Grouting material for bridge-head bumping and preparation method of grouting material

Abstract

The invention relates to a grouting material for a bridgehead bump and a preparation method thereof, and belongs to the technical field of grouting materials. The grouting material is composed of cement, modified silica fume, gypsum, fly ash, mineral powder, ground calcium carbonate and a functional additive. Wherein the modified silica fume is prepared through silica fume ball milling, sodium silicate / calcium titanate slurry compounding, methyl methacrylate surface modification and other processes, and the gelling activity is remarkably improved. The grouting material adopts a step-by-step mixing process: firstly dry-mixing powder, then mixing a solution containing a dispersing agent, a rheological agent, a suspending agent, a retarder, an expanding agent and an early strength agent with the powder through atomization spraying, and curing and forming after high-speed stirring and vacuum defoaming. The product has high compressive strength (28d is greater than or equal to 60MPa), is suitable for harsh environments such as underground engineering and bridge foundation reinforcement, and is obviously superior to a traditional grouting material.

Description

Technical Field

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

[0002] As the core material of grouting technology, the performance of grouting materials is directly related to the quality and effect of grouting projects. Traditional grouting materials often have problems such as insufficient strength, poor durability, shrinkage cracking, etc., which are difficult to meet the high performance requirements of grouting materials in complex geological conditions and engineering structures.

[0003] Bridge head jumping is a driving bump phenomenon caused by the difference in settlement between the roadbed and the abutment at the junction of the highway and the bridge, which seriously threatens driving safety and the durability of the bridge structure. Traditional bridge head roadbed reinforcement mostly uses cement-based grouting materials, but conventional formulas have defects such as low early strength, poor fluidity, and large shrinkage, resulting in weak adhesion between the grouting body and the existing structure interface, and micro cracks and even secondary settlement are easily generated under dynamic loads and alternating temperature and humidity.

[0004] In the existing technology, active admixtures such as silica fume are difficult to fully exert the volcanic ash effect due to the surface hydroxyl agglomeration effect, and the conventional additives are not compatible with the cementitious system, which easily causes slurry stratification and segregation, and cannot meet the stringent requirements of high-flow, self-compacting grouting technology for material workability. Although some grouting materials in current projects increase the strength by increasing the amount of cement, it brings about problems such as concentrated hydration heat and increased shrinkage, which in turn aggravates the risk of differential settlement at the bridge head.

[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: A grouting material for a bridge head jump, wherein the grouting material has the following formula: 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, 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; The modified silica fume is prepared by mixing silica fume, methyl methacrylate, sodium silicate and calcium titanate.

[0008] 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 setting retarder is sodium hexametaphosphate; the expansive agent is magnesium oxide; the early strength agent is triethanolamine.

[0009] Further, the preparation method of the modified silica fume is as follows. S1: Put the silica fume into a ball mill and grind it at a speed of 400 r / min for 20 - 30 min to obtain powder A. S2: Dissolve sodium silicate in deionized water to prepare a sodium silicate solution with a mass fraction of 5 - 7%. Based on the sodium silicate solution, add 1 - 2 wt% of calcium titanate powder, and after homogenization treatment, obtain mixed slurry B. S3: Mix powder A and mixed slurry B in a mass ratio of 1:1, and stir in a constant temperature stirrer at 50 - 60 °C at a speed of 800 r / min for 20 min to obtain mixed slurry C. S4: Add 3 - 5 wt% of methyl methacrylate to mixed slurry C, heat up to 70 - 80 °C, and then continue to stir at a speed of 800 r / min for 10 min to obtain mixed slurry D. S5: Perform centrifugation on mixed slurry D, wash the solid product with deionized water, and after washing, perform drying and pulverization treatment to obtain the modified silica fume.

[0010] Further, the particle size of the silica fume is 0.1 - 0.3 μm, and the specific surface area is 15 - 20 m² / g.

[0011] Further, the parameters of the homogenization treatment in S2 are a rotation speed of 1000 r / min and a duration of 10 - 15 min.

[0012] Further, the parameters of the centrifugation treatment in S5 are a rotation speed of 4000 r / min and a duration of 10 - 15 min.

[0013] Further, the drying and pulverization treatment in S5 is to dry in a vacuum drying oven at 60 - 70 °C until the moisture content ≤ 1.0%, and then pulverize to a particle size of 3 - 5 μm.

