Concrete for bridge precast member containing special ultrafine powder and its preparation method

Abstract

The application relates to the technical field of building materials, and particularly provides a bridge prefabricated component concrete containing special super-fine powder and a preparation method thereof; according to weight parts, the preparation raw materials of the concrete include cement 300-500 parts, coarse aggregate 1200-1600 parts, light aggregate 400-550 parts, water 100-150 parts, super-fine powder 50-100 parts, additive 10-70 parts and reinforcing additive 10-30 parts. By using the organic additive to modify the surface of the reinforcing additive, and by regulating the relative usage amount of the component raw materials of the concrete, the super-fine powder and the additive, the concrete has excellent mechanical properties and workability, does not corrode the metal base material and can delay the corrosion of the metal base material, and meets the production and use environment requirements of the bridge prefabricated component.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, C04B28 / 04, and particularly to a type of concrete for precast bridge components containing special ultrafine powder and its preparation method. Background Technology

[0002] Concrete is one of the main materials in civil engineering. It is made by mixing cementitious materials, aggregates, water, admixtures, and additives in a certain proportion, followed by mixing, compaction, and curing. It is widely used in the construction of buildings, bridges, roads, and other infrastructure. However, with the continuous development of the economy and society, more and more super high-rise and large-span structures are emerging. Ordinary concrete, due to its low strength, high brittleness, poor ductility, and poor durability, can no longer meet the needs of large structures.

[0003] There are two main methods for mechanically strengthening concrete in existing technologies: The first is to improve the tensile strength and toughness of concrete by adding fibers or whiskers. For example, Chinese patent CN116177967B discloses a method for preparing high-strength concrete. This patent avoids problems such as concrete collapse, bleeding, and heat of hydration by using modified whiskers, and also improves the compressive strength of the product. However, its product does not offer any advantage in corrosion resistance to metal substrates. The second method is to optimize the particle size of admixtures to achieve a size-enhancing effect. For example, Chinese patent CN116874265B discloses a high-ductility multi-scale fiber-reinforced cementitious composite material and its preparation method. This patent utilizes the synergistic effect of carbon nanotubes, calcium sulfate whiskers, and steel fibers to fill pores at multiple scales from nanometer to micrometer, micrometer to millimeter, and millimeter to centimeter, inhibiting crack propagation, enhancing the strength and ductility of the material, and modifying the steel fibers to enhance the durability of the material. However, the fiber dispersion in this patent is poor, and the structural strength and structural stability of the product still have room for improvement.

[0004] Therefore, based on the usage environment such as bridges, it is of great practical significance to prepare a type of concrete with excellent mechanical properties, stability, and good corrosion resistance, and to use it to make precast components. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention first provides a type of concrete for precast bridge components containing special ultrafine powder.

[0006] Further, by weight, the raw materials for preparing the concrete include: 300-500 parts cement, 1200-1600 parts coarse aggregate, 400-550 parts lightweight aggregate, 100-150 parts water, 50-100 parts ultrafine powder, 10-70 parts admixture, and 10-30 parts reinforcing agent.

[0007] Furthermore, the coarse aggregate includes, but is not limited to, at least one of crushed stone and gravel.

[0008] Furthermore, the average particle size of the coarse aggregate is 6 mm or more, preferably 6-18 mm.

[0009] Furthermore, the lightweight aggregate includes, but is not limited to, at least one of natural sand and artificial sand, wherein the natural sand includes, but is not limited to, at least one of river sand, lake sand, and mountain sand.

[0010] Furthermore, the average particle size of the lightweight aggregate is 0.15-5 mm.

[0011] Further, by weight, the ultrafine powder component includes 10-30 parts fly ash, 10-25 parts slag powder, 1-10 parts gypsum, 1-10 parts silica fume, 3-15 parts water-reducing agent, and 5-20 parts retarder.

[0012] Furthermore, the retarder includes, but is not limited to, at least one of gluconate, citric acid, tartaric acid, and sugars.

[0013] Preferably, the retarder comprises gluconate.

[0014] Furthermore, the water-reducing agent includes at least one of naphthalene-based water-reducing agents, polycarboxylate-based water-reducing agents, melamine-based water-reducing agents, and aminosulfonate-based water-reducing agents.

