High-toughness concrete as well as preparation method and application thereof

Abstract

The invention provides high-toughness concrete. The high-toughness concrete is prepared from the following raw materials in percentage by volume: 1.5-2.5% of fibers and the balance of an ultrahigh-toughness concrete matrix, the ultrahigh-toughness concrete matrix is prepared from the following raw materials in parts by weight: 400 to 550 parts of cement, 500 to 600 parts of fly ash, 0 to 200 parts of coarse whiting, 150 to 200 parts of silica fume, 500 to 650 parts of fine aggregate, 230 to 260 parts of water and 8 to 10 parts of polycarboxylate water reducing agent. The invention further provides a preparation method and application, and the high-toughness concrete is poured into the geotextile bag for slope reinforcement and protection. The high-toughness concrete disclosed by the invention has good toughness and high strength, can effectively resist external force impact and deformation and reduce generation of cracks, and can be used for slope reinforcement and protection after being filled into geotextile bags.

Description

Technical Field

[0001] The present invention belongs to the technical field of concrete, and particularly relates to a high-toughness concrete and its preparation method and application. Background Art

[0002] In various civil engineering constructions, such as road engineering, railway engineering, water conservancy and hydropower engineering, and mining, etc., they are all threatened by various destructive factors such as weathering, rain erosion, soil landslides, etc. The stability of slopes is a key factor to ensure the safety and normal operation of projects. The instability of slopes will not only cause direct damage to engineering facilities, but may also trigger serious geological disasters, threatening the lives and property safety of surrounding personnel.

[0003] At present, common slope reinforcement and protection methods include masonry protection with rubble, shotcrete protection, bolt and cable support, etc. However, these traditional methods have certain limitations. Masonry protection with rubble has low construction efficiency, poor adaptability to slope topography, and insufficient integrity, and is prone to local damage when subjected to large external forces; although shotcrete protection can improve the stability of slopes to a certain extent, the brittleness of concrete is relatively large, and it is prone to cracks under the influence of factors such as temperature changes and uneven settlement of the foundation, reducing the protection effect. The materials of these traditional methods have insufficient toughness and are prone to failure when subjected to large external force impacts, such as earthquakes and debris flow impacts caused by heavy rain, and cannot effectively guarantee the long-term stability of slopes.

[0004] With the continuous development of engineering construction, the requirements for slope reinforcement and protection technologies are getting higher and higher, and a new technology that can not only improve the overall stability of slopes, but also has good toughness and durability, and is easy to construct is needed. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a high-toughness concrete and its preparation method and application in view of the deficiencies of the above-mentioned prior art. This high-toughness concrete has good toughness and high strength, can effectively resist external force impacts and deformations, reduce the generation of cracks, and can be filled into geotextile bags for slope reinforcement and protection.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is: A high-toughness concrete is made from the following raw materials by volume fraction: 1.5% - 2.5% of fibers, and the balance is an ultra-high-toughness concrete matrix; the ultra-high-toughness concrete matrix is made from the following raw materials by weight: 400 - 550 parts of cement, 500 - 600 parts of fly ash, 0 - 200 parts of heavy calcium, 150 - 200 parts of silica fume, 500 - 650 parts of fine aggregate, 230 - 260 parts of water, and 8 - 10 parts of polycarboxylate water reducer.

[0007] Preferably, the cement is 42.5 Portland cement or 52.5 Portland cement.

[0008] Preferably, the heavy calcium carbonate has a particle size of 700 mesh, with a calcium carbonate content > 90%.

[0009] Preferably, the fine aggregate is natural river sand or manufactured sand; the particle size of the fine aggregate is 70 mesh to 140 mesh.

[0010] Preferably, the fiber is a PE fiber with a length of 13 mm to 18 mm and an average diameter of 45 μm.

[0011] The present invention also provides a method for the above-mentioned high-toughness concrete, and the method is as follows: S1. Mix cement, fly ash, heavy calcium carbonate, silica fume, fine aggregate and polycarboxylate water reducer, and after stirring, obtain a mixture; S2. Add water to the mixture obtained in S1, and after stirring, obtain an ultra-high-toughness concrete matrix; S3. Add fiber to the ultra-high-toughness concrete matrix obtained in S2, and after stirring, obtain high-toughness concrete.