[0014] A preparation method of a grouting material for bridgehead bumping, the preparation method is as follows. A1: Weigh cement, modified silica fume, gypsum, fly ash, slag powder, and heavy calcium by weight, put them into a mixer, and stir and mix at a speed of 120 - 150 r / min for 10 - 15 min to ensure uniform dispersion of the powder. A2: Then, dispersant, rheological agent, suspending agent, retarder, expansive agent, and early strength agent are added to deionized water according to a water-binder ratio of 0.28 - 0.32 and mixed. The mixture is stirred at a speed of 200 r / min in a constant temperature water bath at 70 - 80 °C until completely dissolved to form a transparent homogeneous solution. A3: Increase the speed of the mixer to 600 - 800 r / min, and uniformly spray the transparent homogeneous solution prepared in A2 onto the surface of the powder through an atomizing nozzle while stirring synchronously for 15 - 20 min to obtain a slurry. A4: Transfer the slurry prepared in A3 to a vacuum stirring tank, evacuate to -0.095 - -0.10 MPa and maintain for 6 - 8 min. After removing the bubbles, let it stand and cure for 40 min, and then seal and package to complete the preparation of the grouting material.

[0015] Further, in A3, the pressure of the atomizing nozzle is 0.3 - 0.4 MPa.

[0016] Further, during the preparation process, the ambient temperature is maintained at 25 ± 2 °C and the humidity is ≤ 50%.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. Through the synergistic effect among specific components and the core role of modified silica fume, the grouting material of the present invention realizes an overall improvement in the mechanical properties, volume stability, and construction performance of the material. This grouting material uses 750 - 900 parts of cement as the matrix, and forms a highly active composite cementitious system by introducing 10 - 50 parts of modified silica fume. Its 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 400 r / 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 treatment. Sodium silicate undergoes ion exchange with the Si-OH groups on the surface of silica fume to form a Si-O-Si bonding layer, and the Ca + produced by the dissolution of calcium titanate reacts with SiO2 to generate nano-scale calcium silicate hydrate (C-S-H) pre-nucleation sites, and TiO3 2+ forms a charge barrier by adsorbing on the surface of cement particles to promote the early hydration of C3S; finally, 3 - 5% methyl methacrylate is added and graft polymerization is carried out at 70 - 80 °C. Its double bond initiates a polymerization reaction with the free radicals on the surface of silica fume to form a poly(methyl methacrylate) (PMMA) coating layer. This organic layer not only inhibits the secondary aggregation of silica fume through hydrophobic action, but also forms a coordination bond with Ca 2- in the cement hydration products through carboxyl groups to enhance the interfacial bonding strength. 2+

[0018] 2. In the construction of the cementitious system, the 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, react with Ca(OH)2 to generate secondary CSH and calcium aluminate (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 calcium sulfonite to avoid early excessive expansion; heavy calcium (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, which reduces the slurry porosity to below 8%, and the pore size distribution is 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-to-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 an 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 of mannose and glucuronic acid. In static state, it captures free water through hydrogen bonds to form a high viscosity system. During dynamic shear, the helical structure unwinds to cause a sharp drop in viscosity, and cooperates with HPMC to achieve 6 hours of sedimentation-free stratification of the slurry.

[0019] 3. Sodium hexametaphosphate retarder [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 to 4 hours. At the same time, it is adsorbed on the surface of C3A to inhibit the rapid formation of calcium sulfonate. The expansive agent magnesium oxide gradually hydrates to form Mg(OH)2 in an environment where the pH of the cement paste is greater than 12.4. Its delayed expansion characteristics accurately compensate for the drying shrinkage of the cement matrix. The early strength agent triethanolamine reacts with the lone pair of electrons of the N atom to form calcium sulfate. 2+Form a complex, accelerate the destruction of the surface protective layer of C3S, and significantly improve the compressive strength. There is also a synergistic effect among the components: the highly active surface of the modified silica fume and the polyethylene glycol dispersant jointly reduce the frictional resistance between particles, reducing the yield stress of the paste to below 120 Pa; HPMC and xanthan gum optimize the construction performance through a viscosity complementary mechanism, where HPMC provides static suspension and xanthan gum dominates dynamic rheology; the retarding effect of sodium hexametaphosphate and the accelerating effect of triethanolamine form a kinetic balance to ensure the best match between the workable 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 layer of the modified silica fume is gradually hydrolyzed in the alkaline environment of the cement, and the released methacrylic acid reacts with Ca 2+ to generate an organic calcium salt, which crystallizes and grows in the pores to form a nano-reinforcing phase, enabling the 28-day compressive strength to exceed 65 MPa; the TiO3 introduced by calcium titanate 2- undergoes a redox reaction with the Fe2O3 impurity in the silica fume to generate a FeTiO3 conductive phase, reducing the volume resistivity of the material to the order of 10 4 Ω·cm, endowing it with antistatic function.

