Preset coarse aggregate grouting type high-performance concrete-filled steel tube column and construction method thereof

Abstract

The invention relates to the technical field of building structures, in particular to a preset coarse aggregate grouting type high-performance concrete-filled steel tube column and a construction method thereof.The preset coarse aggregate grouting type high-performance concrete-filled steel tube column comprises a steel tube filled with high-performance concrete; the high-performance concrete is prepared from the following raw materials in parts by weight: 1200 to 1400 parts of high-performance grouting material and 1300 to 1500 parts of coarse aggregate. The utilization rate of the coarse aggregate in the high-performance concrete-filled steel tube column is greatly increased in a preset coarse aggregate slip casting mode, so that the production cost of the high-performance concrete-filled steel tube column is reduced, and the environmental sustainability is improved. The coarse aggregate can play a role in a framework in a high-performance concrete matrix, so that the matrix has more excellent volume stability, and the bonding performance between the steel pipe and core concrete can be effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of building structures, and in particular to a pre-set coarse aggregate grouting type high-performance steel tube concrete column and a construction method thereof. Background Art

[0002] In recent years, with the continuous development of modern engineering technology, buildings and structures have gradually developed towards super-high-rise, super-large span and heavy-load directions. Traditional concrete materials can no longer meet the needs of current major civil engineering projects. Various structures with special functional requirements require concrete to continue to develop in the direction of high reinforcement, high performance and multi-functionality. Although the application potential of high-performance concrete is very large, it still has many disadvantages that have not yet been widely used in actual projects. On the one hand, coarse aggregates are usually eliminated in the mix design of high-performance concrete, resulting in a relatively high amount of cementitious materials such as cement, which is usually 3 to 4 times the amount of ordinary concrete. This not only increases the production cost of high-performance concrete, but also significantly increases carbon emissions, which is not conducive to the sustainable development of the construction field. On the other hand, the shrinkage of high-performance concrete is relatively significant. When it is used in steel tube concrete columns, it is easy to cause internal high-performance concrete to degas and debond. Introducing coarse aggregates into the high-performance concrete system can effectively solve the problems of high cementitious material dosage, hydration heat and large shrinkage. However, due to the limitations of the mixing molding method, the application of coarse aggregates in high-performance concrete has certain limitations. In order to ensure the mechanical properties and working performance of concrete, large-volume and large-size coarse aggregates are not suitable for the preparation of coarse aggregate high-performance concrete. At the same time, the addition of high-density coarse aggregates to high-performance concrete is very likely to cause stratification and segregation. These limitations have led to a relatively high amount of cementitious materials used in coarse aggregate high-performance concrete. Introducing the pre-set coarse aggregate grouting molding method into the preparation of coarse aggregate high-performance steel tube concrete columns can improve the utilization rate of coarse aggregate while reducing the shrinkage of high-performance concrete, and improve the axial compression performance and push-out performance of high-performance steel tube concrete columns. Summary of the invention

[0003] In view of the technical problems existing in the prior art, the purpose of the present invention is to propose a pre-set coarse aggregate grouting high-performance steel tube concrete column and a construction method thereof. The pre-set coarse aggregate grouting high-performance steel tube concrete column of the present invention has the advantages of low cost, high environmental sustainability, and low risk of degassing and debonding.

[0004] To achieve the above object, the present invention is implemented by the following technical solutions:

[0005] The present invention provides a pre-set coarse aggregate grouting type high-performance steel tube concrete column, comprising a steel tube, wherein the interior of the steel tube is filled with high-performance concrete, and the high-performance concrete comprises the following raw materials by weight: 1210-1370 parts of high-performance grouting material and 1310-1460 parts of coarse aggregate.

