Grouting material for bridge head jump and preparation method thereof

Abstract

The present invention relates to a grouting material for bridge head jump and a preparation method thereof, belonging to the technical field of grouting materials. The grouting material is composed of cement, modified silica fume, gypsum, fly ash, mineral powder, heavy calcium and functional additives. The modified silica fume is prepared by ball milling silica fume, compounding sodium silicate / calcium titanate slurry, and surface modification with methyl methacrylate, which significantly improves the gelling activity. The grouting material adopts a step-by-step mixing process: first dry-mix the powder, then mix the solution containing dispersant, rheological agent, suspending agent, retarder, expansion agent and early strength agent with the powder through atomization spraying, and then mature and form after high-speed stirring and vacuum defoaming. The product has high compressive strength (28d≥60MPa), is suitable for harsh environments such as underground engineering and bridge foundation reinforcement, and is significantly superior to traditional grouting materials.

Description

Technical Field

[0001] The invention belongs to the technical field of grouting materials and relates to a grouting material for bridge head jump and a preparation method thereof. Background Art

[0002] Grouting materials are the core materials of grouting technology, and their performance is directly related to the quality and effectiveness of grouting projects. Traditional grouting materials often suffer from insufficient strength, poor durability, shrinkage cracking, and other issues, making them difficult to meet the high-performance requirements of complex geological conditions and engineering structures.

[0003] Bridge bumping is a bumpy ride at the junction of a highway and a bridge caused by differential settlement between the roadbed and abutments. It poses a serious threat to driving safety and the durability of bridge structures. Traditionally, cement-based grouting materials have been used for bridgehead roadbed reinforcement. However, conventional formulations suffer from low early strength, poor fluidity, and high shrinkage. This results in weak adhesion between the grout and the existing structure, and is prone to microcracks and even secondary settlement under dynamic loads and temperature and humidity fluctuations.

[0004] Existing active admixtures like silica fume struggle to fully realize their pozzolanic effect due to the aggregation of surface hydroxyl groups. Furthermore, conventional additives lack compatibility with cementitious systems, easily causing slurry stratification and segregation. This makes them unable to meet the stringent workability requirements of highly fluid, self-compacting grouting processes. While some grouting materials in current projects increase strength by increasing cement content, this leads to concentrated hydration heat and increased shrinkage, exacerbating the risk of differential settlement at bridgeheads.

[0005] Therefore, it is urgent to develop a grouting material for bridge head jumping. Summary of the Invention

[0006] The invention aims to provide a grouting material for bridge head jump and a preparation method thereof, which has the characteristics of high strength.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A grouting material for bridge head bumping, the grouting material has the following formula, calculated by weight, 750-900 parts of cement, 10-50 parts of modified silica fume, 10-50 parts of gypsum, 30-60 parts of fly ash, 10-100 parts of mineral powder, 10-100 parts of heavy calcium carbonate, 1-3 parts of dispersant, 0.1-1 parts of rheological agent, 0.2-0.5 parts of suspending agent, 0.5-1 parts of retarder, 0.1-1 parts of expansion agent, 5-10 parts of early strength agent, and 226-371 parts of deionized water;

[0009] The modified silica fume is prepared by mixing silica fume, methyl methacrylate, sodium silicate and calcium titanate.

[0010] Among them, the dispersant is polyethylene glycol with a number average molecular weight of 2000~4000; the rheological agent is hydroxypropyl methylcellulose; the suspending agent is xanthan gum; the retarder is sodium hexametaphosphate; the expanding agent is magnesium oxide; and the early strength agent is triethanolamine.

[0011] Furthermore, the modified silica fume preparation method is as follows:

[0012] S1: Place silica fume in a ball mill and grind at 400 r / min for 20-30 min to obtain powder A;

[0013] S2: Sodium silicate is dissolved in deionized water to prepare a sodium silicate solution with a mass fraction of 5-7%, 1-2 wt% of calcium titanate powder is added to the sodium silicate solution as a basis, and mixed slurry B is obtained after homogenization;

[0014] S3: Powder A and mixed slurry B were mixed in a mass ratio of 1:1, and stirred at 800 rpm for 20 min in a constant temperature stirrer at 50-60°C to obtain mixed slurry C;

[0015] S4: adding 3-5 wt% of methyl methacrylate to the mixed slurry C, heating to 70-80°C, and continuing to stir at a speed of 800 rpm for 10 min to obtain a mixed slurry D;

[0016] S5: centrifuging the mixed slurry D, washing the solid product with deionized water, and drying and crushing the solid product to obtain the modified silica fume.