[0012] Preferably, the stirring speed in S1 is 55 r / min to 65 r / min, and the stirring time is 3 min to 5 min; the stirring speed in S2 is 120 r / min, and the stirring time is 3 min to 5 min.

[0013] Preferably, after the high-toughness concrete in S3 is naturally cured for 28 d, the tensile strength is 8.4 MPa to 12 MPa, the tensile strain is 5.0% to 7.5%, and the compressive strength is 90 MPa to 120 MPa.

[0014] The present invention also provides an application of the above-mentioned high-toughness concrete. The high-toughness concrete is poured into a geotextile bag for slope reinforcement and protection.

[0015] Preferably, the method for using the high-toughness concrete for slope reinforcement and protection is as follows: Fill the high-toughness concrete into the geotextile bag, connect multiple geotextile bags to form a concrete frame structure in a plurality of cross-shaped patterns, then insert a hollow anchor rod into the slope soil from the hollow part of the cross-shaped pattern, inject cement slurry into the hollow anchor rod, and in the present invention, cement slurry can also be injected into the soil around the anchor rod to form an integral body between the anchor rod and the soil.

[0016] The present invention has the following advantages compared with the prior art: 1. The high-toughness concrete prepared by the present invention has good toughness and high strength, can effectively resist external force impact and deformation, reduce the generation of cracks, and improve the service life of the film bag concrete.

[0017] 2. The high-toughness concrete of the present invention is filled into a geotextile bag, which can adapt to the irregular shape of the slope, closely fit the slope surface, and provide comprehensive protection. In the form of a membrane bag, the construction process is simple, without the need for complex formwork and pouring equipment, which can greatly shorten the construction period and reduce the construction cost.

[0018] 3. During the slope protection process of the present invention, a hollow anchor rod is used, and then cement slurry is injected into it. Under the action of the slurry pressure, it expands outward and embeds into the soil, greatly increasing the anchoring force of the anchor rod, especially suitable for slopes with soft soil, and improving the stability of the anchor rod under complex geological conditions.

[0019] 4. The present invention combines the prepared high-toughness concrete with a geotextile bag to form a protective structure. At the same time, a hollow anchor rod is inserted into the slope soil, and cement slurry is injected into the hollow anchor rod to solve the problems of insufficient toughness, complex construction, poor durability, etc. existing in the existing slope reinforcement and protection, improve the stability and protection ability of the slope, and ensure the long-term safe operation of the project.

[0020] The present invention will be further described in detail below with reference to the embodiments. Specific Embodiments

[0021] Example 1 The high-toughness concrete of this embodiment is made of the following raw materials by volume fraction: 1.5% of fibers, and the balance is an ultra-high-toughness concrete matrix; the ultra-high-toughness concrete matrix is made of the following raw materials by weight: 400 parts of cement, 600 parts of fly ash, 200 parts of silica fume, 650 parts of fine aggregate, 260 parts of water, and 8 parts of polycarboxylate water reducer.

[0022] The cement is 42.5 Portland cement; The fine aggregate is natural river sand; the particle size of the fine aggregate is 70 mesh to 140 mesh; The polycarboxylate water reducer is GK-3000 polycarboxylate superplasticizer, commercially available, purchased from Chang'an Yucai Building Materials Co., Ltd., Shijiazhuang City; The fiber is a PE fiber (ultra-high molecular weight polyethylene fiber) with a length of 13 mm and an average diameter of 45 μm. This PE fiber is commercially available and purchased from Lihe Zhixin New Material Technology Co., Ltd.