[0020] 4. The preparation method of the grouting material described in the present invention significantly improves the material uniformity, density and performance stability through multi-stage process control and parameter synergistic optimization. First, in the raw material pretreatment stage, by adding materials step by step, powders such as cement, modified silica fume, gypsum, fly ash, mineral powder and heavy calcium are mixed at a rotation speed of 120 - 150 r / min for 10 - 15 minutes. This rotation speed range can generate sufficient shear force to break the powder agglomeration, and at the same time avoid pre-hydration phenomena caused by excessive speed leading to micro-powder dusting or local temperature rise. Due to its hydrophobicity after organic-inorganic hybrid treatment on the surface, the modified silica fume preferentially forms a uniformly dispersed composite matrix with cement particles through van der Waals forces and mechanical interlocking during the powder mixing stage. The microsphere effect of fly ash and mineral powder can fill the gaps between cement particles, and the micron-sized particles of heavy calcium further optimize the particle size distribution. This mixing process further improves the bulk density of the powder, laying a foundation for the preparation of a low water-binder ratio paste. Secondly, in a constant temperature water bath environment of 70 - 80 °C, the molecular chains of the polyethylene glycol dispersant are fully extended, the hydroxyl groups of hydroxypropyl methylcellulose (HPMC) form a hydrogen bond network with water molecules, the helical structure of xanthan gum unwinds under the action of heat to expose more binding sites, the ionization degree of the cyclic structure of sodium hexametaphosphate increases at high temperature, and the dissolution kinetics of triethanolamine and magnesium oxide are accelerated. This temperature range not only ensures the complete dissolution of the additives to form a homogeneous solution, but also avoids overheating leading to the degradation of HPMC or the volatilization of triethanolamine. Through the laminar shear field formed by stirring at 200 r / min, the additive molecules are oriented to provide ideal rheological properties for subsequent atomization spraying.

[0021] 5. In the solid-liquid mixing stage, 600~800r / min high-speed stirring and 0.3~0.4MPa atomization spraying are used to evenly cover the surface of the powder with liquid droplets of 50~100μm in size. The centrifugal force generated by high-speed stirring causes the powder to form a fluidized bed state, and the atomized droplets form a nano-scale wetting film on the surface of the powder, driving the liquid phase to quickly penetrate into the pores of the powder through capillary force and surface tension. In this process, the PMMA coating layer of the modified silica fume produces synergistic adsorption with the polyethylene glycol dispersant, and its hydrophobic groups are arranged outward to form a low-friction interface, which reduces the sliding resistance between the powders. At the same time, the high-speed shear force temporarily dissociates the three-dimensional network structure of HPMC and xanthan gum, and the apparent viscosity of the slurry drops to below 500mPa·s, ensuring that there is no dry powder residue or local agglomeration within the mixing time of 15~20 minutes. The vacuum degassing and aging process is to evacuate to -0.095~-0.10MPa and maintain it for 6~8 minutes, so that the residual bubbles in the slurry expand and rupture under the action of the pressure difference, and the micro-shear flow generated by the propeller blades of the vacuum mixing tank significantly improves the density of the slurry. During the 40-minute standing aging process, the retarding effect of sodium hexametaphosphate inhibits the early hydration exothermic peak of cement, stabilizing the slurry temperature at 35~40℃. At this temperature, triethanolamine accelerates the stripping of hydration products on the surface of C3S, and a Mg(OH)2 pre-hydration layer is formed on the surface of magnesium oxide particles, providing a controllable active source for later expansion. DETAILED DESCRIPTION

[0022] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0023] Example 1 A grouting material for a bridge head vehicle jump, wherein the grouting material has 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, 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; The modified silica fume is prepared by mixing silica fume, methyl methacrylate, sodium silicate and calcium titanate.