[0017] Furthermore, the silica fume has a particle size of 0.1-0.3 μm and a specific surface area of ​​15-20 m² / g.

[0018] Furthermore, the parameters of the homogenization process in S2 are a rotation speed of 1000 r / min and a duration of 10 to 15 minutes.

[0019] Furthermore, the parameters of the centrifugal treatment in S5 are a rotation speed of 4000 r / min and a duration of 10 to 15 minutes.

[0020] Furthermore, the drying and crushing treatment in S5 is drying in a vacuum drying oven at 60-70° C. to a moisture content of ≤1.0%, and then crushing to a particle size of 3-5 μm.

[0021] A preparation method of a grouting material for bridge head vehicle jump, the preparation method is as follows:

[0022] A1: Weigh cement, modified silica fume, gypsum, fly ash, mineral powder, and heavy calcium carbonate by weight, place in a blender, and stir at 120-150 rpm for 10-15 minutes to ensure uniform dispersion of the powders.

[0023] A2: Dispersant, rheological agent, suspending agent, retarder, expansion agent, and early strength agent are then added to deionized water at a water-binder ratio of 0.28-0.32 and mixed. Stir at 200 rpm in a constant temperature water bath at 70-80°C until completely dissolved to form a transparent homogeneous solution.

[0024] A3: Increase the mixer speed to 600-800 r / min, spray the transparent homogeneous solution prepared in A2 evenly onto the powder surface through the atomizing nozzle, and stir for 15-20 minutes to prepare a slurry;

[0025] A4: The slurry prepared in A3 is transferred to a vacuum stirring tank, and the vacuum is evacuated to -0.095~-0.10MPa and maintained for 6~8min. After eliminating bubbles, the slurry is allowed to stand and mature for 40min, and then sealed and packaged to complete the preparation of the grouting material.

[0026] Furthermore, the pressure of the atomizing nozzle in A3 is 0.3-0.4 MPa.

[0027] Furthermore, the ambient temperature is maintained at 25±2° C. and the humidity is maintained at ≤50% during the preparation process.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The grouting material of the present invention achieves a comprehensive improvement in the mechanical properties, volume stability and construction performance of the material through the synergistic effect between specific components and the core role of modified silica fume. The grouting material is based on 750-900 parts of cement and forms a highly active composite cementitious system by introducing 10-50 parts of modified silica fume. The modification process is achieved through three steps: silica fume pretreatment, surface activation and organic-inorganic hybridization: first, the original silica fume is ball-milled at 400r / min for 20-30 minutes to further refine the particles and expose more silanol active sites; then 1-2% calcium titanate is added to a 5-7% sodium silicate solution for homogenization, and the sodium silicate is treated by Na + Ion exchange occurs with Si-OH groups on the surface of silica fume to form a Si-O-Si bonding layer, and the Ca generated by the dissolution of calcium titanate 2+ Reacts with SiO2 to form nano-scale calcium silicate hydrate (CSH) pre-nucleation points, TiO3 2- It forms a charge barrier by adsorbing on the surface of cement particles, promoting the early hydration of C3S; finally, 3~5% methyl methacrylate is added for graft polymerization at 70~80℃, and its double bonds initiate polymerization with free radicals on the surface of silica fume to form a polymethyl methacrylate (PMMA) coating layer. This organic layer not only inhibits the secondary agglomeration of silica fume through hydrophobic effect, but also reacts with Ca in cement hydration products through carboxyl groups. 2+ Form coordination bonds and enhance interfacial bonding strength.