[0023] This embodiment also provides a method for the above-mentioned high-toughness concrete, and the method is as follows: S1. Mix the cement, fly ash, silica fume, fine aggregate and polycarboxylate water reducer, and stir at a stirring speed of 60 r / min for 4 min to obtain a mixture; S2. Add water to the mixture obtained in S1, and stir at a stirring speed of 120 r / min for 4 min to obtain an ultra-high toughness concrete matrix; S3. Add fibers to the ultra-high toughness concrete matrix obtained in S2, and stir to obtain high toughness concrete.

[0024] After the high toughness concrete is cured naturally for 28 d, its tensile strength is 8.4 MPa, its tensile strain is 7.0%, and its compressive strength is 90 MPa.

[0025] This embodiment also provides the application of the above-mentioned high toughness concrete. The high toughness concrete is poured into a geotextile bag for slope reinforcement and protection.

[0026] The method for using the high toughness concrete in this embodiment for slope reinforcement and protection is as follows: fill the high toughness concrete into the geotextile bag, connect multiple geotextile bags to form a plurality of concrete frame structures in a well shape, and then insert a hollow anchor rod into the slope soil from the hollow part of the well shape, and inject cement slurry into the hollow anchor rod to form an integral body with the soil.

[0027] The hollow part of the well shape in this embodiment is a square with a side length of 10 cm.

[0028] Cure the geotextile bag filled with high toughness concrete to keep it in a moist state. After the concrete reaches the designed strength, check and repair the slope surface to ensure the protection effect.

[0029] Example 2 The high toughness concrete in this embodiment is made of the following raw materials by volume fraction: 2.0% of fibers, and the balance is ultra-high toughness concrete matrix; the ultra-high toughness concrete matrix is made of the following raw materials by weight: 480 parts of cement, 550 parts of fly ash, 200 parts of heavy calcium, 160 parts of silica fume, 500 parts of fine aggregate, 250 parts of water, and 9 parts of polycarboxylate water reducer.

[0030] The cement is 52.5 Portland cement; The fine aggregate is machine-made sand; the particle size of the fine aggregate is 70 mesh to 140 mesh; The particle size of the heavy calcium is 700 mesh, and the calcium carbonate content is >90%; The polycarboxylate water reducer is GK-3000 polycarboxylic acid high-efficiency water reducer, commercially available, purchased from Chang'an Yucai Building Materials Co., Ltd., Shijiazhuang City; The fiber is a PE (ultra-high molecular weight polyethylene fiber) fiber with a length of 18 mm and an average diameter of 45 μm. This PE fiber is commercially available and purchased from Lihe Zhixin New Material Technology Co., Ltd.

[0031] This embodiment also provides the method for the above high-toughness concrete, and the method is as follows: S1. Mix cement, fly ash, heavy calcium, silica fume, fine aggregate and polycarboxylate water reducer, and stir at a stirring speed of 65 r / min for 3 min to obtain a mixture; S2. Add water to the mixture obtained in S1, and stir at a stirring speed of 120 r / min for 3 min to obtain an ultra-high-toughness concrete matrix; S3. Add fibers to the ultra-high-toughness concrete matrix obtained in S2, and stir to obtain high-toughness concrete.

[0032] After the high-toughness concrete is naturally cured for 28 d, its tensile strength is 9.5 MPa, its tensile strain is 7.5%, and its compressive strength is 105 MPa.

[0033] Pour the high-toughness concrete prepared in this embodiment into a geotextile bag for slope reinforcement and protection, and the method is the same as that in Embodiment 1.

[0034] Embodiment 3 The high-toughness concrete of this embodiment is made of the following raw materials by volume fraction: 2.5% of fibers, and the balance is ultra-high-toughness concrete matrix; the ultra-high-toughness concrete matrix is made of the following raw materials by weight: 550 parts of cement, 500 parts of fly ash, 200 parts of heavy calcium, 150 parts of silica fume, 500 parts of fine aggregate, 230 parts of water, and 10 parts of polycarboxylate water reducer.