[0015] Preferably, the water-reducing agent includes a naphthalene-based water-reducing agent.

[0016] Furthermore, the gypsum includes at least one of fluorogypsum, phosphogypsum, and desulfurized gypsum, preferably desulfurized gypsum.

[0017] Furthermore, the raw materials for preparing the ultrafine powder also include 5-25 parts of hydrated lime. Increasing the amount of hydrated lime can promote the dissolution of metal ions in the system, forming precipitates with activated silica, activated alumina, etc., thereby improving strength. In addition, it can compensate for the demand of organic additives on the hydroxyl groups at the interface of inorganic materials, synergistically constructing an organic-inorganic three-dimensional network structure. Combined with the pore-filling effect of ultrafine powder, it increases the density of the system, improves the adhesion between the components, and thus improves the product strength.

[0018] Preferably, the ultrafine powder component comprises, by weight, 10-28 parts fly ash, 10-25 parts slag powder, 2-8 parts gypsum, 2-8 parts silica fume, 5-10 parts water-reducing agent, 5-20 parts retarder, and 5-20 parts hydrated lime.

[0019] Furthermore, the average particle size of the fly ash is 0.2-10 μm, preferably 0.3-7 μm, and more preferably 0.5-3 μm.

[0020] Furthermore, the average particle size of the slag powder is 0.2-15 μm, preferably 0.5-10 μm, and more preferably 0.7-5 μm.

[0021] Further, the preparation method of the ultrafine powder is as follows: S1, grind fly ash and slag powder to a specified particle size respectively; S2, add fly ash, slag powder, silica fume, gypsum and quicklime to a mixer and mix; S3, add retarder and water-reducing agent to mix.

[0022] Furthermore, the raw materials for preparing the concrete also include 1-10 parts of organic additives; the organic additives are C10-30 organic acid salts with at least one unsaturated bond.

[0023] Preferably, the raw materials for preparing the concrete include 2-8 parts of organic additives.

[0024] Furthermore, the organic additives include, but are not limited to, at least one of sodium eicosapentaenoate, sodium octadecenoate, sodium hexadecenoate, sodium hexadecenoate sulfonate, and sodium C12-C14 alkenyl sulfonate.

[0025] Preferably, the organic additive comprises sodium octadecenoate.

[0026] Further, by weight, the additive comprises 10-50 parts of a compound containing terminal double bonds, 0.5-3 parts of an initiator, and 0.5-2 parts of a crosslinking agent.

[0027] Preferably, the compound containing terminal double bonds includes, but is not limited to, at least one of acrylamide, methacrylamide, dimethylaminopropylmethacrylamide, hydroxyethyl acrylate, and sodium acrylate, and preferably includes acrylamide.

[0028] Furthermore, the initiator includes, but is not limited to, at least one of persulfate and peroxide.

[0029] Preferably, the initiator is a persulfate-hydropersulfate.

[0030] Furthermore, the crosslinking agent is a compound containing two terminal double bonds, specifically selected from at least one of N,N-methylenebisacrylamide, 1,4-butanediol diacrylate, and ethylene glycol dimethacrylate.

[0031] More preferably, the crosslinking agent is N,N-methylenebisacrylamide.

[0032] In a preferred embodiment, when the retarder is sodium gluconate, in addition to complexing with calcium ions to coat cement particles and inhibit cement hydration, sodium gluconate contains a large number of hydroxyl groups, which can tightly bind with metal ions on the surface of metal materials to form a film. Furthermore, its exposed carboxyl groups can chemically bond with -CO-NH2 in acrylamide to form another film. This results in the metal material surface being coated with two organic films, effectively separating the metal material from the organic-inorganic three-dimensional network of the concrete system and slowing down the corrosion of the metal material. The optimal weight ratio of sodium gluconate to acrylamide is 1:(1-3), preferably 1:(1.5-3), which provides the best corrosion inhibition effect on the metal material. Too much sodium gluconate makes it difficult to form a composite coating with high compatibility, resulting in insufficient coating density and poor corrosion inhibition. Too little sodium gluconate makes it difficult to form a complete coating, reducing the density of the coating and decreasing the corrosion inhibition effect.

[0033] Furthermore, the reinforcing agent is fiber and / or whisker, preferably whisker.