[0030] 2. In the construction of the cementitious system, Ca(OH)2 generated by cement hydration reacts rapidly with the highly active SiO2 in the modified silica fume to form a dense CSH gel. 2+ Accelerate, greatly improve the degree of reaction; fly ash (30-60 parts) and mineral powder (10-100 parts) gradually dissociate Al2O3 and SiO2 in an alkaline environment, and react with Ca(OH)2 to form secondary CSH and ettringite (AFt), whose delayed hydration characteristics effectively fill the micropores after 28 days; gypsum (10-50 parts) adjusts SO4 2- The concentration controls the formation rate of ettringite to avoid early excessive expansion; heavy calcium carbonate (10-100 parts) is used as a micron-sized filler (3-5 μm) to form a graded filling with the nanoparticles of modified silica fume, reducing the slurry porosity to below 8%, with the pore size distribution concentrated in the range of 10-50 nm. The dispersant polyethylene glycol (number average molecular weight 2000-4000) binds to the Ca2+ on the surface of cement particles through ether bond oxygen atoms. 2+ Coordination adsorption, its long-chain structure produces a steric hindrance effect, so that the slurry still maintains a certain fluidity at a low water-binder ratio of 0.28~0.32; the rheological agent hydroxypropyl methylcellulose (HPMC) forms a three-dimensional network structure through molecular chain entanglement. When the shear rate increases, the hydrogen bonds break, resulting in a decrease in viscosity. After standing, the network structure is restored, giving the slurry excellent construction performance with a thixotropic index (TI value) of more than 2.8; the suspending agent xanthan gum forms a rigid helical structure through the β-1,4-glucan main chain and the side chains mannose and glucuronic acid. When static, it captures free water through hydrogen bonds to form a high-viscosity system. During dynamic shear, the helical structure unwinds, causing a sharp drop in viscosity, and cooperates with HPMC to achieve 6-hour slurry without sedimentation and stratification.

[0031] 3. Sodium hexametaphosphate retarder through [PO3]6 -6 The ring structure chelates Ca in the liquid phase 2+ and Al 3+ , prolonging the initial setting time to an adjustable range of 2~4 hours, while its adsorption on the surface of C3A inhibits the rapid formation of ettringite; the expansive agent magnesium oxide gradually hydrates to form Mg(OH)2 under the environment of cement paste pH>12.4, and its delayed expansion characteristics accurately compensate for the drying shrinkage of the cement matrix; the early strength agent triethanolamine reacts with the lone pair electrons of the N atom to form calcium sulfate. 2+The formation of complexes accelerates the destruction of the C3S surface protective layer, significantly improving the compressive strength. There is also a synergistic effect between the components: the highly active surface of the modified silica fume and the polyethylene glycol dispersant jointly reduce the friction resistance between the particles, reducing the slurry yield stress to below 120Pa; HPMC and xanthan gum achieve construction performance optimization through a viscosity complementary mechanism, in which HPMC provides static suspension and xanthan gum dominates the dynamic rheology; the retarding effect of sodium hexametaphosphate and the accelerating effect of triethanolamine form a dynamic balance to ensure the best match between the operating time and strength development; the delayed expansion of magnesium oxide is highly synchronized with the cement hydration shrinkage process, effectively eliminating shrinkage stress. In addition, the PMMA coating of the modified silica fume gradually hydrolyzes in the alkaline environment of cement, and the released methacrylic acid reacts with Ca 2+ The organic calcium salt is generated, and the crystal growth of the substance in the pores forms a nano-reinforced phase, which makes the 28-day compressive strength exceed 65MPa; TiO3 introduced by calcium titanate 2- It undergoes redox reaction with Fe2O3 impurities in silica fume to generate FeTiO3 conductive phase, which reduces the volume resistivity of the material to 10 4 Ω·cm level, with anti-static function.

[0032] 4. The grouting material preparation method described in the present invention significantly improves the material uniformity, density and performance stability through multi-stage process control and parameter coordinated optimization. First, in the raw material pretreatment stage, cement, modified silica fume, gypsum, fly ash, mineral powder and heavy calcium are mixed at a speed of 120-150 r / min for 10-15 minutes by step-by-step feeding. This speed range can generate sufficient shear force to break up powder agglomeration and avoid the prehydration phenomenon caused by micro powder dust or local temperature increase due to excessive speed. Modified silica fume has hydrophobicity due to its surface organic-inorganic hybrid treatment. During the powder mixing stage, it preferentially forms a uniformly dispersed composite matrix with cement particles through van der Waals forces and mechanical interlocking. The micron-sized particles of fly ash and mineral powder can fill the gaps between cement particles, and the micron-sized particles of heavy calcium further optimize the gradation. This mixing process further improves the bulk density of the powder, laying the foundation for the subsequent preparation of low water-cement ratio slurry. Secondly, a constant temperature water bath of 70-80°C is used to fully extend the polyethylene glycol dispersant's molecular chains. The hydroxyl groups of hydroxypropyl methylcellulose (HPMC) form hydrogen-bonding networks with water molecules. The helical structure of xanthan gum unwinds under heat, exposing more binding sites. The cyclic structure of sodium hexametaphosphate becomes more ionized at high temperatures, accelerating the dissolution kinetics of triethanolamine and magnesium oxide. This temperature range ensures complete dissolution of the additives to form a homogeneous solution while avoiding overheating that could degrade HPMC or volatilize triethanolamine. The laminar shear field created by stirring at 200 rpm promotes directional alignment of the additive molecules, providing ideal rheological properties for subsequent atomization and spraying.