[0024] Further, the modified silica fume preparation method is as follows: S1: Put silica fume into a ball mill and grind it at a speed of 400 r / min for 25 min to obtain powder A; S2: Dissolve sodium silicate in deionized water to prepare a sodium silicate solution with a mass fraction of 7%. Based on the sodium silicate solution, add 2 wt% of calcium titanate powder. After homogenization treatment, obtain mixed slurry B. The parameters of the homogenization treatment are a rotation speed of 1000 r / min and a duration of 15 min; S3: Mix powder A and mixed slurry B in a mass ratio of 1:1, and stir in a constant-temperature stirrer at 55 °C at 800 r / min for 20 min to obtain mixed slurry C; S4: Add 5 wt% of methyl methacrylate to mixed slurry C, heat up to 80 °C, and continue to stir at a rotation speed of 800 r / min for 10 min to obtain mixed slurry D; S5: Perform centrifugation treatment on mixed slurry D. The parameters of the centrifugation treatment are a rotation speed of 4000 r / min and a duration of 15 min. Wash the solid product with deionized water, and after washing, perform drying and pulverization treatment to obtain the modified silica fume. The drying and pulverization treatment is to dry in a vacuum drying oven at 70 °C until the moisture content ≤ 1.0%, and then pulverize to a particle size of 3 - 5 μm.

[0025] A preparation method of a grouting material for bridgehead bumping, the preparation method is as follows, A1: Weigh cement, modified silica fume, gypsum, fly ash, slag powder, and heavy calcium by weight parts, put them into a mixer, and stir and mix at a rotation speed of 150 r / min for 10 min to ensure uniform dispersion of the powder; A2: Then mix polyethylene glycol 2000, hydroxypropyl methylcellulose, xanthan gum, sodium hexametaphosphate, magnesium oxide, and triethanolamine, and add deionized water according to a water-binder ratio of 0.28 for mixing. Stir in a constant-temperature water bath at 70 °C at a rotation speed of 200 r / min until completely dissolved to form a transparent homogeneous solution; A3: Increase the rotation speed of the mixer to 800 r / min, and uniformly spray the transparent homogeneous solution prepared in A2 onto the surface of the powder through an atomizing nozzle. The pressure of the atomizing nozzle is 0.4 MPa, and stir synchronously for 20 min to obtain slurry; A4: Transfer the slurry prepared in A3 to a vacuum stirring tank, evacuate to -0.10 MPa and maintain for 6 min, eliminate air bubbles, then stand and cure for 40 min, and perform sealed packaging to complete the preparation of the grouting material.

[0026] Maintain the environmental temperature at 25 ± 2 °C and the humidity ≤ 50% during the preparation process.

[0027] Example 2 A grouting material for bridgehead bumping, the formula of the grouting material 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 slag powder, 10 parts of heavy calcium, 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; Among them, the modified silica fume is prepared by mixing silica fume, methyl methacrylate, sodium silicate, and calcium titanate.

[0028] Furthermore, the preparation method of the modified silica fume is as follows, S1: Put silica fume into a ball mill and grind it at a speed of 400 r / min for 30 min to obtain powder A; S2: Dissolve sodium silicate in deionized water to prepare a sodium silicate solution with a mass fraction of 7%. Based on the sodium silicate solution, add 2 wt% of calcium titanate powder, and after homogenization treatment, obtain mixed slurry B. The parameters of the homogenization treatment are a speed of 1000 r / min and a duration of 15 min; S3: Mix powder A and mixed slurry B in a mass ratio of 1:1, and stir in a constant temperature stirrer at 60 °C at a speed of 800 r / min for 20 min to obtain mixed slurry C; S4: Add 5 wt% of methyl methacrylate to mixed slurry C, heat up to 80 °C, and continue to stir at a speed of 800 r / min for 10 min to obtain mixed slurry D; S5: Perform centrifugal treatment on mixed slurry D. The parameters of the centrifugal treatment are a speed of 4000 r / min and a duration of 15 min. Wash the solid product with deionized water, and after washing, perform drying and pulverization treatment to obtain the modified silica fume. The drying and pulverization treatment is to dry in a vacuum drying oven at 70 °C until the moisture content ≤ 1.0%, and then pulverize to a particle size of 3 - 5 μm.