[0035] The cement is 52.5 Portland cement; The fine aggregate is natural river sand; the particle size of the fine aggregate is 70 mesh to 140 mesh; The particle size of the heavy calcium is 700 mesh, and the calcium carbonate content is >90%; The polycarboxylate water reducer is GK-3000 polycarboxylic acid superplasticizer, which is commercially available and purchased from Chang'an Yucai Building Materials Co., Ltd., Shijiazhuang City; The fiber is a PE (ultra-high molecular weight polyethylene fiber) fiber with a length of 15 mm and an average diameter of 45 μm. This PE fiber is commercially available and purchased from Lihe Zhixin New Material Technology Co., Ltd.

[0036] This embodiment also provides the method for the above high-toughness concrete, and the method is as follows: S1. Mix cement, fly ash, heavy calcium, silica fume, fine aggregate and polycarboxylate water reducer, and stir at a stirring speed of 55 r / min for 5 min to obtain a mixture; S2. Add water to the mixture obtained in S1, and stir at a stirring speed of 120 r / min for 5 min to obtain an ultra-high-toughness concrete matrix; S3. Add fibers to the ultra-high toughness concrete matrix obtained in S2, and after stirring, high toughness concrete is obtained.

[0037] After the high toughness concrete is cured naturally for 28 days, the tensile strength is 12 MPa, the tensile strain is 5.0%, and the compressive strength is 120 MPa.

[0038] Pour the high toughness concrete prepared in this embodiment into a geotextile bag for slope reinforcement and protection. The method is the same as that in Embodiment 1.

[0039] The above are only the preferred embodiments of the present invention and do not impose any limitations on the present invention. Any simple modifications, changes, and equivalent variations made to the above embodiments according to the technical essence of the invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A high toughness concrete, characterized in that: The ultra-high toughness concrete matrix is ​​made of the following raw materials in volume fractions: 1.5% to 2.5% fiber, and the remainder is an ultra-high toughness concrete matrix; the ultra-high toughness concrete matrix is ​​made of the following raw materials in parts by weight: 400 to 550 parts of cement, 500 to 600 parts of fly ash, 0 to 200 parts of heavy calcium, 150 to 200 parts of silica fume, 500 to 650 parts of fine aggregate, 230 to 260 parts of water, and 8 to 10 parts of polycarboxylate water reducer.

2. A high toughness concrete according to claim 1, characterized in that: The cement is 42.5 silicate cement or 52.5 silicate cement.

3. The high toughness concrete according to claim 1, characterized in that: The fine aggregate is natural river sand or machine-made sand; the particle size of the fine aggregate is 70 mesh to 140 mesh.

4. The high toughness concrete according to claim 1, characterized in that: The fiber is a PE fiber with a length of 13 mm to 18 mm and an average diameter of 45 μm.

5. A method for preparing the high toughness concrete according to any one of claims 1 to 4, characterized in that: The method is: S1, mixing cement, fly ash, heavy calcium, silica fume, fine aggregate and polycarboxylate water reducer, and stirring to obtain a mixture; S2, adding water to the mixture obtained in S1, stirring, and obtaining an ultra-high toughness concrete matrix; S3. Add fibers to the ultra-high toughness concrete matrix obtained in S2, and stir to obtain high toughness concrete.

6. The method according to claim 5, characterized in that The stirring speed in S1 is 55r / min~65r / min, and the stirring time is 3min~5min; the stirring speed in S2 is 120r / min, and the stirring time is 3min~5min.

7. The method according to claim 5, characterized in that After natural curing for 28 days, the high-toughness concrete described in S3 has a tensile strength of 8.4MPa to 12MPa, a tensile strain of 5.0% to 7.5%, and a compressive strength of 90MPa to 120MPa.

8. An application of the high toughness concrete according to any one of claims 1 to 4, characterized in that: The high-toughness concrete is poured into geotextile bags for slope reinforcement and protection.

9. The use according to claim 8, characterized in that: The method for using the high-toughness concrete for slope reinforcement and protection is: filling the geotextile bag with the high-toughness concrete, connecting multiple geotextile bags to each other and arranging them into multiple tic-tac-toe concrete frame structures, and then inserting hollow anchor rods into the slope soil from the hollow part of the tic-tac-toe shape, and injecting cement slurry into the hollow anchor rods.