[0034] Furthermore, the whiskers include, but are not limited to, at least one of zinc oxide whiskers, zinc sulfate whiskers, and zinc phosphate whiskers.

[0035] Furthermore, the average length of the needle-like structures of the whiskers is 6-20 μm, preferably 10-16 μm; the aspect ratio is 15-25.

[0036] In a preferred embodiment, the weight ratio of the reinforcing agent to the organic agent is 1:(0.1-0.8), preferably 1:(0.1-0.5).

[0037] During the exothermic hydration process of cement, the acid radicals in organic additives such as sodium octadecenoate combine with metal ions on the surface of zinc oxide whiskers and active sites such as silicon and aluminum exposed on the surface of ultrafine powder. Their long-chain structure, through steric hindrance, uniformly disperses the zinc oxide whiskers and other active powders within the system, effectively preventing secondary agglomeration of the powder. Secondly, the double bonds in the octadecenoic acid segments grafted onto the zinc oxide surface may also participate in the polymerization reaction of compounds containing terminal double bonds, such as acrylamide, thereby forming a large organic-inorganic three-dimensional network structure within the system. This three-dimensional network is embedded in CS... In the H-layer, the hydration product layers are more stable and have stronger bonding force, effectively avoiding stress concentration in the system to resist collapse caused by excessive local load, and improving the overall mechanical strength of concrete products. However, excessive whisker addition will destroy the connectivity of the three-dimensional network system and weaken the bonding strength of the interface. When there is too much acrylamide, due to its poor compatibility with cement, it is not conducive to the compatibility of the system and the improvement of mechanical strength. Therefore, it is necessary to strictly control the relative amount of the three to compensate for the loss of compressive strength caused by the polymerization of monomers containing terminal double bonds, and to take advantage of each other's strengths.

[0038] Secondly, this application also provides a method for preparing concrete for precast bridge components containing special ultrafine powder, which is as follows: the raw materials for preparing concrete are mixed and stirred at 100-150 r / min for 10-30 min, and then the concrete is poured into a mold for molding, demolded, and naturally cured at room temperature.

[0039] Beneficial effects

[0040] 1. The concrete of this application has good corrosion resistance and compressive strength, and the concrete meets the requirements of the manufacturing and use environment of bridge precast components;

[0041] 2. The surface of the reinforcing agent in this application is modified with an organic additive, which is a C10-30 organic acid salt with at least one unsaturated bond. The weight ratio of the reinforcing agent to the organic additive is specified to be 1:(0.1-0.8), preferably 1:(0.1-0.5. This can significantly enhance the compatibility and dispersibility of the system, as well as improve the mechanical strength and corrosion resistance of the system.

[0042] 3. This application optimizes the relative amounts of compounds containing terminal double bonds in the retarder and admixtures. The reasonable compatibility effectively improves the density of the protective film and enhances the corrosion resistance of concrete to metal substrates. 4. This application specifies the amount of quicklime added in the raw materials to improve the product strength. Detailed Implementation

[0043] Example

[0044] Example 1

[0045] This embodiment provides a concrete for precast bridge components containing special ultrafine powder; by weight, the raw materials for preparing the concrete include: 400 parts cement, 1400 parts coarse aggregate, 490 parts lightweight aggregate, 120 parts water, 75 parts ultrafine powder, 27 parts admixture, 13 parts reinforcing agent, and 4 parts organic additive.

[0046] The cement is Conch Cement 52.5; the coarse aggregate is crushed stone with an average particle size of 10 mm; the lightweight aggregate is river sand with an average particle size of 3 mm; the reinforcing agent is zinc oxide whiskers with an average needle-like length of 15 μm and an aspect ratio of 20; and the organic additive is sodium octadecenoate.

[0047] The additive components, by weight, are: 25 parts acrylamide, 1 part initiator (potassium persulfate-sodium persulfate), and 1 part N,N-methylenebisacrylamide.

[0048] The ultrafine powder composition, by weight, includes 20 parts fly ash, 16 parts slag powder, 4 parts gypsum, 4 parts silica fume, 7 parts water-reducing agent, 12 parts retarder, and 12 parts quicklime. The average particle size of the fly ash is 2 μm; the average particle size of the slag powder is 3 μm; the gypsum is desulfurized gypsum; the water-reducing agent is a naphthalene-based water-reducing agent; and the retarder is sodium gluconate. The preparation method of the ultrafine powder is as follows: S1, grind the fly ash and slag powder to the specified particle size (grind the fly ash to an average particle size of 2 μm; grind the slag powder to an average particle size of 3 μm); S2, add the fly ash, slag powder, silica fume, gypsum, and quicklime to a mixer and mix; S3, add the retarder and water-reducing agent and mix.