[0029] A preparation method of a grouting material for bridgehead bumping, the preparation method is as follows, A1: Weigh cement, modified silica fume, gypsum, fly ash, slag powder, and heavy calcium by weight, put them into a mixer, and stir and mix at a speed of 150 r / min for 15 min to ensure uniform dispersion of the powder; A2: Then mix polyethylene glycol 2000, hydroxypropyl methylcellulose, xanthan gum, sodium hexametaphosphate, magnesium oxide, and triethanolamine, and add deionized water according to a water - binder ratio of 0.32 for mixing. Stir in a constant temperature water bath at 80 °C at a speed of 200 r / min until completely dissolved to form a transparent homogeneous solution; A3: Increase the mixer speed to 800 r / min, and evenly spray the transparent homogeneous solution prepared in A2 onto the powder surface through an atomizing nozzle. The pressure of the atomizing nozzle is 0.4 MPa, and stir synchronously for 20 min to obtain the slurry; A4: Transfer the slurry prepared in A3 to a vacuum stirring tank, evacuate to -0.10 MPa and hold for 8 min. After removing the bubbles, let it stand and cure for 40 min, then seal and package to complete the preparation of the grouting material.

[0030] Maintain the environmental temperature at 25 ± 2 °C and humidity ≤ 50% during the preparation process.

[0031] Example 3 A grouting material for bridge head bump, the formula of the grouting material is as follows, by weight: 750 parts of cement, 10 parts of modified silica fume, 10 parts of gypsum, 30 parts of fly ash, 10 parts of slag powder, 100 parts of heavy calcium, 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, 227 parts of deionized water; Among them, the modified silica fume is prepared by mixing silica fume, methyl methacrylate, sodium silicate, and calcium titanate.

[0032] Furthermore, the preparation method of the modified silica fume is as follows, S1: Put the silica fume into a ball mill and grind it at a speed of 400 r / min for 20 min to obtain powder A; S2: Dissolve sodium silicate in deionized water to prepare a sodium silicate solution with a mass fraction of 5%. Based on the sodium silicate solution, add 1 wt% of calcium titanate powder, and after homogenization treatment, obtain a mixed slurry B. The parameters of the homogenization treatment are a speed of 1000 r / min and a duration of 10 min; S3: Mix powder A and mixed slurry B in a mass ratio of 1:1, and stir in a constant temperature stirrer at 50 °C at a speed of 800 r / min for 20 min to obtain a mixed slurry C; S4: Add 3 wt% of methyl methacrylate to the mixed slurry C, heat up to 70 °C, and continue to stir at a speed of 800 r / min for 10 min to obtain a mixed slurry D; S5: Perform centrifugation on the mixed slurry D. The parameters of the centrifugation treatment are a speed of 4000 r / min and a duration of 10 min. Wash the solid product with deionized water, and after washing, perform drying and pulverization treatment to obtain the modified silica fume. The drying and pulverization treatment is to dry in a vacuum drying oven at 60 °C until the moisture content ≤ 1.0%, and then pulverize to a particle size of 3 - 5 μm.

[0033] A preparation method of a grouting material for bridge head bump, the preparation method is as follows, A1: Weigh cement, modified silica fume, gypsum, fly ash, slag powder, and heavy calcium according to parts by weight, put them into a mixer, and stir and mix at a speed of 120 r / min for 10 min to ensure uniform dispersion of the powder; A2: Then, polyethylene glycol 2000, hydroxypropyl methylcellulose, xanthan gum, sodium hexametaphosphate, magnesium oxide, and triethanolamine were added, and deionized water was added according to a water-cement ratio of 0.28 for mixing. The mixture was stirred at a speed of 200 r / min in a 70 °C constant temperature water bath until completely dissolved to form a transparent homogeneous solution; A3: Increase the mixer speed to 600 r / min, and evenly spray the transparent homogeneous solution prepared in A2 onto the powder surface through an atomizing nozzle. The pressure of the atomizing nozzle is 0.3 MPa, and stir synchronously for 15 min to obtain a slurry; A4: Transfer the slurry prepared in A3 to a vacuum stirring tank, evacuate to -0.095 MPa and maintain for 6 min. After removing the bubbles, let it stand and cure for 40 min, and then seal and package to complete the preparation of the grouting material.

[0034] During the preparation process, maintain the environmental temperature at 25 ± 2 °C and the humidity ≤ 50%.

[0035] Comparative Example 1 In this comparative example, silica fume was not modified, and the remaining steps were the same as those in Example 1.

[0036] Comparative Example 2 In this comparative example, methyl methacrylate was not added during the modification process of silica fume, and the remaining steps were the same as those in Example 1.

[0037] Comparative Example 3 In this comparative example, sodium silicate was not added during the modification process of silica fume, and the remaining steps were the same as those in Example 1.

[0038] Comparative Example 4 In this comparative example, calcium titanate was not added during the modification process of silica fume, and the remaining steps were the same as those in Example 1.