[0033] 5. During the solid-liquid mixing stage, high-speed stirring at 600-800 r / min and atomizing spray at 0.3-0.4 MPa synergistically coat the powder surface with liquid droplets of 50-100 μm in size. The centrifugal force generated by the high-speed stirring creates a fluidized bed state within the powder. The atomized droplets form a nanoscale wetting film on the powder surface, driving the liquid phase to rapidly penetrate the powder pores through capillary forces and surface tension. During this process, the PMMA coating of the modified silica fume synergistically adsorbs with the polyethylene glycol dispersant, with its hydrophobic groups oriented outward to form a low-friction interface, reducing inter-powder sliding resistance. Simultaneously, high-speed shear forces temporarily dissociate the three-dimensional network structure of HPMC and xanthan gum, reducing the apparent viscosity of the slurry to below 500 mPa·s. This ensures that no dry powder residue or localized agglomeration occurs within the 15-20 minute mixing period. The vacuum degassing and aging process involves evacuating the slurry to -0.095 to -0.10 MPa and maintaining it for 6 to 8 minutes. This allows residual bubbles in the slurry to expand and rupture under the pressure differential. This, combined with the micro-shear flow generated by the propeller blades of the vacuum agitator, significantly improves the slurry's density. During the 40-minute aging process, the retarding effect of sodium hexametaphosphate suppresses the early hydration exotherm of the cement, stabilizing the slurry temperature at 35 to 40°C. At this temperature, triethanolamine accelerates the exfoliation of hydration products from the C3S surface, forming a pre-hydrated Mg(OH)2 layer on the surface of the magnesium oxide particles, providing a controllable active source for subsequent expansion. DETAILED DESCRIPTION

[0034] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0035] Example 1

[0036] A grouting material for a bridge bump, the grouting material having the following formula, by weight, 850 parts of cement, 30 parts of modified silica fume, 30 parts of gypsum, 50 parts of fly ash, 50 parts of mineral powder, 50 parts of heavy calcium carbonate, 2 parts of polyethylene glycol 2000, 0.5 parts of hydroxypropyl methylcellulose, 0.5 parts of xanthan gum, 0.5 parts of sodium hexametaphosphate, 0.5 parts of magnesium oxide, 7 parts of triethanolamine, and 297 parts of deionized water;

[0037] The modified silica fume is prepared by mixing silica fume, methyl methacrylate, sodium silicate and calcium titanate.

[0038] Furthermore, the modified silica fume preparation method is as follows:

[0039] S1: Place silica fume in a ball mill and grind at 400 r / min for 25 min to obtain powder A;

[0040] S2: Sodium silicate was dissolved in deionized water to prepare a sodium silicate solution with a mass fraction of 7%. 2 wt% of calcium titanate powder was added to the sodium silicate solution, and the mixture was homogenized to obtain a mixed slurry B. The homogenization parameters were a speed of 1000 r / min and a duration of 15 min.

[0041] S3: Powder A and mixed slurry B were mixed in a mass ratio of 1:1, and stirred at 800 rpm in a constant temperature stirrer at 55°C for 20 min to obtain mixed slurry C;

[0042] S4: adding 5 wt% of methyl methacrylate to the mixed slurry C, heating to 80°C, and continuing to stir at a speed of 800 rpm for 10 min to obtain a mixed slurry D;

[0043] S5: The mixed slurry D is centrifuged at a speed of 4000 r / min for 15 min. The solid product is washed with deionized water and then dried and crushed to obtain the modified silica fume. The drying and crushing process is to dry the solid product in a vacuum drying oven at 70°C to a moisture content of ≤1.0%, and then crush the solid product to a particle size of 3~5 μm.