[0006] In the above scheme, by adopting the pre-set coarse aggregate grouting high-performance steel tube concrete column, the utilization rate of coarse aggregate can be improved while reducing the shrinkage of high-performance concrete, thereby reducing the use of cementitious materials, reducing costs and improving environmental sustainability. In addition, this method can also improve the axial compression performance and push-out performance of the steel tube concrete column and reduce the risk of degassing and debonding.

[0007] As a further optimization solution of the present invention, the particle size of the coarse aggregate is 15 to 20 mm.

[0008] In the above scheme, limiting the particle size of the coarse aggregate to 15 to 20 mm can ensure that the concrete has a higher strength, and at the same time, such aggregate with a larger particle size is convenient for construction and pouring.

[0009] As a further optimization scheme of the present invention, the 28d compressive strength of the high performance concrete is 90-110 MPa.

[0010] In the above scheme, the 28-day compressive strength of the high-performance concrete ranges from 90 to 110 MPa, which indicates that the prepared high-performance concrete has excellent mechanical properties and can meet the requirements of high-strength structures.

[0011] As a further optimization scheme of the present invention, the high-performance grouting material includes the following raw materials in parts by weight: 774 parts of cement, 60 parts of silica fume, 357 parts of ultrafine mineral powder, 119 parts of expansion agent, 953 parts of quartz sand, 250 parts of water, and 22 parts of water reducing agent.

[0012] In the above scheme, the composition of high-performance grouting materials is described in detail. Through reasonable formula design, the fluidity and durability of concrete can be further improved while maintaining high strength.

[0013] As a further optimization scheme of the present invention, the particle size range of the quartz sand is 0 to 0.2 mm.

[0014] In the above scheme, limiting the quartz sand particle size range to 0-0.2 mm helps to improve the fluidity and filling performance of the grouting material, reduce voids, and improve the density of concrete.

[0015] As a further optimization scheme of the present invention, the expansion agent is a composite of a CaO expansion agent and a HCSA expansion agent.

[0016] In the above scheme, the composite of CaO-type expansion agent and HCSA-type expansion agent can effectively compensate for the shrinkage of concrete, reduce the risk of cracking, and improve the integrity and durability of the structure.

[0017] As a further optimization scheme of the present invention, the mass ratio of the CaO type expansion agent to the HCSA type expansion agent is 7:3.

[0018] In the above scheme, by setting the mass ratio of CaO-type expansion agent to HCSA-type expansion agent to 7:3, the best shrinkage compensation effect can be achieved, and the structural performance of concrete can be further enhanced.

[0019] As a further optimization solution of the present invention, the fluidity of the high-performance grouting material is 33 cm.

[0020] In the above scheme, the fluidity of the high-performance grouting material is 33 cm, which indicates that the grouting material has good fluidity, is easy to construct, and can effectively fill the internal space of the steel pipe and the gaps between the coarse aggregates.

[0021] The present invention also provides a construction method for a pre-set coarse aggregate grouting type high-performance steel tube concrete column, wherein the construction method adopts any one of the grouting methods of method A, method B, and method C:

[0022] Method A:

[0023] Coarse aggregate is placed in the steel pipe in advance, and a grouting pipe is inserted into the mold. The prefabricated high-performance grouting material is injected into the steel pipe through the grouting pipe. The grouting pipe is pulled out while grouting until the inside of the steel pipe is completely filled.

[0024] Method B:

[0025] Coarse aggregate is placed in advance inside the steel pipe, and a pressure grouting machine is used to pump the prefabricated high-performance grouting material at the bottom of the mold until the inside of the steel pipe is completely filled;

[0026] C method:

[0027] A layer of coarse aggregate is evenly laid inside the steel pipe in advance, and a layer of prefabricated high-performance grouting material is poured; when the high-performance grouting material fills the gaps between the coarse aggregates, another layer of coarse aggregate is laid, and another layer of prefabricated high-performance grouting material is poured, and the above operation is repeated until the inside of the steel pipe is completely filled.

