concrete cohesion, with a few small pits appearing. Its 1-day and 28-day strengths were also lower than in Example 1, indicating that the thixotropic enhancer significantly improves the mechanical properties of the concrete paste used in slipform construction of crash barriers. In Comparative Example 8, compared to Example 1, the amount of thixotropic enhancer was increased to 4.8 parts (0.5-2 parts thixotropic enhancer). Since the cold-setting gel and coagulating polysaccharides could not be completely dispersed in water, the performance was unaffected.

[0084] Compared with Example 1, Comparative Example 5 did not add an early-strength hardener, and its 1-day strength was lower than that of Example 1, but its 28-day strength was not affected. This indicates that the early-strength hardener can enable the concrete of the crash barrier to rapidly increase its strength in a short period of time during slipform construction.

Claims

1. An aid for concrete for a slip-form construction of a crash barrier, characterized in that The rheology modifier comprises, by weight: 200-240 parts rheology modifier, 10-24 parts slurry conditioner, 20-30 parts slurry slow-release agent, 0.5-2 parts thixotropic enhancer, 8-10 parts early hardener, 5-12 parts borax, and 682-756 parts water; the rheology modifier comprises zinc sulfate, aluminum sulfate, sodium montmorillonite, sodium hydroxide, polycarboxylate superplasticizer, and water; the weight percentages of each component in the rheology modifier are: 48-52 parts zinc sulfate, 24-26 parts aluminum sulfate, 12-16 parts sodium montmorillonite, 4-6 parts sodium hydroxide, 5-10 parts polycarboxylate superplasticizer, and 890-907 parts water, wherein the polycarboxylate superplasticizer has a solids content ≥26%, a water reduction rate ≥31%, and a slump change ≤40mm after 1 hour; the preparation method of the rheology modifier is as follows: S1. Dissolve zinc sulfate and aluminum sulfate in water to form a solution A with a mass fraction of 8-12%; dissolve sodium hydroxide in water to form a solution B with a mass fraction of 10%. S2. Under the condition of 600 r / min, solution A was added dropwise to a three-necked flask at a constant rate of 3 g / min using a peristaltic pump, while solution B was added dropwise at the same time, so that the pH of the mixed solution was stabilized at 10.0±0.2; after the addition was completed, the temperature was raised to 80℃, and the reaction was continued for 48 h under the condition of 280 r / min. After natural cooling to room temperature, solution C was obtained. S3. At a rotation speed of 300 r / min, sodium montmorillonite was dispersed in water and stirred for 24 h to form a suspension D with a mass fraction of 6%; then solution C was slowly added to suspension D at a constant rate of 10 g / min and stirred for 12 h; then polycarboxylate superplasticizer was slowly added to the above solution at a constant rate of 0.1 g / min and stirred for another 1 h to obtain a rheology modifier. The slurry conditioner comprises tridecyl polyoxyethylene ether phosphate, tridecyl polyoxyethylene ether, phenolic polyoxyethylene ether phosphate, phenolic polyoxyethylene ether, fatty alcohol polyoxyethylene ether disodium succinate, phosphoric acid, and water; the weight proportions of each component in the slurry conditioner are as follows: 16-21 parts tridecyl polyoxyethylene ether phosphate, 2-4 parts tridecyl polyoxyethylene ether, 12-18 parts phenolic polyoxyethylene ether phosphate, 2-4 parts phenolic polyoxyethylene ether, 6-9 parts fatty alcohol polyoxyethylene ether disodium succinate, 2-4 parts phosphoric acid, and 44-60 parts water. The preparation of the slurry conditioner is as follows: under a rotation speed of 80 r / min, tridecyl polyoxyethylene ether phosphate, tridecyl polyoxyethylene ether, phenol polyoxyethylene ether phosphate, phenol polyoxyethylene ether, and fatty alcohol polyoxyethylene ether disodium succinate are mixed in proportions by weight, and then phosphoric acid and water are slowly added and stirred for 30 min to obtain the slurry conditioner; the slurry slow-release agent is acetic acid; the thixotropic enhancer is gellan gum and coagulating polysaccharide; the early hardening agent is one or more of tetrahydroxyethylethylenediamine, tetraethylenepentamine, and diethylene glycol butyl ether.

2. The aid for construction of concrete of a crash barrier slip form according to claim 1, characterized in that The slurry slow-release agent is 0.1 mol / L acetic acid.

3. The aid for concrete of a crash barrier slip form construction according to claim 1, characterized in that The weight ratio of gellan gum to gel polysaccharide in the thixotropic enhancer is 1:0.2-1.

4. The preparation method of the additive for slipform construction concrete of crash barriers as described in claim 1, characterized in that... Includes the following steps: (1) Preparation of rheology modifiers S1. Dissolve zinc sulfate and aluminum sulfate in water to form a solution A with a mass fraction of 8-12%; dissolve sodium hydroxide in water to form a solution B with a mass fraction of 10%. S2. Under the condition of 600 r / min, solution A was added dropwise to a three-necked flask at a constant rate of 3 g / min using a peristaltic pump, while solution B was added dropwise at the same time, so that the pH of the mixed solution was stabilized at 10.0±0.2; after the addition was completed, the temperature was raised to 80℃, and the reaction was continued for 48 h under the condition of 280 r / min. After natural cooling to room temperature, solution C was obtained. S3. At a rotation speed of 300 r / min, sodium montmorillonite was dispersed in water and stirred for 24 h to form a suspension D with a mass fraction of 6%; then solution C was slowly added to suspension D at a constant rate of 10 g / min and stirred for 12 h; then polycarboxylate superplasticizer was slowly added to the above solution at a constant rate of 0.1 g / min and stirred for another 1 h to obtain a rheology modifier. (2) Preparation of slurry conditioner At a speed of 80 r / min, tridecyl polyoxyethylene ether phosphate, tridecyl polyoxyethylene ether, phenol polyoxyethylene ether phosphate, phenol polyoxyethylene ether, and fatty alcohol polyoxyethylene ether disodium succinate were mixed in proportion to weight, and then phosphoric acid and water were slowly added and stirred for 30 min to obtain a slurry conditioner. (3) Preparation of concrete additives for slipform construction of crash barriers: At room temperature, water, rheology modifier, slurry slow-release agent, early hardener, and borax are first added to the mixing tank and stirred until dissolved. Then, thixotropic enhancer is added and stirred for 30 minutes. After stirring for 2 hours, slurry conditioner is added to obtain the additive for slipform construction concrete of crash barriers.

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