Low water sensitivity high performance bridge support grouting material

Abstract

The present application relates to the technical field of bridge engineering materials, in particular to a low-water-sensitivity high-performance bridge support grouting material, which comprises Portland cement, fast-hardening cement, stone powder, silica fume, mineral powder, hemihydrate gypsum, machine-made sand, defoaming agent, expanding agent, polycarboxylate superplasticizer, wood fiber, suspension stabilizer and water. Through the synergistic effect of wood fiber water retention buffering, hemihydrate gypsum hydration regulation, and suspension stabilizer rheological stability, combined with multi-scale particle close packing structure, the grouting material can still maintain stable construction performance within the water addition range of 14% to 16% of the total mass of dry powder, the initial fluidity is not less than 340 mm, the 30 min fluidity is not less than 320 mm, the bleeding rate is 0, there is no segregation and delamination phenomenon, and the mechanical properties are stable and meet the specification requirements. This characteristic greatly reduces the quality risk caused by water addition error in site construction, and significantly improves the construction adaptability.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering materials technology, specifically to a low-water-sensitivity, high-performance bridge bearing grout. Background Technology

[0002] Bridge bearing grout is an important material used in bridge engineering to fill the gap between the bearing base plate and the pier. Its performance directly affects the stress transmission, bearing stability, and durability of the bridge structure. High-quality grout should have good fluidity, high early strength, stable volume properties, and good compactness to ensure that the grout layer at the bottom of the bearing can be uniformly filled and form a reliable support system.

[0003] However, cement-based grouts commonly used in engineering are quite sensitive to changes in water content, usually requiring strict control of the water-to-material ratio. In actual construction, due to complex on-site conditions, errors in manual water addition, and differences in construction equipment, maintaining precise and stable water usage is often difficult. When the water content is too low, the grout is prone to problems such as uneven mixing, insufficient fluidity, and difficulty in filling; while when the water content is too high, it may lead to grout bleeding, decreased strength, or even failure to meet engineering requirements, thereby increasing construction difficulty and affecting project quality.

[0004] Therefore, developing a bridge bearing grout that is insensitive to changes in water consumption and can maintain good construction and mechanical properties within a certain water consumption range is of great significance for improving on-site construction adaptability, reducing construction difficulty, and improving project quality. Summary of the Invention

[0005] The purpose of this invention is to provide a low-water-sensitivity, high-performance bridge bearing grouting material, which solves the technical problems of existing cement-based grouting materials being sensitive to changes in water content, prone to large fluctuations in fluidity due to water addition errors, bleeding and segregation, and significant strength reduction.

[0006] To achieve the above objectives, the technical solution provided by this invention is as follows: A low-water-sensitivity, high-performance bridge bearing grouting material includes a dry powder group and water, wherein the grouting material is formed by mixing the dry powder group and water; The dry powder composition comprises the following components by weight: silicate cement: 100-300 parts; rapid-hardening cement: 100-300 parts; stone powder: 30-100 parts; silica fume: 30-60 parts; mineral powder: 30-90 parts; hemihydrate gypsum: 10-50 parts; manufactured sand: 500-1000 parts; defoamer: 0.5-1.0 parts; expanding agent: 0.1-0.5 parts; polycarboxylate superplasticizer: 3.0-6.0 parts; wood fiber: 0.3-1.0 parts; suspension stabilizer: 0.5-1.0 parts. The wood fiber, hemihydrate gypsum and suspension stabilizer together constitute a low water sensitivity control system; The silica fume, mineral powder, stone powder, silicate cement, rapid-hardening cement, and manufactured sand together constitute a multi-scale particle compaction system.

[0007] Preferably, the silicate cement is ordinary silicate cement of grade 52.5 or above.

[0008] Preferably, the rapid-hardening cement is a sulfoaluminate cement with a setting time of less than 30 minutes.

[0009] Preferably, the stone powder is limestone powder with a fineness of 400-800 mesh.

[0010] Preferably, the bulk density of the silica fume is 300-320 kg / m³, and the mineral powder is S95 grade granulated blast furnace slag powder.

[0011] Preferably, the polycarboxylate superplasticizer is a polycarboxylate-based high-performance superplasticizer with a water reduction rate of not less than 30%.