[0028] As a further optimization scheme of the present invention, the preparation method of the high-performance grouting material comprises:

[0029] Weigh the materials according to the designed ratio, add cement, silica fume, ultrafine mineral powder, expansion agent, quartz sand and water reducing agent into a mixing pot and stir at a low speed. After stirring evenly, add water and stir at a high speed first and then at a medium speed to obtain a high-performance grouting material.

[0030] Compared with the prior art, the technical solution provided by the present invention has the following advantages and beneficial effects:

[0031] 1. The utilization rate of coarse aggregate in high-performance concrete prepared by pre-set coarse aggregate grouting is significantly improved, and the volume content can reach more than 50%, while the maximum volume content of coarse aggregate high-performance concrete formed by ordinary mixing is only about 30%. Compared with cementitious materials such as cement, coarse aggregate has lower carbon emissions and economic costs. Therefore, steel tube concrete columns prepared by pre-set coarse aggregate grouting high-performance concrete have higher environmental sustainability and lower production costs.

[0032] 2. Adding expansion agent and high volume amount of coarse aggregate can effectively reduce the shrinkage of high performance concrete, such as Figure 4 As shown in the figure. The push-out test results show that a larger load is required to push out the core high-performance concrete of the pre-set coarse aggregate grouting high-performance steel tube concrete column, proving that the pre-set coarse aggregate grouting high-performance concrete and the steel tube have good bonding properties. Therefore, the risk of core high-performance concrete de-airing and debonding of the pre-set coarse aggregate grouting steel tube concrete column is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the pre-set coarse aggregate grouting high-performance steel tube concrete column obtained using grouting method A.

[0034] Figure 2 Schematic diagram of the pre-grouted high-performance steel tube concrete column with coarse aggregate obtained by grouting method B.

[0035] Figure 3 Schematic diagram of the pre-set coarse aggregate grouting high-performance steel tube concrete column obtained using grouting method C.

[0036] Figure 4 is the shrinkage value of different types of high performance concrete.

[0037] Figure 5 Push-out load-displacement diagrams for different types of high-performance concrete-filled steel tube columns. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the technical solution of the present invention, the preferred implementation scheme of the present invention is described below in conjunction with specific embodiments, but it should not be understood as limiting the present invention and is only used as an example.

[0039] The experimental methods or test methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials are obtained from conventional commercial channels or prepared by conventional methods unless otherwise specified.

[0040] Example 1

[0041] like Figure 2As shown, in this embodiment, a pre-set coarse aggregate grouting type high-performance steel tube concrete column is prepared by using a pressure grouting machine.

[0042] The high-performance concrete mix ratio is calculated by weight, and mainly includes the following materials: 1210 parts of high-performance grouting material, 1450 parts of coarse aggregate, of which the particle size of coarse aggregate is 15-20mm. The high-performance grouting material mix ratio is calculated by weight, and mainly includes: 774 parts of cement, 60 parts of silica fume, 357 parts of ultrafine mineral powder, 119 parts of expansion agent, 953 parts of quartz sand, 250 parts of water, and 22 parts of water reducer, of which the particle size of quartz sand is 0-0.2mm, and the expansion agent is a composite of CaO type expansion agent and HCSA type expansion agent, and the CaO type expansion agent accounts for 70% of the total expansion agent.

[0043] Construction method of high performance concrete containing coarse aggregate under ordinary mixing:

[0044] (1) Weigh the materials according to the designed ratio;

[0045] (2) Add cement, silica fume, ultrafine mineral powder, expansion agent, quartz sand, and water reducing agent into a mixing pot and stir at a low speed for 2 minutes. After stirring evenly, add water and stir at a high speed for 1 minute, and then stir at a medium speed for 3 minutes to obtain a high-performance grouting material;

[0046] (3) Coarse aggregate is placed in advance inside the steel pipe, and a pressure grouting machine is used to pump fresh high-performance grouting material at the bottom of the mold. The multifunctional screw pressure grouting machine used has a working pressure of 1.5MPa and a maximum flow rate of 1.5m 3 / h, equipped with single-phase power of 4kw.