[0049] The method for preparing concrete for precast bridge components containing special ultrafine powder is as follows: the raw materials for concrete preparation are mixed and stirred at 100 r / min for 15 min, then the concrete is poured into a mold for molding, demolded, and naturally cured at room temperature.

[0050] Example 2

[0051] This embodiment provides a concrete for precast bridge components containing special ultrafine powder; by weight, the raw materials for preparing the concrete include: 300 parts cement, 1200 parts coarse aggregate, 400 parts lightweight aggregate, 100 parts water, 50 parts ultrafine powder, 12 parts admixture, 10 parts reinforcing agent, and 5 parts organic additive.

[0052] The cement is Conch Cement 52.5; the coarse aggregate is crushed stone with an average particle size of 10 mm; the lightweight aggregate is river sand with an average particle size of 3 mm; the reinforcing agent is zinc oxide whiskers with an average needle-like length of 18 μm and an aspect ratio of 25; the organic additive is sodium octadecenoate.

[0053] The additive, by weight, comprises: 11 parts acrylamide, 0.5 parts initiator (potassium persulfate-sodium persulfate), and 0.5 parts N,N-methylenebisacrylamide.

[0054] The ultrafine powder composition, by weight, includes 14 parts fly ash, 12 parts slag powder, 2 parts gypsum, 2 parts silica fume, 5 parts water-reducing agent, 7 parts retarder, and 8 parts quicklime. The fly ash has an average particle size of 3 μm; the slag powder has an average particle size of 1 μm; the gypsum is desulfurized gypsum; the water-reducing agent is a naphthalene-based water-reducing agent; and the retarder is sodium gluconate. The preparation method of the ultrafine powder is as follows: S1, grind the fly ash and slag powder to the specified particle size (fly ash ground to an average particle size of 3 μm; slag powder ground to an average particle size of 1 μm); S2, add the fly ash, slag powder, silica fume, gypsum, and quicklime to a mixer and mix; S3, add the retarder and water-reducing agent and mix.

[0055] The method for preparing concrete for precast bridge components containing special ultrafine powder is as follows: the raw materials for concrete preparation are mixed and stirred at 100 r / min for 15 min, then the concrete is poured into a mold for molding, demolded, and naturally cured at room temperature.

[0056] Example 3

[0057] This embodiment provides a concrete for precast bridge components containing special ultrafine powder; by weight, the raw materials for preparing the concrete include: 500 parts cement, 1600 parts coarse aggregate, 550 parts lightweight aggregate, 150 parts water, 100 parts ultrafine powder, 52 parts admixture, 16 parts reinforcing agent, and 3 parts organic additive.

[0058] The cement is Conch Cement 52.5; the coarse aggregate is crushed stone with an average particle size of 10 mm; the lightweight aggregate is river sand with an average particle size of 3 mm; the reinforcing agent is zinc oxide whiskers with an average needle-like length of 13 μm and an aspect ratio of 17; the organic additive is sodium octadecenoate.

[0059] The additive, by weight, comprises: 47 parts acrylamide, 3 parts initiator (potassium persulfate-sodium persulfate), and 2 parts N,N-methylenebisacrylamide.

[0060] The ultrafine powder composition, by weight, comprises 25 parts fly ash, 20 parts slag powder, 6 parts gypsum, 6 parts silica fume, 10 parts water-reducing agent, 17 parts retarder, and 16 parts quicklime. The fly ash has an average particle size of 3 μm; the slag powder has an average particle size of 2 μm; the gypsum is desulfurized gypsum; the water-reducing agent is a naphthalene-based water-reducing agent; and the retarder is sodium gluconate. The preparation method of the ultrafine powder is as follows: S1, grind the fly ash and slag powder to the specified particle size (fly ash ground to an average particle size of 3 μm; slag powder ground to an average particle size of 2 μm); S2, add the fly ash, slag powder, silica fume, gypsum, and quicklime to a mixer and mix; S3, add the retarder and water-reducing agent and mix.