[0039] The compressive strength performance of the examples and comparative examples was tested with reference to the standard GB 50204-2015, and the test results are shown in Table 1. Table 1 Data table of compressive strength tests of different grouting materials

[0040] From the above experiments, it can be seen that the modified silica fume effectively improves the compressive strength of the prepared grouting material.

[0041] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments with equivalent changes within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A grouting material for vehicle bump at bridge head, 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 slag powder, 10 - 100 parts of heavy calcium, 1 - 3 parts of dispersant, 0.1 - 1 part of rheological agent, 0.2 - 0.5 part of suspending agent, 0.5 - 1 part of retarder, 0.1 - 1 part of expansive agent, 5 - 10 parts of early strength agent, and 226 - 371 parts of deionized water; Among them, the modified silica fume is prepared by mixing silica fume, methyl methacrylate, sodium silicate, and calcium titanate; 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 expansive agent is magnesium oxide; the early strength agent is triethanolamine.

2. The grouting material for bump at bridgehead according to claim 1, characterized in that, The preparation method of the modified silica fume is as follows, S1: Put silica fume into a ball mill and grind it at a speed of 400 r / min for 20 - 30 min to obtain powder A; S2: Dissolve sodium silicate in deionized water to prepare a sodium silicate solution with a mass fraction of 5 - 7%. Based on the sodium silicate solution, add 1 - 2 wt% of calcium titanate powder, and after homogenization treatment, obtain mixed slurry B; S3: Mix powder A and mixed slurry B in a mass ratio of 1:1, and stir in a constant temperature stirrer at 50 - 60 °C at a speed of 800 r / min for 20 min to obtain mixed slurry C; S4: Add 3 - 5 wt% of methyl methacrylate to mixed slurry C, heat up to 70 - 80 °C, and then continue to stir at a speed of 800 r / min for 10 min to obtain mixed slurry D; S5: Perform centrifugal treatment on mixed slurry D, wash the solid product with deionized water, and after washing, perform drying and pulverization treatment to obtain the modified silica fume.

3. The grouting material for bump at bridgehead according to claim 1 or 2, characterized in that, The particle size of the silica fume is 0.1 - 0.3 μm, and the specific surface area is 15 - 20 m² / g.

4. The grouting material for bridgehead bumping according to claim 2, wherein, The parameters of the homogenization treatment in S2 are a rotation speed of 1000 r / min and a duration of 10 - 15 min.

5. A grouting material for bridgehead bump, according to claim 2, characterized in that, The parameters of the centrifugal treatment in S5 are a rotation speed of 4000 r / min and a duration of 10 - 15 min.

6. The grouting material for bump at bridgehead according to claim 2, wherein, The drying and pulverization treatment in S5 is to dry in a vacuum drying oven at 60 - 70 °C until the moisture content ≤ 1.0%, and then pulverize to a particle size of 3 - 5 μm.

7. A preparation method of the grouting material for bridgehead bumping as described in any one of claims 1 - 6, It is characterized in that The preparation method is as follows, A1: Weigh cement, modified silica fume, gypsum, fly ash, slag powder, and heavy calcium by weight, put them into a mixer, and stir and mix at a speed of 120 - 150 r / min for 10 - 15 min to ensure uniform dispersion of the powder; A2: Then add the dispersant, rheological agent, suspending agent, retarder, expansive agent, and early strength agent, and add deionized water according to a water - binder ratio of 0.28 - 0.32 for mixing, and stir in a constant temperature water bath at 70 - 80 °C at a speed of 200 r / min until completely dissolved to form a transparent homogeneous solution; A3: Increase the rotation speed of the mixer to 600 - 800 r / min, and evenly spray the transparent homogeneous solution prepared in A2 onto the surface of the powder through an atomizing nozzle, and stir synchronously for 15 - 20 min to obtain the slurry; A4: Transfer the slurry prepared in A3 to a vacuum stirring tank, evacuate to -0.095 to -0.10 MPa and hold for 6 to 8 minutes. After removing the bubbles, let it stand and cure for 40 minutes, then seal and package to complete the preparation of the grouting material.

8. The preparation method of a grouting material for bridgehead bumping according to claim 7, characterized in that, The pressure of the atomizing nozzle in A3 is 0.3 - 0.4 MPa.

9. The preparation method of a grouting material for bridgehead bumping according to claim 7, characterized in that, During the preparation process, maintain the ambient temperature at 25 ± 2 °C and the humidity ≤ 50%.

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