[0044] A preparation method of a grouting material for bridge head vehicle jump, the preparation method is as follows:

[0045] A1: Weigh cement, modified silica fume, gypsum, fly ash, mineral powder, and heavy calcium carbonate by weight, place in a blender, and stir at 150 rpm for 10 minutes to ensure uniform dispersion of the powders.

[0046] A2: Then add polyethylene glycol 2000, hydroxypropyl methylcellulose, xanthan gum, sodium hexametaphosphate, magnesium oxide, and triethanolamine to deionized water at a water-to-gel ratio of 0.28, mix, and stir at 200 rpm in a 70°C constant temperature water bath until completely dissolved to form a transparent homogeneous solution;

[0047] A3: Increase the mixer speed to 800 r / min, and spray the transparent homogeneous solution prepared in A2 evenly onto the powder surface through the atomizing nozzle at a pressure of 0.4 MPa. Stir for 20 minutes to obtain a slurry.

[0048] A4: The slurry prepared in A3 was transferred to a vacuum stirring tank, vacuumed to -0.10 MPa and maintained for 6 minutes, allowed to stand and mature for 40 minutes after eliminating bubbles, and sealed and packaged to complete the preparation of the grouting material.

[0049] During the preparation process, the ambient temperature was maintained at 25±2°C and the humidity was ≤50%.

[0050] Example 2

[0051] A grouting material for bridge head bumping, the grouting material formula is as follows: by weight, 900 parts of cement, 50 parts of modified silica fume, 50 parts of gypsum, 60 parts of fly ash, 100 parts of mineral powder, 10 parts of heavy calcium carbonate, 3 parts of polyethylene glycol 2000, 1 part of hydroxypropyl methylcellulose, 0.5 part of xanthan gum, 1 part of sodium hexametaphosphate, 1 part of magnesium oxide, 10 parts of triethanolamine, and 371 parts of deionized water;

[0052] The modified silica fume is prepared by mixing silica fume, methyl methacrylate, sodium silicate and calcium titanate.

[0053] Furthermore, the modified silica fume preparation method is as follows:

[0054] S1: Place silica fume in a ball mill and grind at 400 r / min for 30 min to obtain powder A;

[0055] S2: Sodium silicate was dissolved in deionized water to prepare a sodium silicate solution with a mass fraction of 7%. 2 wt% of calcium titanate powder was added to the sodium silicate solution, and the mixture was homogenized to obtain a mixed slurry B. The homogenization parameters were a speed of 1000 r / min and a duration of 15 min.

[0056] S3: Powder A and mixed slurry B were mixed in a mass ratio of 1:1, and stirred at 800 rpm in a constant temperature stirrer at 60°C for 20 min to obtain mixed slurry C;

[0057] S4: adding 5 wt% of methyl methacrylate to the mixed slurry C, heating to 80°C, and continuing to stir at a speed of 800 rpm for 10 min to obtain a mixed slurry D;

[0058] S5: The mixed slurry D is centrifuged at a speed of 4000 r / min for 15 min. The solid product is washed with deionized water and then dried and crushed to obtain the modified silica fume. The drying and crushing process is to dry the solid product in a vacuum drying oven at 70°C to a moisture content of ≤1.0%, and then crush the solid product to a particle size of 3~5 μm.

[0059] A preparation method of a grouting material for bridge head vehicle jump, the preparation method is as follows:

[0060] A1: Weigh cement, modified silica fume, gypsum, fly ash, mineral powder, and heavy calcium carbonate by weight, place in a blender, and stir at 150 rpm for 15 minutes to ensure uniform dispersion of the powders.

[0061] A2: Then add polyethylene glycol 2000, hydroxypropyl methylcellulose, xanthan gum, sodium hexametaphosphate, magnesium oxide, and triethanolamine to deionized water at a water-to-gel ratio of 0.32, mix, and stir at 200 rpm in a constant temperature water bath at 80°C until completely dissolved to form a transparent homogeneous solution.

[0062] A3: Increase the mixer speed to 800 r / min, and spray the transparent homogeneous solution prepared in A2 evenly onto the powder surface through the atomizing nozzle at a pressure of 0.4 MPa. Stir for 20 minutes to obtain a slurry.