[0061] The method for preparing concrete for precast bridge components containing special ultrafine powder is as follows: the raw materials for concrete preparation are mixed and stirred at 100 r / min for 15 min, then the concrete is poured into a mold for molding, demolded, and naturally cured at room temperature.

[0062] Example 4

[0063] This embodiment provides a concrete for precast bridge components containing special ultrafine powder; by weight, the raw materials for preparing the concrete include: 400 parts cement, 1400 parts coarse aggregate, 490 parts lightweight aggregate, 120 parts water, 81 parts ultrafine powder, 21 parts admixture, 13 parts reinforcing agent, and 4 parts organic additive.

[0064] The cement is Conch Cement 52.5; the coarse aggregate is crushed stone with an average particle size of 10 mm; the lightweight aggregate is river sand with an average particle size of 3 mm; the reinforcing agent is zinc oxide whiskers with an average needle-like length of 15 μm and an aspect ratio of 20; and the organic additive is sodium octadecenoate.

[0065] The additive components, by weight, are: 19 parts acrylamide, 1 part initiator (potassium persulfate-sodium persulfate), and 1 part N,N-methylenebisacrylamide.

[0066] The ultrafine powder composition, by weight, includes 20 parts fly ash, 16 parts slag powder, 4 parts gypsum, 4 parts silica fume, 7 parts water-reducing agent, 18 parts retarder, and 12 parts quicklime. The fly ash has an average particle size of 2 μm; the slag powder has an average particle size of 3 μm; the gypsum is desulfurized gypsum; the water-reducing agent is a naphthalene-based water-reducing agent; and the retarder is sodium gluconate. The preparation method of the ultrafine powder is as follows: S1, grind the fly ash and slag powder to the specified particle size (fly ash ground to an average particle size of 2 μm; slag powder ground to an average particle size of 3 μm); S2, add the fly ash, slag powder, silica fume, gypsum, and quicklime to a mixer and mix; S3, add the retarder and water-reducing agent and mix.

[0067] The method for preparing concrete for precast bridge components containing special ultrafine powder is as follows: the raw materials for concrete preparation are mixed and stirred at 100 r / min for 15 min, then the concrete is poured into a mold for molding, demolded, and naturally cured at room temperature.

[0068] Example 5

[0069] This embodiment provides a concrete for precast bridge components containing special ultrafine powder; by weight, the raw materials for preparing the concrete include: 400 parts cement, 1400 parts coarse aggregate, 490 parts lightweight aggregate, 120 parts water, 75 parts ultrafine powder, 27 parts admixture, 10 parts reinforcing agent, and 7 parts organic additive.

[0070] The cement is Conch Cement 52.5; the coarse aggregate is crushed stone with an average particle size of 10 mm; the lightweight aggregate is river sand with an average particle size of 3 mm; the reinforcing agent is zinc oxide whiskers with an average needle-like length of 15 μm and an aspect ratio of 20; and the organic additive is sodium octadecenoate.

[0071] The additive components, by weight, are: 25 parts acrylamide, 1 part initiator (potassium persulfate-sodium persulfate), and 1 part N,N-methylenebisacrylamide.

[0072] The ultrafine powder composition, by weight, includes 20 parts fly ash, 16 parts slag powder, 4 parts gypsum, 4 parts silica fume, 7 parts water-reducing agent, 12 parts retarder, and 12 parts quicklime. The average particle size of the fly ash is 2 μm; the average particle size of the slag powder is 3 μm; the gypsum is desulfurized gypsum; the water-reducing agent is a naphthalene-based water-reducing agent; and the retarder is sodium gluconate. The preparation method of the ultrafine powder is as follows: S1, grind the fly ash and slag powder to the specified particle size (grind the fly ash to an average particle size of 2 μm; grind the slag powder to an average particle size of 3 μm); S2, add the fly ash, slag powder, silica fume, gypsum, and quicklime to a mixer and mix; S3, add the retarder and water-reducing agent and mix.

[0073] The method for preparing concrete for precast bridge components containing special ultrafine powder is as follows: the raw materials for concrete preparation are mixed and stirred at 100 r / min for 15 min, then the concrete is poured into a mold for molding, demolded, and naturally cured at room temperature.