[0047] The strength grade of the steel pipe used is Q355, the thickness is 6mm, the height is 400mm, and the outer diameter of the steel pipe is 108mm.

[0048] After testing, the axial compression peak load of Example 1 is 1711 kN, and the push-out peak load is 386 kN (see Figure 5 ), the maximum shrinkage is 222.84με (see Figure 4 ).

[0049] Example 2

[0050] like Figure 1 As shown, this embodiment adopts the grouting pipe grouting method to prepare the pre-set coarse aggregate grouting type high-performance steel tube concrete column.

[0051] The high-performance concrete mix ratio is calculated by weight and mainly includes the following materials: 1150 parts of high-performance grouting material, 1460 parts of coarse aggregate, of which the particle size of coarse aggregate is 15-20mm. The high-performance grouting material mix ratio is calculated by weight and mainly includes: 774 parts of cement, 60 parts of silica fume, 357 parts of ultrafine mineral powder, 119 parts of expansion agent, 953 parts of quartz sand, 250 parts of water, and 22 parts of water reducer, of which the particle size of quartz sand is 0-0.2mm, and the expansion agent is a composite of CaO expansion agent and HCSA expansion agent, and the CaO expansion agent accounts for 70% of the total expansion agent.

[0052] Construction method of high performance concrete containing coarse aggregate under ordinary mixing:

[0053] (1) Weigh the materials according to the designed ratio;

[0054] (2) Add cement, silica fume, ultrafine mineral powder, expansion agent, quartz sand, and water reducing agent into a mixing pot and stir at a low speed for 2 minutes. After stirring evenly, add water and stir at a high speed for 1 minute, and then stir at a medium speed for 3 minutes to obtain a high-performance grouting material;

[0055] (3) Coarse aggregate is placed in the steel pipe in advance, and a grouting pipe is inserted into the mold. The newly mixed high-performance grouting material is injected into the steel pipe through the grouting pipe, and the grouting pipe is pulled out while grouting. The grouting pipe used is a plastic grouting pipe with a length of 1m and a diameter of 25mm.

[0056] The strength grade of the steel pipe used is Q355, the thickness is 6mm, the height is 400mm, and the outer diameter of the steel pipe is 108mm.

[0057] After testing, the axial compression peak load of Example 2 is 1643 kN, and the push-out peak load is 348 kN (see Figure 5 ), the maximum shrinkage is 245.39με (see Figure 4 ).

[0058] Example 3

[0059] like Figure 3 As shown, this embodiment adopts the method of filling aggregates and grouting at the same time to prepare the pre-set coarse aggregate grouting type high-performance steel tube concrete column.

[0060] The high-performance concrete mix ratio is calculated by weight and mainly includes the following materials: 1370 parts of high-performance grouting material, 1310 parts of coarse aggregate, of which the particle size of coarse aggregate is 15-20mm. The high-performance grouting material mix ratio is calculated by weight and mainly includes: 774 parts of cement, 60 parts of silica fume, 357 parts of ultrafine mineral powder, 119 parts of expansion agent, 953 parts of quartz sand, 250 parts of water, and 22 parts of water reducer, of which the particle size of quartz sand is 0-0.2mm, and the expansion agent is a composite of CaO type expansion agent and HCSA type expansion agent, and the CaO type expansion agent accounts for 70% of the total expansion agent.