[0012] Preferably, the wood fiber is a natural wood fiber that is insoluble in water.

[0013] Preferably, the suspension stabilizer is a powdered rheology modifier composed of a water-soluble polymer and an inorganic layered material; The expanding agent is a plastic expanding agent that can release gas under alkaline catalysis; The defoamer is a fatty alcohol polyether defoamer.

[0014] Preferably, the amount of water added to the grouting material during construction is 14% to 16% of the total mass of the dry powder group.

[0015] Preferably, after the grouting material is mixed with water, its compressive strength is not less than 25 MPa after 24 hours and not less than 75 MPa after 28 days.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention, through the synergistic effect of water retention and buffering by wood fibers, hydration regulation by hemihydrate gypsum, and rheological stabilization by suspension stabilizers, combined with a multi-scale densely packed particle structure, allows the grout to maintain stable workability within a water content range of 14%–16% of the total dry powder mass. The initial flowability is not less than 340 mm, the flowability after 30 minutes is not less than 320 mm, the bleeding rate is 0%, there is no segregation or stratification, and the mechanical properties simultaneously and stably meet the specifications. This characteristic significantly reduces the quality risks caused by errors in water addition during on-site construction, and significantly improves construction adaptability. 2. The initial fluidity of the slurry of the present invention can reach more than 350 mm, and the fluidity remains above 320 mm after 30 minutes, which is far higher than the industry standard requirements. It can quickly fill the narrow gap at the bottom of the support, with high construction efficiency, and is suitable for the filling construction needs of complex support bottoms. 3. The bleeding rate of this grout is 0 within the full water addition range. The grout is uniform and stable, and there will be no stratification phenomenon such as aggregate settling or water floating. This can ensure the overall homogeneity of the grout layer after hardening and avoid defects such as insufficient local strength and uneven shrinkage.

[0017] 4. This grout has moderate plastic expansion capacity, which can effectively compensate for cement hydration shrinkage and avoid settlement and cracking of the grouting layer; at the same time, the material has balanced early strength and late strength performance, with a 24-hour compressive strength of over 27MPa and a 28-day compressive strength of over 80MPa. It has strong load-bearing capacity, high safety reserve, and can ensure the long-term stability of the support under stress. Detailed Implementation

[0019] The specific embodiments of the present invention are as follows: A low-water-sensitivity, high-performance bridge bearing grouting material includes a dry powder group and water, wherein the grouting material is formed by mixing the dry powder group and water; The dry powder composition comprises the following components by weight: silicate cement: 100-300 parts; rapid-hardening cement: 100-300 parts; stone powder: 30-100 parts; silica fume: 30-60 parts; mineral powder: 30-90 parts; hemihydrate gypsum: 10-50 parts; manufactured sand: 500-1000 parts; defoamer: 0.5-1.0 parts; expanding agent: 0.1-0.5 parts; polycarboxylate superplasticizer: 3.0-6.0 parts; wood fiber: 0.3-1.0 parts; suspension stabilizer: 0.5-1.0 parts. The wood fiber, hemihydrate gypsum, and suspension stabilizer together constitute a low water sensitivity control system. Wood fiber can adsorb and slowly release free water in the slurry, releasing water to maintain slurry fluidity when water content is low, and adsorbing excess free water to inhibit bleeding when water content is high. Hemihydrate gypsum can regulate the early hydration rate of rapid-hardening cement and silicate cement, taking into account both slurry fluidity retention and early strength performance. Suspension stabilizer can optimize the rheological structure of the slurry and improve the slurry's anti-segregation ability. The synergistic effect of the three significantly reduces the material's sensitivity to changes in water content. The silica fume, mineral powder, stone powder, silicate cement, rapid-hardening cement, and manufactured sand together constitute a multi-scale particle compact packing system. Among them, silica fume, mineral powder, stone powder, cement, and manufactured sand form a multi-scale particle compact packing system, with powders of different particle sizes filling the pores step by step, reducing the internal porosity of the slurry, increasing the density of the slurry, and at the same time reducing the impact of water consumption changes on fluidity and bleeding.

[0020] Specifically, the silicate cement is ordinary silicate cement of grade 52.5 or above.