[0074] Comparative Example 1

[0075] The method is basically the same as Example 1, except that, by weight, the raw materials for preparing the concrete include: 400 parts cement, 1400 parts coarse aggregate, 490 parts lightweight aggregate, 120 parts water, 72 parts ultrafine powder, 30 parts admixture, 13 parts reinforcing agent, and 4 parts organic additive.

[0076] The ultrafine powder components, by weight, include 20 parts fly ash, 16 parts slag powder, 4 parts gypsum, 4 parts silica fume, 7 parts water-reducing agent, 9 parts retarder, and 12 parts hydrated lime.

[0077] The additive components, by weight, are: 28 parts acrylamide, 1 part initiator (potassium persulfate-sodium persulfate), and 1 part N,N-methylenebisacrylamide.

[0078] Comparative Example 2

[0079] The method is basically the same as Example 1, except that, by weight, the raw materials for preparing the concrete include: 400 parts cement, 1400 parts coarse aggregate, 490 parts lightweight aggregate, 120 parts water, 75 parts ultrafine powder, 27 parts admixture, 16 parts reinforcing agent, and 1 part organic additive.

[0080] Comparative Example 3

[0081] It is basically the same as Example 1, except that the quicklime is replaced with ultrafine slag powder.

[0082] Comparative Example 4

[0083] The method is basically the same as Example 1, except that, by weight, the raw materials for preparing the concrete include: 400 parts cement, 1400 parts coarse aggregate, 494 parts lightweight aggregate, 120 parts water, 75 parts ultrafine powder, 27 parts admixture, and 13 parts reinforcing agent.

[0084] Comparative Example 5

[0085] The method is basically the same as Example 1, except that, by weight, the raw materials for preparing the concrete include: 400 parts cement, 1413 parts coarse aggregate, 504 parts lightweight aggregate, 120 parts water, 75 parts ultrafine powder, 13 parts reinforcing agent, and 4 parts organic additive.

[0086] Comparative Example 6

[0087] The method is basically the same as in Example 1, except that acrylamide is replaced with polyacrylamide. The polyacrylamide is anionic and was purchased from Shandong Canxingge Building Materials Co., Ltd.

[0088] Comparative Example 7

[0089] It is basically the same as Example 1, except that the organic additive is dodecyl phosphate.

[0090] Comparative Example 8

[0091] It is basically the same as Example 1, except that the retarder is barium nitrate.

[0092] Performance testing methods:

[0093] Referring to GB / T50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete", relevant mechanical property tests were conducted; among them, the test method for compressive strength after chloride ion corrosion is as follows: after curing for 28 days, the concrete is immersed in a 5% sodium chloride aqueous solution for 90 days, and then the compressive strength is tested.

[0094] Performance test results:

[0095] The test results are shown in Table 1.

[0096] Table 1

[0097]

[0098]

[0099] Results analysis:

[0100] The results show that the concrete for precast bridge components prepared in Examples 1-5 has better mechanical properties and resistance to chloride ion penetration, with the product obtained in Example 1 exhibiting the best performance.

[0101] Compared to Example 1, Comparative Example 1 used too much acrylamide and too little sodium gluconate, making it difficult to form a complete coating on the metal substrate surface. This resulted in reduced film density and decreased corrosion inhibition. In Comparative Example 2, the amount of organic additives was too small, leading to a decrease in the compressive strength of the prepared concrete. This may be due to two factors: firstly, reduced grafting of inorganic materials such as zinc oxide whiskers in the system, resulting in decreased overall dispersion uniformity; secondly, the smaller amount of organic additives may have less involvement in the three-dimensional network structure, thus leading to a decrease in strength. In Comparative Example 3, the use of ultrafine slag powder instead of quicklime resulted in a decrease in the strength of the product. This may be due to a decrease in the alkalinity of the system, leading to a decrease in the metal ion dissolution rate and consequently, a decrease in the compressive strength of the product.

[0102] In Comparative Example 4, no organic additives were added, and the whiskers may settle in the concrete system, resulting in a relatively weaker interfacial bond strength with the concrete system. This leads to poor compressive strength and corrosion resistance of the product. In Comparative Example 5, no admixtures were introduced, making it impossible to construct a large organic-inorganic three-dimensional network structure in the concrete system. The internal structure of the product is relatively loose, and the film formed solely by sodium gluconate on the metal substrate surface has poor density, thus resulting in poor performance.