[0061] Construction method of high performance concrete containing coarse aggregate under ordinary mixing:

[0062] (1) Weigh the materials according to the designed ratio;

[0063] (2) Add cement, silica fume, ultrafine mineral powder, expansion agent, quartz sand, and water reducing agent into a mixing pot and stir at a low speed for 2 minutes. After stirring evenly, add water and stir at a high speed for 1 minute, and then stir at a medium speed for 3 minutes to obtain a high-performance grouting material;

[0064] (3) Preliminarily lay a layer of coarse aggregate evenly inside the steel pipe, and pour a layer of freshly mixed high-performance grouting material. When the grouting material fills the gaps between the aggregates, continue to lay a layer of coarse aggregate, and then pour a layer of freshly mixed high-performance grouting material. Repeat the above operation until the inside of the steel pipe is completely filled.

[0065] The strength grade of the steel pipe used is Q355, the thickness is 6mm, the height is 400mm, and the outer diameter of the steel pipe is 108mm.

[0066] After testing, the axial compression peak load of Example 3 is 1591 kN, and the push-out peak load is 313 kN (see Figure 5 ), the maximum shrinkage is 278.38με (see Figure 4 ).

[0067] Comparative Example 1

[0068] In this example, a high-performance steel tube concrete column without coarse aggregate was prepared. The high-performance concrete mix ratio mainly includes the following materials by weight: 774 parts of cement, 60 parts of silica fume, 357 parts of ultrafine mineral powder, 953 parts of quartz sand, 250 parts of water, and 22 parts of water reducing agent, wherein the particle size of the quartz sand ranges from 0 to 0.2 mm.

[0069] High performance concrete construction methods:

[0070] (1) Weigh the materials according to the designed ratio;

[0071] (2) Cement, silica fume, ultrafine mineral powder, quartz sand, and water reducing agent are added to a mixing pot and stirred at a low speed for 2 minutes. After stirring evenly, water is added and stirred at a high speed for 1 minute, and then stirred at a medium speed for 3 minutes to obtain high-performance concrete;

[0072] (3) Use the grouting pipe grouting method to inject high performance concrete into the steel pipe.

[0073] The strength grade of the steel pipe used is Q355, the thickness is 6mm, the height is 400mm, and the outer diameter of the steel pipe is 108mm.

[0074] After testing, the peak push-out load of Comparative Example 1 is 147 kN (see Figure 5 ), the maximum shrinkage is 911.89με (see Figure 4 ).

[0075] Comparative Example 2

[0076] In this example, high-performance steel tube concrete columns containing coarse aggregates were prepared under normal mixing. The high-performance concrete mix ratio, calculated by weight, mainly includes the following materials: 475 parts of cement, 37 parts of silica fume, 219 parts of ultrafine mineral powder, 103 parts of quartz sand, 607 parts of standard sand, 131 parts of water, and 5 parts of water reducer, among which the particle size range of quartz sand is 0-0.2 mm, and the maximum particle size of coarse aggregate is 20 mm.

[0077] Construction method of high performance concrete containing coarse aggregate under ordinary mixing:

[0078] (1) Weigh the materials;

[0079] (2) Add cement, silica fume, ultrafine mineral powder, quartz sand, standard sand, and water reducing agent into a mixing pot and stir at a low speed for 2 minutes. After stirring evenly, add water and stir at a high speed for 1 minute and then stir at a medium speed for 3 minutes to obtain mortar slurry. Pour the coarse aggregate into the mixing pot and stir evenly.

[0080] (3) Pour the mortar slurry containing coarse aggregate into the steel pipe.

[0081] The strength grade of the steel pipe used is Q355, the thickness is 6mm, the height is 400mm, and the outer diameter of the steel pipe is 108mm.

[0082] After testing, the axial compression peak load of comparative example 2 is 1883kN, and the push-out peak load is 276kN (see Figure 5 ), the maximum shrinkage is 432.90με (see Figure 4 ).