[0063] A4: The slurry prepared in A3 was transferred to a vacuum stirring tank, vacuumed to -0.10 MPa and maintained for 8 minutes, allowed to stand and mature for 40 minutes after eliminating bubbles, and sealed and packaged to complete the preparation of the grouting material.

[0064] During the preparation process, the ambient temperature was maintained at 25±2°C and the humidity was ≤50%.

[0065] Example 3

[0066] A grouting material for bridge head bumping, the grouting material has the following formula, calculated by weight, 750 parts of cement, 10 parts of modified silica fume, 10 parts of gypsum, 30 parts of fly ash, 10 parts of mineral powder, 100 parts of heavy calcium carbonate, 1 part of polyethylene glycol 2000, 0.1 part of hydroxypropyl methylcellulose, 0.2 part of xanthan gum, 0.5 part of sodium hexametaphosphate, 0.1 part of magnesium oxide, 5 parts of triethanolamine, and 227 parts of deionized water;

[0067] The modified silica fume is prepared by mixing silica fume, methyl methacrylate, sodium silicate and calcium titanate.

[0068] Furthermore, the modified silica fume preparation method is as follows:

[0069] S1: Place silica fume in a ball mill and grind at 400 r / min for 20 min to obtain powder A;

[0070] S2: Sodium silicate was dissolved in deionized water to prepare a sodium silicate solution with a mass fraction of 5%. 1 wt% of calcium titanate powder was added to the sodium silicate solution, and the mixture was homogenized to obtain a mixed slurry B. The homogenization parameters were a speed of 1000 r / min and a duration of 10 min.

[0071] S3: Powder A and mixed slurry B were mixed in a mass ratio of 1:1, and stirred at 800 rpm for 20 min in a constant temperature stirrer at 50°C to obtain mixed slurry C;

[0072] S4: adding 3 wt % of methyl methacrylate to the mixed slurry C, heating to 70° C., and continuing to stir at a speed of 800 rpm for 10 min to obtain a mixed slurry D;

[0073] S5: The mixed slurry D is centrifuged at a speed of 4000 r / min for 10 min. The solid product is washed with deionized water and then dried and crushed to obtain the modified silica fume. The drying and crushing is carried out in a vacuum drying oven at 60°C to a moisture content of ≤1.0%, and then crushed to a particle size of 3~5 μm.

[0074] A preparation method of a grouting material for bridge head vehicle jump, the preparation method is as follows:

[0075] A1: Weigh cement, modified silica fume, gypsum, fly ash, mineral powder, and heavy calcium carbonate by weight, place in a blender, and stir at 120 rpm for 10 minutes to ensure uniform dispersion of the powders.

[0076] A2: Then add polyethylene glycol 2000, hydroxypropyl methylcellulose, xanthan gum, sodium hexametaphosphate, magnesium oxide, and triethanolamine to deionized water at a water-to-gel ratio of 0.28, mix, and stir at 200 rpm in a 70°C constant temperature water bath until completely dissolved to form a transparent homogeneous solution;

[0077] A3: Increase the mixer speed to 600 r / min, and spray the transparent homogeneous solution prepared in A2 evenly onto the powder surface through the atomizing nozzle at a pressure of 0.3 MPa. Stir for 15 minutes to obtain a slurry.

[0078] A4: The slurry prepared in A3 was transferred to a vacuum stirring tank, vacuumed to -0.095 MPa and maintained for 6 minutes, allowed to stand and mature for 40 minutes after eliminating bubbles, and sealed and packaged to complete the preparation of the grouting material.

[0079] During the preparation process, the ambient temperature was maintained at 25±2°C and the humidity was ≤50%.

[0080] Comparative Example 1

[0081] In this comparative example, the silica fume was not modified, and the remaining steps were the same as those in Example 1.

[0082] Comparative Example 2

[0083] In this comparative example, methyl methacrylate was not added during the silica fume modification process, and the remaining steps were consistent with those in Example 1.

[0084] Comparative Example 3

[0085] In this comparative example, no sodium silicate was added during the silica fume modification process, and the remaining steps were consistent with those in Example 1.

[0086] Comparative Example 4

[0087] In this comparative example, calcium titanate was not added during the silica fume modification process, and the remaining steps were consistent with those in Example 1.

[0088] The compressive strength performance of the embodiment and the comparative example was tested with reference to the standard GB 50204-2015. The test results are shown in Table 1.