[0021] As can be seen from the above description, using high-grade silicate cement provides a stable foundation for the later strength and durability of the slurry, improves the density of the hardened body, and enhances the performance stability under fluctuations in water volume.

[0022] Specifically, the rapid-hardening cement is a sulfoaluminate cement with a setting time of less than 30 minutes.

[0023] As can be seen from the above description, the use of rapid-hardening sulfoaluminate cement accelerates early setting and hardening, shortens the construction and curing cycle, and rapidly constructs the slurry skeleton, which helps to suppress high-water-volume bleeding and segregation.

[0024] Specifically, the stone powder is limestone powder with a fineness of 400-800 mesh.

[0025] Specifically, the bulk density of the silica fume is 300-320 kg / m³, and the mineral powder is S95 grade granulated blast furnace slag powder.

[0026] As can be seen from the above description, silica fume plays a micro-filling effect, mineral powder provides pozzolanic activity, and the combination of the two refines the pores, increases the density, reduces the water demand of the slurry, and broadens the range of water compatibility.

[0027] Specifically, the polycarboxylate superplasticizer is a polycarboxylate-based high-performance superplasticizer with a water reduction rate of not less than 30%.

[0028] As can be seen from the above description, the use of high water-reducing polycarboxylate superplasticizer can effectively improve the flowability of slurry, ensure the filling effect of narrow spaces, and at the same time enhance the adaptability to water fluctuations.

[0029] Specifically, the wood fiber is a natural wood fiber that is insoluble in water, and the natural wood fiber is preferably German JRSARBOCEL wood cellulose ZZC-500.

[0030] As can be seen from the above description, natural wood fiber has stable chemical properties, can adsorb and slowly release free water, plays a water-retaining buffering role, is the core component for low water sensitivity regulation, and at the same time enhances the pulp's anti-segregation ability.

[0031] Specifically, the suspension stabilizer is a powdered rheology modifier composed of a water-soluble polymer and an inorganic layered material; The expanding agent is a plastic expanding agent that can release gas under alkaline catalysis; The defoamer is a fatty alcohol polyether defoamer.

[0032] As can be seen from the above description: the suspension stabilizer constructs a rheological network and prevents bleeding and segregation; the plastic expansion agent compensates for hydration shrinkage and avoids settling and cracking; the fatty alcohol defoamer reduces air content and improves density; the three types of additives complement each other and work together to ensure construction and hardening performance.

[0033] Specifically, the amount of water added to the grouting material during construction is 14% to 16% of the total mass of the dry powder.

[0034] As can be seen from the above description, when the water content of the grouting material varies within the range of 14% to 16%, it can still maintain good fluidity, no bleeding, and stable volume properties, while ensuring that the material strength meets the engineering requirements. This effectively reduces the quality risks caused by water addition errors during on-site construction and improves the adaptability and reliability of bridge bearing grouting construction.

[0035] Specifically, after the grout is mixed with water, its compressive strength is not less than 25 MPa after 24 hours and not less than 75 MPa after 28 days.

[0036] Embodiment 1 of the present invention is as follows: The low water-sensitive high-performance bridge bearing grouting material of this embodiment, by weight, has the following dry powder formulation: 200 parts of 52.5 grade ordinary Portland cement, 200 parts of sulfoaluminate rapid-hardening cement, 60 parts of 600-mesh limestone powder, 45 parts of silica fume with a bulk density of 310 kg / m³, 60 parts of S95 grade mineral powder, 30 parts of hemihydrate gypsum, 750 parts of manufactured sand, 4.5 parts of polycarboxylate superplasticizer with a water reduction rate of 35%, 0.3 parts of plastic expansion agent, 0.6 parts of natural wood fiber, 0.7 parts of composite suspension stabilizer, and 0.7 parts of fatty alcohol polyether defoamer; The amount of water added during construction is 14% of the total mass of the dry powder, and it should be mixed evenly.