[0083] The present invention greatly improves the utilization rate of coarse aggregate in high-performance steel tube concrete columns by pre-setting coarse aggregate grouting molding, thereby reducing the production cost of high-performance steel tube concrete columns and improving environmental sustainability. Coarse aggregate can play a skeleton role in the high-performance concrete matrix, so that the matrix has better volume stability and avoids the debonding phenomenon caused by excessive shrinkage of high-performance concrete in high-performance steel tube concrete columns. The pre-setting coarse aggregate grouting molding method prevents the risk of stratification and segregation of coarse aggregate high-performance concrete. In addition, the steel pipe can be used as a casting mold for concrete, and coarse aggregate is placed in the steel pipe in advance for grouting molding, which saves the use of wooden formwork. In summary, the pre-setting coarse aggregate grouting type high-performance steel tube concrete column has relatively excellent performance and broad application prospects. In addition, the present invention provides three different grouting methods, which are suitable for a variety of applications.

[0084] The above are only preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A pre-set coarse aggregate grouting high-performance steel tube concrete column, comprising a steel tube, the interior of which is filled with high-performance concrete, characterized in that: The high-performance concrete comprises the following raw materials in parts by weight: 1210-1370 parts of high-performance grouting material and 1310-1460 parts of coarse aggregate.

2. The pre-placed coarse aggregate grouting high-performance steel tube concrete column according to claim 1, characterized in that: The particle size of the coarse aggregate is 15 to 20 mm.

3. The pre-set coarse aggregate grouting high performance steel tube concrete column according to claim 1, characterized in that: The 28d compressive strength of the high performance concrete is 90-110 MPa.

4. The pre-set coarse aggregate grouting high performance steel tube concrete column according to claim 1, characterized in that: The high-performance grouting material includes the following raw materials in parts by weight: 774 parts of cement, 60 parts of silica fume, 357 parts of ultrafine mineral powder, 119 parts of expansion agent, 953 parts of quartz sand, 250 parts of water, and 22 parts of water reducing agent.

5. The pre-placed coarse aggregate grouting high performance steel tube concrete column according to claim 4, characterized in that: The particle size of the quartz sand is in the range of 0 to 0.2 mm.

6. The pre-placed coarse aggregate grouting high performance steel tube concrete column according to claim 4, characterized in that: The expansion agent is a compound of a CaO expansion agent and a HCSA expansion agent.

7. The pre-set coarse aggregate grouting high performance steel tube concrete column according to claim 6, characterized in that: The mass ratio of the CaO type expansion agent to the HCSA type expansion agent is 7:

3.

8. The pre-set coarse aggregate grouting high performance steel tube concrete column according to claim 4, characterized in that: The fluidity of the high performance grouting material is 33 cm.

9. A construction method of pre-placed coarse aggregate grouting high performance steel tube concrete column according to any one of claims 1 to 8, characterized in that: The construction method adopts any one of the grouting methods of method A, method B, and method C: Method A: Coarse aggregate is placed in the steel pipe in advance, and a grouting pipe is inserted into the mold. The prefabricated high-performance grouting material is injected into the steel pipe through the grouting pipe. The grouting pipe is pulled out while grouting until the inside of the steel pipe is completely filled. Method B: Coarse aggregate is placed in advance inside the steel pipe, and a pressure grouting machine is used to pump the prefabricated high-performance grouting material at the bottom of the mold until the inside of the steel pipe is completely filled; C method: A layer of coarse aggregate is evenly laid inside the steel pipe in advance, and a layer of prefabricated high-performance grouting material is poured; when the high-performance grouting material fills the gaps between the coarse aggregates, another layer of coarse aggregate is laid, and another layer of prefabricated high-performance grouting material is poured, and the above operation is repeated until the inside of the steel pipe is completely filled.

10. The construction method of pre-set coarse aggregate grouting type high performance steel tube concrete column according to claim 9, characterized in that: The preparation method of the high-performance grouting material comprises: Weigh the materials according to the designed ratio, add cement, silica fume, ultrafine mineral powder, expansion agent, quartz sand and water reducing agent into a mixing pot and stir at a low speed. After stirring evenly, add water and stir at a high speed first and then at a medium speed to obtain a high-performance grouting material.

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