[0089] Table 1 Compressive strength test data of different grouting materials

[0090]

[0091] The above experiments show that modified silica fume effectively improves the compressive strength of the prepared grouting material.

[0092] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A grouting material for bridge head bump, characterized in that: The grouting material formula is as follows: by weight, 750-900 parts of cement, 10-50 parts of modified silica fume, 10-50 parts of gypsum, 30-60 parts of fly ash, 10-100 parts of mineral powder, 10-100 parts of heavy calcium carbonate, 1-3 parts of dispersant, 0.1-1 parts of rheological agent, 0.2-0.5 parts of suspending agent, 0.5-1 parts of retarder, 0.1-1 parts of expansion agent, 5-10 parts of early strength agent, and 226-371 parts of deionized water; Wherein, the preparation method of the modified silica fume is as follows: S1: Place silica fume in a ball mill and grind at 400 r / min for 20-30 min to obtain powder A; S2: Sodium silicate is dissolved in deionized water to prepare a sodium silicate solution with a mass fraction of 5-7%, 1-2 wt% of calcium titanate powder is added to the sodium silicate solution as a basis, and mixed slurry B is obtained after homogenization; S3: Powder A and mixed slurry B were mixed in a mass ratio of 1:1, and stirred at 800 rpm for 20 min in a constant temperature stirrer at 50-60°C to obtain mixed slurry C; S4: adding 3-5 wt% of methyl methacrylate to the mixed slurry C, heating to 70-80°C, and continuing to stir at a speed of 800 rpm for 10 min to obtain a mixed slurry D; S5: centrifuging the mixed slurry D, washing the solid product with deionized water, and drying and crushing the solid product to obtain the modified silica fume; Among them, the dispersant is polyethylene glycol with a number average molecular weight of 2000~4000; the rheological agent is hydroxypropyl methylcellulose; the suspending agent is xanthan gum; the retarder is sodium hexametaphosphate; the expanding agent is magnesium oxide; and the early strength agent is triethanolamine.

2. A grouting material for bridge head jump according to claim 1, characterized in that: The silica fume has a particle size of 0.1-0.3 μm and a specific surface area of ​​15-20 m² / g.

3. A grouting material for bridge bump according to claim 1, characterized in that: The parameters of the homogenization process in S2 are a rotation speed of 1000 r / min and a duration of 10 to 15 minutes.

4. A grouting material for bridge bump according to claim 1, characterized in that: The parameters of the centrifugal treatment in S5 are a rotation speed of 4000 r / min and a duration of 10 to 15 minutes.

5. The grouting material for bridge head bump according to claim 1, characterized in that: The drying and pulverizing treatment in S5 is to dry the mixture in a vacuum drying oven at 60-70° C. until the moisture content is ≤1.0%, and then pulverize the mixture to a particle size of 3-5 μm.

6. A method for preparing a grouting material for bridge bump according to any one of claims 1 to 5, It is characterized by: The preparation method is as follows, A1: Weigh cement, modified silica fume, gypsum, fly ash, mineral powder, and heavy calcium carbonate by weight, place in a blender, and stir at 120-150 rpm for 10-15 minutes to ensure uniform dispersion of the powders. A2: Dispersant, rheological agent, suspending agent, retarder, expansion agent, and early strength agent are then added to deionized water at a water-binder ratio of 0.28-0.32 and mixed. Stir at 200 rpm in a constant temperature water bath at 70-80°C until completely dissolved to form a transparent homogeneous solution. A3: Increase the mixer speed to 600-800 r / min, spray the transparent homogeneous solution prepared in A2 evenly onto the powder surface through the atomizing nozzle, and stir for 15-20 minutes to prepare a slurry; A4: The slurry prepared in A3 is transferred to a vacuum stirring tank, and the vacuum is evacuated to -0.095~-0.10MPa and maintained for 6~8min. After eliminating bubbles, the slurry is allowed to stand and mature for 40min, and then sealed and packaged to complete the preparation of the grouting material.

7. The method for preparing a grouting material for bridge bump according to claim 6, wherein: The pressure of the atomizing nozzle in A3 is 0.3-0.4 MPa.

8. The method for preparing a grouting material for bridge bump according to claim 6, wherein: During the preparation process, the ambient temperature was maintained at 25±2° C. and the humidity was maintained at ≤50%.

Images