[0037] Example 2 The low water-sensitive high-performance bridge bearing grouting material of this embodiment, by weight, has the following dry powder component formula: 250 parts of 52.5 grade ordinary Portland cement, 150 parts of sulfoaluminate rapid-hardening cement, 80 parts of 400-mesh limestone powder, 30 parts of silica fume with a bulk density of 300 kg / m³, 90 parts of S95 grade mineral powder, 50 parts of hemihydrate gypsum, 600 parts of manufactured sand, 6.0 parts of polycarboxylate superplasticizer with a water reduction rate of 32%, 0.5 parts of plastic expansion agent, 1.0 part of natural wood fiber, 1.0 part of composite suspension stabilizer, and 1.0 part of fatty alcohol polyether defoamer.

[0038] The amount of water added during construction is 14% of the total mass of the dry powder, and it should be mixed evenly.

[0039] Example 3 The low water-sensitive high-performance bridge bearing grouting material of this embodiment, by weight, has the following dry powder component formula: 300 parts of 52.5 grade ordinary Portland cement, 100 parts of sulfoaluminate rapid-hardening cement, 30 parts of 800-mesh limestone powder, 60 parts of silica fume with a bulk density of 320 kg / m³, 30 parts of S95 grade mineral powder, 10 parts of hemihydrate gypsum, 900 parts of manufactured sand, 3.0 parts of polycarboxylate superplasticizer with a water reduction rate of 38%, 0.1 parts of plastic expansion agent, 0.3 parts of natural wood fiber, 0.5 parts of composite suspension stabilizer, and 0.5 parts of fatty alcohol polyether defoamer.

[0040] The amount of water added during construction is 14% of the total mass of the dry powder, and it should be mixed evenly.

[0041] Example 4 The low water-sensitive high-performance bridge bearing grouting material of this embodiment, by weight, has the following dry powder component formula: 250 parts of 52.5 grade ordinary Portland cement, 150 parts of sulfoaluminate rapid-hardening cement, 80 parts of 400-mesh limestone powder, 30 parts of silica fume with a bulk density of 300 kg / m³, 90 parts of S95 grade mineral powder, 50 parts of hemihydrate gypsum, 600 parts of manufactured sand, 6.0 parts of polycarboxylate superplasticizer with a water reduction rate of 32%, 0.5 parts of plastic expansion agent, 1.0 part of natural wood fiber, 1.0 part of composite suspension stabilizer, and 1.0 part of fatty alcohol polyether defoamer.

[0042] The amount of water added during construction is 16% of the total mass of the dry powder, and it should be mixed evenly.

[0043] Comparative Example 1 Commercially available ordinary bridge bearing grouting material was used and mixed according to the product's recommended water-to-material ratio to serve as a performance control sample.

[0044] The grouting materials obtained by mixing Examples 1-4 and Comparative Example 1 were subjected to performance tests according to the standard "Grouting Materials for Bridge Bearings" (JT / T1130-2017). The main performance test results of each sample are shown in the table below:

[0045] As can be seen from the table above: The low-water-sensitive, high-performance bridge bearing grouting materials provided in Examples 1-4 of this invention consistently meet the requirements of the "Bridge Bearing Grouting Materials" (JT / T1130-2017) standard in terms of all their performance indicators, as specifically shown below: 1. Low water sensitivity and high performance When the water content of the grout of this invention varies within the range of 14% to 16%, the grout still maintains good fluidity and stability, without bleeding or segregation. Simultaneously, the compressive strength of the material consistently meets the technical requirements for bridge bearing grouting materials. This characteristic is mainly due to the water absorption and retention properties of wood fibers, the regulation of the hydration process by hemihydrate gypsum, and the stable rheological structure formed by the suspension stabilizer. These factors give the grout a strong adaptability to changes in water content, thereby significantly reducing the quality risks caused by errors in water addition during construction.

[0046] 2. Excellent construction mobility The initial flowability of Examples 1-4 all reached over 350 mm, and the flowability remained above 325 mm after 30 minutes, significantly exceeding the standard requirements (initial ≥320 mm, 30 minutes ≥280 mm). This indicates that the grout of the present invention has excellent fluidity and flowability retention, enabling it to flow rapidly and fully fill the confined space at the bottom of bridge bearings, thus improving construction efficiency. In contrast, the flowability of Comparative Example 1 is close to the lower limit of the standard, indicating significantly poorer construction adaptability.