[0103] In Comparative Example 6, polyacrylamide was used instead of acrylamide. Although polyacrylamide still provided some adhesion and improved interfacial strength, the chemical coherence, bonding strength, and density of the components were weaker compared to the three-dimensional network constructed through the acrylamide reaction in Example 1. Furthermore, the high molecular weight polyacrylamide could not fill the gaps in the sodium gluconate protective film on the metal substrate surface like the low molecular weight acrylamide, thus failing to improve the film's density. Therefore, its overall performance was poor. In Comparative Example 7, dodecyl phosphate was used instead of sodium octadecenoate. The strength and corrosion resistance of the concrete prepared by this method decreased. This may be because dodecyl phosphate could not synergistically participate in the construction of the organic-inorganic three-dimensional network, failing to further improve the density of the three-dimensional network, resulting in relatively poor performance. In Comparative Example 8, barium nitrate was used instead of sodium gluconate. Barium nitrate was difficult to tightly bind with metal ions on the metal surface to form a film, failing to improve corrosion resistance, thus its corrosion resistance was poor.

Claims

1. A type of concrete for precast bridge components containing special ultrafine powder, characterized in that, The raw materials for preparing the concrete, by weight, include: 300-500 parts cement, 1200-1600 parts coarse aggregate, 400-550 parts lightweight aggregate, 100-150 parts water, 50-100 parts ultrafine powder, 10-70 parts admixture, and 10-30 parts reinforcing agent. By weight, the additive comprises 10-50 parts of a compound containing terminal double bonds, 0.5-3 parts of an initiator, and 0.5-2 parts of a crosslinking agent; According to the weight parts, the ultrafine powder component includes 10-30 parts of fly ash, 10-25 parts of slag powder, 1-10 parts of gypsum, 1-10 parts of silica fume, 3-15 parts of water-reducing agent, and 5-20 parts of retarder, wherein the retarder includes at least one of gluconate, citric acid, tartaric acid, and sugars. The raw materials for preparing the concrete also include 1-10 parts of organic additives, wherein the organic additives are C atoms with at least one unsaturated bond. 10 -C 30 Organic acid salts; The compound containing terminal double bonds is acrylamide; The weight ratio of the retarder to the compound containing terminal double bonds is 1:(1-3). The reinforcing agent is at least one of zinc oxide whiskers, zinc sulfate whiskers, and zinc phosphate whiskers; the weight ratio of the reinforcing agent to the organic agent is 1:(0.1-0.8).

2. The concrete for precast bridge components containing special ultrafine powder according to claim 1, characterized in that, The retarder is gluconate.

3. The concrete for precast bridge components containing special ultrafine powder according to claim 1, characterized in that, The raw materials for preparing the ultrafine powder also include 5-25 parts of hydrated lime.

4. The concrete for precast bridge components containing special ultrafine powder according to claim 1, characterized in that, The organic additives include sodium eicosapentaenoate, sodium octadecenoate, sodium hexadecenoate, sodium hexadecene sulfonate, and C. 12 -C 14 At least one of sodium alkenyl sulfonate.

5. The concrete for precast bridge components containing special ultrafine powder according to claim 4, characterized in that, The organic additive is sodium octadecenoate.

6. The concrete for precast bridge components containing special ultrafine powder according to claim 1, characterized in that, The weight ratio of the retarder to the compound containing terminal double bonds is 1:(1.5-3).

7. The concrete for precast bridge components containing special ultrafine powder according to claim 1, characterized in that, The weight ratio of the reinforcing agent to the organic agent is 1:(0.1-0.5).

8. The concrete for precast bridge components containing special ultrafine powder according to claim 1, characterized in that, The crosslinking agent is a compound containing two terminal double bonds, specifically selected from at least one of N,N-methylenebisacrylamide, 1,4-butanediol diacrylate, and ethylene glycol dimethacrylate.

9. The method for preparing concrete for precast bridge components containing special ultrafine powder according to any one of claims 1-8, characterized in that, The process involves mixing the raw materials for concrete preparation, followed by stirring, solidification, and curing.

Images