[0047] 3. Excellent slurry stability The bleeding rate of the slurry in Examples 1-4 was 0%, indicating that the slurry has good stability during standing and construction, without segregation or bleeding. This performance is mainly due to the water-retaining effect of wood fibers and the regulation of the slurry's rheological structure by the suspending stabilizer, which enables the slurry to remain uniform and stable under different construction conditions.

[0048] 4. Excellent volume stability The vertical expansion rates of Examples 1-4 over 3 hours were 0.18%-0.44%, and the difference between the expansion rates over 24 hours and 3 hours was 0.22%-0.39%, all within the standard range, indicating that the grout has a moderate expansion capacity during the hardening process. This expansion can effectively compensate for the shrinkage during cement hydration, thereby preventing settlement or microcracks in the grout layer and ensuring a stable and reliable support structure between the support and the foundation.

[0049] 5. Stable strength performance The grouting material of this invention exhibits high early and late strength. The 24-hour compressive strength of Examples 1-4 all exceeded 27 MPa, far surpassing the standard requirement of 20 MPa; the 3-day compressive strength was close to 50 MPa; and the 28-day compressive strength exceeded 75 MPa, significantly higher than the standard requirement of 60 MPa. This demonstrates that the material of this invention possesses excellent load-bearing capacity and long-term mechanical properties, and can significantly improve the safety reserve of bridge bearing grouting layers.

[0050] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that variations may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A low-water-sensitivity, high-performance bridge bearing grout, characterized in that, The grouting material comprises dry powder and water, and is composed of dry powder and water. The dry powder composition comprises the following components by weight: silicate cement: 100-300 parts; rapid-hardening cement: 100-300 parts; stone powder: 30-100 parts; silica fume: 30-60 parts; mineral powder: 30-90 parts; hemihydrate gypsum: 10-50 parts; manufactured sand: 500-1000 parts; defoamer: 0.5-1.0 parts; expanding agent: 0.1-0.5 parts; polycarboxylate superplasticizer: 3.0-6.0 parts; wood fiber: 0.3-1.0 parts; suspension stabilizer: 0.5-1.0 parts. The wood fiber, hemihydrate gypsum and suspension stabilizer together constitute a low water sensitivity control system; The silica fume, mineral powder, stone powder, silicate cement, rapid-hardening cement, and manufactured sand together constitute a multi-scale particle compaction system.

2. The low water sensitivity, high performance bridge bearing grouting material according to claim 1, characterized in that, The silicate cement is ordinary silicate cement of grade 52.5 or above.

3. The low-water-sensitivity, high-performance bridge bearing grouting material according to claim 1, characterized in that, The rapid-hardening cement is a sulfoaluminate cement with a setting time of less than 30 minutes.

4. The low water sensitivity, high performance bridge bearing grouting material according to claim 1, characterized in that, The stone powder is limestone powder with a fineness of 400-800 mesh.

5. The low water sensitivity, high performance bridge bearing grouting material according to claim 1, characterized in that, The bulk density of the silica fume is 300-320 kg / m³, and the mineral powder is S95 grade granulated blast furnace slag powder.

6. The low water sensitivity, high performance bridge bearing grouting material according to claim 1, characterized in that, The polycarboxylate superplasticizer is a high-performance polycarboxylate superplasticizer with a water reduction rate of not less than 30%.

7. The low water sensitivity, high performance bridge bearing grouting material according to claim 1, characterized in that, The wood fiber is a natural wood fiber that is insoluble in water.

8. The low water sensitivity, high performance bridge bearing grouting material according to claim 1, characterized in that, The suspension stabilizer is a powdered rheology modifier composed of a water-soluble polymer and an inorganic layered material. The expanding agent is a plastic expanding agent that can release gas under alkaline catalysis; The defoamer is a fatty alcohol polyether defoamer.

9. The low-water-sensitivity, high-performance bridge bearing grouting material according to claim 1, characterized in that, The water content of the grouting material is 14% to 16% of the total mass of the dry powder.

10. The low-water-sensitivity, high-performance bridge bearing grouting material according to claim 1, characterized in that, The grouting material, after being mixed with water, has a compressive strength of not less than 25 MPa after 24 hours and not less than 75 MPa after 28 days.

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